# 2012 Chevy Volt Battery:



## McRat (Jul 10, 2012)

I'm an idiot. Ignore module count. There are 2 - 1kWh banks, and 7 - 2 kWh banks.


----------



## Yabert (Feb 7, 2010)

Awesome!!!!!! Only 2k$ 
I admit that I'm jealous.
Supposed to have 96 modules of 3 cells.
I will follow this thread with interest!


----------



## Lipo Louis (Oct 29, 2012)

It is a 96s3p pack, I have installed a BMS. I really like this pack. What I did, I used the casing of the original bms and made a board inside. Now I use the full 16kWh and the pack is still almost original. I also used the original bms connectors, very neat solution, I will post pictures soon.


----------



## McRat (Jul 10, 2012)

Edit: DOH!! 288 is correct.


----------



## McRat (Jul 10, 2012)

Lipo Louis said:


> It is a 96s3p pack, I have installed a BMS. I really like this pack. What I did, I used the casing of the original bms and made a board inside. Now I use the full 16kWh and the pack is still almost original. I also used the original bms connectors, very neat solution, I will post pictures soon.



I'd love to see a picture of a single cell. 

Without X-Ray vision, I'm seeing 6 cell blades on the 1kWh modules, and 12 cell blades on the 2kWh modules.

I'm puzzled.


----------



## McRat (Jul 10, 2012)

I'm going to make up words for this battery:

Blade - One of the 1/2" thick plastic carriers for the cells.

Module - Either 1kWh or 2kWh with it's own BMS connector. 

Block - Two or three Modules that have their own BMS computer on top.


----------



## rochesterricer (Jan 5, 2011)

So what is the total weight of the pack? 

Two packs together at this price would give you a 32kwh pack for $4k. Not bad at all.


----------



## McRat (Jul 10, 2012)

Advertised weight is 435lb for the entire assembly. I could not weigh it.


----------



## rochesterricer (Jan 5, 2011)

Was the shipping weight on the packing slip or invoice?


----------



## McRat (Jul 10, 2012)

DOH!! Shipping weight with large pallet says 516lb on the bill of lading. So 435lb is probably right. It's a very heavy pallet.


----------



## McRat (Jul 10, 2012)

Freight company weight.


----------



## Lipo Louis (Oct 29, 2012)

http://www.gaccmidwest.org/fileadmi...resentations/Matthe_GM_Battery_panel_Volt.pdf

Inside the pack I found 2 big relays and 3 smaller relays. New price about 200 USD each !

The wiring inside is too thin for my 1000A controller, I measured the Chevy volt on full acceleration at 330A peak.


----------



## McRat (Jul 10, 2012)

Wow! Thanks for the link. So it's a small pouch cell. Must be thin.


----------



## rochesterricer (Jan 5, 2011)

McRat said:


> DOH!! Shipping weight with large pallet says 516lb on the bill of lading. So 435lb is probably right. It's a very heavy pallet.


Thanks. So a 32kwh pack would be right around 900 pounds.


----------



## McRat (Jul 10, 2012)

rochesterricer said:


> Thanks. So a 32kwh pack would be right around 900 pounds.


Only if you were using the factory armor and watercooling. More than 1/2 the Volt battery assy is support hardware.

I need the weight on a single cell. I'm going to guess it's under 1 pound. So 288 lb max for the actual cells in a single battery. Could be a lot less even.


----------



## McRat (Jul 10, 2012)

The Volt cells are very advanced chemistry, optimized for low weight at high discharge rate.


----------



## McRat (Jul 10, 2012)

Here's some more data on it:

https://docs.google.com/file/d/0BwHvhEbCHHEleUp3TUMxOUwzdmM/edit


----------



## palmer_md (Jul 22, 2011)

McRat said:


> The Volt cells are very advanced chemistry, optimized for low weight at high discharge rate.


Watch out, your starting to sound like a Chevy salesman!


----------



## McRat (Jul 10, 2012)

palmer_md said:


> Watch out, your starting to sound like a Chevy salesman!


Chevy bought the licensing for the new tech from Argonne? National Laboratory.

I tried to figure out what the best LiPo's for an EV were, and I think the GM pieces were the top dog in the field.

PS - My daughter is now driving our Volt. I'm sad. 
I love that car.


----------



## liveforphysics (Jan 16, 2014)

Are they no longer running >6 year old manganese spinel cathodes? I thought it used cells kinda on the low side of energy density and cycle life compared with NCA or NCM. 

I did think LG's spiral wrapped ceramic separator was pretty cool, but I don't know if I could call the cells advanced chemistry anymore. 

Regardless though, amazingly good deal for DIY EV building!!! Woot!! I've been tempted to buy one myself. Great job on pulling the trigger and getting one! Huge value/quality advantage over most all other DIY EV battery options. I just wish it wasn't in such a wonky T-shaped layout. Are you stuffing the cells into the Insight in the photo?


----------



## McRat (Jul 10, 2012)

liveforphysics said:


> Are they no longer running >6 year old manganese spinel cathodes? I thought it used cells kinda on the low side of energy density and cycle life compared with NCA or NCM.
> 
> I did think LG's spiral wrapped ceramic separator was pretty cool, but I don't know if I could call the cells advanced chemistry anymore.
> 
> Regardless though, amazingly good deal for DIY EV building!!! Woot!! I've been tempted to buy one myself. Great job on pulling the trigger and getting one! Huge value/quality advantage over most all other DIY EV battery options. I just wish it wasn't in such a wonky T-shaped layout. Are you stuffing the cells into the Insight in the photo?


First I will steal 48vdc worth to finish the Trials Motorcycle. 

Then, turn the Insight into a Volt.


----------



## McRat (Jul 10, 2012)

Once I can weigh a single cell, we will know how advanced the Argonne battery is. It pumps 110kw without breaking a sweat. The Cadillac taps 150kw out of the same battery.


----------



## McRat (Jul 10, 2012)

Here's why I think the GM battery is the current winner:

Volt 16.5 kWh = 149HP is 9HP per kWh
Cadillac 16.5 kWh = 207HP is 12.5 HP/kWh
Tesla S 60 kWh = 302HP is 5HP/kWh
Tesla S Performance 85 kWh = 416HP is 5HP/kWh
Leaf 24 kWh = 107HP is 4.5HP/kWh

The GM battery is set to deliver about twice the output per battery kWh as the other players.

To put it in perspective, if the Tesla S Performance ran the GM battery the same size, it would have the same range, but have a peak HP of 1040. This is Bugatti Veyron territory.


----------



## McRat (Jul 10, 2012)

Lipo Louis said:


> http://www.gaccmidwest.org/fileadmi...resentations/Matthe_GM_Battery_panel_Volt.pdf
> 
> Inside the pack I found 2 big relays and 3 smaller relays. New price about 200 USD each !
> 
> The wiring inside is too thin for my 1000A controller, I measured the Chevy volt on full acceleration at 330A peak.


That 330A out of a 45Ah battery is 7C discharge at the Volt level, and about 10C at the Cadillac discharge rate.


----------



## major (Apr 4, 2008)

McRat said:


> Chevy bought the licensing for the new tech from Argonne? National Laboratory.


I thought they used LG Chem. 



> As of 2011, the Volt's battery cells are produced by LG Chem in South Korea and subsequently shipped to the US, where the battery packs are assembled at a purpose-built facility in Brownstown Township, Michigan owned and operated by GM.[10]


from wikipedia.


----------



## major (Apr 4, 2008)

McRat said:


> Here's why I think the GM battery is the current winner:
> 
> Volt 16.5 kWh = 149HP is 9HP per kWh
> Cadillac 16.5 kWh = 207HP is 12.5 HP/kWh
> ...


This is primarily due to the fact you are comparing EV batteries to HEV or PHEV batteries. The HEV (and PHEV) batteries are sized for smaller energy but similar power so are designed to use higher C-rate cells and often have more robust thermal management systems than the EV batteries.

EnerDel, which I am familiar with, produces two cells for automotive; a power cell and an energy cell. Here is a handy place to see the differences. http://evolveelectrics.com/Enerdel.html


----------



## McRat (Jul 10, 2012)

Well whatever chem it uses was developed at Argonne:

http://www.anl.gov/articles/argonne-battery-technology-helps-power-chevy-volt


----------



## McRat (Jul 10, 2012)

The Enerdel is rated at 5C discharge? That is about where Tesla is at?

DOH!! 15C for 10s. I know the GM battery will do 10C for over 16 seconds. Will it do 15C? Dunno.

But for hobbyist, the Enerdel is priced pretty steep. To get 16kWh, it costs $14,000. I can buy 2 complete wrecked Volts for less than that. Or if I can find that many, 7 batteries.

NOTE: The Volt can go 50mi on a charge, well 49mi. I proved it last month, as have many others. So I'm not sure it's not an EV. It has used <3 gallons of gas in 1500 miles so far. It's never been refueled since December.


----------



## major (Apr 4, 2008)

McRat said:


> The Enerdel is rated at 5C discharge? That is about where Tesla is at?


The power cell is the CP160 and rated at 5C continuous and 15C burst. These are manufacturer's rating which are typically very conservative. I imagine the actual cell capability is similar to the one used in the Volt. I know a fellow who used to work at Compact Power (now LG Chem) on the Volt battery development and have sat thru technical presentations by the company at SAE events. It is a very good product. But there are a number of other products on par with them. 

Here is an interesting take on power capability of Lithium cells. Unfortunately, the LG Chem cell was unavailable for him to test at the time. http://elithion.com/wp_short_discharge_time.php


----------



## major (Apr 4, 2008)

McRat said:


> DOH!! 15C for 10s. I know the GM battery will do 10C for over 16 seconds. Will it do 15C? Dunno.
> 
> NOTE: The Volt can go 50mi on a charge, well 49mi. I proved it last month, as have many others. So I'm not sure it's not an EV. It has used <3 gallons of gas in 1500 miles so far. It's never been refueled since December.


The point is that the cell makers formulate and design the cell for the application. The PHEV cell is optimized for power. The EV cell is optimized for energy. I suspect the Volt battery would not compare well to the Tesla battery on the basis of energy density 

And they once insisted the Volt be called an EREV (Extended Range Electric Vehicle). See post #5 here: http://www.diyelectriccar.com/forums/showthread.php/chey-volt-some-new-pictures-38627.html



McRat said:


> But for hobbyist, the Enerdel is priced pretty steep. To get 16kWh, it costs $14,000. I can buy 2 complete wrecked Volts for less than that. Or if I can find that many, 7 batteries.


You compare a new aftermarket price to that of salvage. But yes, you did find a remarkable value


----------



## McRat (Jul 10, 2012)

major said:


> ...
> You compare a new aftermarket price to that of salvage. But yes, you did find a remarkable value


I don't the think "remarkable value" is unique.

Most wrecking yards have OEM parts price books (now software).

They normally go about 50% of OEM. I probably could have haggled him down to $1500, which is 1/2 of book.

As long as GM lists these at $2995, you should be able to get one at $1500.

And no disrespect towards Enerdel. It appears they have a great product. I just can't justify spending more than a new Volt costs to convert a car into a 110kw AC driveline. Some of the freaking controllers and motors are over $10,000. So a controller, batteries, and motor, would be $35,000.

I started dinking with this stuff about a year or two ago. When I saw how much it was going to cost to modern performance out of an EV, I started looking around.

Now only if I could use the Volt/Cadillac engine. They can be had for just over $2000 for >200HP. But I have no idea how.


----------



## Lipo Louis (Oct 29, 2012)

When I bought the volt pack 16kWh I had the charger and controller in my hands, at least I think it was. I also have seen the electric motor /gearbox. I can buy these parts for cheap. It is a salvage parts store. But to me these parts were too complicated. You probably need everything to get it working. And there were so many extra wires I could not address, also the electric motor was integrated in some kind of gearbox.


----------



## Dustin_mud (May 22, 2012)

Where are you finding these yards, online or keeping them a Secret? Lol


----------



## Yabert (Feb 7, 2010)

Hey McRat.... I was so amazed of your find.... I decided to take one too!
It was awesome! I saw your thread yesterday, I've decide to try to find something on local junkyard and I called, I paid, I took possession 

Now, Lipo Louis, please share all the details and pics you have of your battery


----------



## McRat (Jul 10, 2012)

To state the obvious, get yourself some 1000 volt gloves before working on it.

Remove all the 10mm head screws, including the ones on the front of the tunnel where the foam is.

The front is tight, so have two people lift the cover off. The cover is fiberglass.

There is positive and negative markers on each of the "blocks". Check voltages of each block.


----------



## McRat (Jul 10, 2012)

Yabert, if you don't mind me asking, how much did you pay?


----------



## rmay635703 (Oct 23, 2008)

What are the dimensions of the battery modules with armor? (I had them at one time) but I think in my case I would need a leaf battery just because dimensionally it would fit, whereas volt modules would require signfiicant modifications to either of my cars (and I would keep the armor and plug it into the radiator)

Cheers


----------



## Yabert (Feb 7, 2010)

McRat said:


> Remove all the 10mm head screws... Check voltages of each block.


Well, since I wasn't interested to buy a 435 lbs piece of crap, I've took the time to dismantle the cover at the junkyard. The result was surprising because average voltage of single cell was 3,5v (a little bit low), but the battery was stored a -10°C. So I will discover more details soon.

Tomorrow, lot of disassembly pics for all 

Price: less than 2k$ + gas and lunch to a friend with a trailer...


----------



## mk4gti (May 6, 2011)

Dustin_mud said:


> Where are you finding these yards, online or keeping them a Secret? Lol


You can use car-part.com. I found a volt battery back near by for $1250


----------



## McRat (Jul 10, 2012)

Yabert said:


> Well, since I wasn't interested to buy a 435 lbs piece of crap, I've took the time to dismantle the cover at the junkyard. The result was surprising because average voltage of single cell was 3,5v (a little bit low), but the battery was stored a -10°C. So I will discover more details soon.
> 
> Tomorrow, lot of disassembly pics for all
> 
> Price: less than 2k$ + gas and lunch to a friend with a trailer...


Nice. I had to gamble since mine was shipped 1200 miles.

I haven't found info yet on minimum voltage per cell. LiPo is 3.6 vdc for storage. But these might be different.


----------



## McRat (Jul 10, 2012)

Lipo Louis said:


> When I bought the volt pack 16kWh I had the charger and controller in my hands, at least I think it was. I also have seen the electric motor /gearbox. I can buy these parts for cheap. It is a salvage parts store. But to me these parts were too complicated. You probably need everything to get it working. And there were so many extra wires I could not address, also the electric motor was integrated in some kind of gearbox.


From my reading:

It has 2 electric motors. A big one for propulsion, and a little one for regen. Both can come on as traction motors by the use of clutches and planetaries.


----------



## Dustin_mud (May 22, 2012)

http://youtu.be/0c01VgkT4UM
Found this video last night, not sure if it helps at all.


----------



## McRat (Jul 10, 2012)

rmay635703 said:


> What are the dimensions of the battery modules with armor? (I had them at one time) but I think in my case I would need a leaf battery just because dimensionally it would fit, whereas volt modules would require signfiicant modifications to either of my cars (and I would keep the armor and plug it into the radiator)
> 
> Cheers


Roughly, 65" long, 37" wide, 15" tall.


----------



## Yabert (Feb 7, 2010)

Nice day today 
I've start to open the plastic cover and then remove two bus bar to transform this 386v battery in four module of less than 120v each (safer).
It's really well build and I will enjoy to use all this like that in my Smart (with few modification... of course!) 2012 chevy Volt to Smart Fortwo!

Enjoy the pics of:
-Casing dimension (1 inch = 2,54 cm)
-Module dimension
-Current sensor
-Laminated bus bar
-Cells tabs


----------



## Yabert (Feb 7, 2010)

More battery porn...


----------



## McRat (Jul 10, 2012)

Nice!!! More! More! I won't be able to tear down until this weekend.


----------



## McRat (Jul 10, 2012)

Since these are 12s and 6s modules, I'm going to do the first charging with a RC model balance charger for LiPo. The Thunder 1220 will do 12s LiPo's, and I can make a balance harness. The instructions also say it can check internal resistance of each of the 12/6 blades.

It does not appear to have individual cell balancing from the OEM. It must balance sets of 3 cells, or it would have 48 wires for each 12s module?


----------



## McRat (Jul 10, 2012)

If my math is right, you should be able to safely draw 20HP out of a single 12s module. Which will be perfect for a Trials bike. I'll use just one module, and still have 6 x 12s and 2 x 6s.


----------



## major (Apr 4, 2008)

McRat said:


> It does not appear to have individual cell balancing from the OEM. It must balance sets of 3 cells, or it would have 48 wires for each 12s module?


Cells in parallel are forced balanced due to the parallel connection. The voltage on each of the 3 cells is always equal to each other. So if it is a 3P12S module it only requires the 12 series connected triplets to be balanced with each other.


----------



## McRat (Jul 10, 2012)

DOH! Yeah, I guess on a 2p 4s hobby battery, it just has a 4s connector, not two.


----------



## McRat (Jul 10, 2012)

OK, a Volt pulled into my buddies dealership with 2 bars on the charge meter (< 25% charged), and his GM MDI reported 3.6vdc per cell.

EDIT - What sucks? My $3500 GM Tech II will not work on the Volts. I have to buy an MDI...


----------



## Yabert (Feb 7, 2010)

More details. You can see:

-Cooling plate who consist of two thin aluminum plates (0,008'' each) with 9 pathways for water circulation. Remark the plastic insulating sheet. From my understanding, there is one plate for two cells.
-The 15ah cells. Almost the same size that the plastic case. Remark the really nice ultrasonic welding on the tabs.
-84 lbs. It's the weight of the 4 kwh module (2+2 kwh). So, for me it's clear, this really nice 16 kwh battery weight 336 lbs (at least <350 lbs) when you only consider the cells and their really well designed supports.

Advice: Considering the water cooling passages design, there always stay some quantity of water coolant in the module despite if you pass compressed air. Take care!


----------



## Lipo Louis (Oct 29, 2012)

I did some single cell testing a few months ago, I don't really remember the Internal resistance but it was about the same as a 30C Turnigy Lipo cell.

So 20C should be possible I think, 45AH for a 3p at 20c is 900A which is perfect for my needs.

For my Solition 1 I need max 84 cells at 4,10v fresh of the charger for max 345v
So I skipped a 12s module from the pack.

I removed the original BMS and as you can see on the pictures I soldered inside the BMS box EMUS BMS modules.

It fits perfectly, I even can screw the lid on top and use the original BMS connectors so the whole 350v pack looks original and only 2 CAN bus wires are coming out of the pack 

It is also posible to solder or screw straigh to each cell, there is a lot of space, I also have a A123 pack from a Karma Fisker and that is laser welded which has almost no space to solder or clamp wires for a BMS.


----------



## McRat (Jul 10, 2012)

So a 180 Ah CALB LiFePO4 is 45.86 Wh per pound in it's protective case.

In the block structure, the Volt modules are 47.62 Wh per pound.

So the big advantage would be discharge rate and price, unless you can make a significantly lighter structure.


----------



## sunworksco (Sep 8, 2008)

I'm thinking about using two of these 4KW modules. What are the measurements of each module footprint?


----------



## McRat (Jul 10, 2012)

Roughly 18 x 12 x 11 high for 2 x 2kWh in a block.

There are 4 blocks:

2kWh + 1kWh (72v)
2kWh + 2kWh (96v)
2kWh + 2kWh (96v)
2kWh + 2kWh + 1kWh (120v)


----------



## sunworksco (Sep 8, 2008)

Guess I could use the middle and right rear modules.
I need around 90-100volts for my motor.
How much would these weigh?
The two modules would be 8kw?
If so, that would be perfect for my ultralight RT EV .
I have 34" of inside body width behind the front axle for the battery placement.
Might be tight.


----------



## sunworksco (Sep 8, 2008)

Can anyone make a rough guess what the range would be on a reverse trike that only weighs a total 800Lbs. with battery pack?
I will be using an Astrolight 4535 BLDC, Hall's Effect sensor and Sevcon Gen4 controller. It will use an 8-1 belt drive system. The body is only 3' in width and has a full belly pan. It is the same body as the 1906 Stanley Rocket but in reverse.


----------



## Yabert (Feb 7, 2010)

McRat said:


> 180 Ah CALB LiFePO4 is 45.86 Wh per pound in it's protective case....Volt modules are 47.62 Wh per pound.
> So the big advantage would be discharge rate and price...


From my calculs and based on 3,8v nominal, excluding bms and excluding cooling ports:

Calb CA180ah: 101 wh/kg and 155 wh/L (including screw and bus bars)
Volt cells 45ah: 107 wh/kg and 166 wh/L

So, lighter, smaller, cheaper and more powerful..... but not safer 

Detail of the 4 kwh battery pack (18,625" long) and my first 8s charge.

Thanks Lipo Louis to share details and pics, your lightweight car will be awesome with this battery!


----------



## McRat (Jul 10, 2012)

sunworksco said:


> Guess I could use the middle and right rear modules.
> I need around 90-100volts for my motor.
> How much would these weigh?
> The two modules would be 8kw?
> ...


Yabert posted the weight of the 2x2 block at 84lb. So 168lb for 8kWh, BUT if you leave them in stock configuration, you should probably run water cooling.

I'm thinking that for the bike, I will tear it down and use airflow cooling. I will build a 1P 12s array separated by corrugated plastic 1/8" spacers. I will make the corrugated spacers look like swiss cheese, so the battery surface gets direct air contact, but the corrugation will direct the airflow evenly.


----------



## sunworksco (Sep 8, 2008)

Sounds like a good design. A lot smaller footprint.
How much weight would I eliminate on the 8kw pack if I reassembled them?


----------



## McRat (Jul 10, 2012)

sunworksco said:


> Can anyone make a rough guess what the range would be on a reverse trike that only weighs a total 800Lbs. with battery pack?
> I will be using an Astrolight 4535 BLDC, Hall's Effect sensor and Sevcon Gen4 controller. It will use an 8-1 belt drive system. The body is only 3' in width and has a full belly pan. It is the same body as the 1906 Stanley Rocket but in reverse.


For the bike, the path I'm going is with a 24 lb ME0909 permanent magnet DC motor (<$400 shipped) using a Kelly PMDC controller - KDZ12401,24V-120V,400A,PM with Regen = $479.00. People have run the ME0909 at 72vdc so it should go over 20HP in "boost" mode. Plus it has a similar RPM to a gas engine at 5000rpm x 72v.

The bike won't need regen, 120v or 400a, but it will allow me to reuse it for other projects.

I haven't decided about Honda Insight yet, other than I'm not going AC.
It has to end up with ~100kW of peak power without a lot of added weight.


----------



## McRat (Jul 10, 2012)

sunworksco said:


> Sounds like a good design. A lot smaller footprint.
> How much weight would I eliminate on the 8kw pack if I reassembled them?


The air-cooled 1p 12s config will not save room. It will only save weight. Polycarb corg'd sheet is extremely light, strong, with good temp resistance.


----------



## sunworksco (Sep 8, 2008)

Maybe the 120volt battery module will be adequate for the RT?
After all, the 800Lb. EV is 1/5th the weight of the GM Volt and it will use very low rolling resistance 17" Michelin motorcycle tires.


----------



## McRat (Jul 10, 2012)

Using the polycarbonate I have already (6mm thk), a 1P 12s aircooled stack (48v x 15Ah, 0.7 kWh) = 

84 lb / 2 modules = 42lb per module. Divide by 3 for the 1P build = 14lb. Polycarb spacers are 28.4gm each (50% swisscheesed), I need 13, so 0.8lb, so it will be significantly under 15lb for the battery.

The 6mm polycarb sheet looks like the picture. It weighs 0.81 grams per square inch


----------



## sunworksco (Sep 8, 2008)

Wow!
I'm impressed with the weight reduction.
I am in the solar biz and have used polycarbonate glazing on solar panels for years. They hold up to heat very well, strong too.


----------



## McRat (Jul 10, 2012)

Note: The factory 2kWh module is 36 cells and 45Ah.

I'm making a motorcycle battery. So 12 cells and 15Ah.

I have no idea what a 45Ah air cooled module would weigh. Yet.

I can't seem to get the Driver's Side Rear 2kWh+1kWh to release from it's base.


----------



## McRat (Jul 10, 2012)

OK, a single naked cell is 381 grams, and the "sack" is 6.5" x 9" x 0.219" thick. So the whole 288 cells weighs 241 lb. The aircooling plates are 20lb.

The "ears" are tinned copper and stick out the top about 1" before you cut the weld off. They are 1.750" wide and 0.010" thick. After you cut the ears at the weld, you have about .300" worth of clamp surface.


----------



## McRat (Jul 10, 2012)

Going by the 3.8v rating, that means this chemistry is 15ah x 3.8v = 57wh, or 150wh per kg naked. 6.5 x 9 x .219 = 12.8 sq in, or .21 L, so 57w/.21L is 271wh/L.

So air cooled 48v pack, will be 2.616" thk of battery, and using the 6mm poly spacers, 3.120" = 5.736" thick x 7" wide (boxed) x 10" high (boxed), and at 10C discharge, will make 150a x 48v = ~9hp. Eh. That should be OK for pack 1. About 12lb in the box. So the electric powertrain for this will be ~40lb, or about what the stock ICE engine weighed.


----------



## dougingraham (Jul 26, 2011)

A while ago I started collecting data on OEM EV battery packs. Here is what I had been able to discover about the Volt.

Chevy Volt battery pack:

Consists of LG Chem LiCoO2 pouch cells.

# cells: 288
Kilowatthours:	16 (10 usable)
Nominal voltage:	356?
Amp Hours: 45
Weight of cells:	285.1 lbs (129.6 kg)
Weight of pack:	434.9 lbs (197.7 kg)
Cell wh/kg: 123.457
Pack wh/kg (usable):	50.582
Pack wh/kg (total):	80.931


The usable wh/kg figure is not particularly impressive. My own battery pack made of prismatic cells is this:

My RX-7 battery pack:

Uses GBS-LFMP100AH LiFeMnPo4 cells.

# cells: 51
Kilowatthours:	16.32
Nominal voltage:	163.2
Amp Hours: 100
Weight of cells:	342.2 lbs (155.55 kg)
Weight of pack:	382.5 lbs (173.86 kg)
Cell wh/kg: 104.92
Pack wh/kg:	93.86

My pack seems to top out at about 130kw. Too much sag under the 1000 amp load. But I only actually hit this number for a few seconds at a time. The last number is the one you worry about from a range perspective. Compare both of the above to the Tesla Roadster (I have not done this chart for the Model S).

Tesla Roadster battery pack:

Consists of Panasonic 18650 cells.

# cells: 6831
Kilowatthours: 53
Nominal voltage:	375
Amp Hours: 141
Weight of cells:	676 lbs (307.4 kg)
Weight of pack:	992 lbs (450 kg)
Cell wh/kg: 172.4
Pack wh/kg: 121.87


The Model S is probably a little better.

There is a lot of engineering in those OEM packs to keep them from self destructing. That engineering costs a lot in added mass. The Volt and Leaf packs are worse wh/kg than typical DIY packs made from LiFePO4 prismatics.


----------



## sunworksco (Sep 8, 2008)

I think that is will use Lipos with a fire sprinkler system!


----------



## Karter2 (Nov 17, 2011)

sunworksco said:


> I think that is will use Lipos with a fire sprinkler system!


Well, I guess electrocution is a quicker death than burning !


----------



## McRat (Jul 10, 2012)

dougingraham said:


> A while ago I started collecting data on OEM EV battery packs. Here is what I had been able to discover about the Volt.
> 
> Chevy Volt battery pack:
> 
> ...


The trick for light weight is the ability to hit and sustain target HP with the least weight.

The GM cells will sustain over 150kw in a 16.5kWh pack at OEM settings. How far over will they go? That remains to be seen. No other OEM cells are hitting that kind of discharge with an 8 year minimum life expectancy.

As far as the Lost 6 kWh rumors go? (GM is tight lipped).

1) They plan to be able to extend the lifespan with software editing via the OBDII port.

2) When in Mountain Mode or for people who start their drives from the top of mountains, it allows regen room up top.

3) Fast charge and rapid discharge window. It will charge at 60kW during regen in the Volt, and an unknown higher number for the ELR.

4) Allows prolonged storage or ICE operation when there is no power infrastructure available, without hurting life on a discharged battery.

5) Permits full rated HP regardless of temperature or discharge level.

6) If you only charge to 62% max per cycle, you'll get a higher number of discharge/charge cycles for normal drivers. It needs to hit 3000 cycles in all conditions and temperatures even though it has a high C discharge rate.

etc
etc

Nobody knows for sure yet. But there is nothing that is going to stop hobbyists from using 80%+ capacity.

What is also unknown is the volt of the cells. The design has hit 4.6vdc. I do not know what a full charge voltage is yet. 

Something else about the weight, it includes the armor, the mounting bracket, several BMS and temp sensors modules, ammeter, water system, high power relays, emergency disconnect system (user removable plug, with digital interface) and a main computer. It does not include the charger, the controller, or the OBDII diagnostic computer.

Note: Unless someone has a better balance (Ohaus), the cells weigh 381g repeatably. Seriously. GM says the pack voltage is 355 and 360 depending on what page of the service manual you read. A less than charged cell is 4.088v. So the static voltage of the pack is 400+ even with the 20% unused "top off" area.


----------



## McRat (Jul 10, 2012)

sunworksco said:


> I think that is will use Lipos with a fire sprinkler system!


AFAIK, nothing will put out a lithium fire yet. It would be interesting to see what injected Halon (like I run racing) will do. It is not a smothering agent, a cooling agent, or does it make the fuel unburnable.

When heat activated, it changes the chemistry of the hot gasses and disrupts their ability to combine with oxygen. But it must be where the gases are being emitted. Liquids and solids do not burn, only the gasses they emit. I inject Halon directly in the intake tract, and both exhaust manifolds externally. I use aqueous foam for the driver, from between the legs, and pointed forward at a 45 from both side of the driver, and lastly on the floor.


----------



## McRat (Jul 10, 2012)

While not practical, I'd like to see what liquid nitrogen or liquid CO2 (very high pressure) will do. Would they get the batteries cold enough to stop outgassing?

But both are fairly lethal in a passenger compartment.


----------



## Lipo Louis (Oct 29, 2012)

It is just a lion battery and I treated it as a Lipo cell at 4.20v 100% charged and 3.00v almost discharged. I do have a discharge curve somewhere and I think I got 45ah out of it this way. I will charge to 345v at 84 cells Which is 4.10v . The soltion controller can have max 345v. I hope to get 900A out of it for a few seconds. Which is about 300Kw peak at a 600kg car.


----------



## major (Apr 4, 2008)

McRat said:


> As far as the Lost 6 kWh rumors go? (GM is tight lipped).


The presenters at that SAE event I mentioned in post #31 weren't tight lipped about it. The whole vehicle design centered around the Extended Range EV concept and a reliable validated product life and the primary concern was the battery. The battery needs to perform duty as an EV ESS and as a HEV ESS (Energy Storage System). To meet those requirements they set a minimum SoC and employ an elaborate thermal management system; neither of which would likely be used on a pure EV. And they used a much larger ESS than what would have been required on a pure HEV (one without the 40 mile electric only mode).

The cells themselves were likely a compromise between energy density (as used in EVs) and power density (as used in HEVs). So I suspect your following conclusion is invalid. Cells designed for strictly hybrid use, especially in commercial vehicles, would likely exceed that 9C performance by a long shot.



McRat said:


> The trick for light weight is the ability to hit and sustain target HP with the least weight.
> 
> The GM cells will sustain over 150kw in a 16.5kWh pack at OEM settings. How far over will they go? That remains to be seen. No other OEM cells are hitting that kind of discharge with an 8 year minimum life expectancy.


The Volt LG Chem cell appears to be a very good PHEV cell. But a number of other companies make similar products which meet the requirements. A123, Saft, EnerDel come to mind.


----------



## Karter2 (Nov 17, 2011)

Excellent thread guys, and very informative.
One point I may have missed, but how exactly are the individual cell modules all held together as a unit ?.
Obviously there is something needed to ensure the coolant passages etc are sealed and even apply some compression to the cells judging by the impression pattern on the cell pouches.
Are there long bolts through the plastic module casings, or is some form of compression banding used ?

thanks.


----------



## McRat (Jul 10, 2012)

There are very long bolts that hold the bottom of the blades in tension.

Tops are banded with a steel strap, but the module caps also have plastic spot welds.

The safest way to deal with this battery is to keep the bolts and straps on it, and just remove the blocks from the base, or leave in the T configuration.

To remove individual cells is really risky. This was never intended to be torn down in the field, and probably not intended to be rebuilt.

I'm trying to come up with a safer procedure for removing the individual cells. The cell tabs are tinned copper which is crimped/welded/bonded to a thick tinned copper U-connector.

It would be EXTREMELY easy to dead short adjacent 3p 2s while trying to cut off the top of the tab. If a tool or a cut off tab bridged the thumb-sized gap you have at least 450amps, and probably 2 or 3 times that.

Dead minimum, wear garments appropriate for welding. Even just copper dust could flash and take your eyes out.

ie - I don't recommend disassembling this. But I don't know any better...


----------



## rochesterricer (Jan 5, 2011)

Can the sections of of the T, meaning the cross of the T and the base, be easily separated or is the bottom plate all one piece?


----------



## McRat (Jul 10, 2012)

rochesterricer said:


> Can the sections of of the T, meaning the cross of the T and the base, be easily separated or is the bottom plate all one piece?


There is one band and set of bolts for the T. However, at the two block separation point, it is split by the water manifold, and the base retaining flange is split as well. So by using a little thought, you should be able to clamp each block individually, then separate them, then get new bolts, without removing the plastic welds on top.


----------



## Yabert (Feb 7, 2010)

dougingraham said:


> Chevy Volt battery pack:
> Consists of LG Chem LiCoO2 pouch cells.
> Pack wh/kg (total):	80.931
> 
> ...


Since the chevy Volt cells and their plastic casings weighting around 340 lbs / 16 kwh, they can also be assemble on a more raisonable 360-380 lbs battery pack with modification. So, 92 to 97 wh/ kg is reachable...

Anyway, the most impressive figure is: 90$ / Kwh


----------



## McRat (Jul 10, 2012)

I think the best way to use these will be in 1p4s (or for amp monsters 4p1s) using the cells with forced air cooling. This is 15.2v x 15Ah nominal, or peak voltage of ~16.4v.

I haven't finished the first module yet, but it's going to weigh very close to 1600g. Just over 250 lb for the entire pack.

BUT ... That means construction of 72 batteries. Good news is you can configure your voltage to many different numbers.


----------



## Markijohn (Feb 7, 2014)

So I looked it up, you can buy these packs brand new from Chevy (well, an online wholesaler) for about $2500-2600. That is crazy cheap from what I've seen thus far. For my project, I would like to see 350V, which means I'd need a lot of cells/modules. Quick numbers I've come up with are in the area of 5k-10K just for batteries.

So my question is, is there a downside to buying these packs? They seem to give great power and voltage specs for just over $2k.

And my second question is, how are you charging/managing the cells? What controller brands and PN's are you using? I am trying to get a good estimate of what all I'd need to purchase to make this a complete battery pack for my use.


----------



## rochesterricer (Jan 5, 2011)

Markijohn said:


> So I looked it up, you can buy these packs brand new from Chevy (well, an online wholesaler) for about $2500-2600.


No you can't actually. McRat has already tried that and there have been other threads about that here. GM is selling those at a loss for Volt owners, but you have to own a Volt to get them and they must be installed in your Volt by a Chevy dealership. Bummer I know.


----------



## Markijohn (Feb 7, 2014)

rochesterricer said:


> No you can't actually. McRat has already tried that and there have been other threads about that here. GM is selling those at a loss for Volt owners, but you have to own a Volt to get them and they must be installed in your Volt by a Chevy dealership. Bummer I know.


Oh, ok. Well there is a junkyard on the other side of the state from me that has a pack. They said $2300 for it out right (no control modules, etc., and of course no core from me). So the rest of my previous post still stands.


----------



## McRat (Jul 10, 2012)

I'm going to guess the $2995 list price is for an exchange, but will not be available to anyone without GM high voltage training, ie - Dealer-Installed Only item.


----------



## McRat (Jul 10, 2012)

The A123 20Ah LiFe cell is close to the same outside dimensions, but it .283" (23% thicker), and 492g (23% heavier). Using the 3.2v LiFe number, it's 64whr.
Using the 3.8v number, the GM cell is 57whr, or 11% less power stored. 130wh/kg for the LiFe, and 150wh/kg for GM cell. With a similar variation in volume.

Not a big difference, but the A123 pouch would be a second choice for performance. It's a double whammy. Less weight for the vehicle, means you need less power to git-er-dun. AND with 9% less volume, you can make the vehicle battery area 9% smaller.

EDIT: Change to Wh from W


----------



## major (Apr 4, 2008)

McRat said:


> The A123 20Ah LiFe cell is close to the same outside dimensions, but it .283" (23% thicker), and 492g (23% heavier). Using the 3.2v LiFe number, it's 64whr.
> Using the 3.8v number, the GM cell is 57whr, or 11% less power stored. *130w/kg for the LiFe*, and 150w/kg for GM cell. With a similar variation in volume.


Specific power for the A123 20Ah pouch is 2400W/kg.

ref: http://www.raceyard.de/tl_files/Newsletter/Dateien/A123-AMP20-M1HD-A-1-Data-Sheet.pdf

You probably mixed power and energy. But as far as power density or specific power goes, I would be surprised if the LG Chem cell beats the A123.


----------



## McRat (Jul 10, 2012)

major said:


> Specific power for the A123 20Ah pouch is 2400W/kg.
> 
> ref: http://www.raceyard.de/tl_files/Newsletter/Dateien/A123-AMP20-M1HD-A-1-Data-Sheet.pdf
> 
> You probably mixed power and energy. But as far as power density or specific power goes, I would be surprised if the LG Chem cell beats the A123.


All I have is claims at this point.

If the A123 is 3.2v x 20Ah and the GM is 3.8v x 15Ah, then the numbers stand.

I have both cells and a balance and measuring tools.

What I don't have is a battery dyno. But going by MFR data, the GM cell wins.


----------



## major (Apr 4, 2008)

McRat said:


> All I have is claims at this point.
> 
> If the A123 is 3.2v x 20Ah and the GM is 3.8v x 15Ah, then the numbers stand.
> 
> ...





McRat said:


> A123 is 3.2v x 20Ah


 which is 64 Wh / 496g which equals 129 *Wh/kg*.........not *W/kg*

See the difference? Wh/kg is specific energy. W/kg is specific power.

Yes, the LG Chem cell is higher on the specific energy, Wh/kg.

But I suspect that A123 is higher on specific power, W/kg.

And as a racer, what do you really want? The most energy or the most power for your allotted fuel mass?

edit: I see you corrected your units. So you do see the difference


----------



## McRat (Jul 10, 2012)

Nobody knows how much abuse the GM cells will take, we only know how it behaves in an stock OEM car.

However, I did get to bottom of a 3 mile grade, then nailed it to the top, and watched the kW meter. I started with 23 miles of range (about 2/3), and crested the top at 2 mi of charge left. Speed averaged about 90mph, but even at 2 mi, it did not slow down or turn on the ICE engine.

So the kW/kg max is unknown. It will take 7C discharge until the battery is drained. Supposedly the ELR will take 10C.

Looking at you link for the A123, it lost 1/3 it's voltage by the time it hit 20% SOC.


----------



## rmay635703 (Oct 23, 2008)

McRat said:


> Roughly, 65" long, 37" wide, 15" tall.


What is the width at the back of the "T"? 

To fit I need to see if the width of the dissassembled T fits in my chunnel and up front (it already fits up front, not sure on the chunnel)

Thanx


----------



## McRat (Jul 10, 2012)

rmay635703 said:


> What is the width at the back of the "T"?
> 
> To fit I need to see if the width of the dissassembled T fits in my chunnel and up front (it already fits up front, not sure on the chunnel)
> 
> Thanx


37" at the tee. This is normally just behind the passenger seats, or under them.


----------



## McRat (Jul 10, 2012)

If you are wondering about the cross sectional dims, see Y's CAD model earlier in the thread. All the blocks have the same cross section.


----------



## McRat (Jul 10, 2012)

Of minor interest. GM is flowing a minimum of 315a through a tinned copper strap that is 2mm thick, 17mm wide, and comprised of 7 laminations for flexibility.

Also, the poles are in the same orientation as the A123 pouches, with the tabs at the top, looking from the barcode side, positive is left. 

And I made a mistake. Only the negative tab is tinned copper. The positive is shiny and softer, probably aluminum.


----------



## dougingraham (Jul 26, 2011)

McRat said:


> Of minor interest. GM is flowing a minimum of 315a through a tinned copper strap that is 2mm thick, 17mm wide, and comprised of 7 laminations for flexibility.


A 2mm thick by 17mm wide piece of copper strap would be about the equivalent of 2 gauge wire. So resistance of about 6 inches would be 0.0000768 ohms. Losses at 315 amps in a length that long would be 7.6 watts. The voltage drop would be 0.024 volts.

Or are you saying that there are 7 layers of 2mm x 17mm material? How long is this strap? What does it interconnect?


----------



## McRat (Jul 10, 2012)

dougingraham said:


> A 2mm thick by 17mm wide piece of copper strap would be about the equivalent of 2 gauge wire. So resistance of about 6 inches would be 0.0000768 ohms. Losses at 315 amps in a length that long would be 7.6 watts. The voltage drop would be 0.024 volts.
> 
> Or are you saying that there are 7 layers of 2mm x 17mm material? How long is this strap? What does it interconnect?


All the drive power for the electric motors passes through 2 thin straps, which are segmented to attach blocks together.

The size of these straps without insulation is 2x17mm, but they are a laminate of 7 very thin strips.


----------



## dougingraham (Jul 26, 2011)

McRat said:


> The size of these straps without insulation is 2x17mm, but they are a laminate of 7 very thin strips.


I count 8 layers in the photo and it looks thicker than 2mm. At least I hope it is. That would get rather warm at 300 plus amps if it is 2mm x 17mm.


----------



## McRat (Jul 10, 2012)

My eyes ain't what they used to be. 

OK, 8?

Dims- 0.078" thk x .679" wide.

Anyhow, I've never seen laminated strips used this way. It allows for very tight routing.


----------



## Markijohn (Feb 7, 2014)

McRat said:


> My eyes ain't what they used to be.
> 
> OK, 8?
> 
> ...


TE Connectivity (Tyco) has these laminated pieces called "ISOLams" <- I believe the spelling is correct. I have a data sheet somewhere on my laptop at home. If you guys are interested I can post it up. It gives current ratings and such.

They are VERY handy when it comes to wiring a pack. Though using a drill through the laminates gets kind of messy. The copper just kind of pushes out the other side of each layer and the layers separate. A hammer fixes that!


----------



## major (Apr 4, 2008)

http://www.erico.com/products/EriflexFlexibles.asp 

I've used this stuff for years where it makes sense. It is nice; more flexible than solid bar copper. And no need for terminal ends. Best to use sheet metal tools; punches and shears.

Here's an install I did with it a few years ago: 










major


----------



## sunworksco (Sep 8, 2008)

major said:


> http://www.erico.com/products/EriflexFlexibles.asp
> 
> I've used this stuff for years where it makes sense. It is nice; more flexible than solid bar copper. And no need for terminal ends. Best to use sheet metal tools; punches and shears.
> 
> ...


Very clean cable installations.


----------



## GoAhead92 (Dec 16, 2012)

I found this training video informative on the topic of Volt batteries and salvage yard information. 
http://www.fixhybrid.com/training-videos/


----------



## McRat (Jul 10, 2012)

grandfather said:


> Have you figured out a way to remove individual cells, or is it too risky? If you can provide the steps necessary remove cells from a pack individually or as a group of 3. I don't want to attempt doing so on my project until I know how to do it. Thanks in advance.


I can remove individual cells, but I need a safer procedure. I'll figure it out shortly (har-d-har)...


----------



## Lipo Louis (Oct 29, 2012)

I also thought this copper bar was very thn for more than 300A, I measured 350A peak power at full acceleration. 

I also wonder why there is no fuse inside the whole pack. Not in between the pack but also not a the begin or end. From the pack it goes to the controller and I believe there is no fuse either.

Maybe when the BMS detects an extremely high current it will break the circuit with the relay ? 

Most of the Ebike batterypacks also have a BMS that will shut itself of at a given Amp


----------



## McRat (Jul 10, 2012)

To do the individual cells, get a 26" x 1.75/2.25 bicycle tube. Cut off 1" slices like rubberbands. Put these on all cell welds to insulate.

Get Channellock PN 748, which are long reach cutters: https://www.channellock.com/product.aspx?zpid=407

Start at one end, and SNIP/SNIP/SNIP/SNIP ...

Pull cells out bottom.

Pop-rivet cells together with .032/.064 thick .375 wide and 1.75" long copper strips on the outside for support.

This will pass at least as much current as the 3 small OEM welds.

However... If you are not careful, you could cut the tabs too short. AND you cannot do 3P 1S this way.


----------



## Markijohn (Feb 7, 2014)

Has anyone utilized the OEM BMS from these packs? 

If I go this route, at $12 a module for the miniBMS system, it'll get kind of expensive. Just seeing if anyone has been able to utilize what is already there.


----------



## Yabert (Feb 7, 2010)

Use the OEM bms would be nice, but it seem a little bit complex to me.
If somebody (electrical engineer or ??) is willing to help me to be able to use the OEM bms, it will be nice.

*Food for thought:*
-http://www.driveforinnovation.com/volt-teardown-battery-pack-slide-presentation/
-http://www.embedded.com/print/4391497
-http://www.edn.com/design/automotive/4372600/Teardown-reveals-Chevy-Volt-s-electronic-secrets

And what I learn:
-The bms modules are self powered by the cells (kind of independent from de Chevrolet Volt itself)
-The control module (photo first link P. 20) can potentielly be use to stop a charger at high voltage or controller at low voltage (who are my mains goals).

But now, how I can do to find how all this work? 
There is many wires between the bms boards, but only 9 at the contol module entry. 4 those ones seem to be use for the current sensor (same wires colors) and the 5 others would be for temperature and voltage (low/high voltage signal?).
I've try to read voltage of those 5 pins with all bms in place and another time with one bms disconnected (orange connector), but don't find any interesting signal.

Do any of you have tips for my situation?
Thanks


----------



## McRat (Jul 10, 2012)

You sure the BMS modules are locally powered?

Get the GM pinouts.


----------



## Markijohn (Feb 7, 2014)

Yabert said:


> Use the OEM bms would be nice, but it seem a little bit complex to me.
> If somebody (electrical engineer or ??) is willing to help me to be able to use the OEM bms, it will be nice.
> 
> *Food for thought:*
> ...


I actually am an electrical engineer. Finished up my masters in May. I wrote my thesis on the battery pack design for NCState's EcoCAR2 (www.ncsuecocar2.com). This is heavily sponsored by GM and I have been hitting up my contacts w/ GM to try to get a Volt battery pack, no luck yet. I will see if I can get any information on the BMS. If I get anywhere with that, I'll let you know!


----------



## Yabert (Feb 7, 2010)

Wow! Thanks a lot for your offer Markijohn. It's would be really appreciate!


----------



## Markijohn (Feb 7, 2014)

After reading through the links you posted previously, I'm not sure the stock BMS would be necessarily beneficial to us w/out the ability to reprogram it all. One of the links discusses the fact that GM limits the power and charge ranges. For me, I am not concerned about the ability to drive 100K miles on the pack. I want to drive around town and race the car when I want. Therefore, I want the full power output and full useable range of the pack (100% charge to 20%). 

I'll still research this, but am currently leaning towards an aftermarket solution, though it will cost more $.


----------



## TheSGC (Nov 15, 2007)

Could you provide a closer picture of the processor on the BMS? I'm a Computer Engineer/Electrical Engineer at a very large IC company and if I'm not mistaken I see a JTAG port on that PCB. I'm curious about which processor they are using for the BMS, it might be reprogrammable.


----------



## McRat (Jul 10, 2012)

The BMS has a L9763, an ASIC developed by STMicroelectronics and LG Chem and a 40mhz Freescale S9S08DZ32 ?


----------



## McRat (Jul 10, 2012)

Since the SOC changes based on driver's input, I doubt it's tied into the BMS boards.

The car has a Mountain Mode, which raises the bottom of the SOC window. This can be driver selected.


----------



## McRat (Jul 10, 2012)

Well, the right tools, you can take out the cells "as welded" in 3P 1S.

It actually easier than taking out the individual cells and safer.

Weight per cell is 1153.0g / 3 with the copper tab left on.

There is room to separate the plates for air cooling.


----------



## Yabert (Feb 7, 2010)

TheSGC said:


> Could you provide a closer picture of the processor on the BMS?


Closer than what you can see on the link I gave on the post #111? (first link P.14-15 and 18)
What part?

Good job on cells McRat!


----------



## TheSGC (Nov 15, 2007)

Yabert said:


> Closer than what you can see on the link I gave on the post #111? (first link P.14-15 and 18)
> What part?
> 
> Good job on cells McRat!


Yeah, I'd like to see the model number on the big black IC on the second photo.


----------



## Yabert (Feb 7, 2010)

SGC, the PCB on the page 2 (second pic?) isn't related to chevy Volt battery...


----------



## Yabert (Feb 7, 2010)

For those interested: Cad model of the 4 Kwh module (2+2 Kwh) in Solidwork and Step. 
Please note that I excluded de water cooling port (extrude roughly 1'' on each side) and the BMS board.


----------



## McRat (Jul 10, 2012)

grandfather said:


> Those tools required are??????? Here is how it is done????


I'll write the tutorial starting with a fresh module. This one had a lot of "experimenting" done on it, so I can't accurately give steps, and I started at the wrong end.

The cutting tool that worked best was an oscillating multi-tool with a semi-circular metal blade, available at Harbor Freight for about $30. 

To the best of my knowledge, the center strip of the top black plastic blade holder contains narrow embedded copper strips for the BMS pins. If you cut into that, you'll probably be unhappy.

I'd wait a few days until I can put up some safety stuff on it. But it's doable with cheap tools.


----------



## kennybobby (Aug 10, 2012)

McRat said:


> Well, the right tools, you can take out the cells "as welded" in 3P 1S.


It looks like the LG pouch cell part number is KC313x3, where x3 is the 3p of the KC313. 

There are 13 current collectors coming off of each end of the jelly roll soldered/welded to a header adjacent to the external tab (hence the 13 in the part number). Are the individual pouches 3mm thick by chance? 

It looks like you have a puncture in the pouch near the positive terminal, seen in the second picture lower left corner.


----------



## McRat (Jul 10, 2012)

About .219" thick each pouch.

Haven't wrecked any yet, but the day is young!


----------



## TheSGC (Nov 15, 2007)

Yabert said:


> SGC, the PCB on the page 2 (second pic?) isn't related to chevy Volt battery...


Sorry, I mean on post #111 the second picture with the bare PCB and 9 wires coming out of it.


----------



## Yabert (Feb 7, 2010)

So, this is the control board and not the BMS board.


----------



## janzicek (Jul 27, 2013)

Hello, janzicek here... I put a volt pack in my Solectria Force about a year ago. Junkyard find for about $1300 shipped. So far so good. I also work in the industry and have done extensive teardowns of the volt BMS to benchmark my companies stuff against the volt. Anyway, if you have any questions, I have done a ton of cell level testing and have accrued almost 10,000 miles on my volt cells at this point. Let me know if I can help.

Josh


----------



## McRat (Jul 10, 2012)

janzicek said:


> Hello, janzicek here... I put a volt pack in my Solectria Force about a year ago. Junkyard find for about $1300 shipped. So far so good. I also work in the industry and have done extensive teardowns of the volt BMS to benchmark my companies stuff against the volt. Anyway, if you have any questions, I have done a ton of cell level testing and have accrued almost 10,000 miles on my volt cells at this point. Let me know if I can help.
> 
> Josh


How high of discharge rate is safe for the cells themselves? GM will go 10C (450 amps) on the factory pack structure.

However, I believe the individual cells can be discharged at a higher level.


----------



## janzicek (Jul 27, 2013)

I don't have an exact number, however, in general I can say that for discharge current, as long as you don't overheat the cell and you stay over 2.5V you are not causing damage to the cell. I have tested these cells to 250A continuous (750A total in Volt config.) and have not had any noticeable degradation over 25 cycles tested. I will post some links to my pictures and test data shortly.


----------



## janzicek (Jul 27, 2013)

janzicek said:


> I don't have an exact number, however, in general I can say that for discharge current, as long as you don't overheat the cell and you stay over 2.5V you are not causing damage to the cell. I have tested these cells to 250A continuous (750A total in Volt config.) and have not had any noticeable degradation over 25 cycles tested. I will post some links to my pictures and test data shortly.


Please note, however, that the aluminum cell terminal must be connected to a large heat sinking terminal such as large AWG copper to avoid melting of the cell pouch. The nickel plated copper terminal was fine.


----------



## McRat (Jul 10, 2012)

janzicek said:


> Please note, however, that the aluminum cell terminal must be connected to a large heat sinking terminal such as large AWG copper to avoid melting of the cell pouch. The nickel plated copper terminal was fine.


Are you sure it's nickel? It did not affect my cutting tools. Nickel is harder on tools than steel is. I'm thinking it's tinned.


----------



## Yabert (Feb 7, 2010)

janzicek said:


> I also work in the industry and have done extensive teardowns of the volt BMS to benchmark my companies stuff against the volt... Let me know if I can help.


Awesome news Josh! Thanks to offer your help.
I would like to know if the BMS is able to give a signal if a cell go in a over voltage or under voltage event.
I expect to turn off my charger with the BMS and protect all cells of low voltage during driving.

By the way, awesome price on your Volt battery!


----------



## McRat (Jul 10, 2012)

janzicek said:


> Please note, however, that the aluminum cell terminal must be connected to a large heat sinking terminal such as large AWG copper to avoid melting of the cell pouch. The nickel plated copper terminal was fine.


You're probably right about the nickel plating.


----------



## janzicek (Jul 27, 2013)

There are 3 circuit boards that sense the cell voltages and temperatures, these are the units that are wired to the battery modules with orange connectors / harnesses. On those circuit boards there are over voltage / under voltage comparators (inside the main ASICs) that flag the main controller of an OV/UV condition in case the primary measurement path is compromised. There is an optocoupler that triggers an actual wire (open collector design, main controller pulls up with a resistor to +5V or +12V, and each ASIC has an optocoupler that can pull the line down to 0V). I will look for my board pics and see if I can point them out in the next couple days. Keep in mind you will still need to supply the +12V to these boards when operating in order to wake them up from sleep mode.


----------



## janzicek (Jul 27, 2013)

McRat said:


> Are you sure it's nickel? It did not affect my cutting tools. Nickel is harder on tools than steel is. I'm thinking it's tinned.


Good day,
In my pack the cell terminal is definitely nickel plated copper. First, you can see the copper on the cross cuts or if you take a file to the positive term. Second, pure nickel is magnetic, these terminals are not.

I can't speak for the second gen volt pack, only the 1st.

Cheers,
Josh


----------



## Yabert (Feb 7, 2010)

janzicek said:


> There are 3 circuit boards that sense the cell voltages and temperatures... I will look for my board pics and see if I can point them out in the next couple days. Keep in mind you will still need to supply the +12V to these boards when operating in order to wake them up from sleep mode.


Thanks for this Josh.
I'm actually in position to supply 12v and do many tests on my battery pack. So I will wait for further details.


----------



## Markijohn (Feb 7, 2014)

janzicek said:


> There are 3 circuit boards that sense the cell voltages and temperatures, these are the units that are wired to the battery modules with orange connectors / harnesses. On those circuit boards there are over voltage / under voltage comparators (inside the main ASICs) that flag the main controller of an OV/UV condition in case the primary measurement path is compromised. There is an optocoupler that triggers an actual wire (open collector design, main controller pulls up with a resistor to +5V or +12V, and each ASIC has an optocoupler that can pull the line down to 0V). I will look for my board pics and see if I can point them out in the next couple days. Keep in mind you will still need to supply the +12V to these boards when operating in order to wake them up from sleep mode.


The junk yard I talked to quoted me $2300 for the Volt pack. They said it would be $2300 because I did not have a core, and they would only sell me the pack, no extra controllers. What external controller(s) would be needed to complete the OEM BMS? I'm assuming the BMS in its entirety is not contained in the pack?


----------



## McRat (Jul 10, 2012)

janzicek said:


> Good day,
> In my pack the cell terminal is definitely nickel plated copper. First, you can see the copper on the cross cuts or if you take a file to the positive term. Second, pure nickel is magnetic, these terminals are not.
> 
> I can't speak for the second gen volt pack, only the 1st.
> ...


Thanks,

I was thinking they "tinned" (solder) to assist bonding the pouches at lower temps, but after looking at the bond jaw faces, the cleats on the pouch side is very aggressive and actually pierces the tabs, hence no need for solder.

Although ... I haven't tried to solder to a tab yet.


----------



## McRat (Jul 10, 2012)

Markijohn said:


> The junk yard I talked to quoted me $2300 for the Volt pack. They said it would be $2300 because I did not have a core, and they would only sell me the pack, no extra controllers. What external controller(s) would be needed to complete the OEM BMS? I'm assuming the BMS in its entirety is not contained in the pack?


Offer them less. Junkyard prices are negotiable. 

Core? I'm pretty sure these are only rebuildable at the block level.

$2300 for a 2003/4 is probably a great deal. They hold 16.5 kWh's instead of of 16.0 kWh's.

A 15Ah x 3.8v pouch cell that will routinely discharge at 10C for under $10 is a smoking deal.


----------



## thanzlik (Apr 20, 2012)

So I picked up my 2013 volt pack for $1450 and $350 shipping.  I want to reconfigure to 36s8p. I'm figuring 133.2v nom @ 123.6 Ah. I'd like to keep the cooling portion of the module if possible. I'm going to try to just cut the connecting tabs at the bend in the pack with my oscillating tool. I'd much rather try to separate the welds, but seems not to be a very easy task.


----------



## McRat (Jul 10, 2012)

Don't cut through the center rib, it has full amps in it. Protect the exposed tabs you are not working on with slices of bicycle intertube. Do not cut further down that absolutely necessary. Do not cut horizontally. Sometime the tabs will move and cut them shorter. Vacuum copper dust up often.


----------



## McRat (Jul 10, 2012)

The tabs extend under the connector U. If you cut too deep, you will cut into them.


----------



## McRat (Jul 10, 2012)

thanzlik said:


> So I picked up my 2013 volt pack for $1450 and $350 shipping.  I want to reconfigure to 36s8p. I'm figuring 133.2v nom @ 123.6 Ah. I'd like to keep the cooling portion of the module if possible. I'm going to try to just cut the connecting tabs at the bend in the pack with my oscillating tool. I'd much rather try to separate the welds, but seems not to be a very easy task.


In your situation, I'd probably keep the bolts in, do not cut cells apart, and opt for a controller that can handle 200v. You will be 6p x 48s. You can drop max voltage to the motor through the controller. This is mearly a matter of easy cabling. Each 3p12s (qty 7) module has a positive and negative terminal. So do the 3p6s modules (qty 2).

Once you commit to 4p you have a do a lot of contruction and testing for water tightness. 8p is probably going to draw more amps than the factory U connectors can deal with. 4p might also.


----------



## thanzlik (Apr 20, 2012)

Ive been driving a 24 lead cell in my s-10. Basic conversion. 1231c controller 9" warp. I don't want to shell out another $2-3k to upgrade controller right now. I was going to try to get my multi tool blade between the u and the tabs and hopefully be able to just cut the crimps. I have the pack broke down into 9 modules right now. Was going to try to separate them later today. I'll try to post a pic update later. Thanks for all the advice. If I wanted to just upgrade the controller it would be much easier and I'd split it into 2 separate 175v 45aH packs and parralel the packs. Just want to utilize all of my available energy.


----------



## McRat (Jul 10, 2012)

I'm mostly concerned with not getting anyone hurt. I'd feel awful if my posts in this thread sent someone to the hospital.

I got blasted with copper plasma from a 3ph industrial circuit due to a faulty device. I was stupid. I did not take good safety procedures. I nearly died at the UCI burn unit because for some stupid reason, my pancreas shut down. $175,000 hospital bill for 1 week.

What is going to happen if you short that pack, is it will spray you with copper. The volts won't kill, but the burns can maim you. If you've removed all the interconnects, the packs are 48v, but if the cutting tool you use shorts one cell blade, it will go way over 350a on thin metal.


----------



## Yabert (Feb 7, 2010)

Hi thanzlik

As McRat said, it will be really sad to destroy this battery pack simply because you only have a 144v Curtis controller. I strongly suggest you to considere the Soliton Jr at 1820-1900$. Once you will sell the Curtis and the contactor, the cost stay low and your drivability will be awesome with 20% more torque and around 100 Kw of peak power.

Or at least, try 30S 9P (3x 2+2+1 Kwh). In this case, you need to cut only one tab...


----------



## thanzlik (Apr 20, 2012)

I appreciate the concern. I'm familiar with electricity and electronics. I plan on working with only one crimp at a time. No voltage potential, no current flow. Yes the 3+v between anode and cathode present some voltage, but that low of voltage can only arc at best to 2-3mm, probably closer to 1mm in actuality. That being said, a trail of filings can give quite a good conductive path for 2700+w of potential discharge in one group of cells. This is also why I want to separate the crimp and not cut the U interconnect.


----------



## McRat (Jul 10, 2012)

thanzlik said:


> I appreciate the concern. I'm familiar with electricity and electronics. I plan on working with only one crimp at a time. No voltage potential, no current flow. Yes the 3+v between anode and cathode present some voltage, but that low of voltage can only arc at best to 2-3mm, probably . That being said, a trail of filings can give quite a good conductive path for 2700+w of potential discharge in one group of cells. This is also why I want to separate the crimp and not cut the U interconnect.


At least get a bicycle tube and protect from falling tools, or a power tool kicking back.

It's not the volts. There is enough amps in those 3p connections to vaporize the tabs, and spray copper/aluminum. I'd venture a guess that a short will be more than 20C which is 900 amps, and 3.6kW.

This is a staged pic. I wear a leather glove under the 1000v glove in case something blows.


----------



## thanzlik (Apr 20, 2012)

I was reffering to the voltage of one cell, not the entire
18 module block I'm going to test it on. I will cover the other tops. I'm going to take safety precautions. If the short is from the + and - of the entire module then its a possibility of Almost 20kw for 10s. I estimated to 3v for the 2.7kw. If I can just cut down between the crimped leads and the U interconnect this will be less schlag floating around vs cutting through the interconnect.


----------



## McRat (Jul 10, 2012)

thanzlik said:


> I was reffering to the voltage of one cell, not the entire
> 18 module block I'm going to test it on. I will cover the other tops. I'm going to take safety precautions. If the short is from the + and - of the entire module then its a possibility of Almost 20kw for 10s. I estimated to 3v for the 2.7kw. If I can just cut down between the crimped leads and the U interconnect this will be less schlag floating around vs cutting through the interconnect.


Good! Like I said, I just don't want folk to get hurt. The tool can jump. In one position you can be at 7.8v x 45a (900a) if the tool jumps.

Post up if you can cut the tabs off the U connectors. I failed.

If you look at my pic, see the white stickers on the center web? If you accidently cut into that, it has copper connectors to each blade embedded in the plastic. It will go bang.

Yeah, I'm a fraidy-cat . I've got 10lb of titanium body parts, hundreds of stitches, broken bones, 80% hearing loss, all from racing.

But many people are reading this thread, and might assume this something that isn't a big risk. Not you, but others who read this might learn from "experience". That's the both the worst way and best way to learn...

If you survive!


----------



## z_power (Dec 17, 2011)

It probably wouldn't hurt to discharge pack in series till one or more cells reach lowest SOC; there would be almost no energy to make serious bang.


----------



## thanzlik (Apr 20, 2012)

Yes, anyone who attempts this please be safe! I take no personal responsibility for anyone who thinks they want to try this! 


So I did a quick experiment. I heated one tab and pryed on it a bit very gently with a small flat screw driver. Just used a hair dryer. The other tab nothing. The tab I heated I was able to cut without destroying the crimp. The one I didn't left me with 3 holes. The pic is the worst of the 2.


----------



## thanzlik (Apr 20, 2012)

Anyone have pics of the underside of the top black plate? How do the BMS wires connect to the interconnect tabs? For the sake of saving the tabs it may be best to cut the interconnect at the first bend towards the top. Just would like to know where the BMS wires might run if anyone has the top off of a module.


----------



## sunworksco (Sep 8, 2008)

I for see someone creating an enterprize for building customized Volt battery packs to customer's order.
I would be ordering. With my luck, I would be fried to a crisp!


----------



## McRat (Jul 10, 2012)

thanzlik said:


> Yes, anyone who attempts this please be safe! I take no personal responsibility for anyone who thinks they want to try this!
> 
> 
> So I did a quick experiment. I heated one tab and pryed on it a bit very gently with a small flat screw driver. Just used a hair dryer. The other tab nothing. The tab I heated I was able to cut without destroying the crimp. The one I didn't left me with 3 holes. The pic is the worst of the 2.


If a hair dryer helped, then they are probably tinned, not nickel plate. A hair dryer would not make nickel softer, nor have any significant effect on a weld.

As far as I can tell, those U-connectors are longer than you can see. They go into the edge of the center rib. The BMS wires are molded into the center rib.

So, they have a top cap with wide slots to permit the tabs to slid in. The top cap has all the U-connectors, terminals, and support post molded in. Now, they slide one pouch in, put in a permeable spacer, a blade, another pouch, an alum cooling plate, another blade, then the last pouch. Now they crimp the tabs to the U-connectors with what amounts to a spot welder at low temp with special jaws.


----------



## Doctorbass (Dec 12, 2008)

Hey guys, 
Dont forget that the max C rate a cell can do have nothing compare to the C-rate when shorted!!

for exemple i tested a 5s1p of little 18650 1.3Ah cells from a 1.5Ah liithium makita pack, huess what??... 

My Fluke dc clamp meter 337 measured 968 amp !!! thru the little 4 gauge wire i used to short these.

these cells was rated 15C and total Ah was 1.3 x 5 = 6.5Ah only...

Now imagine 45Ah of 10C continuous rating cells....

Just two A123 20Ah cells in parallel can deliver 800A for 10 second... now imagine when shorted!!

But.. i see that the nickel junctions between each of the volt 3P cells have 3 holes in them... i guess it's to act like a fuse. The distance look ok so it should work as a fuse i'm pretty sure.

I would not be surprized if for few milisecond these 3p cels could deliver 3000-4000amp.

but what make short dangerous is ALSO the voltage!.. its, that parameter that make the copper to vaporize and fly in the air ( explode)

you can short a 0.1V cell that sdisplay 10000 amp and it will not be so fantastic.. but raise that voltage by a factor of 1000 and now you will heve all the joules to heat material in a pretty impressive manner! 

Doc


----------



## thanzlik (Apr 20, 2012)

So I tried a different method after the cutting disc gave me less than desired results for tab remnants. New method seems to work well, but takes a good amount of time. I may just take a couple cells from each of the smaller modules to get to my nom v closer to 144v. I really hate to lose some storage, but it'll take me a week to try to remove all of these.


----------



## dutchlincoln (May 6, 2012)

Hello Guys, i'm reading this with great interest, and i have a bit off-topic question.
I am really interested in a Chevy Volt battery pack as well, but i live overseas in europe and have no clue where to get one...
Can one of you help me a bit with this, maybe some contacts of a scrapyard that has these packs? I'd really appreciate it...

Thnx.


----------



## rmay635703 (Oct 23, 2008)

dutchlincoln said:


> Hello Guys,
> I am really interested in a Chevy Volt battery pack as well, but i live overseas in europe and have no clue where to get one...
> Maybe some contacts of a scrapyard that has these packs? I'd really appreciate it...
> 
> Thnx.


Given that the volt is mainly a US car... 

Carpart.com (batteries)
Copart.com (whole car)

Batteries or whole junk cars show up on the above sites, I cannot recommend sending them from the US overseas due to the risk and potential legal and cost issues, you will need to determine how you country handles things like this from legal, environmental and an economic (tax standpoint) before you jump on the first pack to show up on carpart.com

That said those are likely the only way you will find one besides ebay.

Good Luck
Ryan


----------



## dutchlincoln (May 6, 2012)

Hi, thanks for the quick reply.
We have some of them over here, but not that many ineed.
Over here they're mainly Opel Ampera (the same car, different logo/brand)

Just took a peek at Carparts.com, but that doesn't look like a scrapyard? (by the way: what a horrible website...)




rmay635703 said:


> Given that the volt is mainly a US car...
> 
> Carpart.com (batteries)
> Copart.com (whole car)
> ...


----------



## Yabert (Feb 7, 2010)

I'm highly interested to use the Volt BMS for my battery. I'm actually in position to create high voltage event and low voltage event to be able to discover which wire will give signal to stop charger or warn the driver.
But for this, as janzicek said, I need to supply 12v to the BMS: 


janzicek said:


> There are 3 circuit boards that sense the cell voltages and temperatures, these are the units that are wired to the battery modules with orange connectors / harnesses. On those circuit boards there are over voltage / under voltage comparators (inside the main ASICs) that flag the main controller of an OV/UV condition in case the primary measurement path is compromised. There is an optocoupler that triggers an actual wire (open collector design, main controller pulls up with a resistor to +5V or +12V, and each ASIC has an optocoupler that can pull the line down to 0V). I will look for my board pics and see if I can point them out in the next couple days. Keep in mind you will still need to supply the +12V to these boards when operating in order to wake them up from sleep mode.


Now, I've only been able to find the negative 12v. It's was not too difficult because I saw the control board was ground to the car and the color black of the wire has closed the debate (I hope!).
So, if someone here can help me to find the 12v+ with all the indications below, please let me know.
The grey-red wire seem logical, but ???


----------



## janzicek (Jul 27, 2013)

Good evening all, sorry for the delay. I have attached a ppt showing the VTSM (cell sensing circuitry from the volt pack). This is the low voltage section (black connector). If someone were to use the stock bms to detect over voltage and undervoltage you would use the pin I have labeled as OV/UV flag. this pin should float at 5V and if there is an issue it will be pulled to GND. For the VTSM to wake up and function, 5V must be applied at 5V and GND.

















If you are trying to use additional functionality of the BMS you will likely need to be able to decode the CAN communication.

Please let me know if you have questions,
Best Regards,
Josh


----------



## janzicek (Jul 27, 2013)

Good evening Yabert. 

What you have listed as GND is attached to the chassis GND of the vehicle, but it is only capacitively coupled to the wire harness 12V GND. 

The 12V gnd is properly identified in your picture, if fact there are 14 GND pins in that connector. 

The line that you have labeled as +12V??? is actually a +5V supply from the VITM (the board you have pictured) to the VTSMs.

This 5v supply powers the low voltage section of the VTSMs (CAN transceivers and wakeup). This is how you will need to wakeup the boards so the OV/UV flagging will work.









Cheers,
Josh



Yabert said:


> I'm highly interested to use the Volt BMS for my battery. I'm actually in position to create high voltage event and low voltage event to be able to discover which wire will give signal to stop charger or warn the driver.
> But for this, as janzicek said, I need to supply 12v to the BMS:
> 
> Now, I've only been able to find the negative 12v. It's was not too difficult because I saw the control board was ground to the car and the color black of the wire has closed the debate (I hope!).
> ...


----------



## Yabert (Feb 7, 2010)

Wow! Thanks a lot for those informations Josh.
I will be able to start some OV/UV testing this week.


----------



## Yabert (Feb 7, 2010)

I've performed a discharge test at 1/8C on a cells (3P) today. Result, over 47Ah.
The line at 40Ah is because I needed to restart test since my Icharger was set at 40Ah max capacity.

Despite that test, I wasn't able to find any OV or UV signal providing by one of the pin. I've connected 5v on the first pin and GND on the second of the VITM board.
I've charge to 4.22v and discharge to 3.2v, but no change on the few pins entering in the VITM. I didn't found any 5v floating...




janzicek said:


> Please let me know if you have questions,


Do you know the value of the OV/UV. The voltage when the signal is supposed to be there?
Do you know if the BMS actively balance the cells?
Do you know if this BMS only work if the battery is link in 96 series or if each module work independently (30s, 24s, 24s and 18s)?

Thanks


----------



## McRat (Jul 10, 2012)

1/8C isn't an important number.


----------



## Yabert (Feb 7, 2010)

McRat said:


> 1/8C isn't an important number.


Nice to see you like my contribution and my effort 
Help me debugging the BMS and I will test the cells at 10C in my Smart!


----------



## dutchlincoln (May 6, 2012)

Hi,

Now i bought a second Vectrix VX-2, i'm highly interested in a battery pack.
Is there anyone that will sell me 2pcs of 16S packs? (approx. 2x 2kw/h?)


----------



## Yabert (Feb 7, 2010)

I've not worked a lot with the BMS recently and I've not been able to find the OV/UV signal.
If any one can find an error in my procedure or help me that could be nice.

So, I've connect 5v at the two first pin of the VITM connector. Represented by the pins 1 and 2 on the VITM. After, I've searched a signal on the others pins of the VITM connector and directly on the VTSM boards.
From what I understand, it should have a floating 5v somewhere in the VITM connector and this one should disapear during OV/UV event. Right? How find it?

Also


Yabert said:


> Do you know the value of the OV/UV. The voltage when the signal is supposed to be there?
> Do you know if the BMS actively balance the cells?
> Do you know if this BMS only work if the battery is link in 96 series or if each module work independently (30s, 24s, 24s and 18s)?


Thanks


----------



## rmay635703 (Oct 23, 2008)

This dead in the water?

I am contemplating getting one, but in my case it would stay in the casing and be formed into a bumper 

Also would only do basic monitoring and observe top and bottom limits.


----------



## hmincr (Jan 20, 2012)

If anyone is interested in selling a 4KW part of a Volt Battery, I am interested. It would be shipped to Florida, 32967.

If not, I will be in the states in July, maybe, and searching for one. I would be interested in selling off a part of one.


----------



## chaseadam (Mar 20, 2014)

*Re: 2012 Chevy Volt Battery*

I just received a Chevy Volt battery and would like to know what the expected voltages are. Supposedly they are NMC lithium ion cells, so the chemistry indicates a 4.2 max voltage.

The pack is rated at 360V with 96 "cells" at 3.75V each (higher than normal NMC, but the battery label could be incorrect).

What would you recommend as the high and low side of voltage to keep me from killing this battery? I am currently charging to 4V and the lowest I have discharged is 3.5 (voltage when I received it)

Any ideas what voltages indicate certain capacities for a poor man's gas gauge?

I *may* have some extra cells left over if someone is interested in a few modules. They break down into 2kwh modules, but come in the following configurations: 2+2, 2+2+1, 2+2+(2+1). PM if interested.


----------



## chaseadam (Mar 20, 2014)

I also tested the 2+2 pack in my Lectric Leopard (96V) and "thrashed" the battery at ~160A and the voltage drop was ~1V. I am going to love this battery.


----------



## hmincr (Jan 20, 2012)

If it were me, I would run between 4.10 top voltage and 3.5 bottom voltage. 

Anything above or below, you are getting to the edge of ruining the battery cells.

Sent you a PM.


----------



## piotrsko (Dec 9, 2007)

Just bought one out of LA for $ 2300 delivered. Wrecker yards are afraid of these because of all the hype. We'll see what shows up. Wrecker yards pretty much deal with dealers and other yards not general public. Cost me 200 more for the privilege.

I can buy all the Ford Escape modules I might ever need for less than $ 750 each 
But couldn't get chemistry, capacities or voltages quick online. Needs more research.

GMOnline says "oops, sorry, we can't sell you these, here's your money back."


----------



## piotrsko (Dec 9, 2007)

FWIW Ford Escape: 330 v 5.5 ah. NIMH. rated,@1.8 kWh. $0.41 w/h @$750 a pack. 27¢ @500. 100 lbs ish. Tempting............. no lipo balance hassle, run them till they die. Couldn't get a C Rate. SFO transit says they are bomb proof


----------



## Yabert (Feb 7, 2010)

More informations for peoples who can try to help me and others guys with Volt BMS.
Other good info and questions post 162 to 170.


----------



## piotrsko (Dec 9, 2007)

You can't test it without taking it apart. Saw 352 volts. 

You all didn't notice the hall effect current sensor between #1 & #2 packs? Lem model DHAB S/44 (+/- 600 Dc amps)

Thinking the remote bms boards might work stand-alone. Items # 2,3,5 in Yaberts post


----------



## Elanimal28 (Nov 18, 2013)

Yabert said:


> Help me debugging the BMS and I will test the cells at 10C in my Smart!


I don't know if this helps but I found it interesting. at the 7:28 min mark he shows the bms board and describes it.

https://www.youtube.com/watch?v=0c01VgkT4UM


----------



## hmincr (Jan 20, 2012)

Went halves with another guy and we are about to get it shipped to him, and he will ship me 8KW. Should have mine in a month or so, depending.


----------



## green_EV 2000 (May 2, 2014)

3.8v, should it is NMC ,no LFP


----------



## 2Slow4u (Apr 26, 2012)

Its up to you how much of the SOC window you want to use... But I would highly recommend CC-CV charging to 4.08V max per cell and never going below 2.7V/Cell under load except for cold temperatures, then you can drop down to 2.1V/Cell when temps are sub 0'C.

Keep the cells below 45'C and they should be nice and happy. Below 35'C and they will last even longer.

Be careful, watch for coolant leaks, monitor isolation, and play it safe.


----------



## MitchJi (Dec 14, 2007)

Hi,


McRat said:


> Well, the right tools, you can take out the cells "as welded" in 3P 1S.
> 
> It actually easier than taking out the individual cells and safer.
> 
> ...


I think you could remove the entire "1S-3P blade" if you removed the bottom of the "U-shaped tabs"?

I think you could do that with an abrasive blade on a radial arm saw, or maybe on a Sliding Miter Saw . I would cover the entire top of the subpack with a piece of wood with a slot just wide enough to expose the bottom of the "U".

It might be best to use a saw with a shop vacuum attached to minimize the metal filings, although the piece of wood might provide sufficient protection.


----------



## MitchJi (Dec 14, 2007)

HI,

Some thoughts on the BMS:

When charging/discharging are the cell level HVC and LVC controlled by the BMS hardware or controlled by the CANBUS software? It seems likely to me that this is controlled by the BMS, which means if you can live with the reduced capacity you can probably make it work.

When you divide the modules to meet your requirements can you keep all the cells with their BMS chips? If not it's probably not useable? 

But otherwise you could charge the pack (if necessary while supplying 5v or 12v to the BMS chips?) after charging one parallel group a little high and monitor the cell voltages. Does the OEM BMS keep it in range (it should)? Why would the CANBUS be necessary?

Discharge is more likely to involve the CAN bus, but you could discharge the pack after discharging one parallel group a little low and see if it cuts the power before the group gets low enough to damage the group. If it does not you could try the same thing, while monitoring the bus. It should be relatively easy to figure out.


----------



## piotrsko (Dec 9, 2007)

There is a requirement to have five volts regulated on the BMS power strip. Grey w red tracer, don't see a return. (Case ground???). Some people say that the bms are battery-powered, some people say that the five volts is a reference voltage and not bms power. I think it's both. if you get the reference voltage up to 5.25 then I would think that the cell monitoring BMS voltages would adjust accordingly upwards. Not a lot of technical data available on the internal battery systems. Not much data regarding anything electronic on this car on the net. Lear is REALLY good keeping stuff proprietary. I do know that if you leave everything intact with 0 mods, and original harness, the battery manager module should do its bms thing on its own for hvc, temp, mains disconnect in the event of ecm failure.


----------



## halestorm (Apr 28, 2009)

Yabert said:


> More informations for peoples who can try to help me and others guys with Volt BMS.


where did you get these prints (in post 178)?


----------



## halestorm (Apr 28, 2009)

Has anyone connected these in parallel AT THE TABS? If I connect the modules in parallel using the studs then what I get is a series-parallel combination. I think it'd be better to parallel each cell, but I'm not sure how to make a good high current solid contact to the tabs between modules.


----------



## bigmouse (Sep 28, 2008)

A very interesting thread! I'm wanting to pick up a Volt battery as well, but I'm worried about getting a dead one. Has everyone who bought one from a wrecker had good voltage upon delivery? Did you have any indication of how long they had been at the yard, or how much charge was in them when the car arrived?

After being disconnected, will these discharge themselves to destruction from sitting over the course of several (6-8) months?

Also, I've been trying to find information on the front module with the relays in it. I managed to find a block diagram of that part, which seemed to suggest that the relays were powered externally to the battery. Can anyone confirm this? I'd like to know if it's possible to energize the relays by applying 12v from a small battery to pins on one of the battery front connectors to be able to read the pack voltage from the main DC connector. This would allow me to check the voltage on a pack before buying it, assuming they're not willing to let me take it apart in their yard. The place I'm talking to isn't even sure I'd be allowed in the yard to visually inspect.

I'm an electrical engineer in the field of EVs, so once I get ahold of one of these, I feel like I could do a lot to get it working in different applications. I'd be putting them in a BMW and hopefully using the OEM BMS.

If anyone on here has a Volt battery in the SF bay area, I'd be interested to look it over with you!


----------



## rwaudio (May 22, 2008)

bigmouse said:


> A very interesting thread! I'm wanting to pick up a Volt battery as well, but I'm worried about getting a dead one. Has everyone who bought one from a wrecker had good voltage upon delivery? Did you have any indication of how long they had been at the yard, or how much charge was in them when the car arrived?
> 
> After being disconnected, will these discharge themselves to destruction from sitting over the course of several (6-8) months?
> 
> ...


I have a volt battery, after taking everything apart I have my doubts on being able to activate the contactors with 12v, the control will be external, but I'd put money on it being on a CAN bus.


----------



## piotrsko (Dec 9, 2007)

All the relays and what not are powered by the 12v bus, control and reference is "regulated" 5 vdc. Some of the components like the heaters are battery voltage, those are rare and Orange colored. Powered off, they go inert, so maybe a couple of years storage before internal resistance kills them. They don't stay long enough in the yards to worry about discharge, physical damage would seem to be the problem. I would say if they hold coolant they are good. Condition would be a factor of how far they were run down immediately before the accident, but once again, Chevy seems to have that handled well. Chevy also guaranteed then for like the length of financing, so perhaps 2000 charge cycles before MTBF?

Yes the bloody things are CAN controlled, and I believe the BMS to be useless to a DIY builder because I squeeze 2 kWh more into my pack (5+ miles range).

My $0.02 YMMV


----------



## eldis (Sep 3, 2013)

It might be interesting to get our hands on the CAN bus traffic log (especially the ignition start + few seconds). Then we could replay parts of the stream to the battery and see what happens  It would certainly help with some of the reverse engineering works (just like getting the wiring diagram somewhere..)

Do you guys know anyone with a (working) Volt to capture such data?

I agree with the opinion that the internal BMS system is rubbish for us - since there is no datasheet available for the LG chem battery analog frontend, we can forget about trying to reprogram the MCU on these modules with a custom firmware.


----------



## bigmouse (Sep 28, 2008)

eldis said:


> I agree with the opinion that the internal BMS system is rubbish for us - since there is no datasheet available for the LG chem battery analog frontend, we can forget about trying to reprogram the MCU on these modules with a custom firmware.


It's very likely that the modules are only monitoring. They wouldn't require any reprogramming, just a new "main" board to read the voltages and temperatures, and command the bypasses on and off as appropriate.


----------



## eldis (Sep 3, 2013)

bigmouse said:


> It's very likely that the modules are only monitoring. They wouldn't require any reprogramming, just a new "main" board to read the voltages and temperatures, and command the bypasses on and off as appropriate.


Yes, that would be the case if there would be only the LG Chem analog frontend. It is most likely SPI based, just like bq76PL536 that Tesla is using. If I recall correctly, on every Chevy BMS board there is an MCU reading out and configuring this frontend. After that you have a CAN interface (plus few safety OVL UVL flags). If you don't replace this MCU, I would expect that you cannot get more capacity, even if you would reverse-engineer every CAN packet. Balancing is usually done on this low level, you don't want some high level module on the other side of the car to make these decisions.

My Chevy pack will arrive in few days, so then I'll do some investigation about our options. The best solution IMHO is to make BMS boards compatible with built-in connectors. I have a Tesla-like prototype of such BMS system.


----------



## piotrsko (Dec 9, 2007)

From what I have seen and heard, the modules are hardwired to shutdown charge by bypassing. If someone could get the modules to run in stand-alone mode you might be able to fiddle with the endpoint by increasing the 5 v reference, but that is SWAG by me. Might not even be a reference, but system power. Chevy does refer to 5v as reference on their pinouts, and it is a rather thin wire.


I was hoping by now someone would have figured this out, but the Volt forums don't mention hot prodding the pack this way. They seem to be annoyed by pack discharge problems of some.


----------



## eldis (Sep 3, 2013)

piotrsko said:


> Chevy does refer to 5v as reference on their pinouts, and it is a rather thin wire


There is most likely an internal zener diode reference for ADCs (unless you are referring to comparators somewhere), so even if you would manage to move max voltage, you would also move the min 
I'm not sure how OVL UVL flags work here (I don't have my modules yet), but most likely they are stored in SPI registers of LG Chem chip, readout by a micro and then outputed from micro pins. Usually in the SPI map there is a register that sets up these hard max min values at which you get these flags (my experience with similar chips).

I'm going to take one of the modules out, make a test rig with my own old super crappy salvaged notebook cells and see how the board reacts to those - misbalance, under,over voltage etc. I do not want to mess with my Volt pack and to bring it deliberately out of balance


----------



## piotrsko (Dec 9, 2007)

At this point, upping the reference for OVL is ok because I don't use the contactors and the data would only go to a status device. During run it would be a simple circuit to readjust the reference back to 5 for UVL. I had thought Chevy was using a comparator circuit, but might be wrong.

Fwiw: seems really hard to imbalance a used pack. I've got 6 months, 2500 miles, perhaps 100 cycles and recently worst cell was .01 volt less than highest.


----------



## eldis (Sep 3, 2013)

piotrsko said:


> I had thought Chevy was using a comparator circuit, but might be wrong.


Maybe they do - I don't want to speculate too much at this point. I'll try to post my findings when I reverse engineer the layout. My 2013 pack will be here soon ^^ It was a pain to get it to Europe


----------



## aeroscott (Jan 5, 2008)

eldis said:


> There is most likely an internal zener diode reference for ADCs (unless you are referring to comparators somewhere), so even if you would manage to move max voltage, you would also move the min
> I'm not sure how OVL UVL flags work here (I don't have my modules yet), but most likely they are stored in SPI registers of LG Chem chip, readout by a micro and then outputed from micro pins. Usually in the SPI map there is a register that sets up these hard max min values at which you get these flags (my experience with similar chips).
> 
> I'm going to take one of the modules out, make a test rig with my own old super crappy salvaged notebook cells and see how the board reacts to those - misbalance, under,over voltage etc. I do not want to mess with my Volt pack and to bring it deliberately out of balance


 Small loss on the low side moving higher(volt cutoff) and big gain on the high side going higher.


----------



## eldis (Sep 3, 2013)

Do we have a pinout/ cable description for the battery entry module?
I started to reverse-engineer this block on the board level, so it would make my job much easier.


----------



## dotrick (Sep 4, 2014)

Hello,

I want to use this battery too... I need some help too...

I want to read CAN bus ( I already have a Arduino kit) to know the voltage of each cell and use the electronic board with contactors and relays...

You can find enclosed the schematic of the contactors and relays of the 2013 Chevy Volt Battery.
























I have to understand the other electronic board between this board and the main CPU board...


----------



## dotrick (Sep 4, 2014)

Any information about signals/Pinouts for CN1 and CN2


----------



## eldis (Sep 3, 2013)

Bonjour dotrick, thanks!
I already did the same thing myself two days ago, and reverse-engineered insides on the relay module on the board level.

For the external connectors, I think you will find the attached document very interesting.

PS: when I get home I can post the complete service manual for Chevy Volt / Opel Ampera (8110 pages, large size..). I'm pretty sure that most people here working with this battery already have it, although I'm not quite sure why they don't want to talk about it. (few pages back you can find a post from a guy making similar screenshot from the same document).


----------



## bigmouse (Sep 28, 2008)

eldis said:


> For the external connectors, I think you will find the attached document very interesting.


That's exactly what I think many of us were looking for! It looks like the contactor coils (or at least control for them) is brought out discretely on those connectors. It should be possible to close contactors without CAN and without opening the battery. This could be handy for those who want to verify voltage before purchasing (assuming we have access to the pack at the yard).



eldis said:


> PS: when I get home I can post the complete service manual for Chevy Volt / Opel Ampera (8110 pages, large size..). I'm pretty sure that most people here working with this battery already have it, although I'm not quite sure why they don't want to talk about it. (few pages back you can find a post from a guy making similar screenshot from the same document).


Personally, I didn't know this was available. It would certainly be handy to have. Thanks!


----------



## eldis (Sep 3, 2013)

bigmouse said:


> It looks like the contactor coils (or at least control for them) is brought out discretely on those connectors. It should be possible to close contactors without CAN and without opening the battery.


Yes, you are right. Yesterday I tried all of them and it works nicely. Beware of precharge circuit - there is a relay but after you also have to control the signal marked like precharge PWM or something. In theory you can just open that transistor and no need to ramp it up. I'm not quite sure why Chevy thought it is necessary to have a double stage precharge control.. Also the PWM might not like 12V - this is the only part of the circuit I didn't test yet. Most likely 5V would turn the mosfet on. 

In case you are not interested in this PWM functionality, it's just a matter of soldering a bridge over that transistor to have it always conductive (and control just a relay). I can post later on which one and where to do that if people are interested.


----------



## rwaudio (May 22, 2008)

For scrap yard testing (battery out of vehicle and disconnected) there is no need to precharge. There is no load (IE controller capacitors) on the battery and if the main contactor coils are available, just turn them on.


----------



## eldis (Sep 3, 2013)

rwaudio said:


> For scrap yard testing (battery out of vehicle and disconnected) there is no need to precharge. There is no load (IE controller capacitors) on the battery and if the main contactor coils are available, just turn them on.


Agreed. I was talking about how to use it in the car - if you are lucky enough (don't have to ship this battery pack across the globe as I did), it is very easy to turn on the whole pack with just two wires (three pins) hooked up to a car battery and inserted into X1 connector.


----------



## rwaudio (May 22, 2008)

eldis said:


> Agreed. I was talking about how to use it in the car - if you are lucky enough (don't have to ship this battery pack across the globe as I did), it is very easy to turn on the whole pack with just two wires (three pins) hooked up to a car battery and inserted into X1 connector.


Very nice! I'm also interested in that document, do they talk about the BMS and it's wiring?


----------



## eldis (Sep 3, 2013)

Here you have it guys - the full manual. It is practically impossible to navigate through it, but it works and contains everything. If anyone can provide some stable place for this file, feel free to post a new link:
http://fso.kvalitne.cz/Service_Manual.pdf


----------



## dotrick (Sep 4, 2014)

Yeeeeeeesssssssss! !!!!!!!!!!

Thank you so much!


----------



## bigmouse (Sep 28, 2008)

eldis said:


> Here you have it guys - the full manual. It is practically impossible to navigate through it, but it works and contains everything. If anyone can provide some stable place for this file, feel free to post a new link:
> http://fso.kvalitne.cz/Service_Manual.pdf



Awesome! Thanks


----------



## EVisa (Jun 30, 2014)

Has anyone used the panasonic aev14012 contactors (found at the front of the Volt battery pack) in their conversions? Do these contactors work with a Curtis 1238 controller? I'm using 4 96V modules in parallel.

The manual says that the coils are 12V (120A nominal, 225A 3min, 400A 30 sec.).
http://www.alldatasheet.com/datasheet-pdf/pdf/534545/PANASONIC/AEV14012.html

I am about to buy a different contactor (24V), while I have these two beauties sitting on the shelf.


----------



## aeroscott (Jan 5, 2008)

Hydrogen gas must help cool the arc.


----------



## EVisa (Jun 30, 2014)

So we need to be careful not to drill any accidental holes through them then (which shouldn't happen anyway off course ).


----------



## bigmouse (Sep 28, 2008)

eldis said:


> Yes, you are right. Yesterday I tried all of them and it works nicely. Beware of precharge circuit - there is a relay but after you also have to control the signal marked like precharge PWM or something. In theory you can just open that transistor and no need to ramp it up. I'm not quite sure why Chevy thought it is necessary to have a double stage precharge control.. Also the PWM might not like 12V - this is the only part of the circuit I didn't test yet. Most likely 5V would turn the mosfet on.
> 
> In case you are not interested in this PWM functionality, it's just a matter of soldering a bridge over that transistor to have it always conductive (and control just a relay). I can post later on which one and where to do that if people are interested.


The document attached earlier with the pinouts of X1 and X2, there are three contactors (relays) listed. Pin 4 is labelled "High-Voltage Battery (-) Relay Control". Pins 2 and 6 are "High-Voltage Battery 1 and 2 (+) Relay Control". Pins 7 and 9 are similarly listed for "High-Voltage Battery 3 (+ and -) Relay Control". Which of these terminals need to be powered to close the contactors so that pack voltage can be measured at the HV connection?

My assumption is that Pin 4 is a commong ground for contactors 1 and 2, and that 3 is the precharge relay. Can someone confirm/correct this for me?

I'm expecting my battery to arrive in the next few days and would like to be able to test the pack voltage quickly before accepting delivery.


----------



## piotrsko (Dec 9, 2007)

My experience was: without disassembly there is no fast accurate way to test voltage unless you made a harness. If the pack is newer, and the vehicle was running, chances are the battery is above 245 volts as long as the battery has not sat for a long while. You can power the all the relays, but if the Orange fuse plug disable device is missing or blown, it is still an open circuit string, so two measurements will need to be made. And the connectors are a joy to probe. Hope they hacksawed it out leaving you wire stubs.

My wrecker was cool in that he gave me a 10 day exchange window.

Chevy put a lot of thought into these and many common possible scenarios. My rule of thumb is: as long as they don't leak coolant, they should be good.

My $0.02 YMMV


----------



## hmincr (Jan 20, 2012)

PIOTRSKO, Is there ANY more info you could offer, on how to check a Volt battery for acceptable voltage ?? I have a lead on one for Monday, but, the guy has NO idea of what the voltage might be. It has been out of the wrecked car for 4 months, but, no way to see what the capacity-voltage is before removal. 

I have been all over the 'net watching videos, searching for ANY info, but, you are the closest one to being able to help, with your "Tricky" connection probing comment. 

Thanks, Harold


----------



## piotrsko (Dec 9, 2007)

That is the gutsy thing about VOLT batteries. You either disassemble or have some way to power up the relays. Like I said earlier, if they don't look damaged enough to leak, they are probably ok. I would think shelf life is at least 6 months. I don't know this deal's specs, but less than $2 grand sitting on your floor for a full complete pack with both coolant pipes and hacksawed harnesses stubs is going to be a fair deal. I didn't need 380-400 volts, so anything more than 1/2 pack was acceptable for me. If it has been sitting for 4 months, the owner is in a pickle and can't dump it anywhere. Negotiate accordingly as they can be bought everywhere for $2500, even (yes, I looked) AUTOZONE. 

If you have a really high input impedance DVM, you can get a voltage across the Orange disarm fuse big contacts that is +/- 20% of pack value for a second or so as some of the internals discharge. Be quick here because you have a second or two only and it takes a long while to recharge(?). My crude guesstimate was you want to see more than 276. Mine was 312 for a pack that was disassembled to read 380. (BTW another negotiation point: they are SUPPOSED TO BE 388[ ha ha ha]) And no I don't remember which one was positive. 

Look at it another way: 2500 is 14 cents a WH. you can't even buy used FLA for that price.


----------



## hmincr (Jan 20, 2012)

OK, Thanks, Piotrsko. I had found one earlier, in Michigan, that has sat for nearly 10 months, on the ground, in an unheated shed, going through part of the winter. Guy would not even TRY to help with voltages, shipping, opening the cover, ( I would to make the sale). NOTHING. 

Would not negotiate. I was REALLY afraid of that one, being winter is hard on these batteries. 

My take is Lead could be checked to make sure Voltage is up. These can't be checked easily, and, I'm not flush with cash, so, need to do all I can to make the best of a buy. 

Appreciate the extra info. 

Harold


----------



## eldis (Sep 3, 2013)

hmincr said:


> Would not negotiate. I was REALLY afraid of that one, being winter is hard on these batteries.
> 
> Harold


Don't be so worried about it. I got mine from some small scrapyard on the other side of the world (that's USA for me), so including all the shipping and everything, it's a lot of risk. But hey, battery arrived fine, all cells within 0.01V.


----------



## Duncan (Dec 8, 2008)

eldis said:


> Don't be so worried about it. I got mine from some small scrapyard on the other side of the world (that's USA for me), so including all the shipping and everything, it's a lot of risk. But hey, battery arrived fine, all cells within 0.01V.


Hi Eldis
I am on the other other side of the world
How much did your pack cost? - Shipping cost?
And where did you get it?


----------



## eldis (Sep 3, 2013)

Duncan said:


> Hi Eldis
> I am on the other other side of the world
> How much did your pack cost? - Shipping cost?
> And where did you get it?


Got the 2013 model for $1500. I also bought the inverter + HV charger, as I intend to use them in my next car (current one runs on Prius inverter and completely custom electronics). In total I payed $2100 for everything - battery, inverter, HV charger and all the cables associated with these modules. Then shipping/handling was $1000 to Switzerland (get ready to arrange everything yourself, they will not do it for you). Origin somewhere in Georgia, can't remember.. some local scrapyard.

PS: Don't take other parts than the battery unless you really want to dive deep. Everything is CAN based.


----------



## boekel (Nov 10, 2010)

I'm offered an almost new battery here in the Netherlands, car (Opel Ampera) has only 1600 km's on it, fire damage, battery unharmed.

Only they ask 3250 euro's for it  ($3850)

What would be a fair price for a 'fresh' battery pack like this?


----------



## z_power (Dec 17, 2011)

It's a buyer's market, especially in Europe where you can't legally convert car in half of countries... I'd propose 1/3 of value of same capacity of new LiFePo4 to balance lower cycle life, lack of warranty and risk of some or all cells being DOA.


----------



## EVisa (Jun 30, 2014)

Hi, I think I recognize the battery you are talking about. If i'm right that we are talking about the same car (light-grey, right-rear fire damage, similar mileage/asking price), I will admit I was somehow spooked by the fact that a) the right-rear tyre melted, and b) these batteries don't like the heat. 

I got mine at a much better price, although I was tempted towards this one as well (at first), again assuming we're talking about the same car.

The scrapyard has some pictures on its website. Post them here. Some more experienced people might offer you more detailed advice. 

Keep us posted


----------



## boekel (Nov 10, 2010)

EVisa said:


> Hi, I think I recognize the battery you are talking about. If i'm right that we are talking about the same car (light-grey, right-rear fire damage, similar mileage/asking price), I will admit I was somehow spooked by the fact that a) the right-rear tyre melted, and b) these batteries don't like the heat.
> 
> I got mine at a much better price, although I was tempted towards this one as well (at first), again assuming we're talking about the same car.
> 
> ...


Thanks!!

It's a gray / silver car, license plate: 5-KBF-47
No pictures on their website.

I'll offer 1500 if it's not sitting for to long and no apperent heat damage...
The car is only 40 km away from here so I might take a look if the price comes down.


----------



## hmincr (Jan 20, 2012)

Had my Son call about 1 yesterday. Been advertized for 3 months. Price FIRM, $2500.00 + shipping, IF they would ship it. Son offered $1500.00 and the guy nearly blew his mind. Son simply stated, call me next month at my price, because after 4 months with NO maintenance, it's a crap shoot whether it even HAS voltage.  Without a way to test for voltage, one has no idea if the battery is sitting at 20% capacity left or not. I can't afford to take that chance, at that price.


----------



## whiteggs (May 21, 2010)

I'm looking to using only 21 cells. From the link below, the seller mentions 12 cells for a 2Kwh pack which is incorrect. Isn't it supposedly 36 cells?

http://hybridautocenter.com/HAC4/in...k-chevrolet-volt-45v-45ah-12-cells&Itemid=605

BTW, Does anyone have individual cells to sell?


----------



## chaseadam (Mar 20, 2014)

There are 12 cell groups (3 cells per group) in a 2kwh pack. I would not recommend breaking a cell group apart as the tabs are spot welded or pressed together at the tab at the top of the pouch.


----------



## dj10703 (Mar 31, 2014)

So what after market bms are you using?


----------



## halestorm (Apr 28, 2009)

I just ordered an Elithion Pro


----------



## bigmouse (Sep 28, 2008)

A quick note for all those buying aftermarket BMS for their Volt batteries: I'm developing a plug-in module that will work with the OEM BMS that comes already installed on these packs.

I have two of these batteries for my own project and I've managed to crack the CAN for the OEM BMS boards. I can read the individual cell voltages and the temperature sensors over CAN. The only part of the CAN decoding left for me to do is figure out how to command the cell-level bypass for balancing. I've got a start on that (can turn bypass on for one cell) and am figuring out the rest of it now.

What I'm making replaces the BMS box at the front of the battery and just plugs in to the existing harness. At the moment I'm using a CAN dongle and PCAN Explorer on a laptop to monitor the pack and control the bypass. Once I get the CAN DBC finalized, I'll be designing a board which will plug in to the string to allow full BMS functionality. This will also use the original current sensor for state-of-charge tracking.

Before I start designing the PCB, I wanted to post here and ask those who are using these batteries (or who intend to) what sort of interface/features you want on the car-side of the BMS? For my own application, I'm planning on having a J1772 interface for public EVSEs, CAN control of the Elcon/TCCH chargers, an RGB LED charge indicator (for display of status while charging), and CAN to the rest of the car (to communicate with my inverter and instrument cluster). It wouldn't be too difficult to put drivers for controlling contactors on there too.

Anything additional to what I listed that you lot would want to see on such a plug-in module? Since this uses the BMS boards that come with the pack, it should cost significantly less than a complete aftermarket BMS. I'm hoping to have this wrapped up in the next 6 months or so.


----------



## esoneson (Sep 1, 2008)

bigmouse,

Do you happen to have the request/response CAN message formats for getting the pack voltage? It sure would be helpful in my volt battery setup. I don't have a need for BMS but do use CAN messages to start/stop my Volt charger. Can (pun intended) you help me out with this? Or will you make your CAN messages available to the open source Volt efforts?

Thanks,

Eric
1995 BMW 318i, Warp 9, volt battery & charger


----------



## bigmouse (Sep 28, 2008)

I believe the pack voltage is calculated in the OEM BMS box at the front of the battery. The individual modules on the cells only report cell voltages. Pack voltage could be calculated from the sum of those.

There are two CAN busses associated with the battery. The internal bus connects the main BMS box to the BMS cell monitoring and bypass boards. The external bus connects the main BMS box to the rest of the car. The two busses run at different bit rates and aren't "passed through". I'm only dealing with the internal bus.

I'm not sure yet whether I'll post the CAN messages for the internal bus.


----------



## EVisa (Jun 30, 2014)

Respect Bigmouse! Keep up the good work.


----------



## Ai! (May 9, 2014)

I wish someone could hack the Leaf CAN(((


----------



## piotrsko (Dec 9, 2007)

Are you going to be able to modify base operating voltages? I'm running at 400v and don't care to reduce cell charge levels.

What I need: accurate coulomb counting in and out, dead or low cell warnings, auto shut off as close to 4.15 v per cell as I can get, pack shut down at 240 sitting, pack warning at 175 under full load.


----------



## eldis (Sep 3, 2013)

esoneson said:


> Do you happen to have the request/response CAN message formats for getting the pack voltage? It sure would be helpful in my volt battery setup. I don't have a need for BMS but do use CAN messages to start/stop my Volt charger. Can (pun intended) you help me out with this? Or will you make your CAN messages available to the open source Volt efforts?
> 
> Thanks,
> 
> ...


Hi Eric, I've also done some experiments with Chevy Volt BMS - I believe that the front module actually gives you the real voltage of the pack (as summing up individual cells would not be that accurate). That's the purpose of that HV connector on this module (among other things, like checking the precharge sequence).

If there is some interest in the readout of original CAN BMS, and there will be no one else to make this information public, maybe I can release it once there is some time to finish the decoding - I have some captures and the protocol seems to be simple enough. I didn't pursue this idea of re-using the original BMS, as it is crap (no offense to GM engineers, this was done by LG corporation). But yeah, if someone wants to keep this system for the sake of pure readout of voltages and current, it is possible.


----------



## esoneson (Sep 1, 2008)

Eldis,

Thank you for your contributions to the Volt parts deciphering effort.
I built an isolated voltage reader for my pack. Very simple. I am taking the Volt pack and re-configuring it to half the voltage and double the Ah, so basically 200Volts, 90Ah. I can calibrate the pack voltage to the nearest .2 volts which should work fine, but I would really like to see if I could use the pack module and CAN messaging to confirm. It would also be very useful to see other info from that module like amps being pulled at any point in time. If I have enough room I will add additional 200Volt, 45Ah increments in series as money, time and room allow. 

I know that the Volt charger will allow you to configure the pack voltage from 200-416(?) volts. So I am assuming that there may be limits for the data available from the Battery Module. Having the CAN message formats may give some indication to those limits.

Thanks for you help, it is much appreciated.

Eric


----------



## eldis (Sep 3, 2013)

Chevy Volt charger works very nicely between 200-400V - you just command a current and voltage over CAN, and it will terminate the charge on your requested voltage. So if you aim to a safe number, no damage will be done to your pack  Plus the Volt charger tops up your 12V battery as well (only when the AC power is present).

How to control this charger over CAN is nicely described on evtv.com forum. I managed to charge my 200V Prius battery and 12V lead at the same time, with minimum effort.


----------



## Markijohn (Feb 7, 2014)

Isn't the main BMS controller, located outside the pack? 

If everyone is going to be hush-hush about their reverse engineering of the pack, I would be willing to start this effort and be open with my findings. But I only have the battery pack, and most of the front part of the pack was damaged due to the severe front end damage of the car it was pulled from.


----------



## Vanquizor (Nov 17, 2009)

I'd be willing to toss somebody the front end off my pack and/or a reasonable sum of cash for a simple method of displaying the highest and lowest voltage in the pack, and tripping a relay when these pass a specified value.

I'm not looking forward to pulling a pile of taps out to a bank of celllog 8's on my dash...


----------



## piotrsko (Dec 9, 2007)

Fast way to do that is with something like a light objects 404 style smart meter. Or at least that is how I do it. Controller monitors current, start and stop voltages are done in the 404.

All these offers of CAN communication feel like vapourware.


----------



## Vanquizor (Nov 17, 2009)

I was under the impression that the 404 was just pack level monitoring- can it actually do cell level?


----------



## eldis (Sep 3, 2013)

piotrsko said:


> All these offers of CAN communication feel like vapourware.


As I said few posts ago, the CAN protocol does not look very difficult. If someone would actually want to crack it, it would be done by now - just like the Chevy charger and DC/DC module. Just plug your favourite CAN sniffer to the battery and experiment. This is actually a bit easier, as the module spits the data on it's own - most likely you would not have to send anything back to get cell voltages (might be a different story for battery pack voltage and current).

As we (couple of colleagues and I) didn't like the Chevy BMS at all, plus it being completely proprietary, we are making our own BMS system pin to pin compatible with the Chevy Volt original BMS modules. The system is semi-distributed, with up to 12 cells per board, all board interconnected with a current-mode bus. The master (spitting out the data on CAN and controlling Chevy relays/precharge) is a simple board with TI Launchpad on top (basically a better arduino). Of course this does balancing and Ah counting as well.

We will eventually put this out as an open source - maybe a colleague of mine will be willing to sell a few tested units. But you know how it is with the DIY crowd - if something costs more than a bare-bone sum of components on the board, people will claim it is too expensive. That's why I told him not to get his hopes too high about actually getting his development time even payed.


----------



## Markijohn (Feb 7, 2014)

eldis said:


> As we (couple of colleagues and I) didn't like the Chevy BMS at all,


What is wrong w/ the Chevy BMS? - Just curious to what you see as the downfalls.



eldis said:


> We will eventually put this out as an open source - maybe a colleague of mine will be willing to sell a few tested units. But you know how it is with the DIY crowd - if something costs more than a bare-bone sum of components on the board, people will claim it is too expensive. That's why I told him not to get his hopes too high about actually getting his development time even payed.


I'd be interested in purchasing some boards if I don't pursue the reverse engineering of the OEM setup. I'd love to help in the alpha/beta testing if possible. What kind of reasonable time line would you be looking at before boards were made?


----------



## eldis (Sep 3, 2013)

Markijohn said:


> What is wrong w/ the Chevy BMS? - Just curious to what you see as the downfalls.
> 
> I'd be interested in purchasing some boards if I don't pursue the reverse engineering of the OEM setup. I'd love to help in the alpha/beta testing if possible. What kind of reasonable time line would you be looking at before boards were made?


Thanks for your interest, Markijohn. The Volt BMS is designed around a custom chip made by LG Chem (supposedly manufactured by ST). LG Chem, being an Asian company, does what they do the best - there is no datasheet, no documentation, specs sheet.. I guess that the original idea was to create a cheaper copy of BQ76PL536A from Texas Instruments (that's the chip our BMS and Tesla is using). LG seems to fail a bit when it comes to stackability of modules (basically overcoming the voltage difference between modules) - that's why there has to be 2-3 (depending on the module) microcontrollers on every board.

I would expect that these modules are hard-coded to use the pack very conservatively - using much smaller portion of capacity than is available. This is perfectly fine for a plug-in hybrid, as cycle life is the main concern. Most people in the DIY will probably prefer getting more range and let's say only 5 years of the pack life. By then much better cells will most likely be available for cheap, increasing the range even further. 

The PCB version 2 of our board is nearly finished, then we have to manufacture it, and the rest is in the firmware - where we only have a barebone (but working) prototype. The firmware is updated by USB anyway, so not much trouble there. Realistically it is less then two months to ship something of that. I'll have to ask my colleague about it.

The module I'm actually designing and putting into 2nd round of production soon is a bit more challenging (and fun) - it is an universal motor controller, natively compatible with Toyota Prius and Chevy Volt inverters. It replaces the main DSP unit inside, and talks directly to drivers and IGBTs. I'm quite excited about this, and the prototype of this system works nicely in my EV. Once the new version is in production, I will write more about it.

So just some teasing for now (I love that term vapourware used by piotrsko!):
- Natively supports Chevy Volt and Toyota Prius 2nd gen inverters, new ones can be easily added later
- can run two FOC cores in paralel - we are talking dual AC motor support
- Motors do not have to be identical, separate torque control
- New motors can be learned automatically (without me actually owning your motor..)


----------



## stevefed (Feb 23, 2015)

Hey Folks,

Just joining in to the conversation. Working on my own project, a Porsche 914 that was previously set up to run lead-acid from one of the Electro Automotive kits many years ago. After reading through most of this (it is 25 pages!) started looking on-line and found a few Volt packs about 400 miles away, and a friend with a truck and trailer willing to make the trip with me to get one. There are two offered with modules and one that is just the battery pack. It sounds like there's a lot of distaste for the BMS that comes with the Volt. Would it be in my best interest to try to just buy the battery pack without the modules? Please understand I know practically nothing and am much more comfortable attaching the transmission to the motor than ripping apart the battery pack, putting together strings of 120v and setting up a BMS (getting my 1,000 volt gloves first thing).

Any advice, encouragement or words of caution greatly appreciated!


----------



## bigmouse (Sep 28, 2008)

eldis said:


> I would expect that these modules are hard-coded to use the pack very conservatively - using much smaller portion of capacity than is available.


The modules on the Volt are used only for voltage and temperature monitoring, and for switching the resistive balancing on when commanded by the main box at the front of the battery. They won't do anything they're not told to do over CAN. They don't "use" the pack in any particular way. That's all up to the programming of the "master".

The way I see it, the cell monitoring is already there and robust (OEM quality with all the engineering resources and validation behind it). All that is needed is something that can speak CAN to monitor the voltages, temperatures, and current sensor (ADC). The amount of the pack you use is up to your own programming. The interface with the cell modules doesn't need to be anything more than 4 wires (5 if you're using the fault line).

The biggest mark against the OEM BMS modules for DIY use is the very low bypass current, but they aren't meant to balance on every charge anyway. Just balance gradually, spanning several charge cycles, and only as needed.


----------



## halestorm (Apr 28, 2009)

stevefed said:


> Just joining in to the conversation. Working on my own project, a Porsche 914 that was previously set up to run lead-acid from one of the Electro Automotive kits many years ago.


Well what do you know, so am I!

I converted my 914 several years ago (http://www.evalbum.com/2500) went through two lead acid packs and decided I couldn't stomach going through another one -- the weight, the mess, the hassle! But I couldn't afford lithium, so the car has sat for years ... until now that I have found the Volt!



stevefed said:


> There are two offered with modules and one that is just the battery pack.


I don't understand the distinction; do you mean without the BMS modules? And what is the price differential? 

I'm not a blogger but decided to somewhat tersely blog parts of my Chevy Volt experience. Let me know if you have any questions.


----------



## eldis (Sep 3, 2013)

bigmouse said:


> The modules on the Volt are used only for voltage and temperature monitoring, and for switching the resistive balancing on when commanded by the main box at the front of the battery. They won't do anything they're not told to do over CAN.


I guess that's good news for some people wanting to reuse it! I can recall in this or similar thread an information, that all the fault signals are triggered based on pre-programmed (conservative) values, so during an EV operation, the BMS would be very often in error state even though levels are perfectly safe. 

Do you intend to make the CAN packets' protocol public?


----------



## stevefed (Feb 23, 2015)

Hey halestorm, right on! Hopefully I can learn from you and have some sense of what the heck I am doing when I get the batteries. Right now I've just fixed some leaks in the trans and gotten it back with the motor. As far as the modules, I'm not sure, it's just everything that comes with the package when it's all pulled out in the "T" form with the cover from the car. The other one without it is just listed as "batteries without modules." The price is just about the same, around 2k, plus the $300 no core exchange fee. I don't know if the "batteries only" package includes BMS, but it sounds like one can be done relatively(?!) simply.


----------



## bigmouse (Sep 28, 2008)

I haven't figured out what the "with" and "without" modules means in the wrecker inventories. I don't think they know either. None of them are opening the pack up. Most of the ones I've contacted don't even know what the battery is. I had one place send me an inverter, then a DC-DC converter, before they finally figured out which part the battery was and sent me that. The two that I bought were the same part, but one was labelled as "without modules" and the other was labelled as "with".


----------



## stevefed (Feb 23, 2015)

Well, that's great that you got them to ship. The closest I could find is three of them that are all 400 miles away and the guy said since they're batteries he can't ship them. Although I saw at least one picture someone posted with "OK To Ship" right on the cover of the pack.


----------



## Duncan (Dec 8, 2008)

stevefed said:


> Well, that's great that you got them to ship. The closest I could find is three of them that are all 400 miles away and the guy said since they're batteries he can't ship them. Although I saw at least one picture someone posted with "OK To Ship" right on the cover of the pack.


Damn - I wish I could get some that close


----------



## stevefed (Feb 23, 2015)

Oh, don't get me wrong. I'm going to get them. A road trip is in the works, with my friend with 3 kids just dying to have an excuse to get out of Dodge for a run there and back. That is, unless I can find something closer beforehand.


----------



## bigmouse (Sep 28, 2008)

stevefed said:


> Although I saw at least one picture someone posted with "OK To Ship" right on the cover of the pack.


I think that sticker gets applied at the factory. It's the same sticker in the same place on every pack I've seen.


----------



## halestorm (Apr 28, 2009)

stevefed said:


> As far as the modules, I'm not sure, it's just everything that comes with the package when it's all pulled out in the "T" form with the cover from the car. The other one without it is just listed as "batteries without modules." The price is just about the same, around 2k, plus the $300 no core exchange fee. I don't know if the "batteries only" package includes BMS, but it sounds like one can be done relatively(?!) simply.


OK, I think I see. As Steve already suggested, the one W/O modules is probably without some other external components. I didn't realize this was a wrecking yard which, as he points out, is not going to be disassembling the "T" shaped battery pack. So I am assuming that the "modules" are some extra external bits you don't need. Use that as an argument (maybe) to get the price down on the one w/o "modules". But $2300 for the battery pack isn't too bad.

I also drove almost 400 miles to pick up mine.

It is big and heavy. I don't remember exactly but probably in the neighborhood of 500-600 pounds. They fork lifted it into the back of my pickup truck and I had to disassemble it to get it out. Disassembly will take about an hour+, so take that into consideration.

Which drive system do you have, the Azure Dynamics? The series voltage of the Volt pack is too much for the AC24LS, even if the motor is wired in Delta configuration. BUT, sorry, that is a conversation for another thread. Keep this one on topic for the Chevy Volt. If you want to talk about the other, email me or let's start another thread.


----------



## altermontrealiste (Jun 5, 2014)

thanks for the infos guys ; found a deal and will have one tomorrow 

just to recap, what is the best method you found to take out the cells from the packs?


----------



## stevefed (Feb 23, 2015)

I watched this video, along with the pics that others had posted on this thread. It's pretty straight forward, I just kept it slow, SAFE, and steady. The only variation on this video I took was putting on a pair of 1,000 volt gloves once the top cover came off, just to be overly careful. Nothing like 370 volts to get your attention!

https://www.youtube.com/watch?v=00tTckGUv7I

sF


----------



## stevefed (Feb 23, 2015)

Whoops, sorry, just reread your post and realized you want to take the cells from the packs. Whoa, can't help you with that one!
sF


----------



## altermontrealiste (Jun 5, 2014)

Indeed Steeve, safety first ; first step I took is to separate it in 3 for transport and further segment it by removing the bars on top : 48-60v is still dangerous, but less than >300v

I will try the hairdryer trick to separate cell tabs from metal U clamps

Anybody has the technical drawings of the plastic cell holders?


----------



## eldis (Sep 3, 2013)

I'm still trying to identify (and buy) the metal water connectors used on the control block module. Anyone has an idea what fitting it is or where to buy it?


----------



## bigbadbob (Jan 17, 2015)

i am running a striped down 2014 volt battery pack, wired for 96 volts, weight about 280 lbs for full pack but lots of parts cut off, i even cut down the side to remove most of the cooling tubes, no bms dont belive in them just use a top stop charger set for 97 volts. over 1000 miles so far in a very light vw fiberglass kit car , very fast with a ac31 motor about 120 miles per charge if i take it easy. lots of fun. planing a new build two volt battery packs wired for 144 volts 34 kw and a ac 50 motor very light exo skeleton car three wheeler harley rear wheel as the drive 2 seater 800 lbs should go like stink.


----------



## altermontrealiste (Jun 5, 2014)

thanzlik said:


> Yes, anyone who attempts this please be safe! I take no personal responsibility for anyone who thinks they want to try this!
> 
> 
> So I did a quick experiment. I heated one tab and pryed on it a bit very gently with a small flat screw driver. Just used a hair dryer. The other tab nothing. The tab I heated I was able to cut without destroying the crimp. The one I didn't left me with 3 holes. The pic is the worst of the 2.


So, just the heat from a dryer can melt the link between the tabs and the u-clamp?


----------



## Yabert (Feb 7, 2010)

altermontrealiste said:


> So, just the heat from a dryer can melt the link between the tabs and the u-clamp?


NO!
There is ultrasonic welding... heat from a dryer do nothing (except slightly warm the battery)
Don't try to separate the cells except in an extreme case. IMHO, separate the cells is stupid. If you need different cells capacity or cells configuration, buy a different battery...
or carefully cut the tabs. That stay an option


----------



## piotrsko (Dec 9, 2007)

eldis said:


> I'm still trying to identify (and buy) the metal water connectors used on the control block module. Anyone has an idea what fitting it is or where to buy it?


Fwiw: they look like a type called SCHRADER, or at least the males I got with my battery did.

I would think that you need to find a wrecking yard that has a car close to you and go visit, unless you can google the specs. It might even be a chevy online part, albeit pricey


----------



## altermontrealiste (Jun 5, 2014)

Yabert said:


> NO!
> There is ultrasonic welding... heat from a dryer do nothing (except slightly warm the battery)
> Don't try to separate the cells except in an extreme case. IMHO, separate the cells is stupid. If you need different cells capacity or cells configuration, buy a different battery...
> or carefully cut the tabs. That stay an option


Actually, keeping the cells in 3p packs would be fine by me ; I want to make 20s packs out of it and I don't need the fancy (heavy) watercooling since it's for e-scooters (maybe 40A max discharge)

Would have taken Nissan Leaf modules... if anyone near Montréal wants to trade


----------



## Yabert (Feb 7, 2010)

altermontrealiste said:


> Actually, keeping the cells in 3p packs would be fine by me ; I want to make 20s packs out of it and I don't need the fancy (heavy) watercooling since it's for e-scooters


The Volt battery is separated in smaller pack of 12 and 6 cells in series.
So, 18S will perfectly fit your application (67.5v nominal and 45Ah for 3Kwh ∼60 lbs . Take a look at P.5 from this thread.
The water cooling systems integrated on the cells is only composed of really light aluminum foil and the plastic parts aren't really heavier than your ''projected'' new support for the bare cells (see P.6).

Use it like this and you will have reliability and fun on your e-scooter.


----------



## PorscheFan5 (Mar 24, 2015)

bigbadbob said:


> i am running a striped down 2014 volt battery pack, wired for 96 volts, weight about 280 lbs for full pack but lots of parts cut off, i even cut down the side to remove most of the cooling tubes, no bms dont belive in them just use a top stop charger set for 97 volts. over 1000 miles so far in a very light vw fiberglass kit car , very fast with a ac31 motor about 120 miles per charge if i take it easy. lots of fun. planing a new build two volt battery packs wired for 144 volts 34 kw and a ac 50 motor very light exo skeleton car three wheeler harley rear wheel as the drive 2 seater 800 lbs should go like stink.


Bob,

I would like to know more about the Volt battery: where did you get it, what is their configuration, what work needs to be done to dismantle and use them etc. I am working to convert my Boxster and am looking to use 144v with my Netgain Warp 9. A 34kw configuration at that price from two Volt packs would be great alternative to buying LiFePO4 batteries...

Thanks!


----------



## altermontrealiste (Jun 5, 2014)

PorscheFan5 said:


> Bob,
> 
> I would like to know more about the Volt battery: where did you get it, what is their configuration, what work needs to be done to dismantle and use them etc. I am working to convert my Boxster and am looking to use 144v with my Netgain Warp 9. A 34kw configuration at that price from two Volt packs would be great alternative to buying LiFePO4 batteries...
> 
> Thanks!


 If you are in the usa, there's http://hybridautocenter.com that has them (near Las Vegas), but you can check with your local garage / scrap yard ; got a complete one for 2500$ without BMS, seperated in 3 so I could carry it in a car


----------



## Yabert (Feb 7, 2010)

Yabert said:


> absolutely no exemplar of this awesome battery should finish his life at the scrapyard...


... still more than 20 Chevy volt battery available on different scrapyards: http://car-part.com/


----------



## Ampster (Oct 6, 2012)

I've read the thread but still have a question about the pack. What are the size of groups of modules (module = 3p cells) that are easily separated? My goal is to have a 40 to 60 volt pack for home storage. I saw on the Hybrid Auto site that there were 12s and 6s groups. I would rather buy a whole pack than the higher priced smaller groups, if I can get the pack I want.
Note is my assumption correct that there are two 6s3p groups and seven 12s3p groups? That would be 96 modules and 288 cells in the pack.


----------



## aeroscott (Jan 5, 2008)

2units of 6 cell packs will 48 volts max if in series . the rest are all 48 volt max ,
12 cells= 3 to 4 volts per cell or 36 to 48 volts if you can run the house inverter in that range, that's what I do . I get inverter cutoff at 3.12 volts/ cell or 37.44 v. cells all bolt up to leads like this


----------



## Ampster (Oct 6, 2012)

aeroscott said:


> 2units of 6 cell packs will 48 volts max if in series . the rest are all 48 volt max ,
> 12 cells= 3 to 4 volts per cell or 36 to 48 volts if you can run the house inverter in that range, that's what I do . I get inverter cutoff at 3.12 volts/ cell or 37.44 v. cells all bolt up to leads like this


Thanks, that answered my question. My inverters lowest shutoff is 40 volts which would be 3.33 per cell which would leave me some room at the bottom and not stress the cells.


----------



## halestorm (Apr 28, 2009)

Any of you that has the Chevy Volt battery and doesn't need the end plates with the 90 degree hose barbs? I need two such plates. I have about four with the straight barbs that I could give in exchange. Thanks, Dave.

http://914electric.blogspot.com


----------



## rwaudio (May 22, 2008)

halestorm said:


> Any of you that has the Chevy Volt battery and doesn't need the end plates with the 90 degree hose barbs? I need two such plates. I have about four with the straight barbs that I could give in exchange. Thanks, Dave.
> 
> http://914electric.blogspot.com


I don't have any extra 90 degree barbs either, but it would be nice to set up some sort of "exchange" for spare volt battery parts. I had to 3d print some block off plates to set them up in the configuration that I needed.

914's are great, I'm putting almost 2 complete Volt packs in one. Only 90 of 96 cells in each pack as it's the voltage limit of my inverter.


----------



## Elanimal28 (Nov 18, 2013)

Yes. I would like a couple of the wiring harness that plugs on top of the battery for my bms.


----------



## halestorm (Apr 28, 2009)

rwaudio said:


> I don't have any extra 90 degree barbs either, but it would be nice to set up some sort of "exchange" for spare volt battery parts. I had to 3d print some block off plates to set them up in the configuration that I needed


Your blog is great but left me with more questions. How did you 3D print the parts you need? Anyone can 3D print now but the hard part (to me) seems to be the input-- where did you get the model for them? How could I, for instance, 3D print the 90 degree hose barb pieces?

Also, are you using a BMS?


----------



## rwaudio (May 22, 2008)

halestorm said:


> Your blog is great but left me with more questions. How did you 3D print the parts you need? Anyone can 3D print now but the hard part (to me) seems to be the input-- where did you get the model for them? How could I, for instance, 3D print the 90 degree hose barb pieces?
> 
> Also, are you using a BMS?


Well you have to model the part you want to 3D print. I'm not sure that I would recommend home 3D printing the barbs, the blanking plates worked just fine, but I did give the mating surface a layer of silicone and let it dry before assembly to ensure there were no leaks.

I also wouldn't use the gasket unless there were no other options, printed with Ninjaflex it's a bit firmer than a stock gasket and there is a slim chance there might be a gap in the layers that wouldn't compress causing a very slow leak. I didn't actually use the gasket I printed, I just wanted to see if it was possible.

No BMS, the packs won't be fully charged, nor fully discharged, if they show signs of drifting I'll deal with it later.


----------



## halestorm (Apr 28, 2009)

rwaudio said:


> Well you have to model the part you want to 3D print. I'm not sure that I would recommend home 3D printing the barbs, the blanking plates worked just fine, but I did give the mating surface a layer of silicone and let it dry before assembly to ensure there were no leaks.


Right, but *HOW* did you create a 3D model of these parts. I don't think I'm going to pursue this route for the 90 deg barbs I need, so this is more of a general interest question now. 

So you are dumping the heat exchanger into the passenger compartment? What about days when you don't want to heat the cabin? Do you have a separate heat exchanger for the rear or do you run coolant lines between the front and rear compartments?

I'm installing Chevy Volt batteries also in a 914 and I haven't settled on how to do the cooling. I'm possibly going to install the heater but don't really expect to use it here in Los Angeles. Cooling is going to be my biggest issue, and where to put the heat. I'm anticipating a transmission cooler for both the front and rear batteries.

Thanks,


----------



## rwaudio (May 22, 2008)

halestorm said:


> Right, but *HOW* did you create a 3D model of these parts. I don't think I'm going to pursue this route for the 90 deg barbs I need, so this is more of a general interest question now.
> 
> So you are dumping the heat exchanger into the passenger compartment? What about days when you don't want to heat the cabin? Do you have a separate heat exchanger for the rear or do you run coolant lines between the front and rear compartments?
> 
> ...


I'm not good at 3D modeling so I basically cheat, scan or photograph the most complex 2d plane and then in a CAD program add the third dimension.

In Canada we have the opposite problem, I'll need to heat the batteries but not cool them. Ambient temperature is very seldom above 30C, and with two packs in parallel with 282A max draw (141A per pack) we won't be loading them very hard at all. My 944 cruises at 8-13kw depending on speed, at 355v that's very little continuous current and it's shared between two packs, if anything the 914 might even be more efficient. I plan to run the pump anytime the car is driving or charging so that the coolant maintains the batteries at a similar temperature. I am monitoring a front pack and a rear pack so either will trigger the heater to come on. The heat exchanger will dump heat into the cabin, but really only if the fan is turned on. I blocked off most of the main inlet below the windshield so the fan will have to be on to get any heat transfer to the cabin, so heating just the the batteries is not a problem, but if the batteries need heat there's a pretty good chance the passengers do too.

I do have coolant hoses running through the old air passages in the door sills to the rear of the car, keeping it all in one system, but two loops in an attempt to keep the temperature of all packs as close to the same as possible. I think that's the biggest variable that would contribute to cell drift is if one pack is consistently a very different temperature to another.


----------



## piotrsko (Dec 9, 2007)

I have a 5 gallon tank sitting at ambient in the truck bed. For a 1/2 hour's trip which is 9 kWh, the temperature rise is about 10 degrees. I'm my case, I'm not sure what a cooler would get me.


----------



## halestorm (Apr 28, 2009)

This is interesting data. So you are simply moving water through the batteries without a radiator? You measure a 10 degree change in 5 gallons of water after using 9 kWh. What is the temperature of the water? (IE. Changed 10 deg from what to what?) I know you said you have a 5 gal reservoir but do you know what is the total volume of water in the system? Thanks,


----------



## Vanquizor (Nov 17, 2009)

I don't know that the temperature of the water is relevant- from the data all we can really say is that the 5 gal of water picked up ~125 watt hours of energy from somewhere. Problem is its not really a closed system so we have no clue what other gains or losses there are...

How about some details on the system/trip- sunny? cloudy?

Is there a build log somewhere?


----------



## piotrsko (Dec 9, 2007)

System volume 5 gallons including perhaps 3/4 gal in pack. Really hard to drain pack entirely without disassembly. Fwiw filled 5 gal of chevy 50/50 prefix into tank, which has air gap

Does not matter about conditions, seems to be 10 degree above whatever is ambient in covered bed using stick on rv window temp gauge.

No build, too many trolls about original FLA pack.

IMHO I believe the 48s12p split pack doesn't get that hot during use except locally internally.


----------



## altermontrealiste (Jun 5, 2014)

halestorm said:


> Any of you that has the Chevy Volt battery and doesn't need the end plates with the 90 degree hose barbs? I need two such plates. I have about four with the straight barbs that I could give in exchange. Thanks, Dave.
> 
> http://914electric.blogspot.com



I only have the straight ones left ; if you have them too, converting them to 90deg with parts in the plumbing isle of your local hardware store (glue and pvc tube) could do the job ; using flexible tubing can make the job easier


----------



## halestorm (Apr 28, 2009)

altermontrealiste said:


> I only have the straight ones left ; if you have them too, converting them to 90deg with parts in the plumbing isle of your local hardware store (glue and pvc tube) could do the job ; using flexible tubing can make the job easier


Yes, I test-fitted a 1 inch PVC elbow onto the existing barb and it seems like it would work except that I don't have space for it; it's too thick. I'm trying to fit these into a tight space. The Volt 90 deg barb is a little more compact and just barely fits into the space I have available. I've located one; still need one more. Thanks,


----------



## halestorm (Apr 28, 2009)

Do you guys have the Volt batteries under thermostatic control? I'm looking for an adjustable liquid thermostat I could use.


----------



## eldis (Sep 3, 2013)

halestorm said:


> Do you guys have the Volt batteries under thermostatic control? I'm looking for an adjustable liquid thermostat I could use.


The Chevy Volt battery has a built-in battery heater, and several temperature sensors - you can use any temperature regulator to control this.


----------



## rwaudio (May 22, 2008)

eldis said:


> The Chevy Volt battery has a built-in battery heater, and several temperature sensors - you can use any temperature regulator to control this.


I'm using the stock heater (you need to be close to the stock voltage for it to work well, guys re configuring for lower voltages are out of luck). The modules have 10k NTC thermisters built in, easy to interface with a temperature controller, simply have it turn on/off at the desired temperature. There are some nice high voltage relays and contactors built into the front module to do the HV switching as well.


----------



## halestorm (Apr 28, 2009)

To what temperature are you regulating the batteries, and how did you come to select that value?


----------



## diyecjbentz (Jul 9, 2015)

Greetings all. I recently leased a new 2015 Volt. Up front, I do not have 1% of the electronics knowledge y'all have. But I have one simple question. Has anyone done or designed a method for DC fast charge of the Volt battery? If so, hopefully one that can be adapted to my new Volt, so I don't have to keep spending 4.5 hrs at a 240 charge station every day.

It looks to me like it would be a simple hack into the high voltage DC cables coming out of the battery pack. But my fear is that high-voltage DC charge into those connections would fry some (much?) of the electronics connected to the entire battery pack.

Of course, I know I would kill my warranty on the car, and will not try anything too risky. But if any of you have put DC voltage to the battery back, was able to charge it without frying the electronics, I figure the risk isn't terribly high.

Any info is appreciated. Thanks for posting all of your hard work!

Cheers.
James


----------



## Ampster (Oct 6, 2012)

It will be cheaper to buy a 240v EVSE for your home. Also try one of the Chevy Volt Forums to see if anyone has hacked a Volt for Chademo.


----------



## diyecjbentz (Jul 9, 2015)

Ampster said:


> It will be cheaper to buy a 240v EVSE for your home. Also try one of the Chevy Volt Forums to see if anyone has hacked a Volt for Chademo.


 Ampster, thanks for the reply.

I have read a number of the gm-volt forum entries, but have yet to find anyone trying a DC connection to the volt. This DIYEC forum has done more hands on manipulation with the Volt battery than anyone on the Volt forum. That's what caught my attention.

The issue with the 240EVSE at home is same as anywhere. The 4.5 hrs for full charge. Also, I live in an apartment with no external electrical plugs and the cost to install EVSE is about $3000. Then when I move from the apartment, it all stays behind. 

I was hoping to find someone that has applied DC to the Volt battery to see if it burns out any of the Battery Control electronics. If not, then it will be pretty simple to add a DC charger to the Volt.

It seems that fast charging the battery, however, significantly reduces the life of the battery. So, there's a trade-off. Faster charge, more usefulness, for earlier battery replacement.

But, when you can buy a Volt battery for $2500, it seems almost reasonable to go for shorter life, faster charge.


----------



## aeroscott (Jan 5, 2008)

I've charged from a volt pack ( broken down to 48 volts , 8 packs parallel) to a Spark pack (1/8 of a A123 pack discharged to 42 volts). It draws about 150 amps for less then 1 minute .Charge amps keeps tapering down. Using jumper cables . I would think the inrush would be the only problem .


----------



## piotrsko (Dec 9, 2007)

Show me the data points where FAST charging lowers battery life in a factory Volt set-up. Everything I have seen is anecdotal in forums. I haven't seen the upper charge limit demonstrated, possibly because you have a hard time delivering huge currents at 380 volts. OTOH, you could do a treadmill arrangement for the drive wheels and use regeneration to really fast charge, but you will need about 100:hP to power the treadmill.

If you are recharging in 4.5 hour's, you are effectively pushing the limit of what your house system can provide, so you need custom power inputs which are pricey.

You could buy a couple of packs, charge them, and then use those packs to recharge your vehicle.


----------



## diyecjbentz (Jul 9, 2015)

piotrsko said:


> Show me the data points where FAST charging lowers battery life in a factory Volt set-up. Everything I have seen is anecdotal in forums. I haven't seen the upper charge limit demonstrated, possibly because you have a hard time delivering huge currents at 380 volts. OTOH, you could do a treadmill arrangement for the drive wheels and use regeneration to really fast charge, but you will need about 100:hP to power the treadmill.
> 
> If you are recharging in 4.5 hour's, you are effectively pushing the limit of what your house system can provide, so you need custom power inputs which are pricey.
> 
> You could buy a couple of packs, charge them, and then use those packs to recharge your vehicle.


 
re: losing battery life with DC fast charging, it's something I read. But here: http://www.torquenews.com/2250/results-dc-fast-charging-study-are-good-news-ev-owners I just found that it is not true after all.

re: special connectors for DC charging, yes, I think it's complicated if done right (i.e. monitoring battery conditions during charge). I was hoping for a somewhat barbaric hack.... pos to pos, neg to neg, sit back and wait. But, I wouldn't want to brick my $32k car due to ignorance, so it's probably not going to happen.


----------



## aeroscott (Jan 5, 2008)

A dc motor controller if capable of high voltage could control the inrush


----------



## halestorm (Apr 28, 2009)

piotrsko said:


> System volume 5 gallons including perhaps 3/4 gal in pack. Really hard to drain pack entirely without disassembly. Fwiw filled 5 gal of chevy 50/50 prefix into tank, which has air gap
> 
> Does not matter about conditions, seems to be 10 degree above whatever is ambient in covered bed using stick on rv window temp gauge.


Technically, conditions do matter since the specific heat changes with temperature. But what matters more is the unit of temperature. I'll take a guess and assume you're talking Fahrenheit since another message from you said something about 50 degrees, which would be pretty hot if Celsius. So a 10 degF change is closer to a change of about 5 Kelvin.

Assuming pure water and a heat capacity for pure water of 4.187 kJ/kgK, the amount of energy required to raise the temperature of 5 gallons of water by 5 Kelvin is approximately 396kJ, or ~ 110Wh. For your 1/2 hr drive about 55W of power is going in to the water from the batteries.

This is probably an underestimate since I'm not accounting for any losses in the system (I.E. the water could be losing energy through conduction and radiation).


----------



## diyecjbentz (Jul 9, 2015)

Can I ask again: has anyone tried DC charging the intact Volt battery? If so, what was the outcome.

Thank you.
Jim


----------



## Ampster (Oct 6, 2012)

This may seem like a smart-ass comment, but as far as the battery is concerned it is always seeing DC. I am not sure why it would matter to the battery if the DC came from the on board charger or some connection between the charger and the battery. The complexity of DC charging a Volt would be finding that spot and then coordinating the control signals between the battery and the BMS. Prior posters have alluded to those issues.


----------



## diyecjbentz (Jul 9, 2015)

Ampster said:


> This may seem like a smart-ass comment, but as far as the battery is concerned it is always seeing DC. I am not sure why it would matter to the battery if the DC came from the on board charger or some connection between the charger and the battery. The complexity of DC charging a Volt would be finding that spot and then coordinating the control signals between the battery and the BMS. Prior posters have alluded to those issues.


 Not a smart ass answer to someone that doesn't know enough (me).

I've seen all the pics of dismantling the battery, and I see the main connection in the front that transfers DC to the electric motor.
I figure if I can just find a wiring harness for the battery connection at the front of the battery from a crashed Volt, I can build an adapter there to connect 350VDC to the battery and direct charge it. Seems it might only take 1-2 hrs. But I know nothing about controlling the current flow to avoid burning up the circuitry that exist all over the battery structure. 

If it could be done, you could sell an aftermarket DC charging kit to every volt owner that has one old enough to be out of warranty already. Assuming you fuse it to avoid destroying their car. Somehow, the cooling system will still have to operate to keep the battery temp stable.

Mine is just 2 months old, and I'd hesitate to void my warranty with some DC charging hack, however, it would be extremely tempting.

Thanks for the response.


----------



## Duncan (Dec 8, 2008)

Hi Diyecjbentz

You are missing the problem
The problem is NOT getting the juice into the battery
The problem is getting the "juice"

Where are you going to get 100amp at 350v?

That's 35Kilowatts or about twice as much as would be supplied to a good sized house

Tesla gets over this with their "Superchargers" by having a bank of batteries to draw on

It's like filling a swimming pool - you can do it with a hose but it will take a long time and messing with the nozzle won't help


----------



## diyecjbentz (Jul 9, 2015)

Duncan said:


> Hi Diyecjbentz
> 
> You are missing the problem
> The problem is NOT getting the juice into the battery
> ...


 A good question I have not put much thought into. 

What is the most 240VAC home outlet could be modified to be? I know it can be converted to 350VDC with rectifiers and coils and such, but I have no idea how much current can be drawn from a standard home 240VAC outlet.

Would it be enough to make things noticeably better than the 3.3kw L2 chargers?

Can anyone other than Tesla owners access the SuperChargers?

Thanks for your feedback.


----------



## piotrsko (Dec 9, 2007)

Series of comments: on a fully functioning Volt, all the systems are vehicle controlled. The coolant pump can come on during charge if it gets too hot.

If your house was built before 1980 it is limited to 100 amps at the mains or 50 amps on a 220 circuit, assuming it has not been re paneled. After 1980 the mains get upgraded to 200 amps, so may be 75 amps on a leg. Since I have never seen a plug / socket rated higher than 50 amp, this is speculative. Base voltage of 240 gives you 336 p-p. Filtering at these power levels will be exciting and huge in size.

Switching and wiring is going to be expensive, and fyi 4 ga romex was $8 a foot. Wonder what a 25 ft extension cord will cost in materials. I figure a grand for the relays that control the dc side.

In this configuration, figure about an hour to recharge at 12kWh. Except for the most die hard volt owners, I can't see this being profitable aftermarket.

Go for it. Zappa says: "Reality is a mother."


----------



## Ampster (Oct 6, 2012)

If I remember the original question or statement of issues it seemed the AC capacity was the limitation. Duncan essentially nailed the issue. It is about capacity. FWIW you can look at one of the large breakers near the meter and that will probably be your capacity in Amps (240v) that will give you a starting point.


----------



## diyecjbentz (Jul 9, 2015)

piotrsko said:


> Series of comments: on a fully functioning Volt, all the systems are vehicle controlled. The coolant pump can come on during charge if it gets too hot.
> 
> If your house was built before 1980 it is limited to 100 amps at the mains or 50 amps on a 220 circuit, assuming it has not been re paneled. After 1980 the mains get upgraded to 200 amps, so may be 75 amps on a leg. Since I have never seen a plug / socket rated higher than 50 amp, this is speculative. Base voltage of 240 gives you 336 p-p. Filtering at these power levels will be exciting and huge in size.
> 
> ...


Thanks for the electronic / cost details.

Well, you've convinced me it's out of my league. However, I bet many Volt owners would quickly give up say $1500 for this "device" if it was available, just to be able to use their car, full charge, after an hour. 

If you're trying to figure the break-even for having used gasoline instead of this expensive electric alternative, for them that wouldn't be the point. It's just having electric all the time that makes it worth the extra money.

I'm thinking ultimately of a device that will plug into a 240 outlet anywhere you go. Portable. Kind of like the included 120VAC charge cable included with the car.

If I had the cash, I would "go for it" and build a prototype, but would want to test it on a self standing volt battery from a wrecking yard first off. Then on an older, well used 2011-12 Volt, to avoid ruining a completely good newer Volt.

After that, eBay all the way.


----------



## Ampster (Oct 6, 2012)

There are a number of portable devices on the market that plug into these receptales at 240v and amperages ranging from 15 to 40 Amps. Google EVSE if you want to see some examples.


Tony Williams on the RAV4EV forum is building a Chademo add on for his RAV. I couldn't get the final price but it is somewhat north of $1500.


----------



## Duncan (Dec 8, 2008)

_I'm thinking ultimately of a device that will plug into a 240 outlet anywhere you go. Portable. Kind of like the included 120VAC charge cable included with the car._

OK sanity check
Most 240v outlets are limited to 15 amps

I5 amps at 240v = 3.6Kw - which is the MOST you can draw from that outlet
Now you know why the L2 chargers are 3.3Kw

In my house I have a Dryer outlet this is 240v and 25amps so it has to use a special plug - 240v x 25 amps = 6Kw
This is right at the limit for standard mains cable so it has its own dedicated line from the consumer unit
Anything higher you would need to have a dedicated line using a heavier cable (Costly)


----------



## diyecjbentz (Jul 9, 2015)

Duncan said:


> _I'm thinking ultimately of a device that will plug into a 240 outlet anywhere you go. Portable. Kind of like the included 120VAC charge cable included with the car._
> 
> OK sanity check
> Most 240v outlets are limited to 15 amps
> ...


Alright, then. That puts it in simple terms. The L2 chargers are already charging to the max possible at 3.3kw for most 240VAC outlets. 

That means my dream of driving all over, catching a quick 1hr full charge here and there, isn't going to happen.

Guess I have to accept the 4.5 HR L2 charge time on my Volt and start saving my pennies for a Tesla. The Volt will do nicely in the meantime. Current "lifetime" mpg is 80.

Thanks for the feedback and details to help me understand what I had in mind.


----------



## Duff (Jul 29, 2015)

Don't forget that just about every RV park has sites with 50-amp 240V power available. Even if you had to pay for a full night's stay (generally less than $40, often less than $20), you could still get a pretty quick charge--instead of 3.3kW, that would be more like 12kW max.


----------



## dcb (Dec 5, 2009)

Duff said:


> Don't forget that just about every RV park has sites with 50-amp 240V power available.


I still see a lot of 3 prongers at campsites, so 240v isn't a given. Even if it is a 14-50 nema it isn't guaranteed, so make sure you have a 120v backup plan.


----------



## tomofreno (Mar 3, 2009)

All RV parks I've charged at have NEMA 14-50 as well as the 3 prong 30A receptacles, usually more of the latter though. I periodically charge at two parks, one charges me $2.00, the other nothing - because he said, I'm doing the right thing. Charging at 8 - 9 kW with the EMW charger permits me to add miles fairly fast. About 45 miles per hour for 9 kW. I never use 120V, waaay too slow, unless you charge at work.


----------



## diyecjbentz (Jul 9, 2015)

tomofreno said:


> All RV parks I've charged at have NEMA 14-50 as well as the 3 prong 30A receptacles, usually more of the latter though. I periodically charge at two parks, one charges me $2.00, the other nothing - because he said, I'm doing the right thing. Charging at 8 - 9 kW with the EMW charger permits me to add miles fairly fast. About 45 miles per hour for 9 kW. I never use 120V, waaay too slow, unless you charge at work.


This is a cool alternative I never thought about!


----------



## stevefed (Feb 23, 2015)

Hi folks, I posted in here a while back, and got a great 120v system going with 3 strings from a volt battery in my 73 Porsche 914 and it's been driving like a dream for months! Like any good enthusiast, I want more of everything, 144v for faster acceleration, and more strings for more range. I recently found a Volt that someone is parting out and willing to make quite a deal with me on if I pull the battery pack out of the car myself. Has anyone every done this? I had no problem slowly and carefully taking the T shaped batter apart, but this sounds like it could be a whole new challenge. I would definitely have help from at least one friend, and once pulled(dropped?) out of the car would plan to disassemble right there to load into my truck. Any thoughts?


----------



## piotrsko (Dec 9, 2007)

Well it's 500 lbs in factory trim so you need some sort of lifting device. It also comes out the bottom, probably easier to Jack the car way up, use a lift, whatever, and a couple of tranny jacks to lower.

An impact wrench would help here too, many bolts to remove.


----------



## halestorm (Apr 28, 2009)

I was going to suggest a pair of transmission jacks, too. But add, another way to do it, depending on the reach of the transmission jacks, is to remove the wheels so you can lower the car further, onto the jacks, remove the bolts holding the battery pack, then lift the car away from the battery, which you then roll out from under the car.


----------



## hmincr (Jan 20, 2012)

To get maximum room under the car, use a wide board, plywood maybe and some 3/4" or so pipe (PVC) to run the battery out from under the car. 

Same way to load it, use the rollers under the battery onto the boards up into the truck. Take some rope and use it to hold slack while getting a second grip to shove the battery up. It's only #500, so, not nearly as hard to move as one thinks. 

That's how I moved mine up a drive way, by myself.


----------



## stevefed (Feb 23, 2015)

Thanks folks! Sounds like it's a project worth doing, especially for the price.


----------



## stevefed (Feb 23, 2015)

Hey, I was also wondering if anyone knew the size of the nuts that need to be removed to get the battery out? I'd like to avoid buying a whole set of large sockets, and figuring they're probably quite large, maybe 22mm or more? I know all the nuts that hold the cover on the battery are 10mm. Also, does anyone know what size the nuts are on the metal plate/cover on the bottom of the car? Thanks again folks, planning on going and getting this on Saturday, and no tools there so need to make sure I have everything I need.


----------



## stevefed (Feb 23, 2015)

I was wondering if anyone has ever tried mounting a string of batteries laying down as opposed to standing up? I want to get another string in my Porsche 914 and the only way I can, without some major fabrication, is to lay them down, as they're just too tall to stand up and be able to close the trunk. Is this dangerous, stupid, non-functional? Anyone try it before, or know if they have to stand up to work properly? Any info greatly appreciated!!


----------



## Ampster (Oct 6, 2012)

The only issue others have encountered with prismatics is if they need to vent.


----------



## bigmouse (Sep 28, 2008)

I'm planning on doing this in my BMW. Pouch cells are not sensitive to orientation. They're used in phones after all! The Nissan Leaf has them mounted both flat and on end.

Prismatics have free electrolyte I believe, which is why orientation is a concern.

My only concern with the orientation will be coolant flow, but I'll make sure my inlets are on the bottom and outlets at the top so bubbles don't get caught.


----------



## EVisa (Jun 30, 2014)

Hi Stevefed

I encountered the same problem with my build. I had to split up one 4Kwh string into two 2Kwh strings, and the only way to make the smaller strings fit, was to mount them upside down. It makes things trickier for a number of reasons, but it works.


----------



## polodiy (Oct 25, 2015)

Just read full thread. Lots of useful information, thank you so much for that!

If understand correctly Chevy Volt pack has 2 24v/45Ah modules and 7 48v/45Ah modules.

Can the 48v/45Ah modules be divided into 2 24v/45Ah?

I want to buy Chevy Volt pack to build couple 24v packs.


----------



## rwaudio (May 22, 2008)

polodiy said:


> Just read full thread. Lots of useful information, thank you so much for that!
> 
> If understand correctly Chevy Volt pack has 2 24v/45Ah modules and 7 48v/45Ah modules.
> 
> ...


Technically this would be possible but not easily. Unless you are ready for some modification and fabrication I would consider the smallest modules the way you describe them above 7x 48v/45ah and 2x 24v/45ah.


----------



## Maniaccts (Nov 7, 2015)

I've got 2 24v and 5 48v on ebay check em out


----------



## stevefed (Feb 23, 2015)

Wow, sorry for the delay in thank you's! I was caught in the job, and the project. Did get the 5th string of 120v mounted on their side in the rear trunk of my 914. Took it out for a test drive today and all seems good. Now I just need to test my range. With 5 strings of 120v I'm hoping for closed to 80mi on a charge. I'm still getting used to driving by gas stations. I tend to check the price and consider popping in for a "top-off" before remembering what I'm driving. I guess I need more miles in it to get used to just driving on by!


----------



## stevefed (Feb 23, 2015)

Have a couple shots of the 5 strings of batteries, two over the old mid-engine site, one in the back trunk with the controller and cooling system, and two in the front trunk with the charger. Thanks for the help and support everyone, really digging the project!


----------



## Duncan (Dec 8, 2008)

Hi Guys

I have bought a Volt pack - won't actually see it for another couple of months

How about the charger? - is there any way of making it work?


----------



## piotrsko (Dec 9, 2007)

Evtv has the can dongle, but I haven't seen any open source stuff.


----------



## Tomdb (Jan 28, 2013)

if you dig aroudn you can find the canbus commands for the charger.


----------



## Tony Bogs (Apr 12, 2014)

The scrap Chevy (Opel) packs are a steal. Only negative point:
prof Dahn (Dalhousie uni) says that at least one gen of packs is a blend of two chemistries.


----------



## Duncan (Dec 8, 2008)

Tony Bogs said:


> The scrap Chevy (Opel) packs are a steal. Only negative point:
> prof Dahn (Dalhousie uni) says that at least one gen of packs is a blend of two chemistries.


Why would that be a problem?


----------



## Tony Bogs (Apr 12, 2014)

One chemistry is very sensitive to high temperatures, the other moderately.
Needs temperature monitoring or active thermal management.


----------



## piotrsko (Dec 9, 2007)

Kinda a shotgun approach to killing houseflies: exactly what temperatures do the batteries have issues with??

I want to see hard studies not just YouTube educated opinions.


----------



## Tony Bogs (Apr 12, 2014)

Prof Dahn is the new battery expert at Teslamotors. His research shows: degradation at approximately 30 degrees C if I remember correctly.


----------



## piotrsko (Dec 9, 2007)

Haven't seen him around town yet, 

Still want to see published and peer reviewed papers.

32C is where the batteries seem happiest, and no rumors and innuendo from Phoenix volt owners.


----------



## Tony Bogs (Apr 12, 2014)

Same blend of chemistries is in the Leaf, says Dahn. 
Isn't there a class action filed against Nissan by Leaf owners in hot states? Their cars ran of juice very quickly. 
Nissan didn't equip the Leafs with active thermal management, GM did with the Volt, says Dahn. Great guy, Dahn. His epic presentation is on the web.
I love sausages, but not the factory.


----------



## Moltenmetal (Mar 20, 2014)

Note that Chevy Volts have ACTIVE cooling of their batteries- they have a dedicated refrigerant evaporator for cooling the batteries, not just coolant running to an air-cooled radiator. Volts are VERY complex, with an incredible number of systems and parts. It's amazing they work as well as they seem to.


----------



## piotrsko (Dec 9, 2007)

IMO,AFAIK Mostly undocumented hyperbole and misinformation on the web regarding these batteries by so called "experts". They are the ev equivalent to a battle tank.

You dont hear Volts cycling in Phoenix in the summer sun. Their owners, (a whiney bunch) would be all over the forums complaining about lower battery life OR partial failures. They complain about everything else constantly and incessantly.

Doc Dahn isnt building any new and earth shaking new technology here in Reno, at least for 5 more years. So says the official game plan.

Still need to see peer reviewed data. Until then, smoke and mirrors.

I know what Chevy has done, and it is by careful observation of actual hardware and factory published manuals not YOU Tube videos on shakey cell phones.


----------



## Moltenmetal (Mar 20, 2014)

http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/

I am making no claims to know one way or another a) what chemistry is used in the Volt packs or b) what the temperature effect on that chemistry is in terms of durability or capacity fade. But I can be pretty confident that they would NOT have gone to the bother of putting in ACTIVE battery cooling, with a dedicated refrigerant-cooled coolant exchanger and dedicated TXV, if the chemistry they were using did not show a propensity for some degradation when it gets hot.


----------



## Tony Bogs (Apr 12, 2014)

Yeah, if that isn't hard enough, what is? 

And it does make the packs a steal. Well managed.


----------



## piotrsko (Dec 9, 2007)

Read your own quotations. 

It isn't dedicated, its shared with inverter, motor, charger using a 3 way control valve (critical path failure if I ever saw one).


----------



## Moltenmetal (Mar 20, 2014)

Presumably, none of those other components (motor, inverter, charger) would require refrigerant cooling! They'd all be OK with something much simpler- exchange to air via a radiator. The only reason I see for a dedicated refrigerant chiller and TXV (costly parts) is the batteries.

I'm not saying the batteries turn into pumpkins beyond 30 C, or 40 C. But they are probably getting pretty pumpkinlike at 50 C, or else you'd have seen this extra expense and complexity eliminated from the design.


----------



## dcb (Dec 5, 2009)

re: time to failure/reported failures, there are a few other variables to consider

If you agree with the popular theory that the biggest leaf lifespan problem is time at full charge at elevated temperatures,

how many people actually charge their volts on a regular basis when gas is $2/gal?

Since these were purchased for extended range, and they have a smaller pack than the leaf, how much time do they spend at full charge even when charged regularly?

the default charge level on the leaf is %100, you have to deliberately set it to %80 via convoluted timers. What is the default level of charge on the volt?


----------



## Tony Bogs (Apr 12, 2014)

It would be way too expensive to use ACTIVE cooling on inverter, motor and charger. 
No, I'm an electrical engineer, the only part that is really sensitive to temperature is the battery pack. 
And cost is THE major design factor in automotive engineering. 

I haven't seen anything (certainly not on this topic) that would contradict or undermine Dahn findings.


----------



## Brute Force (Aug 28, 2010)

I can't speak for other Volt owners, put mine starts off every day at 100% charge. The only time it uses gas is the occasional road trip.

Since the BMS is a top balance system, it has to charge to 100% to function.


----------



## dcb (Dec 5, 2009)

Brute Force said:


> Since the BMS is a top balance system, it has to charge to 100% to function.


If you have to balance every charge, there is something seriously wrong with your batteries/system.


----------



## Brute Force (Aug 28, 2010)

It only checks the balance, then makes very small adjustments if needed. As you know, battery packs don't go out of balance very quickly unless there is a problem.


----------



## dcb (Dec 5, 2009)

but what is that based on? are you monitoring each cell to confirm balancing activity?

what do you mean %100 charged? Chevy and nissan may define %100 differently, nissan might go to 11 when charging by default.


----------



## e*clipse (Aug 2, 2009)

Great topic! A big thank you for all the folks who posted good info about this pack. 

A little bit ago, someone asked about what was involved with removing a pack. Here is a good rundown. It's a teardown by DesignWest of a Volt.

https://docs.google.com/file/d/0BwHvhEbCHHEleUp3TUMxOUwzdmM/edit?pli=1

A couple of questions:

It appears from the above link that GM fastens these cells to this bottom plate as the primary battery structure. I've read elsewhere that this plate is pretty heavy. Does anyone have it's weight? Also - this plate is crash-worthy - as evidenced by the many junkyard packs available. How are the cells mounted to the bottom plate? Is there any other re-enforcement?

Also, a while back folks posted that they were making an adapter for the BMS interface. Any progress on this, or alternatively, any CAN bus data?

Thanks again,
E*clipse


----------



## piotrsko (Dec 9, 2007)

Perhaps 100+ lbs for mounting and box and etc. They mount with a bracket across the bottom plastic case flange both sides. They are 480 lbs assembled, yabert said he got that down to something like 80 kgs for pouches alone. 

Haven't seen any good bms spoofing open source, too easy to modify the charger and use that as a package deal for control. Each module is supposed to be stand alone, so perhaps if you supplied 12 power and 5v control to the module it would regulate. I gave up waiting and adopted a no BMS attitude.


----------



## e*clipse (Aug 2, 2009)

Thank you! 

It looks like these volt cells don't need much balancing. Perhaps a simple measurement only type bms would be fine, with some ability to manually balance if there's a problem. It looks like there's room for a small circuit board between the U-shaped connectors. I'm currently playing with a Linear Technology setup that measures 12 cells per circuit. It's proving itself very accurate and it puts only a tiny vampire load on the cells.

Thanks for the info. I'm going to start looking for one.. 

- E*clipse


----------



## Yabert (Feb 7, 2010)

piotrsko said:


> They are 480 lbs assembled, yabert said he got that down to something like 80 kgs for pouches alone.


336 lbs for pouches + pouches supports (plastic and steel parts). So around 144 lbs for the battery box + contactors + bus bars + current sensor + disconnect.



e*clipse said:


> I'm currently playing with a Linear Technology setup that measures 12 cells per circuit. It's proving itself very accurate and it puts only a tiny vampire load on the cells.


That should be very interesting if you are talking about 8 modules (45v) to manage 96 cells.
Explanation: I personally think than a BMS who verify each group of 12 cells (45v) and compare it with the 7 others groupes of 12 cells is way enough to protect a 96S battery pack in case of any voltage difference between groupe will activate a signal (stop charger or warn driver).

So, do you talking about that? Let us know. Thanks


----------



## Tony Bogs (Apr 12, 2014)

I'm thinking along the same lines. Give a a "time for battery service" warning based on the V/I characteristic (impedance). 
Service: check single cells with a "handheld" instrument. 
Measure pack current and the voltage & temperature of groups of thermally coupled cells in a xxS pack under pulse load. 
How many cells in a group? To be determined, based on practical considerations and specs.


----------



## johnsiddle (Jun 22, 2011)

Has anyone come up with a good way of making a high amp connection to the U connectors or half U in the case of blocks being split up?
regards john


----------



## Ampster (Oct 6, 2012)

I visited Hybrid Auto a few months ago. He has made some custom copper straps for his packs of Volt cells.. Different lengths and hole configurations for different combinations of parallel cells.

Sent from my SM-N910T using Tapatalk


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> I visited Hybrid Auto a few months ago. He has made some custom copper straps for his packs of Volt cells.. Different lengths and hole configurations for different combinations of parallel cells.
> 
> Sent from my SM-N910T using Tapatalk


Hi Ampster.
Thanks for the post, did you happen to see exactly how he made the connection onto the U links, in my pack there are no holes just the tabs from the cells welded in a sandwhich with the U link.
I don't much like the idea of trying to drill holes in these to connect power interconnect cables.
For instance I want to connect a 30 block to a 24 block but remove 12 modules from this 24 block. I will then need to connect a power cable to the cut U link to give me 42 modules in series to give me 172.2v (42X4.1v). 
I think this question was asked early on in this thread but no one answered it.
Regards John


----------



## Maniaccts (Nov 7, 2015)

To get 42s couldnt you just connect a 96v a 48v and a 24v. I would use the same bus bar that they were originally all connected with in the first place.


----------



## favguy (May 2, 2008)

Hi John,
Just seen this. I've e-mailed you, but now I see what you are doing, thought I'd chip in. 

Have you actually took all the top covers off the batteries yet? You will be pleasantly surprised to find you don't need to cut anything to get what you need! 

All the batteries you have break down to 7 x 12 module blocks and 2 x 6 blocks. each block already has its own terminals. All you need to do is remove the top banding, joining links, then bottom clamping bolts and you can match and mix the module blocks to suit, then clamp back together using appropriately long 6mm theaded bar for the bottom bolts.


----------



## johnsiddle (Jun 22, 2011)

favguy said:


> Hi John,
> Just seen this. I've e-mailed you, but now I see what you are doing, thought I'd chip in.
> 
> Have you actually took all the top covers off the batteries yet? You will be pleasantly surprised to find you don't need to cut anything to get what you need!
> ...


Ok Guys.
I was trying to be clever (the wife says its something I am not good at) and was looking at it from the (three) chargers point of view.
I was looking to make 3 X 14 modules.
But both your ideas are perfect.
I had only briefly taken the tops off to count the modules just after I got them and didn't look too close at the connections.

Now life is easy. Thank you!!!!
Merry Christmas to you all...


----------



## Ampster (Oct 6, 2012)

johnsiddle said:


> Hi Ampster.
> Thanks for the post, did you happen to see exactly how he made the connection onto the U links, in my pack there are no holes just the tabs from the cells welded in a sandwhich with the U link ................
> Regards John


I am sorry, I reviewed my notes and it was a Nissan pack that I had seen. Subsequently you have gotten some better responses.

Sent from my SM-N910T using Tapatalk


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> I am sorry, I reviewed my notes and it was a Nissan pack that I had seen. Subsequently you have gotten some better responses.
> 
> Sent from my SM-N910T using Tapatalk


Thanks Ampster.
I was being a bit thick anyway and making life more difficult for myself.

I hope you have a Merry Christmas and a Happy New Year.

John


----------



## johnsiddle (Jun 22, 2011)

*Re: 2012 Chevy Volt Battery: Watercooling the modules.*

Hi Guy's.
Does anyone know how the cooling liquid, water etc, circulates around these blocks.
Two of my blocks have blanking plates on the end and I cannot see any way across to the other side for a return.

I worked out yesterday that I cannot fit all my blocks in the boot (they are too big by 1.5 modules) so have decided to mount two 12 blocks in the front and seeing as I have now got space in the boot I thought I might as well water cool them.

Hope you are all having a good Christmas.
Regards John


----------



## Hugh-Falls (Aug 9, 2010)

The individual cells in the modules are held together at the top with banding. Would it be possible to cut off the water cooling manifolds on each side and substitute an additional band at the bottom for the tie rods/holes that have been cut off? The cut off could be done nicely on a radial saw or even with a skillfully guided hand saw.

This would yield a compact brick shaped module.


----------



## johnsiddle (Jun 22, 2011)

Hugh-Falls said:


> The individual cells in the modules are held together at the top with banding. Would it be possible to cut off the water cooling manifolds on each side and substitute an additional band at the bottom for the tie rods/holes that have been cut off? The cut off could be done nicely on a radial saw or even with a skillfully guided hand saw.
> 
> This would yield a compact brick shaped module.


The oversize was in the length, width wise, stacks of room to run two blocks side by side.
I am not sure how important the water cooling requirement on my car will be so I am going to plumb in a small header tank and a small oil cooler rad just in case. 

I will post some pic's later.

Happy New Year.....

Regards John


----------



## johnsiddle (Jun 22, 2011)

Here is some pics, starting from the first strip down.
I have only just started the wiring and plumbing is waiting for som silicon pipe to arrive.
Although they are strapped to the floor of the boot the insulation packing is to make sure they don't swing sideways when I go around a corner at 90MPH..... 
The two blocks are also strapped together at the top with pull down straps to the bottom to stop the top clamps sliding up and possibly shorting out.



The next post will be back on my own thread.


----------



## Hugh-Falls (Aug 9, 2010)

For the water heating/cooling circuit of the batteries, it would probably be simpler to use an automobile heater assembly which has all the needed elements for regulating the temperature, like fans, thermostats, coolant valves, shutters, etc. Also you have a vast collection from which to choose and the price is right.


----------



## johnsiddle (Jun 22, 2011)

Hugh-Falls said:


> For the water heating/cooling circuit of the batteries, it would probably be simpler to use an automobile heater assembly which has all the needed elements for regulating the temperature, like fans, thermostats, coolant valves, shutters, etc. Also you have a vast collection from which to choose and the price is right.


Thanks for the tip, I will look into it.


----------



## johnsiddle (Jun 22, 2011)

Since the last post I have been looking at cooling requirements and according to various internet post's charging at 0'C is a no no.

So my problem is I need to start water flow in order to test the temp of the pack, and a consequence of that is pushing water thro the rad.
Now if the air temp is at or below zero then all I will be doing is to cool the pack down to low temps.
If I do not start the coolant flowing because it is cold outside, how do I know what the pack temp is?, Since there are multiple cells to consider where is the best position to place a temperature probe? 
Is the linking points of the cells a good place to fix a probe, I was thinking of those little bimetal probes set with a temp of 30'C or 40'C.
If I use NC probes connected in series, if one opens due to temp then that will signal cooling required for everyone.
OR 
Do I set up a heater system to maintain a constant pack heat at the beginning of charge, bypassing the radiator and then switching the rad back in and heater off as required, active irrespective of the outside temperature?

Or do I forget about cooling during the charge cycle (to start with I only have 9amps current availability so maybe they wont get hot) and only bring the cooling into action during the drive.

So many questions.... How do you guy's do it..
regards John


----------



## Tomdb (Jan 28, 2013)

There must be some temperature sensors in the pack already.

Check this presentation, (probably repost in this thread)

https://drive.google.com/file/d/0By5MvU_4AFykSy1aaU1MQkYxeUk/view


----------



## johnsiddle (Jun 22, 2011)

Tomdb said:


> There must be some temperature sensors in the pack already.
> 
> Check this presentation, (probably repost in this thread)
> 
> https://drive.google.com/file/d/0By5MvU_4AFykSy1aaU1MQkYxeUk/view


Good link Tom but finding the connections is easier said than done, I tried to isolate each cell connection but some cells appear have more than one connection to the socket on the top so I gave up, to get it wrong could be dodgy.
I am hoping that since the tabs are a metal connection to the Lithium then heat transfer will be rapid. Hence the thought that the U connectors would be a good place.
John


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> Good link Tom but finding the connections is easier said than done, I tried to isolate each cell connection but some cells appear have more than one connection to the socket on the top so I gave up, to get it wrong could be dodgy.
> I am hoping that since the tabs are a metal connection to the Lithium then heat transfer will be rapid. Hence the thought that the U connectors would be a good place.
> John


Any other solution than using the internal temperature sensors is less than optimal. Here you have the pinout for those orange connectors, so you can use the sensors. Be careful in either case.


----------



## Tomdb (Jan 28, 2013)

I will almost bet they are using 10K thermisters. Because they have a "low" reference and an temp signal, and located above each other on the connectors.


----------



## piotrsko (Dec 9, 2007)

Yabert posted connector pinouts early on in one of these chevy battery strings. I verified his are correct.

If you have a factory pack there are thermistors everywhere: coolant input, output, control boards, fuse, inside battery pack every couple of cell groups.....

Running the batteries with preheat to say 40c would be nice, no huge need for cooling them during charge. (Or at least up to 50c here in Reno and 10 amps). Not really a need to cool them during run. (At least up to 800 amps tested and perhaps 500 watts into coolant tank). YMMV.

But what could I possibly know from running them for two years, 500 cycles, 3000 miles, 70% DoD?


----------



## johnsiddle (Jun 22, 2011)

Thanks Guy's you are just the people I hoped would reply.
Your experience is invaluable.
The printouts of the BMS sockets will do the trick, I couldn't find Yaberts post on the subject but I am sure the manual details are correct.
It looks like the Temp sensors are on the same connectors in each block, so I will sort out a controller to pick them up and use them.
I suppose the only problem is knowing what they read at 40'C, the batteries are a bit big to to put in an oven.
I have however bought a digital temp reader and probe from Ebay which I could use to main the temp of water being pumped around the block whilst reading the onboard sensors.

I was interested to see that you do not consider cooling a requirement how ever I think I will go with designing/incorporating a pre-heat system for here in the UK in winter. Not sure what air temperatures you get in Reno apart from the 50'C you mentioned, that would be wishful thinking in the UK.
At least it will only be used when charging, so I will be able to use 240v valves for the job of bypassing the rads.

Perhaps the Chevy heater unit could be used if I can figure out the voltage it is run on, when I remember where I put it for safe keeping. Old age is not a very good friend of the memory.
Thanks again.
Regards John


----------



## Brute Force (Aug 28, 2010)

Temperature sensor values from the 2012 Chevy Volt Service Manual:

Temperature Resistance (typical)
-40C  75.5K
-20C 21.5K
0C 7.2K
20C 2.7K
40C 1.2K
60C 0.5K
80C 0.3K
100C 0.16K

Hope that helps!


----------



## johnsiddle (Jun 22, 2011)

Brute Force said:


> Temperature sensor values from the 2012 Chevy Volt Service Manual:
> 
> Temperature Resistance (typical)
> -40C 75.5K
> ...


Thanks Mate,
That's perfect, I will go for a 30C +- 5C, I read that 30C is a good temp to charge/run at.
This should be easy enough to implement with a micro Arduino or three.
Thanks again.
John


----------



## piotrsko (Dec 9, 2007)

The heater in the coolant input connector wanted pack voltage, heat is reduced at 1/2 voltage by about 1/2. It is only a 10 amp relay running it so maybe 1500-2000 watts rating at pack power.

These Batteries REALLY prefer being at >35c

In the summer in Reno it will stay at 40-50c for a month or two. 35c is the morning low.

Temp sensor is in the same position on long or short connectors, but it is easier to find the wire color in the harness to be sure.


----------



## johnsiddle (Jun 22, 2011)

piotrsko said:


> The heater in the coolant input connector wanted pack voltage, heat is reduced at 1/2 voltage by about 1/2. It is only a 10 amp relay running it so maybe 1500-2000 watts rating at pack power.
> 
> These Batteries REALLY prefer being at >35c
> 
> ...


Thanks Mate.
I was just looking at the temp sensors/sensor, it looks like they are isolated from the rest of the pack, so that makes life easier.
I think I can do the basic sensing/switching using ne555 timer chips, one chip for doing the basic on/off heat circulation and a second one to sense if things get too hot (say 45'C) to bring in the rad, fan and circulation pump and lock out the heater, turning off at about 35'C if the outside air gets it down that far, we don't have very hot summers here.

I shall aim to heat 35'C, +5 -0 as per your advice.

I have my spare 12 module pack on my desk, when I brought it in from the car the temp sensor was reading 20k (its cold here in the UK at present) but after a couple of hours in the house (no heating on) it is now reading about 15k.
I have only found the one sensor so far and the reading is between pins 9 and 18. Maybe there is only one in a 12 pack.

Maybe the heater will work OK at 240V ac, if I can find where I put it. 
According to the presentation on here the circulation pump is in the same part as the heater, if that is so, it can only be in the other pipe connector. 
I will have to investigate that, I thought that just had a temp sensor in.

John


----------



## johnsiddle (Jun 22, 2011)

Thinking about it, for heating, I only need to control the temp of the coolant which can be done separate to the pack sensors.
Then only use the pack sensors to over-ride things if things get too hot. IE: block out the heater and open up the rad and circulation pump.

John


----------



## johnsiddle (Jun 22, 2011)

johnsiddle said:


> Thinking about it, for heating, I only need to control the temp of the coolant which can be done separate to the pack sensors.
> Then only use the pack sensors to over-ride things if things get too hot. IE: block out the heater and open up the rad and circulation pump.
> 
> John


Just checked out the other pipe fitting, just as I thought it is just a temp sensor, but I also found the heater and that has a temp sensor as well same as in the other fitting. 
So if the heater can be made to work that will be very useful, the sensor is reading about 3.5k at body temp (wrapped my hand around it to warm it up) so that can be used.

The heater is reading about 72ohms if it will withstand 240v (3.33amps) it will be about 799watts. That would work, just a bit slower to warm the pack.
My calculations put it at about 2kwatt at 350v (5.34amps)
At 160v pack voltage, it is only about 350watts, but that might be useful given the pack will be generating a bit as well. It will start off from the house hot as the charge point will be connected all the time it is in the drive.

I will try 240 on it later and see what happens.
John


----------



## Vanquizor (Nov 17, 2009)

Does anyone have the dimensions of the hold down brackets that clamp the modules to its base? I tossed mine before recording and now regret it...


----------



## eldis (Sep 3, 2013)

Vanquizor said:


> Does anyone have the dimensions of the hold down brackets that clamp the modules to its base? I tossed mine before recording and now regret it...


I think that a detailed CAD model of the entire battery assembly would be nice (if anyone cares to bother) 

Vanquizor, I'll be in my workshop later this week, so in the worst case I'll measure them for you.


----------



## Duncan (Dec 8, 2008)

piotrsko;
These Batteries REALLY prefer being at >35c
[/QUOTE said:


> Where does that come from?
> 
> 35C is hotter than it ever gets here!
> 
> I was under the misapprehension that battery life went down over 30C


----------



## eldis (Sep 3, 2013)

Duncan said:


> Where does that come from?
> 
> 35C is hotter than it ever gets here!
> 
> I was under the misapprehension that battery life went down over 30C


Are we talking degrees Celsius? I always enjoyed this comparison - batteries are like humans. If you're too cold or too hot, they are too


----------



## puddleglum (Oct 22, 2008)

piotrsko said:


> These Batteries REALLY prefer being at >35c
> In the summer in Reno it will stay at 40-50c for a month or two. 35c is the morning low.


Are you talking ambient temp or battery temp? I know you're the expert when it comes to repurposing these packs, but your temps (95F/35C) are a lot higher than what GM is saying they regulate the battery temperatures to. http://gm-volt.com/2013/05/03/volt-battery-thermal-management-system-in-the-hot-arizona-sun/
Are you sure you have your F/C temp conversion right? Just wondering why you are saying to keep them so much hotter. Also, if it gets to 122*F (50C) in Reno I never want to go there.  They start issuing extreme heat advisories here above about 85F


----------



## piotrsko (Dec 9, 2007)

Yup I'm about 10/ 20 degrees high in my lousy F / C conversions. Sorry I'll stay Fahrenheit. 100/105 degrees in reno for highs (but it is a dry heat) 85 for lows . Batteries are happiest at 85 providing max current which doesn't drop off as you go hotter. Some studies say life degrades at higher temps, I haven't experienced that yet. They do perform poorly at <70, but so do I.

It appears that the engineers thought about everything that could affect life and backed off for their specifications. Still dont hear parked volts cycle in parking lots, though.


----------



## johnsiddle (Jun 22, 2011)

So what you are all saying is that 30-35c is a good temp range to run these batteries at.
Pretty much back where I started.
Regards John


----------



## johnsiddle (Jun 22, 2011)

*Re: 2012 Chevy Volt Battery: Heater*

Just put 240v ac on the Volt heater.... Brillient heats up very quickly without any coolant and being in it own case complete with temp sensor, which went down to 230ohms very quickly, makes it perfect.
Just need to fix an exit pipe to it ( didn't have the original fixings) and it will be ready to incorporate. 
John


----------



## Yabert (Feb 7, 2010)

johnsiddle said:


> ... I couldn't find Yaberts post on the subject ...
> It looks like the Temp sensors are on the same connectors in each block


Good point.
Resolved!


----------



## johnsiddle (Jun 22, 2011)

Yabert said:


> Good point.
> Resolved!


Hi Yabert.
I noticed none my connectors have wires on pin1 and pin10 even though the printouts from the manual shows temp sensors on pin1 and pin2, and another sensor on pin9 and pin10 with another low ref on pin18.

Since I only have a resistance between pin9 and pin18 as in your picture I assume there is only one temp sensor per connector.
My pin2, although showing as a low ref and having a wire connected, does not seem to connect to anything in the pack, certainly not in the 12 pack.
Maybe they have reduced the number of temp sensors in my pack. 
I guess as long as I have sensors dotted about the packs that should be sufficient.
John


----------



## Brute Force (Aug 28, 2010)

Connector pinouts from the 2012 Chevy Volt Service Manual:

Pin---Function
1-----Not Used
2-----Low Ref Battery
3-----Cell 2 Voltage
4-----Cell 4 Voltage
5-----Cell 6 Voltage
6-----Cell 8 Voltage
7-----Cell 10 Voltage
8-----Cell 12 Voltage
9-----Battery Module Temperature
10----Not Used
11----Cell 1 Voltage
12----Cell 3 Voltage
13----Cell 5 Voltage
14----Not Used
15----Cell 7 Voltage
16----Cell 9 Voltage
17----Cell 11 Voltage
18----Battery Module Temperature Low Reference

Or

Pin---Function
1-----Not Used
2-----Cell 12 Voltage
3-----Cell 14 Voltage
4-----Cell 16 Voltage
5-----Not Used
6-----Not Used
7-----Not Used
8-----Cell 18 Voltage
9-----Battery Module Temperature
10----Not Used
11----Cell 13 Voltage
12----Cell 15 Voltage
13----Not Used
14----Not Used
15----Not Used
16----Not Used
17----Cell 17 Voltage
18----Battery Module Temperature Low Reference


----------



## johnsiddle (Jun 22, 2011)

Brute Force said:


> Connector pinouts from the 2012 Chevy Volt Service Manual:
> 
> Pin---Function
> 1-----Not Used
> ...


Thanks Mate, that's a big help, obviously they have changed the specs..
John


----------



## johnsiddle (Jun 22, 2011)

I noticed Yabert has connected all of his cells in parallel, is this something everyone has done?
I know you would need to do this if using a BMS on each cell group.

The way I was planning to do it was to put each block of 14 cells in parallel and charge in three groups of 14 cells using an Arduino nano to check the block voltage (57.4v for 14 cells at 4.1v) and control each charger as required. 
Topping up when/if the voltage drops to 55.5v (3.99v per cell) whilst parked.

Can anyone see a problem with this idea?
Regards John


----------



## puddleglum (Oct 22, 2008)

piotrsko said:


> Batteries are happiest at 85 providing max current which doesn't drop off as you go hotter. Some studies say life degrades at higher temps, I haven't experienced that yet. They do perform poorly at <70, but so do I.


If that is the case, I'm thinking a heating system for these is far more important than a cooling system in a cold northern climate. Are these packs going to require constant heating to have them work in subfreezing temps? Will they need to be heated first in order to charge and then kept warm to have them ready to drive? Does GM preheat them in the Volt? I haven't been able to find anything to say how they keep them warm in winter other than running the gas engine. Not an option for us.


----------



## ken will (Dec 19, 2009)

puddleglum said:


> If that is the case, I'm thinking a heating system for these is far more important than a cooling system in a cold northern climate. Are these packs going to require constant heating to have them work in subfreezing temps? Will they need to be heated first in order to charge and then kept warm to have them ready to drive? Does GM preheat them in the Volt? I haven't been able to find anything to say how they keep them warm in winter other than running the gas engine. Not an option for us.


I agree, for those of us fortunate to live away from the Equator, Heating is more important than cooling the batteries.

Using stationary electric power when possible to preheat the system, insulation,and limited battery power to keep the system from getting too cold, seems the most efficient.


----------



## piotrsko (Dec 9, 2007)

I run them at at least 50 to charge, then depending on outside temp I warm them to 60-70 in the hour before work, done with timers and a relay on the interlock of the ELCON charger. If I'm not using the car it stays at ambient which right now is 20. If it is below 60 I turn off the coolant pump and go commando. I never run coolant to charge, but I charge at 1/10C or 9 ish amps but my pack is 196v 90ah split.

I had a pump power wire fail one time on the way to work, freaked out until I noticed the coolant coming out of the pack STILL wasn't all that warm.

Note: to work included monster hill that comes close to melting the comm on my motor by using about 6 Kwh to pull.

YMMV


----------



## halestorm (Apr 28, 2009)

Yabert said:


> Good point.
> Resolved!


Please describe the mechanical connections to the cell tabs shown in the photo of post #393.


----------



## Yabert (Feb 7, 2010)

halestorm said:


> Please describe the mechanical connections to the cell tabs shown in the photo of post #393.


Everything is here (p. 30-31): http://www.diyelectriccar.com/forums/showthread.php/smart-fortwo-ev-high-power-version-51472p30.html


----------



## Duncan (Dec 8, 2008)

Question for you guys
What are the differences between 2011 - 2015 battery packs?
How much less should I pay for a 2011 pack than a 2014 pack?


----------



## halestorm (Apr 28, 2009)

Yabert said:


> Everything is here (p. 30-31): http://www.diyelectriccar.com/forums/showthread.php/smart-fortwo-ev-high-power-version-51472p30.html


So, if I understand correctly, you just TIG welded copper wire to the cell tabs?

Incidentally, my Porsche 914 with Chevy Volt batteries is now online; took my first drive last night! Drove another 28.8 mi today.

What voltage are you charging your Volt cells to? And how low do you allow them to discharge?


----------



## piotrsko (Dec 9, 2007)

Afaik: 2011 to present: software differences on discharge levels in the controller.

I charge to 4.1. Discharge to 3.5 standing. In my case absolute limp home limit is 3.2. But I will expect cell damage which I havent seen yet.

1.5 to 2.0 @ 400 amps

Newer means less cycles used. What a 2011 is worth??? Offer a grand. Early adopters got them for 500 to 750 until wreckers found out they were worth something and now charge accordingly.


----------



## johnsiddle (Jun 22, 2011)

Hi Guy's
I have confused myself again, what it the minimum pack temperature for charging a Chevy pack, below which you should not start to charge, is it 20C or 25C.?
I read it some where and can not find it again.

I have just finished my Arduino Nano based temp controller and suddenly thought, have I set it wrong at 25C.

I have finished the three 57.4v charger controllers, basically an Arduino Nano is used in each to sense the pack of 14 cells voltage and turn the charger off at 57.4c which is roughly 4.1v per cell. it also turns it back on if the cell voltage drops below 3.91v to keep the pack topped up.

regards


----------



## johnsiddle (Jun 22, 2011)

Ok Guy's
Doing a search on Google got me several pages and the opinion is that Li-Ion packs should not be charged below zero C.
Apparently anything up to 30C is a good place to start charging so I have changed my program to check for pack temp below and including 15C. 
At least the pack will start charging quicker.

Also charging above 45C is a no no as well, but as my program stops the charging above 36C and starts to cool it, 45C is already covered.


----------



## halestorm (Apr 28, 2009)

johnsiddle said:


> Also charging above 45C is a no no as well, but as my program stops the charging above 36C and starts to cool it, 45C is already covered.


How do you cool it?


----------



## johnsiddle (Jun 22, 2011)

Hi mate.
I have got a radiator and fan assy from a watercooled scooter, I then fitted an electric central locking solenoid to a 3 port zone valve, plus a 12v water pump (actually a 24v diesel transfer pump which works on 12v) to push coolant thro the system.
These parts are all controlled by an Arduino Nano which senses the temp leaving the pack, it also checks the sensor that is in the original heater which is used to heat the pack, incase it loses coolant and the heater over heats .
Depending on the temp, the zone valve either bypasses the radiator or allows it thro, the pump is going all the time and the heater, fan and rad are all switched in as required.

All I need to do now is plumb it in.


----------



## mons2b (Nov 17, 2015)

has anyone tried using one of the many simple bms circuits on ali express? or any of the other sites for their Volt batteries? Im looking for an affortable solution. I want to use 48v modules in parallel to achieve 144v. I find it hard to get my head around how a 144v charger will work with such BMS designs. IVe looked at Mini BMS but it still seems expensive. Using the below I could get by with 6 of them.

http://www.batterysupports.com/44v-...-lithium-ion-lipolymer-battery-bms-p-268.html

 *44V 48V 50.4V 30A 12S Lithium ion / LiPolymer Battery Pack BMS for E-bike*
 *12S 30A Li-ion / LiPO Battery protection board.*











 *Applicable for *
 43V (3.6V * 12S) lithium battery & packs
44V (3.7V * 12S) lithium battery & packs
50.4V (4.2V * 12S) lithium battery & packs

 Lithium battery (Li-ion)
 Prismatic Lithium Polymer battery (Li-Po)

 *Technical Parameters:*
 Balanced current: 60mA (VCELL = 3.90V when)
 Balanced for: 4.20 ± 0.05 V
 Over-charged Protection: 4.2 ± 0.05 V
 Over-charged Release: 4.05 ± 0.05 V
 Over-discharged Protection: 2.9 ± 0.05 V
 Over-charged delay: 5mS
 Over-current Protecton: 30 A
 Supports Max. Continuing Discharge Current: 30A
 Static power consumption: less than 200uA
 Short-circuit protection function: disconnect the load from the recovery.

 *Dimension*: 129mm * 53mm

 *The main functions*: Over-charged, Over-discharged protection, short circuit protection, over-current protection, with Balancing function.


----------



## johnsiddle (Jun 22, 2011)

mons2b said:


> has anyone tried using one of the many simple bms circuits on ali express? or any of the other sites for their Volt batteries? Im looking for an affortable solution. I want to use 48v modules in parallel to achieve 144v. I find it hard to get my head around how a 144v charger will work with such BMS designs. IVe looked at Mini BMS but it still seems expensive. Using the below I could get by with 6 of them.
> 
> http://www.batterysupports.com/44v-...-lithium-ion-lipolymer-battery-bms-p-268.html
> 
> ...


Hi Mate.
Firstly, I assume you mean 48v modules in series, not parallel.

I did look at these BMS but came up with two problems, three if you count cost.
Firstly you need to make a connection to each of the cells, ok if you have access to a Tig welder not so easy if not.
Secondly you also need to buy three chargers, the ones they recommend only charge at 4A (a bit slow I fear) unless you can find one that will charge at 151.2v at, I believe 9/10amps min, not an easy option nor cheap.
Or buy three 50.4v chargers also not cheap, they also need to have isolated outputs otherwise you will get fuses blowing each time you connect them, unless you use relays to break the series connections of the pack when you want to charge (this would need at least two high current relays in the main power lines, not a good option).

A lot of the guy's on here do not think full top and bottom balancing is required, myself included although if all the cells were connected by nuts and bolts it would be easier to implement and an added luxury.
A long time ago, I saw a build on one of the other forums (the one with lots of different conversions of all types) where he made a small and simple controller for each of his cells using zeners and a bit more circuitry, but I have not been able to find it since, that was I believe, a top balancing BMS.

The important thing as far as I am concerned is max and min temperature of the packs and max and min voltages of the cells or pack in total.

My method is to use the three 55v 9A power supplies (which will go up to about 58v) I used to charge my flooded leads and to use an Arduino Nano on each PSU to switch off the charger when the pack (I am using three blocks of 14 cells) voltage reaches 57.4v (4.1v per cell) and switch back on at 54.6v (cell voltage 3.9v) to top it up and keep it fresh. I use 10A relays to isolate the chargers out puts when not charging, to prevent any chance of pack leakage back through the chargers.
I understand it is better to stop at 4.1v per cell to extend life, also I believe the cell voltage continues to rise a little after charging has stopped, although if the charge is slow enough this tends not to happen. I am hoping 9A is slow enough.

I am also using a fourth Arduino Nano to check the temperature of the coolant leaving the pack and delay charging until it reaches 16C ( considered a safe lower temp for charging Li-on cells) and to stop charging if the temp rises to 36C and above(considered unsafe for charging Li-on cells), switching on the pump, heater, radiator etc, depending on the coolant temperature.

I know this doesn't answer your question but I hope it is food for thought.
Good Luck.
John


----------



## mons2b (Nov 17, 2015)

johnsiddle said:


> Hi Mate.
> Firstly, I assume you mean 48v modules in series, not parallel.
> 
> I did look at these BMS but came up with two problems, three if you count cost.
> ...


Hi John

I was going to use a 144v charger that will auto cut off at that voltage. Would the charger infact need to cut off at 150v?
Also re the tabs on the batteries. Apparently they are soft. Why not gently bend then over and drill a suitable hole for a bolt into it. one by one. with the nearby tabs covered to prevent shorts. then gently bend them back one by one.

Also instead of Arduinos why not just use simple temperature control circuits that are a dime a dozen on the various electronics websites. Would seem a cheaper easier option? Thats what I plan to try along with a suitable relay and either blow air down the water channel or pump coolant.


----------



## halestorm (Apr 28, 2009)

johnsiddle said:


> Hi Mate.
> 
> Firstly you need to make a connection to each of the cells, ok if you have access to a Tig welder not so easy if not.


There is built-in easy access to each cell for BMS purposes (not high current, though). Just use the existing BMS connector. I cut one end off the BMS cable and wired it to my Elithion BMS boards. The other end attaches to the batteries.


----------



## mons2b (Nov 17, 2015)

halestorm said:


> There is built-in easy access to each cell for BMS purposes (not high current, though). Just use the existing BMS connector. I cut one end off the BMS cable and wired it to my Elithion BMS boards. The other end attaches to the batteries.


Hi Dave.

If you use that connector in that manner does the charging go through those BMS's also how are the batterys connected out for the high current "main line" to the controller? I want to have 3x48v modules in the trunk and the other three up the front under the hood. ie 144v
n parallel jointed at the front then feed to the controller. Excuse my ignorance. Ive been doing my best to read up on this but still find it confusing. 

John


----------



## halestorm (Apr 28, 2009)

No, the charging does NOT go through the BMS. They are fairly light gauge wires connecting the BMS boards to the cells, maybe 20 ga (?). The high-current connections are through the 6mm studs on either end of a module. Now, if you need high current connections to each cell tab, there was someone on the forum here that spot-welded copper wire to each tab but I don't think you need that. What you want to do sounds exactly as I did (except that I used more than 3 48v modules. 

In my case, I made two serial strings of modules, one of 3x38 + 3x24, and the other 4x48 + 1x24, for a total of two 216v series strings. I then placed those two strings in parallel, all using the 6mm stud posts on the modules and 2 ga welding cable. That gives me 216v/90Ah in total. You can see some pictures of that in evalbum page.

Because they are in series, each cell needs his own BMS. I spent as much on the BMS as I did on the batteries, with 108 cell boards.


----------



## johnsiddle (Jun 22, 2011)

halestorm said:


> There is built-in easy access to each cell for BMS purposes (not high current, though). Just use the existing BMS connector. I cut one end off the BMS cable and wired it to my Elithion BMS boards. The other end attaches to the batteries.



I was going to use a 144v charger that will auto cut off at that voltage. Would the charger infact need to cut off at 150v?
Also re the tabs on the batteries. Apparently they are soft. Why not gently bend then over and drill a suitable hole for a bolt into it. one by one. with the nearby tabs covered to prevent shorts. then gently bend them back one by one.

Also instead of Arduinos why not just use simple temperature control circuits that are a dime a dozen on the various electronics websites. Would seem a cheaper easier option? Thats what I plan to try along with a suitable relay and either blow air down the water channel or pump coolant. 



Hi .

You are of course correct Halestorm, I had forgotten about those connections.
I am not sure how you connect those BMS bds from the likes of Alibaba to cater for 144v or in this case 151.2v (assuming 4.2v) or 147.7v (assuming 4.1v).
144v only gives 4v per cell which although useful, is somewhat low on full capacity.

Perhaps you could post details of your Elithion BMS Bds and how you have connected them. I would find the info useful, as I am sure, would others. 

Others have used air to cool, I am not sure what sort of winter temps you guy's get but up here in UK we need heat as well.
If you google 'charging Li-on batteries, near to and below freezing is a no no as is above 40C.
I don't know how easy air gets through the cooling pouches, you might need a bit of pressure to make sure. Also make sure you filter the air because cleaning dust out of those pouches would be near impossible.
Again with the cheap temperature controllers, you would need to make sure they operate in the range you want, they are cheap after all.

I am all for experimenting (this is what this forum is about after all) and going cheap, but with a battery pack that in my case cost £1650 I want to be as sure as possible that I am not going to destroy it by experiments and by going too cheap.
Arduino Nano's are only about £2 each and with a few added components and a bit of simple programming need not cost very much.
But being an electronics engineer I always go for the most sophisticated method and usually waste money in the process. Your approach is probably better than mine.

John


----------



## johnsiddle (Jun 22, 2011)

halestorm said:


> There is built-in easy access to each cell for BMS purposes (not high current, though). Just use the existing BMS connector. I cut one end off the BMS cable and wired it to my Elithion BMS boards. The other end attaches to the batteries.


Hi Halestorm.
I like your build but one thing that worries me having seen a picture of a battery pack that expanded due to so discharge fault. The thread was on this site somewhere.
I notice you do not have any banding at the top of the packs, if any cells decided to swell up, the metal end plates at the end do not seem to be ridged enough to contain the pack at the top.

just a thought.
Regards John


----------



## mons2b (Nov 17, 2015)

with fans i was thinking one fan pushing on one end and on the other end another one sucking the air out. A filter is a good idea.
In NZ it doesnt get more than say -4 where I am and thats during the middle of the night when I will have it in my garage which doesnt tend to go below zero. I may put warm fuzzy blankets over the batts when i charge them after getting home in winter.  Or prehaps ill just have some insulation around them. Undecided. Right now trying to find someone in the USA willing to take my money. Its hard as they want a US credit card. Ill keep trying.


----------



## halestorm (Apr 28, 2009)

johnsiddle said:


> I was going to use a 144v charger that will auto cut off at that voltage. Would the charger infact need to cut off at 150v?


I suppose that depends on what you want out of a BMS -- is the "M" for "management" or "monitor"? I use the Elithion Pro BMS as a battery management system; the BMS has full control -- control over the battery charger and control over the motor controller. So in that case you want a dumb charger. I didn't end up with a dumb charger (my Elcon charger has smarts) so I have it programmed for a voltage higher than I would want, so that the "smarts" never kick in. The BMS then commands the charger when to turn off.

Similarly for the motor controller. I have an Azure Dynamics DMOC, which has various built-in protections, all of which I have now disabled. The Elithion tells the DMOC to cut back on power if it thinks it is discharging too much, and will disable the regen in the motor controller.

But, if you don't want to manage the batteries then you probably need a smart charger. In that case you have to decide up front what level you are going to charge to (unless you have a user-programmable charger). I've already changed my mind twice on the high end of my cell voltage, but this is all easily tweaked in my BMS. The Volt cells can go to 4.15v/cell, so that's 49.8v/module, or 149.4v total in your case.



johnsiddle said:


> Also re the tabs on the batteries. Apparently they are soft. Why not gently bend then over and drill a suitable hole for a bolt into it. one by one. with the nearby tabs covered to prevent shorts. then gently bend them back one by one.


I don't think they are quite that soft. The tabs themselves might be that soft but they are spot welded onto a U-shaped piece which is quite rigid. I don't think you can do what you are suggesting.



johnsiddle said:


> Also instead of Arduinos why not just use simple temperature control circuits that are a dime a dozen on the various electronics websites. Would seem a cheaper easier option?


Cheaper and easier than what? There are thermistors already embedded in each module; what could be easier than using what is already there? Or perhaps I just don't understand what you want to do here.




johnsiddle said:


> I am not sure how you connect those BMS bds from the likes of Alibaba


Connect each signal on the connector indicated in their diagram here,







to the appropriate pin on the Volt BMS connector.




johnsiddle said:


> to cater for 144v or in this case 151.2v (assuming 4.2v) or 147.7v (assuming 4.1v).
> 144v only gives 4v per cell which although useful, is somewhat low on full capacity.


I've been charging to only 4.05v, and have been thinking of going to 4.0v/cell. Again, the Elithion gives me full control over that.



johnsiddle said:


> Perhaps you could post details of your Elithion BMS Bds and how you have connected them.


I've attached a couple of shots from my notebook; the first shows the pinout of the Volt BMS connector and the second shows how those connect to my Elithion cell boards. Also attached are a couple of photos of the completed boards.


----------



## halestorm (Apr 28, 2009)

johnsiddle said:


> Hi Halestorm.
> I notice you do not have any banding at the top of the packs, if any cells decided to swell up, the metal end plates at the end do not seem to be ridged enough to contain the pack at the top.


That photo was taken at an early stage; I do have banding. I also have the bus bars at the top, to both the cell posts and the attachment posts. The bands are not as rigid as the original steel bands. I used what I could find. At work I have the heavy plastic banding material (and tools) for banding items to pallets, so that's what I used. It can stretch somewhat, but it does put a bit of a squeeze on the cells.


----------



## halestorm (Apr 28, 2009)

johnsiddle said:


> Others have used air to cool, I am not sure what sort of winter temps you guy's get but up here in UK we need heat as well.
> If you google 'charging Li-on batteries, near to and below freezing is a no no as is above 40C.
> I don't know how easy air gets through the cooling pouches, you might need a bit of pressure to make sure.


They are designed for liquid thermal management (heating/cooling). I took the heaters out -- I don't need heaters in Los Angeles. My biggest concern is cooling, but I'm not going to add a refrigerant compressor to my car. I'm going to add water pump and a radiator and just run it open loop and hope for the best.


----------



## mons2b (Nov 17, 2015)

Re the temp control boards I was merely making the point they are less than 10 usd each vs whatever a audiweno or however its spelt costs. I dont quite follow what defines a smart vs dumb charger. I do not have a lot of money so I am sailing close to the wind as they say but trying to achieve an acceptable result. Hense I am going to use a motor and controller and charger from china that are far cheaper than the mainstream choices on this form. Of course I cant have my cake and eat it so things like regen are not available to me. The controller will be locked to the motor settings wise. The charger is non adjustable once it leaves the factory. They will program whatever voltage cut off I want but again its locked after that. That may seem annoying but the charger is far less than half the price of the usual type of charger quoted here. It will cut off at whatever voltage I ask them to set it to. I dont see how I can have a BMS make the charger do anything?


----------



## halestorm (Apr 28, 2009)

mons2b said:


> I dont quite follow what defines a smart vs dumb charger.


There is a discussion on chargers on Elithion's site here. By "smart" charger I meant a charger which has a specific profile (voltage/current) programmed for your type of batteries and size of pack.


----------



## johnsiddle (Jun 22, 2011)

halestorm said:


> There is a discussion on chargers on Elithion's site here. By "smart" charger I meant a charger which has a specific profile (voltage/current) programmed for your type of batteries and size of pack.


That was an interesting article, I didn't realise that the BMS killed the charge to every cell when just one went high, I thought it just bypassed that cell and let the others carry on charging.
The problem I had with this approach was that as the cells went offline the full voltage was being concentrated on the ones that were left, which is not good.

I shall now start looking at a future re-design of my chargers controllers and see how I can monitor 14 cells per charger based on this article.

Thanks for posting it .
John


----------



## Ampster (Oct 6, 2012)

I haven't read the article in a while but my understanding is they all use shunt resistors to bleed off current. Therefore the voltage doesn't get concentrated on the remaining cells. There are at least two set points. One, the balancing setpoint when the shunt resistors are enabled. This is on a cell by cell basis. Another, when one cell goes above the max set voltage, the BMS send a signal or opens a relay that stops charging. I believe the latter is the safety feature referred to in the article.

Sent from my SM-N910T using Tapatalk


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> I haven't read the article in a while but my understanding is they all use shunt resistors to bleed off current. Therefore the voltage doesn't get concentrated on the remaining cells. There are at least two set points. One, the balancing setpoint when the shunt resistors are enabled. This is on a cell by cell basis. Another, when one cell goes above the max set voltage, the BMS send a signal or opens a relay that stops charging. I believe the latter is the safety feature referred to in the article.
> 
> Sent from my SM-N910T using Tapatalk


The article implies that turning off the chargers is the whole basis of the charging procedure, I got the impression that they just wait until the voltage has dropped before re-connecting the chargers. 
It is possible shunt resistors are switched in to bleed an over charged cell down, but they don't mention this. It would speed the charge process for the rest of the pack though rather than putting the pack in limbo while the cell voltage drops.
I am not sure Vauxhall (Chevy) use bleed resistors either as I do not see any resistors in their BMS modules that would dissipate any appreciable current without burning out.


----------



## halestorm (Apr 28, 2009)

Yes, the Elithion switches in shunt resistors for balancing. They are tiny however, and can't take very much power. I've seen mine balance, and one comes on here and there, briefly, until it gets too hot (it measures temperature of the cell board, too), then goes off for awhile, comes on again, etc.


----------



## johnsiddle (Jun 22, 2011)

halestorm said:


> Yes, the Elithion switches in shunt resistors for balancing. They are tiny however, and can't take very much power. I've seen mine balance, and one comes on here and there, briefly, until it gets too hot (it measures temperature of the cell board, too), then goes off for awhile, comes on again, etc.


Is it possible for you measure the resistance of one of the resistors please so I can get an idea of what is required?


----------



## Ampster (Oct 6, 2012)

It is not so much what is required. It is a question about how much current you want to shunt. Use Ohms law to compute that. If I recall correctly the lower the resistance the more current is shunted between the positive and negative. . Are you trying to bleed down manually?

Sent from my SM-N910T using Tapatalk


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> It is not so much what is required. It is a question about how much current you want to shunt. Use Ohms law to compute that. If I recall correctly the lower the resistance the more current is shunted between the positive and negative. . Are you trying to bleed down manually?
> 
> Sent from my SM-N910T using Tapatalk


I am well familiar with ohms law, it is just that if I am going to design my next version of charger/bms I would like to know resistance value others use as a bleed so I can incorporate it. 
If I know the resistance I can work the rest out.


----------



## Ampster (Oct 6, 2012)

My EMUS boards from Elektromotus are 5W 2.7 Ohm.

They do get hot when balancing.

Sent from my SM-N910T using Tapatalk


----------



## Duncan (Dec 8, 2008)

Different question
The volt pack comes with a "service disconnect" - it has the two large terminals and some small terminals
It is quite a heavy thing (mine has the lever thing to connect/disconnect broken)

What is inside it??? - is there a fuse in there??


----------



## piotrsko (Dec 9, 2007)

3-400 amp fuse, couple voltage sense, leads and a thermistor


----------



## johnsiddle (Jun 22, 2011)

Duncan said:


> Different question
> The volt pack comes with a "service disconnect" - it has the two large terminals and some small terminals
> It is quite a heavy thing (mine has the lever thing to connect/disconnect broken)
> 
> What is inside it??? - is there a fuse in there??


I have just had a look on mine, there appears to be a short on the big ones as you might expect seeing as it is in the main line. I don't think it is a fuse as there is no easy way to get in and replace it.
If there is a fuse it has got to be about 350/400amps as the big cutout relays are rated at about 350amps.
The other two pairs appear to have a resistor on each of about 400ohms presumably just signalling the controllers that the link is out.


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> My EMUS boards from Elektromotus are 5W 2.7 Ohm.
> 
> They do get hot when balancing.
> 
> Sent from my SM-N910T using Tapatalk


That looks very much like my calculation, I found out on the site that they bleed about 2amps so at 4.2v divided by 2a = 2.1ohm 5 watt is a little low but it depends how much it is bleeding down from and I guess as soon as the voltage reaches 4.2v the bleed is cut off.

Thanks for that.


----------



## Ampster (Oct 6, 2012)

Those boards are generally used for LiFeP0 so voltages are closer to 3.5v

Sent from my SM-N910T using Tapatalk


----------



## WolfTronix (Feb 8, 2016)

johnsiddle said:


> I am well familiar with ohms law, it is just that if I am going to design my next version of charger/bms I would like to know resistance value others use as a bleed so I can incorporate it.
> If I know the resistance I can work the rest out.


Another data point... 
The Leaf OEM BMS uses 430 ohm shunt resistors, the 1206 size marked "431":


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> Those boards are generally used for LiFeP0 so voltages are closer to 3.5v
> 
> Sent from my SM-N910T using Tapatalk


Close enough I think.
Thanks


----------



## johnsiddle (Jun 22, 2011)

WolfTronix said:


> Another data point...
> The Leaf OEM BMS uses 430 ohm shunt resistors, the 1206 size marked "431":


That seems high, at 4.2v they would only bleed 9ma, however that is closer to the ones in my Ampera/Chevy BMS boards which I had already discounted.

thanks anyway.


----------



## Monstarr (Feb 10, 2016)

I am gonna use liquid heating inside a Govecs type scooter for precharge heating LG chem 10s2p pack (which are fairly similar to volt). Plan is to make a coolant circuit with an heatexchanger (with hattached eating thermal pad), waterpump, coolant reservoir & thermostat.

So when temps are low the thermostat switches on running coolant through the 230 VAC thermal padded (from 3D printer?) heatexchanger and then warming the battery system. 
I could also add a second thermostat which switches the charger at a higher temp so that it wont be charging when the battery is cold.

Coolant systems for EVs are a different ballgame but I found out you can find usefull parts (at least for smaller EV's) in the pc liquid cooling industry.


----------



## WolfTronix (Feb 8, 2016)

johnsiddle said:


> That seems high, at 4.2v they would only bleed 9ma, however that is closer to the ones in my Ampera/Chevy BMS boards which I had already discounted.
> 
> thanks anyway.


430 ohms, 9ish mA is correct, I measured it in this video with the balance resistor being commanded to be on and off:
http://youtu.be/E-hDNjh4qyc

Enjoy,
Wolf


----------



## Duncan (Dec 8, 2008)

Hi Guys
Couple of questions
The Chevy Volt charger
If I get one is it reasonably easy for me to use?
Can it be used without the BMS?
Can I reset it to a lower voltage?
(I only have room for 6 of the 48v modules and the 2 off 24v modules)

Where is it on the car?
What does it look like?

I have tried e-mailing the scrapyard I bought my battery from - no joy there 
I haven't been able to make the Partscom site recognize a "battery charger" - what else do they call it??

I've taken my battery apart into the three big modules - very nice looking kit!
Next stage is
Remove the side entry from the T module - replace two blanking plates with hose barbs
Make the other two modules into one with 3 x 48v + 1 x 24v - blanking plates at one end, hose barbs at the other 
Those two will fit neatly into my battery area


----------



## bigmouse (Sep 28, 2008)

Duncan said:


> Hi Guys
> Couple of questions (...)


Charger works independently from the BMS, with the right CAN messages. It works down to about 200V and up to 400+V (I don't remember the exact numbers). It's behind the passenger side (assuming LHD vehicle) headlight, in front of the tire.

There's some info on the CAN messages on the evtv forum, though I'm loathe to send anyone over there. If you want the details, the thread is here. You have to log in to see it. If you don't want to, let me know and I'll either post it here or send it in a PM.

Best bet to find one is to search car-part.com for some generic Volt part (like a headlight) and call them up asking about the charger. They might not know what you're talking about so you'll have to describe it to them. Wrecking yards don't yet know their way around EVs. Don't pay more than about $250-300 for one. The Chevy Spark EV has the same charger and it responds to the same commands. I have both types, only difference is the direction of the coolant ports. A google image search of "Lear Charger Volt" will bring up photos.


----------



## mjcrow (Jan 5, 2008)

On car-part dot com, search for chevy volt, (choose a model year), Hybrid Converter/Inverter, Charger (RH front engine compartment).

Hope this helps


----------



## bigmouse (Sep 28, 2008)

mjcrow said:


> On car-part dot com, search for chevy volt, (choose a model year), Hybrid Converter/Inverter, Charger (RH front engine compartment).
> 
> Hope this helps


This assumes that they've even inventoried the charger, which assumes they know what it is. Most yards I've tried to buy from had no idea. I got sent a DC-DC converter twice before they actually sent a charger the first time. Headlights are high-demand items. That will at least tell you whether there's a Volt in their yard or not.


----------



## Duncan (Dec 8, 2008)

Hi Bigmouse
Looking at your BMW battery mounts - how are you restraining the batteries?

Are you clamping onto the bottom protrusions the way Chevy do or are you clamping at the top as well?


----------



## bigmouse (Sep 28, 2008)

Duncan said:


> Hi Bigmouse
> Looking at your BMW battery mounts - how are you restraining the batteries?
> 
> Are you clamping onto the bottom protrusions the way Chevy do or are you clamping at the top as well?


For the upright batteries, I'm clamping them by the ridges at the bottom, same as Chevy did. For the batteries laying on their sides, I found a piece of C-channel that the bottom of the battery fits in to. It rests in there, and on another flat section futher "up" the battery to support its weight, then it's clamped down on to that arrangement from above. Like so:









The orange straps are so that I can lift the battery out of the box from above. This will allow me to extract them once the box skins have been installed and there's no more access from underneath.

Sorry, I don't have a picture looking in to an empty box. Here's a photo looking at the box from outside. The forward piece in the bottom of the box is the channel, open-side upwards. The square tube further back is for the battery to rest on. It's thicker than the channel so that the battery sits flat rather than being lower at the back than the front.


----------



## Duncan (Dec 8, 2008)

Hi Guys
I have taken the front module apart,

Two big contactors and three little ones

The circuitry I assume is the pre-charge - how does it work? Is it a time delay or does it measure voltage and switch when the voltage is up?

The green circuit board with the contactors looks like just some resisters,

Very neat white pre-charge resister

The connectors to the contactors - 8 pins + 6 small pins

The circuit board on the aluminium - I assume this does the precharge

Of the three little contactors I assume 
One for pre-charge
one for heater
one for?????

I was thinking about just going into the back of the big 14 way connector and powering the contactors manually
How easy would it be to use the existing circuitry ??


----------



## eldis (Sep 3, 2013)

Duncan said:


> Hi Guys
> I have taken the front module apart,
> 
> ...
> ...


Easy enough - few pages back I've posted a wiring diagram for this module. All these relays are externally controllable over those two connectors (X1, X2) in the front. The aluminium-encapsulated board is just BMS master, it (surprisingly) does not affect the contactors' operation.

Edit: by encapsulated board I meant the one that is screwed from the back of this module (you don't have a photo of it posted), not the internal circuitry - that you probably want to keep..


----------



## Duncan (Dec 8, 2008)

Hi Eldis
I hate to be thick but I can't find your post with the pinouts of those connectors,
I have found the 20 page one but it is the connectors on the top of the modules


----------



## Tomdb (Jan 28, 2013)

http://www.diyelectriccar.com/forums/showthread.php?p=518730#post518730

here you go


----------



## eldis (Sep 3, 2013)

Tomdb said:


> http://www.diyelectriccar.com/forums/showthread.php?p=518730#post518730
> 
> here you go


Thanks, Tom!


----------



## johnsiddle (Jun 22, 2011)

Ampster said:


> I haven't read the article in a while but my understanding is they all use shunt resistors to bleed off current. Therefore the voltage doesn't get concentrated on the remaining cells. There are at least two set points. One, the balancing setpoint when the shunt resistors are enabled. This is on a cell by cell basis. Another, when one cell goes above the max set voltage, the BMS send a signal or opens a relay that stops charging. I believe the latter is the safety feature referred to in the article.
> 
> Sent from my SM-N910T using Tapatalk


Hi Guy's
Thinking further about this system, the charger has to be turned off whilst the bleed resistors do their job unless you add bleed resistors capable of bypassing the whole of your charge current plus some discharge current from the cell, which could be lots of amps (only 9A in my case but still a lot) which would generate a whole lot of heat.

The two options for the two bleed resistors quoted on here, 430ohm and 2.7ohm would only bleed off 9ma and 1.5A at 4.1v cell voltage, in my case that would leave 7.5 amps going into the cell.
The cell would still be charging not dis-charging. 

The only way to stop the cell voltage rising with the charger still running would be a fat zenner rated at 4.1v or whatever you want the max voltage to be but at a current capability to bypass (in my case ) 9 amps plus the discharge current from the cell, still an awful lot of heat generated.
37+ watts, a big waste.
If all the zenners started to voltage limit (conduct) before the charger switched off, a staggering 516.6watts of heat would be generated for 9 amp charge and 14cells..

Another other option (not very credible), is one charger per cell/pouch each with its own cutout relay and bms.

The project I am working on at the moment, which might or might not work, is a small pcb situated between the connector fins which has two precision voltage sensors to read the cell/pouch voltage of both pairs of pouches and if either is too high, triggers a bleed resistor of 3ohm to be connected and via an opto isolator signals the charger for that group of cells (I am using blocks of 2 X 14 pouches in parallel with 57v charger) to turn off until the cell/pouch voltage has dropped.

This will mean I have to make 28 x 3 = 84 pcbs to cover all the cells/pouches, still if they work out cheap enough it might work, unless I put a link wire across the blocks to parallel each cell/pouch like others have done on here, but that will only divide the pcb count in half.

It will be interesting to know how others have solved the problem.
John


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> Hi Guy's
> Thinking further about this system, the charger has to be turned off whilst the bleed resistors do their job unless you add bleed resistors capable of bypassing the whole of your charge current plus some discharge current from the cell, which could be lots of amps (only 9A in my case but still a lot) which would generate a whole lot of heat.
> 
> ...
> ...


This idea always emerges after certain time. No matter how often you write about it, someone will come with it again 

John, although in theory you are right (the bleeding current is really small), in practice bleeding 9A makes no sense. First we have to clear one thing:
- cells don't go out of balance by themselves, so you only have to cover for tiny differences in self-discharge

That is once you have your pack balanced, it stays balanced with only few mA of balancing capability. Over time the pack will always approach perfectly balanced state (unless a cell goes bad, and then no amount of balancing current will save it). The charger has to be able to stop once first cell reaches it's terminal voltage (or stay at predefined max if the max voltage of the whole pack max is reached sooner).

You've probably seen the Chinese BMS, with massive balancing resistors. That might apply for the B-grade and C-grade garbage cells, but anything else just does not need more than few mA of balancing. Tesla's 85kWh pack also balances just a few mA, and everything works perfectly. Important is to understand the system, don't try to solve a problem that is not there


----------



## bigmouse (Sep 28, 2008)

Eldis is correct. Also important to note is that at the top of the charge, you won't be at high current anyway. These cells use CCCV (Constant Current -> Constant Voltage) charging. By the time you're at top of charge, the current is well under 1A anyway. If you need to balance at any current higher than that, then you have a serious problem. If you're not top balancing, then you balance as needed (at any time) anyway, likely based on open circuit voltage.


----------



## johnsiddle (Jun 22, 2011)

eldis said:


> This idea always emerges after certain time. No matter how often you write about it, someone will come with it again
> 
> John, although in theory you are right (the bleeding current is really small), in practice bleeding 9A makes no sense. First we have to clear one thing:
> - cells don't go out of balance by themselves, so you only have to cover for tiny differences in self-discharge
> ...


Hi Eldis.
Thanks for the post.
Understanding the system is just what I am trying to do.
I was not advocating the use high bleed currents just replying to Ampster's post in which he said that he thought the bleeders came online whilst the chargers were still charging and he thought charging was only switched off as a secondary safety measure (he did say he had not read the article I posted to be fair).
I said that large bleeders were not a good solution but would probably be the only solution if the charger was to remain online.
I had forgotten that the charge current would probably be very low at this point.
Unless, if a cell went high voltage (faulty) quite early on when the other cells were discharged. If the bleeder/s came on at that point with the charger still charging there would be the potential for quite a high dissipation in the bleeder limited only by the resistance of the bleeder which would probably burn out.

My mention of 9 amps was just indicating that that is my limit I believe there are chargers that will go much higher.

There are at least two commercial systems out there that bleed at different rates (both mentioned in this thread) 430ohms (9ma) and 2.7ohms (1.5A)
that's quite a range.

Are you saying that, forgetting faulty cells, the charger should switch off completely when the first cell reaches max required voltage or should it switch back on when the first cell has dropped so that the others can catch up until the pack voltage reaches it desired terminal voltage?
Obviously if the pack voltage reaches its desired terminal voltage first, then that is charging completed and the charger is then finished.

I am not trying to solve a problem that's not there I am just trying to understand the one that is.
One problem that is there, is identifying when a cell has gone faulty and its resistance has gone high, as I see it the rest of the pack not getting sufficient charge is about the only way you would know. Unless you monitor every cell and get a status back.
Regards John


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> ...
> 
> I am not trying to solve a problem that's not there I am just trying to understand the one that is.
> One problem that is there, is identifying when a cell has gone faulty and its resistance has gone high, as I see it the rest of the pack not getting sufficient charge is about the only way you would know. Unless you monitor every cell and get a status back.
> Regards John


Judging from my experience with OEM systems, the safest and most reliable is when you indeed measure and balance each cell. You set your minimum pack voltage and your minimum cell voltage (to know when to shut down the car during operation). Whatever is reached sooner, trips the system (or drastically reduces the power).

Then you do the same for charging. As bigmouse stated, as you approach the full charge, the current goes quickly down. Let's say you set your end of charge on 1/10 of full charge current. Cell balancing usually kicks in when you are close to full, and bypasses a bit of current of the highest voltage cell(s). Then if pack is already balanced, most likely your charging current drops close to zero and it's done. If there would be a misbalance on any cell and the highest would reach max sooner than the current drops, your charger has to end the charge prematurely. Next time the balance will improve further, and after few cycles you get into balanced state.

I'm an advocate of very small bypass currents. Takes time to balance the pack, but it will get there, and stay there. If there is a critical fault (shot transistor in the balancer for example), it will take days to bleed your cell to dangerous levels - so you might notice in time and save your cells. Others might take different approach. Maybe someone has few cells really close to the motor and they regularly overheat and suffer from misbalance, so more balancing is needed. It's important to note that cell capacity difference does not mean not balanced pack.

Pick whatever works for your project.


----------



## Duncan (Dec 8, 2008)

Hi Guys

I have modified my Volt pack, 
I now have two assemblies – each has three 2Kwhr modules and one 1Kwhr module for a total of 14Kwhrs
I can fit both of these assemblies nicely in the front battery compartment 
I just don’t have enough room to fit two 8Kwhr packs
Not sure what I will do with the 2Kwhr pack left over

Each 7 Kwhr assembly has blanking plates on one end and two short pipe ends on the other

I have drilled out the spot welds holding the bits that locate the cells onto the big T shaped part that goes under the Volt
This gives me some really nice light weight brackets to clamp the cells down exactly as they were designed to be clamped,
I’m thinking about cutting the long one down to the same length as the other and welding the two of them to some tubes which I will bolt into 
my battery compartment


Voltages and Charging

From what I have seen on this thread the volt cells are from 3.4v to 4.1v - 3.75v Nominal - (Yabert’s graph)
So with 82 cells in series (each one is actually 3 in parallel) I should see 278v to 336v – (58v operating range)
If I go from 285v to 325v (40v) that is about 70% of the total range – 70% of 14Kwhrs = 9.8Kwhrs
At my 260watthrs/Km at 100kph that would be 38Km 
I have reduced the frontal area by 15% and I hope by covering the passenger area and the boot area with a tonneau cover to reduce the drag a bit 

Mains voltage here is 230v – which when rectified gives a maximum voltage of 325v
Mains is +/- 6% - so 216v to 243v – or when rectified 304v to 344v
So I should be able to make a very simple charger with:
A bridge rectifier, some capacitors for smoothing and a resistance to control the current 

The maximum voltage would be 40v 
So for 10 amps I would start with a 4 Ohm resister 
A 3Kw heating element will have a resistance of about 17 Ohms – less when cold
So four of these elements in parallel should limit my current to about 10 amps – each will only have about 3.3amps and 40v across it – 132Watts – 5% of rated power

10 amps to start with – as the battery voltage climbs the current will drop so it would take about two hours to get a 50% charge, 
about 5 hours for an 80% charge and 7 hours for a 90% charge 

Ripple = Current / Frequency x Capacitance 
So for 10 amps and 20v ripple at 100Hz I would need 0.005Farrads – 5 MilliFarrads - 5mF – 5000MicroF
That is quite a lot – about $200 worth – can I get away with less?

I would include my old JLD404 as a high voltage switch to shut off at 325v – for when the mains is a bit higher

What do you think – can I make a real cheap and cheerful of should I cough up $600US (about $1000NZ) for a Volt charger?


----------



## eldis (Sep 3, 2013)

I would definitely go for a proper charger.. Otherwise you are just converting everything else into heat. That might be fun in the winter, not so practical (or safe) in the summer. These heaters have to have the airflow, so you gotta put them somewhere reasonably safe and vented. Either go for the Volt charger, or at least go for that nasty series capacitor solution (check Damien's youtube channel for that). I wouldn't recommend it either (horrible power factor, polluting the grid), but better than just wasting it in heat.


----------



## hmincr (Jan 20, 2012)

Duncan, I should be in US within 3 weeks and checking on another Volt battery. I can actually check around for a Chevy or other brand charger, if that time frame suits you. 

What exact charge voltage will you be needing ?

Harold


----------



## Duncan (Dec 8, 2008)

Hi Eldis

Because my required voltage is so close to my "mains voltage" I calculate that I will only be losing a small percentage as heat
It looks like I start off at about 13% losses but as the battery voltage rises that drops off so that by a 90% charge (90% of my max charge not the max I could put in it) I will have only lost 7% to heat through my resister pack
A total of 640watthrs loss to heat

If I was charging something like a 150v pack using this method it would be horrendous but because I'm charging from 285v to 325v and my "source" is 325v I don't lose that much
Would a "proper" charger be that much better than 93%?

As far as I can see the major advantage with a proper charger is that it would be a lot faster and would get me topped up a bit better


----------



## Duncan (Dec 8, 2008)

Hi Harold

I am going to use 82 cells in series
From Yaberts chart (1/8C discharge) I will be going from about 285v to 325v - If I had a proper charger I would probably go to about 330v - possible a little more


----------



## eldis (Sep 3, 2013)

Duncan said:


> Hi Eldis
> 
> Because my required voltage is so close to my "mains voltage" I calculate that I will only be losing a small percentage as heat
> It looks like I start off at about 13% losses but as the battery voltage rises that drops off so that by a 90% charge (90% of my max charge not the max I could put in it) I will have only lost 7% to heat through my resister pack
> ...


Can't argue with the math. If the numbers are correct, then efficiency-wise you are not gaining anything by having a real charger, except for rate of charge. Some might prefer higher current.
Make sure the charging cuts off properly, mains voltage is not exactly spot on and can vary greatly.


----------



## Duncan (Dec 8, 2008)

Hi Eldis
Re - the numbers
I'm a mechanical engineer! (retired) so could one of you electrical types do a sanity check
My assumptions
Mains voltage - 230v +/-6% (from our legislation)
Converting that with a bridge rectifier gets - 325v - or more accurately 100Hz up and down peaking at 325v
Sticking some capacitors in leaves the peaks the same and fill in the gaps
Ripple = Current / Frequency x Capacitance 
So for 10 amps and 20v ripple at 100Hz I would need 0.005Farrads – 5 MilliFarrads - 5mF – 5000MicroF


The cells - Yabert did a 1/8C discharge - I am going to do a charge starting at 1/4C and tapering off
So I will use Yabert's numbers - they will be closer to accurate as the current drops
4.1v x 82cells = 336v
3.4v x 82 cells = 278v
If I discharge down to 285v and apply my 325v I get a 40v difference
Assuming that the cells have effectively zero resistance and I want 10amps I need 4 Ohms
With 4 Ohms I will be dissipating 400 watts in the resister pack while putting 10 x 285 = 2850 watts into the battery - Total 3250 watts - wasting 12%


The battery will charge up
Towards the end the batter will be at 321v - with the supply at 325v - only 4v so only 1 amp
Resister will be dissipating 4v x 1 amp = 4 watts - the battery will be absorbing 321v x 1 = 321 watts - total 325watts - wasting 1.2%


Across the charge I got about 7% loss


Things that could go wrong


The initial voltage will be higher (as I'm charging) so the current will be lower
Solution reduce the load resistance


The battery will have a significant resistance - this will reduce the current 

Solution reduce the load resistance

The mains could be at the +6% - 344v - which would be 4.2v/cell
Use my JLD404 as a cut off at 325v

I expect to do a bit of adjusting of the resistance - I was thinking about using 3Kw heating elements for hot water systems in a small water tank - NOT on the vehicle

So sanity check please....
What am I missing or not understanding?


----------



## johnsiddle (Jun 22, 2011)

Duncan said:


> Hi Eldis
> 
> Because my required voltage is so close to my "mains voltage" I calculate that I will only be losing a small percentage as heat
> It looks like I start off at about 13% losses but as the battery voltage rises that drops off so that by a 90% charge (90% of my max charge not the max I could put in it) I will have only lost 7% to heat through my resister pack
> ...


I think that charging straight from the mains could potentially be lethal, you could end up with a car parked outside your house that would electrocute everyone and everything that touched it.
I am sure it would be illegal in the UK but possibly NZ authorities might take a different view.
Just a thought.....


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> I think that charging straight from the mains could potentially be lethal, you could end up with a car parked outside your house that would electrocute everyone and everything that touched it.
> I am sure it would be illegal in the UK but possibly NZ authorities might take a different view.
> Just a thought.....


HV pack must always be isolated. So you can hold your hand on the chassis and the other finger on phase and be fine (okay, you won't be since the chassis is grounded through wheels, and phase is referenced to ground). But it will not be pack voltage or the non-isolated charging that kills you


----------



## johnsiddle (Jun 22, 2011)

eldis said:


> HV pack must always be isolated. So you can hold your hand on the chassis and the other finger on phase and be fine (okay, you won't be since the chassis is grounded through wheels, and phase is referenced to ground). But it will not be pack voltage or the non-isolated charging that kills you


Good in theory, but not much room for a mistake or water leak from the rain.
Rather you than me.


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> Good in theory, but not much room for a mistake or water leak from the rain.
> Rather you than me.


And that's the reason why every OEM car has a ground fault detection. The contactors will not close if there is any low-ohmic connection between chassis and anywhere in the HV system.


----------



## johnsiddle (Jun 22, 2011)

eldis said:


> And that's the reason why every OEM car has a ground fault detection. The contactors will not close if there is any low-ohmic connection between chassis and anywhere in the HV system.


The operative words being OEM not HB (home built).


----------



## eldis (Sep 3, 2013)

johnsiddle said:


> The operative words being OEM not HB (home built).


Okay, so back to the original question. How is an isolated charger going to protect you in any way? If you develop a ground fault (and HV pack voltage appears on the chassis), the charger will not see this anyway, and you will still die 
I'm not saying that isolation on the charger is meaningless, but it is important to know what it can or cannot do for you. Anyway, this is getting a bit off-topic. Sorry about that.


----------



## WolfTronix (Feb 8, 2016)

The power company will hate you... 
You will not be power factor corrected, and drawing all your current at the little peaks when the rectified voltage exceeds your pack voltage. 

My dad was using the front end of a Vicor Mega Pack, which takes universal mains and boost converts with power factor correction to 360V.

Then he used a rather large (2ft long, 3" diameter) variable resistor to limit the current into the battery pack.


----------



## Moltenmetal (Mar 20, 2014)

Duncan- I don't see a problem with your plan. And the caps will do a decent job of flattening the peaks. Can you get by with less? Maybe. But don't forget about the inrush to charge those caps when you turn it on, either- what's your plan for that?

If I had to do my project again, I'd have given serious consideration to just using a big Variac plus a bridge and some caps and a current limiting resistor, with the BMS turning off a contactor on the AC when the first cell tops out. Not much different than the power supplies I made years ago for small argon lasers. The Variac would allow you to lose less across your ballast resistor, but at 7% mean you're already quite efficient.


----------



## Moltenmetal (Mar 20, 2014)

...but you also know that these electrical guys have forgotten more than I will ever know on the subject...but don't stand on ceremony- get it spelled out as to why your plan is a bad one and all those fancy semiconductors are actually required!


----------



## mons2b (Nov 17, 2015)

eldis said:


> And that's the reason why every OEM car has a ground fault detection. The contactors will not close if there is any low-ohmic connection between chassis and anywhere in the HV system.


A solution for ground fault detection gave me a headache. Im currently planning on installing a secondary DC motor (powered by the drive battery) to spin my air compressor with the bonus benefit of hopefully allowing me a waiver on ground fault detection because of the fabulous brush dust the motor will generate. (NZ guidelines are vague, they stipulate install if its practical.)

Anywaaaay Eldis do you know of any ground fault detector thats not the hugely expensive thing from Germany?


----------



## eldis (Sep 3, 2013)

mons2b said:


> A solution for ground fault detection gave me a headache. Im currently planning on installing a secondary DC motor (powered by the drive battery) to spin my air compressor with the bonus benefit of hopefully allowing me a waiver on ground fault detection because of the fabulous brush dust the motor will generate. (NZ guidelines are vague, they stipulate install if its practical.)
> 
> Anywaaaay Eldis do you know of any ground fault detector thats not the hugely expensive thing from Germany?


Not from top of my head. There should be quite a few such devices available. I'm planning on adding the ground fault detection directly on PCBs of some of my toys later on.


----------



## mons2b (Nov 17, 2015)

eldis said:


> Not from top of my head. There should be quite a few such devices available. I'm planning on adding the ground fault detection directly on PCBs of some of my toys later on.


If you find anything thats not expensive let me know. Home based RCDs are not able to be used.


----------



## rwaudio (May 22, 2008)

I'm not sure if this has been talked about yet or not, it didn't come up in search. (I'm not sure why it took me so long to figure this out!?!)

Want to quickly, easily and CHEAPLY test the individual voltages of 6 and 12 cell chevy volt modules??

Cell Log 8 plus the stock Battery to BMS cable, pinout/spacing is all good, just need to get rid of the shroud on the Cell Log 8

Modify the Cell Log 8 slightly by trimming off the top "shroud" that covers the pins and has the - 1 2 3 4 5 6 7 8 + labeling on it. Trim it off flush with the main body of the unit. I simply scored it with a utility knife and snapped off the plastic.

Insert the cell log into the bottom row of pins aligned with either the first 8 or last 8 (yeah there's overlap measuring 12 cells)

Just move the connector from module to module to quickly check the cell voltages. It's not a bad idea to verify the accuracy of the Cell Log 8 before completely trusting it.

For the 6 cell connector you must align the lowest pin of the cell log 8 with the first populated wire, two pins will stick out past the connector, but luckily the connector housing doesn't interfere.


----------



## mons2b (Nov 17, 2015)

rwaudio said:


> I'm not sure if this has been talked about yet or not, it didn't come up in search. (I'm not sure why it took me so long to figure this out!?!)


Thank you. This is very helpful.


----------



## Duncan (Dec 8, 2008)

THANKS !!!
That looks really useful

Now I have seen a Cellog 8M and a Cellog 8S - 

Will this work on both? - or which?
Thanks again


----------



## Karter2 (Nov 17, 2011)

8M and 8S are physically identical with most functions also common.
The "S" version has additional logging and memory facility which can be very useful to record what is happening to cell voltage inder load .


----------



## mons2b (Nov 17, 2015)

*Re: 2012 Chevy Volt Battery: hmmm*

I have a question. Well a few. With these cells to baby them a little is 4.2v ok or is that stretching them. Better to go to 4.1? 4.0?
Lastly using 4.2 as the example do you set your charger to stop at 168volts for a setup of 144v motor and controller? 6 (3x12 in parallel) of the 12 cell modules split front and back for a 144v nominal setup.


----------



## piotrsko (Dec 9, 2007)

Im not a bms person, BUT, if you are going to push 4.2 it gets dicey because some cells will eventually go over on charge. That is where you need a bms. I stop at 4.07 mainly bcause it works out to be 195 on half a pack on my equipment. I was running 196/197 until i smelled the electrolyte smell one sunny morning. Havent smelled it since.

Remember all your measuring equipment has tolerances unless they have been calibrated against a standard.

I would stop at 164 without bms run that for a bit, see if some cells run high, then adjust up or down. I cant give advice abojt using a bms. You also need to see what the controller max input is and back off a bit from that.


----------



## mons2b (Nov 17, 2015)

piotrsko said:


> Im not a bms person, BUT, if you are going to push 4.2 it gets dicey because some cells will eventually go over on charge. That is where you need a bms. I stop at 4.07 mainly bcause it works out to be 195 on half a pack on my equipment. I was running 196/197 until i smelled the electrolyte smell one sunny morning. Havent smelled it since.
> 
> Remember all your measuring equipment has tolerances unless they have been calibrated against a standard.
> 
> I would stop at 164 without bms run that for a bit, see if some cells run high, then adjust up or down. I cant give advice abojt using a bms. You also need to see what the controller max input is and back off a bit from that.


The cheaper chargers are factory locked. What should I set the voltage to for 4.0 volts (4.0 best for long cell life?) per cell on a setup with 6x 12 chevy cells setup as 144v nominal parallel?


----------



## piotrsko (Dec 9, 2007)

Convention is : series then parallel in a pack. 6s12p is 24v @ 180 ah 4.32 kwh.

You have a 36S12P so 144 is your end of charge. 149.4 is max cahrge, 108 is minimum, 90 @ high current draw


----------



## Duncan (Dec 8, 2008)

Hi John
If you go back on this thread you will find an actual Chevy volt curve - I think it was Yarbert's

Have a look at that and decide how close to the top you need to take it - I'm only going to go to 3.9v - BUT that does lose a bit of capacity


----------



## Duncan (Dec 8, 2008)

I posted these on my build thread but I thought they should go here as well

The Battery bracket/holding tray is made from the Chevy bits and weighs 5kg

- This is my way of getting the air out 
With the current forecast I have a couple of days before I will need to ensure I have anti-freeze in there

I was even able to re-use the rubber sheets that Chevy used in the battery mountings


----------



## Moltenmetal (Mar 20, 2014)

You'll still need to vacuum fill the first time Duncan, or to do a really high velocity flush. The flow channels between cells are pocketed and there is no high point vent. You either need to vacuum fill or you'll be running with air pockets for a long time, i.e. until the remaining air dissolves. It's possible that these channels between cells will flush fill, but I doubt they'd do so completely. A vacuum fill would ensure best cooling, and that's what you want- otherwise, why bother at all?

BTW the Volt has its own dedicated refrigerant evaporator and TXV for the cell cooling loop. Amazingly complex cars, the Volt- it surprises me that they are as reliable as they seem to be.


----------



## Duncan (Dec 8, 2008)

Hi Molten

I filled the battery with it on its end so the air didn't have to go uphill
using a hose so lots of flow - and I left the hose on for about an hour

I think that I should have got rid of the air in the battery - so I'm hoping not to need a vacuum
I may rig one up anyway - thoughts?


----------



## Karter2 (Nov 17, 2011)

Duncan said:


> - I'm only going to go to 3.9v - BUT that does lose a bit of capacity


 A bit of capacity being approx 40%...!!


----------



## Duncan (Dec 8, 2008)

Hi Karter
The Chevy cells seem to have a linear voltage/charge from 3.4v - 4.1v (from Yabert's graph)
So 3.9v is 0.2v down from max or about 28% down

So not quite as bad as the 40% - but it does keep me well away from the top!

Even with that I should still end up with twice as much range as I used to have


----------



## Karter2 (Nov 17, 2011)

Duncan, 
Voltage is not an accurate indicator of capacity. (Ahr)
I dont have data at hand for the Volt cell, but most other similar chemistry Lipo cells have significant extra capacity near the top of the voltage range .
You could check by using a logging charger on one cell, and recording how much extra Ahr is adsorbed by the cell above 3.9v, .
Even from Yaberts discharge graph you can see that 3.9v leaves you 12-14 Ahr short of full capacity, and unless you are planning to run down into the "death zone" below 3.4v, you are onlu leaving yourself 25Ahr of useable capacity from a 47 Ahr cell (set).!!
Whilst there is much to be said for avoiding those low voltage areas below 3.5v, the same is not true of the top voltage areas with capacity (and voltage) which could be used to your advantage.
Remember , a charging cell sits at CV ( accepting more charge) for quite some time once the max charge voltage is reached, but the rough rule for most lipo is ..
4.2v = 100% capacity
4.1v = 80%
4.0v = 70-75%
3.9v = 60-65%
3.5v = 5%


----------



## Duncan (Dec 8, 2008)

Hi Karter
The devil is in the details - and that changes with the actual chemistry used!
so far the only actual data I have is Yarbert's test results 

I will see what happens when I get back together and back on the road


----------



## Yabert (Feb 7, 2010)

Duncan said:


> so far the only actual data I have is Yarbert's test results


Personally, I charge my top balance pack up to 4,06v since more than half a year now with great success.
I'm very happy with my top balance pack, but as I wrote on my build thread, I will use the chevy Volt bms to charge at higher voltage when I need a bit more range.

I hope to release here more details about the Volt bms in the next months.


----------



## mons2b (Nov 17, 2015)

Yabert said:


> Personally, I charge my top balance pack up to 4,06v since more than half a year now with great success.
> I'm very happy with my top balance pack, but as I wrote on my build thread, I will use the chevy Volt bms to charge at higher voltage when I need a bit more range.
> 
> I hope to release here more details about the Volt bms in the next months.


Hi Yabert

I would be very interested if you can find a way to make the existing BMS modules work. I read online today they may function on some level if you feed 12 volts into the right pins but I dont know if thats true?


----------



## mons2b (Nov 17, 2015)

Duncan said:


> I posted these on my build thread but I thought they should go here as well
> 
> The Battery bracket/holding tray is made from the Chevy bits and weighs 5kg
> 
> ...


Hi Duncan

Love your pipe work. Very cool. Can you please tell me the gauge of the pipes as I want to do something similar between my batteries under the hood and the rear ones in the back. What pump do you think will have enough grunt to push through my three front batteries and three rear batteries with the length of pipe under the car as well? 
I see this mention of vacuum filling. Not sure how that would work. It does sound expensive. At this stage I dont think ill put a heater into the loop at least initially. 
Ive read online that 4.2 volt per cell is actually 80% charge in these cells as per Chevy factory settings? Is that right?


----------



## Karter2 (Nov 17, 2011)

mons2b said:


> .
> .....Ive read online that 4.2 volt per cell is actually 80% charge in these cells as per Chevy factory settings? Is that right?


 To be blunt ,...No its not true.
That would imply 5+ volts for a full charge , which is unheard of for lithium technology cells.
Also their spec sheets state 4.2 volt max .

Note: 
Most Li cells can be "overcharged" to higher voltages (such as 5 v,) but they are not stable at those levels and the chemistry degrades rapidly to effectively destroy the cell.


----------



## Moltenmetal (Mar 20, 2014)

When you charge these batteries to 4.2 volts, what voltage do they settle back to once the charger is disconnected?


----------



## piotrsko (Dec 9, 2007)

4.2 volts. When i charge to 195 they end up at 194.7 which is the accuracy limits of the Vtvm, vom, dvom equipment i have.


----------



## dougingraham (Jul 26, 2011)

Moltenmetal said:


> When you charge these batteries to 4.2 volts, what voltage do they settle back to once the charger is disconnected?


Depends on how long you let the CV phase run on. If you hold it at 4.2 volts for several hours it pretty much stays at 4.2 volts.

If you charge them at 1C and stop charging the moment they reach 4.2 volts they will settle back to about 4.1 volts. But this is one of those things that is affected by temperature. Higher charge currents will result in a lower settle voltage and a lower SOC. Lower charge currents will result in a higher settle voltage and a higher SOC. (Assuming you stop charging the instant the voltage reaches 4.2 per cell.)


----------



## Karter2 (Nov 17, 2011)

Here are some random thoughts that just poped into my head ....
As Doug says above , a cell "charged" to 4.2 v, but not left on the CV phase , will settle back to 4.1 v, which generally means about 80% of full capacity.
Most commercial EV suppliers..GM, Tesla, Nissan, etc, suggest you can charge to 80% capacity in a much reduced time period.
The CV phase of a Li charge can be 30-40% of the total full charge time ( even without BMS balancing) .
So i wonder if these "quick 80% recharges". Are just a simply charging to 4.2v/cell but cuting off the entire CV phase ??


----------



## Duncan (Dec 8, 2008)

Nahh

Charging at 1C? - that is like a supercharger!
A more normal charge rate near the end of a charge would be 1/20th C - or less!

From Yabert's graph the difference between 4.2v and 4.1v is nothing like 20% - more like 5%!

4.2v - 4.0v is about 10%


----------



## Moltenmetal (Mar 20, 2014)

Karter2, that sounds right.

That is a dangerous 20% of capacity to go after in my opinion. It has to be adding significantly to cell capacity degradation, spending all that time at high constant voltage during that long CV phase. You'd be better served with 20% more cells and skipping it.


----------



## rwaudio (May 22, 2008)

Karter2 said:


> Here are some random thoughts that just poped into my head ....
> As Doug says above , a cell "charged" to 4.2 v, but not left on the CV phase , will settle back to 4.1 v, which generally means about 80% of full capacity.
> Most commercial EV suppliers..GM, Tesla, Nissan, etc, suggest you can charge to 80% capacity in a much reduced time period.
> The CV phase of a Li charge can be 30-40% of the total full charge time ( even without BMS balancing) .
> So i wonder if these "quick 80% recharges". Are just a simply charging to 4.2v/cell but cuting off the entire CV phase ??


You are more or less correct, the numbers might vary slightly but as soon as you hit the CV phase current starts to drop off and the "fast charge" stops being so fast.

LiFePO4 works the same way, but due to the different chemistry a fast charge takes you closer to 90-95%


----------



## Karter2 (Nov 17, 2011)

Moltenmetal said:


> Karter2, that sounds right.
> 
> That is a dangerous 20% of capacity to go after in my opinion. It has to be adding significantly to cell capacity degradation, spending all that time at high constant voltage during that long CV phase. You'd be better served with 20% more cells and skipping it.


Maybe, but i dont think the 4.2 charge is a big killer as much as leaving a cell at full charge for extended periods..24hrs + ?
The real cell killer is discharging too low,..down the "cliff", and high charge rates,...1C+,( which is what must happen for a full recharge in under 1hr)


----------



## Duncan (Dec 8, 2008)

Hi John
The pipe is standard plumbing pipe - the type you solvent weld together - I think its 15mm

The reason for the vacuum fill is that the inlet and outlet are at the bottom - with the cooling passages above them - so it's difficult to get the air out

I fixed that by filling mine with the battery on its end - so the water outlet was above the cooling passages 
Then I ran a hose through it for about an hour - then when it was all full of water I dropped it back down 
And added some antifreeze mixture - just in case

As far as flow rate and heating cooling I have just ordered a "solar pump" from Banggood
http://www.banggood.com
12v Solar Hot Water Pump
8liters/min
About $30NZ delivered
How much heat do I need to dissipate???- say its 3Kw - at 8 liters/min the temperature rise will be about 6C

So the water coming from the batteries will be 6C warmer than the water going to the batteries 
Sounds OK to me - I will find out when I use it

As far as heating v cooling - the battery wants to be 25C - 30C - here in Southland the air temperatures rarely reach 25C
I think I will be heating a LOT more often then cooling
*
*


----------



## mons2b (Nov 17, 2015)

Duncan said:


> Hi John
> The pipe is standard plumbing pipe - the type you solvent weld together - I think its 15mm
> 
> The reason for the vacuum fill is that the inlet and outlet are at the bottom - with the cooling passages above them - so it's difficult to get the air out
> ...


HI Duncan. My understanding and correct me if im wrong is the battery is damaged from getting too warm but if its too cold its not damaged but range drops. Is this correct? Or does driving it cold cause damage too?
I will have to google how vacuum fills work. Wouldnt your fluid just run out again as soon as you lowered the battery back down and if you capped it then it would still run out when you went to connect the hoses up? For my setup I wasnt planning on heating the batteries but I am interested in insulating them so they might warm naturally under use.


----------



## Duncan (Dec 8, 2008)

Hi John
Dunno about damage - Chevy seem to have gone to some lengths to control the temperature - and I do intend using as much power as I can! - possibly abusing it slightly

I checked - 15mm high pressure plumbing pipe is what I used

My water can't just flow out because the ends of the pipe are the highest points! 
So I can just angle it into place and then couple up the rest of the system - then I will have to be very careful not to pump any air into the battery


----------



## piotrsko (Dec 9, 2007)

In my 3 year , 8000 mile, 750 charge experience: you are being too paranoid.

I pull 400 amps for 6 minutes on monster hill. Longer if I get caught at the red light 1/2 way up. The pack temp rises ten degrees.

Figure 10% reduction in everything when they are below 60 f. I DONT cool when ambient is below 60f seems like a waste.

My $0.02 YMMV


----------



## mons2b (Nov 17, 2015)

piotrsko said:


> In my 3 year , 8000 mile, 750 charge experience: you are being too paranoid.
> 
> I pull 400 amps for 6 minutes on monster hill. Longer if I get caught at the red light 1/2 way up. The pack temp rises ten degrees.
> 
> ...


Hi Piotrsko

 We are probably paranoid due to the trouble getting these batteries across the ocean to us. They are pretty much our "precious". 
Do you know if the cold affects the batteries in a damaging way or just lowers the range on the day?

Also can someone please tell me once and for all what i need to get a factory locked charger set to for my 144 (72 cell) volt setup? Ie final voltage and any other relevant instructions to pass to the agency who will configure the charger for my situation. Different people say different things lol. Id like to keep it conservative ie around 80 percent charge maybe slightly more. 4 volts a cell?


----------



## piotrsko (Dec 9, 2007)

Then use chevy's parameters: 4.04 to 4.05 volts for every cell you have in series.

For chevy: 388 volts divided by 96 series. For your 36s12p 144 nominal:145.692 volts. Max IMHO 149 v. Never exceed 151 with an accurate and super reliable BMS because this is the ragged edge.

Nominal is an odd term here, it was used for FLA with a different charge / discharge hysterisis.

Pick a level you are comfortable with, buy that, be happy. It should be about 144 volts.

I have not seen where they are damaged by cold ( so far down to 0 f ) but my data is observational only


----------



## bigmouse (Sep 28, 2008)

Just a quick teaser pic. My BMS reading my 28kWh worth of Volt cells using the OEM BMS.


----------



## Duncan (Dec 8, 2008)

eldis said:


> Yes, you are right. Yesterday I tried all of them and it works nicely. Beware of precharge circuit - there is a relay but after you also have to control the signal marked like precharge PWM or something. In theory you can just open that transistor and no need to ramp it up. I'm not quite sure why Chevy thought it is necessary to have a double stage precharge control.. Also the PWM might not like 12V - this is the only part of the circuit I didn't test yet. Most likely 5V would turn the mosfet on.
> 
> In case you are not interested in this PWM functionality, it's just a matter of soldering a bridge over that transistor to have it always conductive (and control just a relay). I can post later on which one and where to do that if people are interested.


Hi eldis
About two years ago you posted 
"I can post later on which one and where to do that if people are interested"

I'm interested! 

I am intending to use the two big contactors and the pre-charge contactors 
Under manual control

I would also like to use the other contactors to switch the wires to the charger on,

There are three contactors 

So 
one switches the pre-charge
one switches the heater on/off

One switches the power to the charger and DC/DC ??
Is it a two pole contactor?
Does it switch the voltage to the charger and DC/DC on at the same time?

Or am I missing something


----------



## Duncan (Dec 8, 2008)

Hi Guys
If eldis is not available can anybody else help??

Making some progress

Battery in it's new home
- Do you like the Chevy Power sticker?

Battery cover

Controller on cradle over battery


----------



## hmincr (Jan 20, 2012)

message deleted


----------



## stevefed (Feb 23, 2015)

Just finished rereading almost all of this string again. So much great information! I posted a little while back about going up to 144v from 120 on a Porsche 914. Thanks for getting back to me (not enough info!), I think I've got it all figured out, and have replaced DC converter and charger. However, I do have a question to the group. I'm going now to 4 parallel strings of 144v, put together from a couple Volt batteries. My questions is, in order to get the right shunt to run my digital SOC, as well as analog volt and amp meters (can't help myself, I love the way they look!), what size shunt should I be using? Or, more honestly, how much amperage should I expect to be generating? And what should I reset my limits to on my Zilla controller (hopefully not more than 1000a as that's my limit on the 1K), once I get ready to reset it from the 120v settings? I've got a 500a shunt on there now, but I'm thinking I should up it.


----------



## piotrsko (Dec 9, 2007)

Depends on the Failure point of your motor. Id leave the amp settings alone for now. Batteries should be good for 2000 amps easy with big time sag, not so much at 500a. If you keep on banging the amp needle against the stops, get a bigger shunt, and possibly soon after a new motor. Voltmeter is the same. Range should be awesome.


----------



## stevefed (Feb 23, 2015)

Thanks so much for the info! Psyched for the range and increase in performance. Also understand that I am pretty much the "Forrest Gump" of DIY electric car conversions. I really appreciate your patience in answering my questions without alluding to the fact that they only reinforce the fact that I have next to no idea what the heck I'm doing.


----------



## Duncan (Dec 8, 2008)

Finally getting around to mounting that triangular unit with the two big contactors and three little ones

I have a wiring diagram from (I think) Eldis and several from the manual
BUT - none of them seem to line up with what I actually have!

I'm currently poking around - I seem to have identified two big clonks and three little clicks by energizing wires leading to the module

For my old contactors I put diodes across the input coils 

Do these contactors need diodes? and why didn't Chevy put diodes in right next to the contactor coils


----------



## piotrsko (Dec 9, 2007)

On my 2011 pack there were diodes on the 10 amp relays.


----------



## Duncan (Dec 8, 2008)

piotrsko said:


> On my 2011 pack there were diodes on the 10 amp relays.


What about the two big ones?

The reason I'm a bit worried is that without the diodes I really can't blow much up bit if there are diodes and I connect backwards....

How much current can one of those diodes take? - If I test using my power supply can I set the max current so it doesn't blow them up and still have enough to activate the contactor


----------



## piotrsko (Dec 9, 2007)

May have been on the big ones, on the control board, but that was 2+ years ago and I wasnt looking for them. Figure a transient of a couple amps for a millisecond or so. The relays should run on an amp but thats a swag.


----------



## mons2b (Nov 17, 2015)

HI Duncan do we need to put diodes on our contactors?


----------



## Duncan (Dec 8, 2008)

Hi
I have tried to use the diagrams that eldis posted and the ones from the workshop manual
Total failure - neither the colours or the pin positions seem to match mine

As I don't understand the electronics I decided to remove board that has the three small contactors on it and test the connections

I now know how to connect and energize
The two big relays
Two of the small ones to energize the charging wires
And the pre-charge

I'm simply not going to use the board with the electronics and I will solder the wires to the external connectors directly to the board with the relays on it

I will take some pictures when I'm done
Chevy don't seem to use external diodes so I'm assuming that either there are diodes inside the relays or that they are not needed


----------



## Duncan (Dec 8, 2008)

As I said I have used the Chevy module without the electronics

I can 
Energize the two big contactors - that connects the battery to the controller
Use two of the small contactors to connect the battery to the charging port
That was easy
Bit more difficult - but if I energize the third contactor and the one that I use to connect the charger line to the negative terminal I can have the pre-charge resistor from the battery to the controller

I also have the Chevy service disconnect/fuse in place

Cooling/heating
Currently I have a small pump a thermocouple and a liquid reservoir from a power steering pump 

No heating or cooling yet - need to see which I need


----------



## Duncan (Dec 8, 2008)

Hi Guys
I took my car out for a spin - very nearly!
I gave it full throttle at 50Kph and spun both back wheels - nearly lost it!

I have found a problem with the Chevy contactors - that slight overcurrent seemed to weld them both ON
- Not sure how high the current went I was too busy keeping on the road but the controller is set to 1200amps

So I'm now having to sort out another set of contactors


----------



## joeblack5 (Apr 21, 2009)

BigMouse and others any word on a simple app like the battery function in the leaf spy app from wattsleft .

I use his leafspy app for my converted solectria force with 2 packs of 48 cells in parallel. His approach with bluetooth and a cell phone is really handy.

It would be nice if something similar can be done per bms module of the chevy volt.

Later J


----------



## johnsiddle (Jun 22, 2011)

Hi Guy's
Sorry to be a pain but I thought early on in this thread that someone posted a list of the pack resistance against temperature as read at pins 9 and 18.
Apparently it is nominally 10k and rises with temp but I need to be more accurate and dont know at what temp the pack reads 10k.

I have been right the thread but can not see it, does anyone still have such a list they can share with me?

regards John


----------



## johnsiddle (Jun 22, 2011)

johnsiddle said:


> Hi Guy's
> Sorry to be a pain but I thought early on in this thread that someone posted a list of the pack resistance against temperature as read at pins 9 and 18.
> Apparently it is nominally 10k and rises with temp but I need to be more accurate and dont know at what temp the pack reads 10k.
> 
> ...


Its OK guy's
I found it the second time I went thro this thread.


----------



## HansMarjan (Dec 27, 2016)

Lipo Louis said:


> It is a 96s3p pack, I have installed a BMS. I really like this pack. What I did, I used the casing of the original bms and made a board inside. Now I use the full 16kWh and the pack is still almost original. I also used the original bms connectors, very neat solution, I will post pictures soon.


I am new on this but Anyone experience on connecting THE unit to a solar installation as Back-up. I have a complete unit lying in my garden doing nothing.


----------



## Ampster (Oct 6, 2012)

HansMarjan said:


> ....Anyone experience on connecting THE unit to a solar installation as Back-up. I have a complete unit lying in my garden doing nothing.


I have an Outback inverter running off a 48 volt pack. My solar panels are on micro Inverters which are grid tied. I use the Outback for backup and load shifting so I optimize the solar generated at peak rates. I couple them informally via the AC side which is pretty inefficient. Most hybrid Inverters run at low voltages under 60 volts. The new Tesla Powerwall uses a solar string of over 300 volts and a pack of the same voltage. The challenge in integrating that stuff will be finding the equipment that runs at your battery voltage. The charge controller, the solar string and the DC input to the inverter all need to be nearly the same voltage or you will have additional losses and expense going through a DC to DC converter.


Sent from my SM-N910T using Tapatalk


----------



## Dirkimus Max (Jan 15, 2014)

janzicek said:


> Hello, janzicek here... I put a volt pack in my Solectria Force about a year ago. Junkyard find for about $1300 shipped. So far so good. I also work in the industry and have done extensive teardowns of the volt BMS to benchmark my companies stuff against the volt. Anyway, if you have any questions, I have done a ton of cell level testing and have accrued almost 10,000 miles on my volt cells at this point. Let me know if I can help.
> 
> Josh


Hi Josh!
I just got a 2015 Volt pack to put into my 1996 Solectria Force with a 325 Brusa controller. Would you be willing to share your Volt pack implementation into your Solectria? Would love to hear what you did: Pack configuration? Battery distribution, front/back? Did you use all or part of the BMS (or other)? Did you use liquid heating/cooling and if so, how? Where did you set your Brusa settings (controller and charger)? Have you decoded any of the CANbus info? How's it going overall? (o: Thanks much!


----------



## HansMarjan (Dec 27, 2016)

Hello josh,
I have THE Total pack still intact, THE management modules on THE pack are also still intact. Someone i think if i connect THE pack to a inverter of around 360 volt it should work as a battery Back-up in my home solar system and should do its own cell balancing. I should then have a BMS unit ( which normally resides under the driver seat) to connect it to the inverter to manage the voltage and current levels and monitor the temperature. All of that should be available at the front end plug of the unit. Like the tesla power wall can work at 340 volt I believe. I hoped GM would come u with a solution package like Nissan no BMW do, but no dice.
Another way is to canlbalize the pack, put the differen packs in parallel at 48 volts and go the old fashioned way then I need to rewire the plugs in order to monitor all the cells also in parallel and put them together on an available BMs module.


----------



## HansMarjan (Dec 27, 2016)

Ampster thanks for your reply: you refer to the D.C. Solution from tesla which I would prefer too. They also suggest a solution with an 220 act to 340 D.C. Inverter going back and forth. Still the prime BMS is still the problem.
I am not sure I am responding correctly this way but all the same thanks


----------



## HansMarjan (Dec 27, 2016)

Ampster said:


> I have an Outback inverter running off a 48 volt pack. My solar panels are on micro Inverters which are grid tied. I use the Outback for backup and load shifting so I optimize the solar generated at peak rates. I couple them informally via the AC side which is pretty inefficient. Most hybrid Inverters run at low voltages under 60 volts. The new Tesla Powerwall uses a solar string of over 300 volts and a pack of the same voltage. The challenge in integrating that stuff will be finding the equipment that runs at your battery voltage. The charge controller, the solar string and the DC input to the inverter all need to be nearly the same voltage or you will have additional losses and expense going through a DC to DC converter.
> 
> 
> Sent from my SM-N910T using Tapatalk


Ampster thanks I responded in # 533


----------



## rwaudio (May 22, 2008)

Dirkimus Max said:


> Hi Josh!
> I just got a 2015 Volt pack to put into my 1996 Solectria Force with a 325 Brusa controller. Would you be willing to share your Volt pack implementation into your Solectria? Would love to hear what you did: Pack configuration? Battery distribution, front/back? Did you use all or part of the BMS (or other)? Did you use liquid heating/cooling and if so, how? Where did you set your Brusa settings (controller and charger)? Have you decoded any of the CANbus info? How's it going overall? (o: Thanks much!


I did a Volt pack in a '96 Solectria force. If you reconfigure slightly the entire pack fits in the rear. You give up liquid cooling/heating, however with the load a force is going to put on the batteries (in two parallel banks) they aren't going to require cooling unless your ambient temperature demands it. As for heating, it would be nice, but you would then need to split the pack front/rear. We are using the stock heating pad which won't heat the volt pack as efficiently but it'll still do it.

Photo attached of the configuration, but once the pack is broken down into the normal groupings out of the car, the smallest module stays as is (minus the cooling ports) and goes in the front portion of the box. The longest module is too long, so I took out the 6 cell block and added it to the middle size module (making the long and middle size modules about the same) All cooling ports were removed, the fit is so perfect you'd think it was meant to fit a solectria!

To reconfigure the pack you need some long clamps, 8x M6 threaded rod (48" and cut to size) and a few M6 nuts. If you have a die to rethread the existing rods you can use the ones that are now too long for the longest pack and you only need to get 4x M6 threaded rods. Not all of the pastic covers will fit, and you give up the tension bands at the top of the larger modules. 

Be careful when you split the packs, you get coolant everywhere!

The wiring in the photo was temporary based on cables we had laying around, we just needed to get the pack on a charger it had already been stored a bit too long at a low state of charge. If you have the stock 3.3kw Brusa charger it can be reconfigured to charge the volt pack configured as 48S. Charge to between 4.1 and 4.15v per cell. Ditch the BMS and get yourself a cell log 8, the pinout is identical to the BMS cables and you can simply cut off part of the shroud from the cell log 8 and plug it into the stock cable (watch polarity), check the cells on a schedule that makes you comfortable and you become the BMS. To be thorough reprogram the LVC on the controller to match the volt pack so there is less risk of over discharge, and the max regen voltage to an appropriate value as well.


----------



## Dirkimus Max (Jan 15, 2014)

Thanks so much for taking the time to put together your reply for me, rwaudio!
I did see in another post the use of the CellLog 8 on Volt packs, and believe it or not mine just arrived yesterday  I agree with you that the smaller load of the Solectria wouldn't produce near as much heat in the cells, but I live in Las Vegas, NV, so I am concerned about battery heat, as it gets to 110 and more easily here. The local heat rolling off the pavement while driving in those temperatures is even higher. But I have several months to work on that! 
In the meantime, I'll figure out a way to log battery temperatures from the internal thermistors (thanks to all who posted Volt data and manuals here; that will make it straightforward for me to do that!)
I'll keep you posted on my progress if you are interested.
Cheers!
DMax


----------



## piotrsko (Dec 9, 2007)

Fyi I live in reno and summer heat isn't a problem, being cold is.


----------



## Dirkimus Max (Jan 15, 2014)

piotrsko said:


> Fyi I live in reno and summer heat isn't a problem, being cold is.


Okay, thanks, piotrsko, I'll be sure to get the electric heating mat back in there to warm them up when needed!


----------



## akseminole (Jan 5, 2014)

I bought a 2 kWh Volt module from an eBay seller, 11 cells are at 3.92v, one cell on the end is at 3.8v. 
What should I do to bring this cell to the same range as the rest of the cells?


----------



## jontscott (Apr 28, 2016)

I would top that cell off to 3.92 like the others and then charge the whole pack to 4.05 per cell (watching that they stay balanced). Then once balanced at 4.05 on the top I would discharge the 12 cells together to 3.5 volts (4 matching 12v headlights work well) again watching that they stay balanced.

I realize everyone has their own view on using a BMS but I personally think having a BMS to monitor your cells for under/over voltage is important. I have seen basically no drift on my cells once balanced, but I still like to have a BMS watching them so that I can always go see the high and low cells and sleep well at night knowing they are balanced. Do you have the stock LG Chem BMS with it?


----------



## akseminole (Jan 5, 2014)

I only have a single module, so I don't think so? It has the BMS plug in on top.


----------



## Ampster (Oct 6, 2012)

jontscott said:


> ......................... but I personally think having a BMS to monitor your cells for under/over voltage is important. I have seen basically no drift on my cells once balanced, but I still like to have a BMS watching them so that I can always go see the high and low cells and sleep well at night knowing they are balanced. ........


Despite the naysayers, I agree. I am a retired CFO and view a BMS as a management information system. It boils down to how much effort a person want to spend monitoring each cell. To me repetitive tasks are boring and inefficient. I am also a visual learner and seeing the graph of cell voltages and or the table of shunting cells is a quick way to become intimate with your pack.

Sent from my SM-N910T using Tapatalk


----------



## Dirkimus Max (Jan 15, 2014)

jontscott said:


> I would top that cell off to 3.92 like the others and then charge the whole pack to 4.05 per cell (watching that they stay balanced). Then once balanced at 4.05 on the top I would discharge the 12 cells together to 3.5 volts (4 matching 12v headlights work well) again watching that they stay balanced.
> 
> I realize everyone has their own view on using a BMS but I personally think having a BMS to monitor your cells for under/over voltage is important. I have seen basically no drift on my cells once balanced, but I still like to have a BMS watching them so that I can always go see the high and low cells and sleep well at night knowing they are balanced. Do you have the stock LG Chem BMS with it?


Greetings, jontscott! Thanks for msg. I was wondering how to use the original LG Chem BMS boards with my Volt Pack in my Solectria. Are you currently using them in your application? If so, how did you use them (i.e., wire them/communicate with them)? Thx! DMax


----------



## jontscott (Apr 28, 2016)

So using the stock LG BMS system (as a complete setup) is very straight forward, just connect power and a 500kbps CAN receiver (diagrams are in this thread somewhere.) The BMS automatically spits out voltage and current data for the whole pack CAN ID 0x210 and individual cell voltages in CAN ID 0x200, 0x202, 0x204, 0x206. I should draw a diagram on how the data is packed in to the bits since it is rather tricky to explain, if you charge/discharge the pack and watch the binary data the boundaries are very clear... just binary values counting basically. Look for the bits that toggle the most they are the LSB's and the rest falls into place fast.

If however you just want to use one BMS sub-module then that is harder, I have kinda worked out part of that communication process on 125kbps CAN but that involves writing CAN packets and gets complicated fast. At this time I have decided using the whole thing as one pack works fine for my UPS backup (with a 360v to 12v DC to DC) and breaking it down in to smaller modules would take time I would rather spend on other activities


----------



## HansMarjan (Dec 27, 2016)

Jontscott, thanks, indeed using THE suppliers solution Would be THE best. I would then chose for tesla powerwall however. Which I will be using in my house in holland
That's why I was looking for a GM solution. For here in Curaçao where I have the volt batty pack.
Probably the best to rewire it to 48 volt and put with a popular BMS on to the SMA inverter I have installed. Thank you all for the info


----------



## jontscott (Apr 28, 2016)

My brother got a Chevy Volt battery and charger from a junk yard. I did not want to break the battery modules down (since that seemed messy and lots of work.) To get AC power out of the setup what we ended up doing is converting the ~360v HV pack down to ~24v with two 12v server power supplies (internally the first thing they do is convert the input to DC and then boost it to ~380 volts conveniently) in series and then feeding that into an APC UPS that converts it back to 120v AC... Quite a hack job but it works for longer term power outages.

While rewiring the pack to 48 volts is possible (I think people have done it on these forms) I imagine it would be allot of work. For me to rewire for my 24v inverter would have required a 7 series config so I guess you would want something like 14 cells in series, possible I am sure but be careful you don't short anything.

As a computer programmer after I got my CAN Bus hardware worked out tracing down patterns in the data stream (while charging and discharging the pack) quickly gave me the numbers I cared about to sleep well at night knowing the odds of fire are low


----------



## Dirkimus Max (Jan 15, 2014)

jontscott said:


> To get AC power out of the setup what we ended up doing is converting the ~360v HV pack down to ~24v with two 12v server power supplies (internally the first thing they do is convert the input to DC and then boost it to ~380 volts conveniently) in series and then feeding that into an APC UPS that converts it back to 120v AC... Quite a hack job but it works for longer term power outages.


Greetings! I was curious if, using the Volt pack as a whole house backup, were you ever concerned about the battery temperature? Are you monitoring temp?
Did you do liquid cooling on the pack?
Thanks!

DMax


----------



## Ampster (Oct 6, 2012)

Dirkimus Max said:


> Greetings! I was curious if, using the Volt pack as a whole house backup, were you ever concerned about the battery temperature? Are you monitoring temp?
> Did you do liquid cooling on the pack?
> Thanks!
> 
> DMax


I use a tempurature probe provide by my inverter for my Nissan Leaf pack. It never gets warm but the biggest discharge it might see is 1500 Watts. I charge it at 2000 Watts.

Sent from my SM-N910T using Tapatalk


----------



## alannasar (Oct 15, 2012)

jontscott said:


> So using the stock LG BMS system (as a complete setup) is very straight forward, just connect power and a 500kbps CAN receiver (diagrams are in this thread somewhere.) The BMS automatically spits out voltage and current data for the whole pack CAN ID 0x210 and individual cell voltages in CAN ID 0x200, 0x202, 0x204, 0x206. I should draw a diagram on how the data is packed in to the bits since it is rather tricky to explain, if you charge/discharge the pack and watch the binary data the boundaries are very clear... just binary values counting basically. Look for the bits that toggle the most they are the LSB's and the rest falls into place fast.
> 
> If however you just want to use one BMS sub-module then that is harder, I have kinda worked out part of that communication process on 125kbps CAN but that involves writing CAN packets and gets complicated fast. At this time I have decided using the whole thing as one pack works fine for my UPS backup (with a 360v to 12v DC to DC) and breaking it down in to smaller modules would take time I would rather spend on other activities


Jontscott,
if I want to use the original BMS system as you mentioned, how do I connect power? how many volts and what pins?
Is there a problem using the original BMS if the pack is broken up in half and placed in parallel (180 volts 90 ah instead of series stock configuration 360 volts 45 ah)?
Thanks
ALan


----------



## bigmouse (Sep 28, 2008)

alannasar said:


> Jontscott,
> if I want to use the original BMS system as you mentioned, how do I connect power? how many volts and what pins?
> Is there a problem using the original BMS if the pack is broken up in half and placed in parallel (180 volts 90 ah instead of series stock configuration 360 volts 45 ah)?
> Thanks
> ALan


The modules on the batteries are wires in a daisy chain so you can put the voltage and CAN on at any point in the chain (though termination should be on the ends)
Battery Harness wire colors:
Gy/Rd 5V
L-Bu/Gry CAN H
Wh/Ye CAN L
Bk/Vt GND
L-Bu HV Fault

You can break the pack in half as you describe, but the stock BMS controller may not work anymore like that. The modules are all isolated from each other and from the low-voltage stuff, so you can hook them up however you want and they'll read the voltages and temperatures. Paralleled strings require their own set of considerations covered in other threads.


----------



## slloyd (Jun 7, 2017)

that was an amazing thread, read entire thing. 

Bigmouse, nice to see you around. i post as HighHopes over on ES. small world


----------



## rmay635703 (Oct 23, 2008)

What happened to McRat?


----------



## akseminole (Jan 5, 2014)

What(if any) differences exist between different shades of green in the Chevy Volt modules?
Does the shade correlate with different years or was it just whatever shade of green plastic the factory had at the time?

Another question: will anything be harmed by mix and matching between different year modules? A '13 12s with a '12 6s for instance.


----------



## rmay635703 (Oct 23, 2008)

Volt modules are perfectly matched within the entire battery.

Mixing will cause you to actually need a BMS to keep everything safe and in spec


----------



## akseminole (Jan 5, 2014)

Thank you Rmay, that is good to know.

So does anyone have any suggestions about the shade of the battery modules?
Or does it mean nothing and I should move on with my inquiries to more useful topics?


----------



## piotrsko (Dec 9, 2007)

I believe the green plastic case pieces are made by different vendors. The way to verify cell groups is by the part tag. Same number same cells same year


----------



## Scottydog (Nov 4, 2014)

Great thread this, very useful for me as I purchased a 2kWh and a 1kWh module for my electric scooter conversion which had 60Ah GBS cells. 

Took if for a test run and wow what a difference! The bike used to struggle to put out 120A, now it puts out 260A no sweat! The bike has over double the power! I probably need to fit larger cables as there does seem to be a fair bit of volt drop with the cutting out briefly at full chat, probably the low voltage limit of the controller kicking in. 

What I am curious about is how waterproof is the module in the segmented area and should I consider sealing this section?


----------



## swoozle (Nov 13, 2011)

Does anyone have theories as to what the metal banding at the top of the cell block does? It's not under tension so it can't be fulfilling any continuous structural role. 
Does it just prevent the cell connections from stress if the pack is flexed end-to-end?

Do folks leave it off or use another banding method when reconfiguring packs?


----------



## Duncan (Dec 8, 2008)

swoozle said:


> Does anyone have theories as to what the metal banding at the top of the cell block does? It's not under tension so it can't be fulfilling any continuous structural role.
> Does it just prevent the cell connections from stress if the pack is flexed end-to-end?
> 
> Do folks leave it off or use another banding method when reconfiguring packs?


Hi
I resized the banding so it fitted my new pack configuration just as tight as originally - steel banding is a lot stiffer than the plastic so it acts as a brace even without much tension in it


----------



## piotrsko (Dec 9, 2007)

Over time the cellpacks swell. The banding holds all the packs together and restricts that swelling.. imagine a stack of Legos


----------



## swoozle (Nov 13, 2011)

I've reconfigured a Volt pack into two parallel strings of 3 45V modules and 1 22V module (2 separate 42S3P strings).

Is there any advantage or disadvantage to making parallel connections between the two strings at the module terminals?

See attachment.


----------



## swoozle (Nov 13, 2011)

The battery heater/temp sensor outlet thread is apparently the same as a 3/4 garden hose thread (3/4-11.5NH). It's easy to find a hose-barb / threaded adapter. This one happens to be nylon and with a little thread removal seems to hold the o-ring just fine, though I have yet to pressure test it.


----------



## BogdanT (Sep 15, 2018)

swoozle said:


> I've reconfigured a Volt pack into two parallel strings of 3 45V modules and 1 22V module (2 separate 42S3P strings).
> 
> Is there any advantage or disadvantage to making parallel connections between the two strings at the module terminals?
> 
> See attachment.


Is it just me or you shouldn't parallel between modules for your setup. You will destroy the 6s as it's only 22.5V, others are 45V


----------



## swoozle (Nov 13, 2011)

BogdanT said:


> Is it just me or you shouldn't parallel between modules for your setup. You will destroy the 6s as it's only 22.5V, others are 45V


At each parallel connection the voltage is the same.


----------



## brian_ (Feb 7, 2017)

BogdanT said:


> Is it just me or you shouldn't parallel between modules for your setup. You will destroy the 6s as it's only 22.5V, others are 45V


Are you confusing parallel and series?

The 6s modules are in *parallel *only with each other, so they see the same voltage and there is no problem.
Of course the 6s modules are in *series *with 12 s modules, but all modules have the same capacity (all cells identical and 3 parallel cells in every module) so the fact that they pass the same current is appropriate.


----------



## BogdanT (Sep 15, 2018)

BogdanT said:


> Sorry guys, I swear I saw a 6S in parallel with a 12S. But there's no such thing, so I should probably stop posting before I have my coffee in the morning.


----------



## arber333 (Dec 13, 2010)

brian_ said:


> Are you confusing parallel and series?
> 
> The 6s modules are in *parallel *only with each other, so they see the same voltage and there is no problem.
> Of course the 6s modules are in *series *with 12 s modules, but all modules have the same capacity (all cells identical and 3 parallel cells in every module) so the fact that they pass the same current is appropriate.


Theoreticaly it should be good, BUT reality can make us fools. The 12S modules have higher potential than 6S and as such have higher tendency for voltage to vary during acceleration/regen. dU means dI and so there could be some amps flying inside cell connections unaccounted for. Maybe it would be a good idea to also parallel individual cells to lower dU between modules.

I have one Ampera battery and after i convert my car i intend to add another one to have 32kWh of energy. How i will do it is still not clear to me. I would rather not take apart this very sturdy system. But space and parelelling consideration may demand i take apart the cells and connect them first in paralell and then in series for 96S6P battery.

If you can demonstrate that as you propose in plan B is good, i can try the same.


----------



## swoozle (Nov 13, 2011)

I'm going to use an ADC to monitor module temps with the built-in thermistors. Are there practical limits/guidelines for running the sensing wires? 

Like will I be ok with a 3' wire run from the modules to the ADC? 
Is it adequate to twist the pair or does it need to be shielded?


----------



## Emyr (Oct 27, 2016)

swoozle said:


> I'm going to use an ADC to monitor module temps with the built-in thermistors. Are there practical limits/guidelines for running the sensing wires?
> 
> Like will I be ok with a 3' wire run from the modules to the ADC?
> Is it adequate to twist the pair or does it need to be shielded?


It's generally better to have shorter analogue sections and longer digital sections than vice versa so you don't have to take account of voltage drop and noise between the sensor and the ADC.


----------



## swoozle (Nov 13, 2011)

swoozle said:


> I'm going to use an ADC to monitor module temps with the built-in thermistors. Are there practical limits/guidelines for running the sensing wires?
> 
> Like will I be ok with a 3' wire run from the modules to the ADC?
> Is it adequate to twist the pair or does it need to be shielded?


To answer my own question:
https://electrical-engineering-portal.com/thermistor-motor-protection

"Some practical recommendations for the type of cables that should be used are as follows:

Distances ≤ 20 m – Standard parallel cable is acceptable
Distances ≥ 20 m, ≤100 m – Twisted pair cable is necessary
Distances ≥ 100 m – Screened twisted pair (STP) cable is necessary
High level of interference – Screened twisted pair (STP) cable is necessary
The screen should be earthed at one end only."


----------



## inwo (Oct 19, 2017)

Of course it's better to parallel connect. Impossible to maintain long term balance without connecting as in bottom drawing.
Best is to connect cell to cell parallel, then there are only 42 cells to watch.



https://www.ebay.com/itm/232719725165


----------



## arber333 (Dec 13, 2010)

jontscott said:


> So using the stock LG BMS system (as a complete setup) is very straight forward, just connect power and a 500kbps CAN receiver (diagrams are in this thread somewhere.) The BMS automatically spits out voltage and current data for the whole pack CAN ID 0x210 and individual cell voltages in CAN ID 0x200, 0x202, 0x204, 0x206. I should draw a diagram on how the data is packed in to the bits since it is rather tricky to explain, if you charge/discharge the pack and watch the binary data the boundaries are very clear... just binary values counting basically. Look for the bits that toggle the most they are the LSB's and the rest falls into place fast.
> 
> If however you just want to use one BMS sub-module then that is harder, I have kinda worked out part of that communication process on 125kbps CAN but that involves writing CAN packets and gets complicated fast. At this time I have decided using the whole thing as one pack works fine for my UPS backup (with a 360v to 12v DC to DC) and breaking it down in to smaller modules would take time I would rather spend on other activities


I am trying to use complete Volt/Ampera battery with BMS.
Can you describe where in msg 0x210 is the voltage of complete pack? Also the pack current? I would need that for EVTVdue BMS/Charger/Alarm controller. 
Do you have any references to other values?
Do you know maybe if Volt BMS ever balances cells? 
Is there automatic balancing command? Is there a command to switch charger off? Is there a command to reduce power to car?

tnx

Arber


----------



## Thomasa (Nov 28, 2018)

In my 3 year , 8000 mile, 750 charge experience: you are being too paranoid.

I pull 400 amps for 6 minutes on monster hill. Longer if I get caught at the red light 1/2 way up. The pack temp rises ten degrees.

Figure 10% reduction in everything when they are below 60 f. I DONT cool when ambient is below 60f seems like a waste.

My $0.02 YMMV


----------



## electricsailor (Mar 25, 2011)

Question; I'm using a 7 Kw group of Volt batteries and might have overcharged them. I'm measuring 4.63 volts from most of the cells. Is that too high?


----------



## arber333 (Dec 13, 2010)

electricsailor said:


> Question; I'm using a 7 Kw group of Volt batteries and might have overcharged them. I'm measuring 4.63 volts from most of the cells. Is that too high?


Discharge the whole group at once to cca 3.8V per cell! The longer you keep cells so high the worst the damage will be.

A


----------



## jon volk (Aug 13, 2018)

Having stumbled my way through this whole thread, there is still something I am a bit unclear on. If I use the Volt battery pack as configured from the factory, does the main BMS require any external input if you are just letting it maintain the individual cells. I understand the connections required to read the CAN messages, but is it essentially internally powered and autonomous in its normal day to day function? I hope it makes sense what Im asking.


----------



## swoozle (Nov 13, 2011)

Not to ignore your question, but I don't know the answer. I'm going to use just the slaves since my pack is chopped up. 

Another question: why have the number of volt packs on car-part.com dropped to almost none? When I started looking in July-ish there were a dozen (and I picked one up). Now there are very few to none. Is it seasonal? I need another.


----------



## piotrsko (Dec 9, 2007)

Because everybody and their brother are buying them for cheap solar storage.

They also didn't make a million Volts, and the people who tend to wreck cars have been pretty much been weeded out by now.

Waiting IS.


----------



## Mandres (Sep 20, 2018)

Would it be ok to run these modules mounted upside down (with the terminals pointed towards the ground)? 

They'll fit into my motorcycle frame much easier if I can stagger the modules one up, one down so that the cooling passages nestle together. 



Do pouch cells care which way they're mounted?


----------



## brian_ (Feb 7, 2017)

Mandres said:


> Would it be ok to run these modules mounted upside down (with the terminals pointed towards the ground)?


An extreme example of packing Volt modules into a car is the work mfor100 has done in his 911 RSR with Tesla Motor...; the module mounting arrangements for front and rear are shown in post #51 and post #80.



Mandres said:


> Do pouch cells care which way they're mounted?


I can't think of any reason why orientation would matter to the cells. Structure and cooling arrangements for the modules might be more of a concern, although that 911 shows that that they don't need to be upright.


----------



## Mandres (Sep 20, 2018)

Great link, thank you!


----------



## swoozle (Nov 13, 2011)

arber333 said:


> I am trying to use complete Volt/Ampera battery with BMS.
> Can you describe where in msg 0x210 is the voltage of complete pack? Also the pack current? I would need that for EVTVdue BMS/Charger/Alarm controller.
> Do you have any references to other values?
> Do you know maybe if Volt BMS ever balances cells?
> ...


Did you figure this out?

I'm trying to understand the minimum necessary to get the slave boards to spit out the cell voltages. Does the master board (the Battery Energy Control Module) need to be connected to the slaves or will the slaves just spit out CAN if powered?


----------



## swoozle (Nov 13, 2011)

jon volk said:


> Having stumbled my way through this whole thread, there is still something I am a bit unclear on. If I use the Volt battery pack as configured from the factory, does the main BMS require any external input if you are just letting it maintain the individual cells. I understand the connections required to read the CAN messages, but is it essentially internally powered and autonomous in its normal day to day function? I hope it makes sense what Im asking.


Jon, what are "the connections required to read the CAN messages"? I have the pinouts and can physically access the inter-slave CAN bus, but so far haven't seen ongoing traffic. Does the master need to be connected? Do all of the battery module connections need to be in place? 
With one slave I see a blip of initial activity and then the bus goes quiet. 
Thanks


----------



## arber333 (Dec 13, 2010)

swoozle said:


> Did you figure this out?
> 
> I'm trying to understand the minimum necessary to get the slave boards to spit out the cell voltages. Does the master board (the Battery Energy Control Module) need to be connected to the slaves or will the slaves just spit out CAN if powered?


Me too...
I had sucess when connecting master unit to the slaves by their internal cable. When you connect master you take the other cable X1 connector that connects to temp sensors and relays and make connection like this:
1 - Black - Ground
2 - Red - 12V
3 - White/Black - CAN_Low
4 - Light Blue - CAN_High
9 - Black - Ground
14 - Brown/Red - 12V
15 - Orange/Yellow - 12V
16 - Light Green/Light Blue - 12V 

Other cables are mainly temp sensors etc...
EDIT: Well... i am seeing two twisted pairs. Is there another CAN line in the master output? I am not seeing any traffic there...

BMS master should wake up slaves and you should get 500kbps CAN traffic on wires 3 and 4 with msg at adress 0x200, 0x202, 0x204, 0x206, 0x210....
What msgs mean in there i still am not sure. Should be group voltages, cell temp and current sensor feedback.

The internal CAN between slaves runs at 125kbps and is more complicated as i see it. 
Did someone check function of other cable that connects to the relays? Do you have a pinout?

Also i tried to charge cells to 4.1V and BMS didnt lift a finger.... Cells are beautifully level there. Max 0.01V difference between cells. I am not sure if its worth to impose balancing on them. I dont want to break perfectly good system. I just want to know how to access individual voltages, complete pack voltage and current reports. To know cell reports would be enough for me.

A


----------



## swoozle (Nov 13, 2011)

arber333 said:


> Me too...
> I had sucess when connecting master unit to the slaves by their internal cable. When you connect master you take the other cable X1 connector that connects to temp sensors and relays and make connection like this:
> 1 - Black - Ground
> 2 - Red - 12V
> ...


Pinouts etc. are in the Ampera service manual that is in the wild. I can't remember where I got it but there are links in the forum here. Search for Ampera Service Manual.

More details on the CAN frames are in here:
https://github.com/tomdebree/AmperaBattery


----------



## swoozle (Nov 13, 2011)

I know other people have done this but I can't find the info in clear form anywhere, so...

I got a BMS slave to spit out battery module cell voltages and temperatures. Right now I'm working with only one slave connected to one 45V battery module, but it should work (or be not too difficult to figure out) with all of them connected.

I've got a CAN hat (Canberry Dual, CAN termination resistor installed) on a Pi connected to the slave CAN lines. 

On giving the slave 5V, it spits out some frames including the voltage frames (but not temp?) and waits.
...
can1 46E [6] 0C 3A 0C 36 0C 3A
can1 46D [6] 0C 39 0C 37 0C 36
can1 47E [6] 0C 35 0C 3A 0C 3B
can1 47D [6] 0C 36 0C 33 0C 34
These are the voltage frames and can be decoded using the info in the Tom deBree program on github.

If you send the slave a CAN frame ID 200 containing 0x020000, it will spit out everything again and include the temperature frame (in this case 7ED):
can1 200 [3] 02 00 00
can1 46D [6] 8C 38 0C 36 0C 36
can1 47D [6] 8C 35 0C 33 0C 34
can1 7ED [8] 0C 79 00 00 00 00 10 92
can1 46E [6] 8C 3A 0C 36 0C 3A
can1 47E [6] 8C 35 0C 3A 0C 39

It's easy enough to just listen in on the CAN-bus traffic between the master and slaves and not have to prompt the slaves but since nobody has apparently figured out how to trigger cell balancing, I don't see any reason to have the master in the loop.


----------



## bilbo (Oct 31, 2017)

Using the full pack unaltered and thus having the "master BMS" (BECM) in the loop has several benefits. I am using a Volt gen 2 full pack in a solar installation and only interfacing with it through the connectors on the front of the battery. In doing this you get the BECM, contactors, fuses, HV wiring, heater, plumbing, countless $$$ in engineering services and increased high voltage safety for "free". 

Canbus recordings of a gen 1 Volt (i.e. the car) have helped to decode the following Canbus frames transmitted by the gen 1 BECM:
- cell voltages: 0x200 0x202 0x204 0x206, 
- pack voltage/current: 0x210, 
- module temperatures: 0x302 and
- coolant temperature(s): 0x460. 

Using the gen 1 frame information the gen 2 BECM frames were deciphered.
Note the Gen 2 BECM is connected to 2 Canbus networks. The BECM responds to OBD requests on the second canbus (rate 500 K). This can be used to retrieve the the BECM power source voltage (i.e. the 12V battery voltage) and reams of other data I have not attempted to decipher. I suspect the Gen 1 does the same.


----------



## bilbo (Oct 31, 2017)

I have started trying, so far without success, to find the balancing commands the HPCM2 issues to the BECM. It is not apparent that anyone else has figured this out. Note the user bigmouse figured out some of the details for the BMS slave (VICM) balancing but never published any of it.

*If someone could post a complete list of the frames IDs (i.e. 0x200, 0x202...) broadcast by the Gen 1 BECM it would help* to narrow down the candidate frames out of the HPCM2.

Unfortunately without any idea how the VICMs are commanded to balance ( i.e. handshake of cell ids or cell ranges or array of 96 bits broadcast over a couple of labels or just enables balancing and leaves it to the BECM or ...) it will be very challenging to figure out the balancing commands. * If anyone has the slightest clue of how the HPCM2 commands the BECM to balance cells please post or PM me.*

FYI the BECM on the gen 2 volt apparently has the same part number as the Chevy Bolt BECM so maybe there is hope from the direction...


----------



## swoozle (Nov 13, 2011)

So apparently the slaves throw a minor hissy fit if they are attached to a pack that isn't the standard configuration. I'm not done playing with all of the permutations, but there's apparently some component of the progressive voltage at a particular cell tied into the CAN frame IDs. 

My pack is split into two 42S sub-packs ((42S3P)2P)? yes, one 12 cell module is unused) and when I attach slaves to both sub-packs I start getting duplicate frame IDs. 
Duplicate frames I can deal with without too much trouble. Since I'm only using the slaves for monitoring it just means a little more sleuthing if I get a cell that needs balancing.

The more significant problem is that a group of 4 cells goes missing. For instance right now I have all slaves hooked up to all 84 cells. Only 80 show up in the CAN frame data. Depending on how I distribute the cell taps among the slaves, the duplicate CAN IDs change, but always only 80 cell readings.

And it scales down. At the simplest level I can put slave 1 (the one with 2 12-cell taps and one 6-cell) on the appropriate number of battery modules. Unless I choose battery modules that are in sequential series, I only get 26 readings back. Not 30.

And no, it doesn't matter which modules I attach to.
- Attach to 30 sequential cells in sub-pack A, 30 cell voltages get spit out.
- Attach to 24 cells in sub-pack A and 6 in sub-pack B, only 26 voltages get spit out. Of course it's going to be a bitch and a half to figure out which 4 go missing.

But more investigating to do. I hope I don't end up having to set up two separate CAN buses, one for each sub-string.


----------



## swoozle (Nov 13, 2011)

More experimenting. The slaves like to be on sequential modules and don't like to have a battery module input unfilled. There's something magic about groups of 8 sequential cells. 
Except for the 6-cell modules of course.

It occurred to me to try wiring another slave connector onto one of the slave-battery cables and essentially feeding the connections from 12 cells into both slave inputs but if they are designed around blocks of 8 sequential cells, that won't help. I might give it a shot anyway. Seems unlikely to do any damage.


----------



## swoozle (Nov 13, 2011)

What would you consider a voltage variation between cells that is significant enough to warrant addressing?

My pack (at its current state of charge) varies between 3.841 and 3.856 as reported by the Volt BMS. Precision of the measurement appears to be a few thousandths of a volt.
Seems like the pack should be ok to a variation of 2 or 3 hundredths of a volt or more, but that's a guess. 

What do you all use?


----------



## arber333 (Dec 13, 2010)

swoozle said:


> What would you consider a voltage variation between cells that is significant enough to warrant addressing?
> 
> My pack (at its current state of charge) varies between 3.841 and 3.856 as reported by the Volt BMS. Precision of the measurement appears to be a few thousandths of a volt.
> Seems like the pack should be ok to a variation of 2 or 3 hundredths of a volt or more, but that's a guess.
> ...


I would consider 0,05V difference under load (!) cause for concern and yellow light alert. 0,08V or 0,1V difference under load would be red alert and below 3.4V BMS should put the car in "turtle" mode. It shopuld also display which cells are at fault. I guess that shouldnt be too hard to acomplish. Manual balancing should be achieved at the SOC top at 4,1V/cell directly from connector via Y adapter cable. I would just create a regulator circuit to allow draining or charging a single cell to 4.1V from 230Vac.


----------



## swoozle (Nov 13, 2011)

Sigh. 
And @#*!&@#!!?!

To recap, been trying to use the Volt BMS BICMs (slaves) to monitor a pack made of 2 parallel strings of 42 cells (3 large modules and 1 small module in each string). One large module remains unused.

The slaves work except that the one partially populated slave doesn't report voltages for 4 of the 12 cells connected to it.

After about 3 weeks of leaving the slaves hooked up to the pack (with no change of voltage for the cells that are reporting), I looked at the 4 unreported cells. *3 of them were discharged to ~2.4 volts*. Why three?? The fourth is unchanged. I'm charging them up to see if there is permanent damage. There was nothing else connected to the pack. And the two parallel strings weren't connected either.

ARG.

Lesson learned. Don't use a slave unless all of the pack module inputs are populated.


----------



## swoozle (Nov 13, 2011)

swoozle said:


> What would you consider a voltage variation between cells that is significant enough to warrant addressing?
> 
> My pack (at its current state of charge) varies between 3.841 and 3.856 as reported by the Volt BMS. Precision of the measurement appears to be a few thousandths of a volt.
> Seems like the pack should be ok to a variation of 2 or 3 hundredths of a volt or more, but that's a guess.
> ...


I picked up another Volt pack. A 2013 with 69k miles on it. When I cracked it open and checked the cell voltages they were all within a 17mV range. Given the accuracy of the measurement (Celllog8s), I'm guessing that the Volt BMS threshold for initiating balancing is on the order of .02V (20 mV).


----------



## jon volk (Aug 13, 2018)

Does anyone happen to have a part number for the contact pins used on the black BMS connectors? Id like to modify the harness a bit for length but despise unnecessary splices.


----------



## swoozle (Nov 13, 2011)

jon volk said:


> Does anyone happen to have a part number for the contact pins used on the black BMS connectors? Id like to modify the harness a bit for length but despise unnecessary splices.


These? 

The "OEM Connector" number should eventually lead to pins:
https://www.mouser.com/ProductDetai...X2vQ1I9OqlKv9/OgMC3V5egwnZLMJnWjF405sWsddaQ==


----------



## swoozle (Nov 13, 2011)

swoozle said:


> These?
> 
> The "OEM Connector" number should eventually lead to pins:
> https://www.mouser.com/ProductDetai...X2vQ1I9OqlKv9/OgMC3V5egwnZLMJnWjF405sWsddaQ==


I got curious myself. Looks like these are them:
https://www.mouser.com/ProductDetai...kh82d7cDA4KZPGw2IAWOBN4IAbsI5FZ/IEBdeeFjRSg==


----------



## jon volk (Aug 13, 2018)

Perfect. Thanks!
Of course I just placed a Mouser order yesterday.


Sent from my iPhone using Tapatalk


----------



## Tomdb (Jan 28, 2013)

I have gotten my BMS to work with these slaves now, thanks to Swoozle for finding the keep live message.

Github: https://github.com/tomdebree/AmperaBattery

I have identified that slaves 1, slaves 2&3 all run a 8 cell sub system with each own dedicated can transceiver and temp sensor.

Slave 4 has 6 cell sections.

You can provide any of the sections with the full cell amount to get the can messages to appear on the bus.

Currently I am after someone to assist in decoding the temperature info in messages 0X7E'n' , where n is slave section id number. First two bytes contain the value of the thermistor, I just do not know the ratio.

Also if someone has a capture of the slave can bus with master functioning during for example charging that would be of great help for finding the Balancing commands.


----------



## bilbo (Oct 31, 2017)

Tomdb said:


> I have gotten my BMS to work with these slaves now, thanks to Swoozle for finding the keep live message.
> 
> Github: https://github.com/tomdebree/AmperaBattery
> 
> ...


Hi Tom I hope this helps. 

I am not working with the slaves but have decoded some of the labels from both the gen1 and gen2 master BMS (BECM). I am fairly confident in the numbers below. It is likely the same or similar encoding is used by the slaves. 

For both Gen 1 and Gen 2 the temperatures are encoded in msg 0x302 in one byte per sensor with a bias of -40 and scale of .5 deg C. If Byte 0 bit 2 == 0, sensors 1-6 are encoded in bytes 1-6. If Byte 0 bit 2 == 1, sensors 7-9 are encoded in bytes 1-3, -40 is encoded in the unused bytes. As the gen 2 battery only has 6 temp sensors Byte 0 Bit 2 is not relevant. For the gen 2 battery the sensors are numbered by there position in the pack such that sensor 1 is adjacent to the most negative cell and sensor 6 is adjacent to the most positive cell. The Gen 1 is probably the same.

FYI the battery coolant heater inlet and outlet (gen 1 only) temperature are encoded in 0x460 with the a bias of -40 and a scale of .125 deg C. Each is 10 bits long starting at Byte 1 Bit 1 and Byte 2 Bit 17.

I really would like to understand how the slaves are "instructed" to balance. If you find anything out perhaps I could help with debugging and investigation as I have a Gen 1 car and many canbus recordings. In addition I have a complete Gen 2 battery powering a solar system (still a work in progress) with many canbus recordings as well.


----------



## swoozle (Nov 13, 2011)

In fact I was just messing with this a couple of hours ago. The code I got from somewhere (your BMS??, actually I think) was not quite right. It involved &-ing the first byte with 0x03, shifting left 8 and adding the second byte. That works up until 72F and then falls apart. This is the slave-to-master bus of course, not the master-to-car (BECM) bus.

I am NOT a coder so this is a mess, but here's what works for me (python, btw):

There are actually two positions in the CAN frame for the temps. Some show up in bytes 0 & 1, and some in bytes 2 & 3. EDIT: This may be a result of the way my pack is chopped up. I have two parallel strings of 42 cells.


```
Temp1 = ((msg.data[0]) << 8) + msg.data[1]
                    if Temp1 > 0:
                        Temps[temp_num] = ((Temp1* 0.07)- 287.0)* -1.0

                    Temp1 = ((msg.data[2]) << 8) + msg.data[3]

                    if Temp1 > 0:
                        Temps[temp_num] = ((Temp1* 0.07)- 287.0)* -1.0
```

Oh yah, as I mentioned in the PM, I have a full Gen1 pack out of the car that I might be able to do some work on if you need it. Though it would probably be easier for bilbo to get the charging info you want from his car.

Lastly, I'm a little confused by your description of slave 1. My Gen1 slave 1 spits out one 6-cell group (2 frames of 3 cells) and three 8-cell groups (2 frames of 4 cells each). Which fits as it monitors one 6-cell module and two 12-cell modules.



Tomdb said:


> I have gotten my BMS to work with these slaves now, thanks to Swoozle for finding the keep live message.
> 
> Github: https://github.com/tomdebree/AmperaBattery
> 
> ...


----------



## swoozle (Nov 13, 2011)

Thinking about it, I might be able to (relatively) easily do some very relevant experiments depending on how partial of a pack the BECM would be happy with. 
I don't have a means of charging a full 360V Volt pack. I can manage a half-pack and lower. So if the BECM wouldn't throw a hissy fit over having just a couple of slaves fully populated, I could raise one cell's voltage, put the partial pack on charge and sniff the traffic.

Do we have any idea when cell balancing is initiated? I'm assuming it's towards the top of SOC, but where?
Is it known that it happens while charging?
And I'm also assuming that it balances by bleeding off charge. Is there any reason to think otherwise?


----------



## Tomdb (Jan 28, 2013)

Yes you could unplug some slaves to see if the BECM keeps sending the right messages.

Slaves have 'large' smd bleed resistors, thus these will only be used at end of charge balancing most likely.



For temperatures, having looked up the values of an 10K NTC and then used a potiometer to replicate various points canbus data was evaluated and the following relationship was found.

x = 7Ex messages Byte 0 and 1 

Temperature in Celcius = -0.0324x + 118

As always my latest version of code which contains all the decoding and control is on github: https://github.com/tomdebree/AmperaBattery


----------



## arber333 (Dec 13, 2010)

Tomdb said:


> Yes you could unplug some slaves to see if the BECM keeps sending the right messages.
> 
> Slaves have 'large' smd bleed resistors, thus these will only be used at end of charge balancing most likely.
> 
> ...


Hm... i would be willing to experiment with Volt cells. I have 288 of them here. I dont plan to put them in a car very soon. I have 3kW Eltek charger capable of bringing them up. 
Can you tell me how much up do i bring them for them to start balancing? Like 4.1V? Or i can charge them up to 4V and then observe when resistors get hot. From there i can charge 1 cell with 1A 4.2V charger. If all cells are near balancing there will be less trouble later when i must level down the chosen cell.
You have a preference which cell to use? Maybe the negative most in a row?

I can record the 125Kb traffic on CAN as well as 500Kb. I wanted to play with CAN bridge for y while so i can try to paralel traffic on my laptop. 

A


----------



## Duncan (Dec 8, 2008)

Going from my experience with (abusing) Volt cells I think that you would have to deliberately unbalance some cells before the balancing function would have anything to do


----------



## CanadaLT28 (Oct 15, 2011)

Duncan said:


> Going from my experience with (abusing) Volt cells I think that you would have to deliberately unbalance some cells before the balancing function would have anything to do



Duncan, do you mean that a full pack could be safely charged using something like a JLD404?, basically a set of programmable range relays that run off a shunt? Some EV converters use them. What are you using on your car?



I've read pretty well this whole post and it seems 3-4 of you guys are close to being able to make something to work with the stock BMS(s) and charger(s). Is it possible that something could be available for me to BUY within 6 months to put into my truck? This is one of the last issues I have that I cannot resolve on my own.


----------



## Duncan (Dec 8, 2008)

Hi Canada LT28

I could not fit a whole pack in my car - I'm using 6 of the 2kWh modules and both of the 1 kWh modules 
No room for the seventh 2 kWh module

I have them in series and I charge to 340v using a Brusa charger I got cheap
It basically just charges up to 340v and shuts down

On page 48 of this thread - post 477
Tell you how to use a cheap Cell Log 8 to make an individual cell tester

I use mine to check every six months or so - I have to remove my controller to do so not more often

If you have a bit more space then you could use this to test every cell in about 10 minutes

I'm pulling up to 1200 amps - so I'm not being kind to my cells


----------



## [email protected] (Mar 12, 2019)

Hi Everyone,

Could someone help identify part numbers for the coolant line connectors on a Volt? I have two packs, haven't disassembled them yet, even plastic cover is still no. So which connectors should I use for coolant lines?

Thank you
Henry


----------



## boekel (Nov 10, 2010)

[email protected] said:


> Could someone help identify part numbers for the coolant line connectors on a Volt? I have two packs, haven't disassembled them yet, even plastic cover is still no. So which connectors should I use for coolant lines?


It's just a 20mm hose connector (or maybe 13/16"?)


----------



## [email protected] (Mar 12, 2019)

A very helpful answer. I'll go to a store and tell them "I need just a 20mm hose connector, or maybe 13/16"
...




boekel said:


> It's just a 20mm hose connector (or maybe 13/16"?)


----------



## boekel (Nov 10, 2010)

[email protected] said:


> A very helpful answer. I'll go to a store and tell them "I need just a 20mm hose connector, or maybe 13/16"
> ...


Happy to be of service 

To clarify: one of the hose connectors measures 20mm, the other 20,5mm Luckily hoses are a bit flexible, so choose your flavor.

to be even more helpful , I added a picture, the modules have hose connectors, so maybe you only need hoses, depending on what you want to built.


----------



## swoozle (Nov 13, 2011)

[email protected] said:


> Hi Everyone,
> 
> Could someone help identify part numbers for the coolant line connectors on a Volt? I have two packs, haven't disassembled them yet, even plastic cover is still no. So which connectors should I use for coolant lines?
> 
> ...


I'm not sure what you are asking. The system uses silicone hose clamped on to barbs built-in to the battery endplates. There are no fittings as such. I used 3/4" ID coolant hose (non-silicone) and it works fine.


----------



## swoozle (Nov 13, 2011)

I suggest we move the BMS discussion here:
https://www.diyelectriccar.com/forums/showthread.php/chevy-volt-factory-electronics-183098.html

There's already some good info (CAN logs, etc).


----------



## piotrsko (Dec 9, 2007)

I think the question is about the Schrader style fittings that enter the pack.


----------



## lobrien (Aug 4, 2014)

If you are talking about the conenctors on the front of the pack interface (alongside HV connectors) then someone else posted that a standard 3/4in US hose fitting will screw in place of where the fancy locking connectors are now, you just need to unscrew them


----------



## swoozle (Nov 13, 2011)

Weird speed-bump that I have stumbled over in using these batteries with their BMS, #293:

BICMs 2 and 3 (BMS slave modules) each have two pins on their communication connector that are tied together. Each is different (pins 16/9 and pins 20/21). The BICM reads those to know which one it is, #2 or #3. The wiring info in the manual doesn't tell you that.

If you talk to the BICM without those wire loops in the connector it will respond just fine, EXCEPT: ONE of the reported cell values (out of 24 in that BICM) will be close to zero.
Very strange. And very confusing to track down if (like me) you didn't notice the wire loops.


----------



## WattsUpDoc (Sep 25, 2019)

Just getting caught up on this thread - a fantastic collection of data!

I've stumbled across a deal on a Volt battery in town, so I'm looking at options for fitting it into my plans for a VW Golf, currently targeting a NetGain Hyper9 144V setup. To keep the voltage down but still use the whole battery, I'm looking at reconfiguring it into 4 chains of 96V each (3 chains of 2x48V modules in series, one chain of 48V + 24V + 24V).

Has anybody had experience running this configuration? Are there any obvious downsides that I'm neglecting, or alternative higher-voltage motor/controller options I should consider?

Thanks!


----------



## Duncan (Dec 8, 2008)

The biggest problem is that 96v may not be enough for highway speed!

I started with 144v - 44S with my Headway cells worked fine top speed above 110 kph and felt good

Then I put a bigger pack in - more in parallel but down to 130v (40S)

That was not good - the back EMF killed the power at higher rpms - I was now 100 kph flat out!

That was with an 11 inch motor - a 9 inch will have less back EMF - but even so at 96v you may find that you can't get to highway speeds

I'm now running most of a Volt pack - but all in series - 340v


----------



## inwo (Oct 19, 2017)

I make pcb's that use the original harness and prewired harness that parallel up to 3. (or more) Output to jst plugs. Fits oem enclosure.
Also an adaptor harness that makes the 2 x 6s look like a 12s. 2p24s shown.


----------



## WattsUpDoc (Sep 25, 2019)

inwo said:


> I make pcb's that use the original harness and prewired harness that parallel up to 3. (or more) Output to jst plugs. Fits oem enclosure.
> Also an adaptor harness that makes the 2 x 6s look like a 12s. 2p24s shown.


I like that setup - very tidy! I haven't dug into all the BMS details yet, but do you route the parallel'd harness to the Volt BMS, or run your own?


----------



## inwo (Oct 19, 2017)

I use cheap Chinese bms up to 32s. After that I've been using a super cheap 7s cascadable "bms?" to monitor with bluetooth. I have that on my Miles truck using 8pcs on 40s LTO. 2 boards for every 10s module.
Up to 24s I often forgo bms and use 24s active balancers. They can also be cascaded by overlap. Boards are available that were custom made for a boat builder. Connects 3 x 12s = 36s Volt to 3 active balance boards.


----------



## WattsUpDoc (Sep 25, 2019)

Duncan said:


> The biggest problem is that 96v may not be enough for highway speed!
> 
> I started with 144v - 44S with my Headway cells worked fine top speed above 110 kph and felt good


Good point! Were you running a single speed, or with a transmission? I'm planning on keeping a 5 speed manual in this setup. 

I've been trying to find the motor constant (Kv) and resistance specs on the Netgain motor that would let me model maximum speed vs pack voltage under varying load, but haven't come across them. Trying to estimate that from their power performance charts, I see them running up to 7200RPM on a 120V supply, but torque starts dropping at about 2200RPM, and peak power is at 3600 RPM. So I can see that being an issue with the low pack voltage - I'll need to do some more math...


----------



## major (Apr 4, 2008)

Hi Watts,

I assume you're referring to the series wound motor. As such it has a variable Kv. Unlike PM motors, the series motor flux varies with load. And its series resistance is likely on the order of 10 milliohms or less.

Regards,

major


----------



## brian_ (Feb 7, 2017)

WattsUpDoc said:


> I've been trying to find the motor constant (Kv) and resistance specs on the Netgain motor that would let me model maximum speed vs pack voltage under varying load, but haven't come across them. Trying to estimate that from their power performance charts, I see them running up to 7200RPM on a 120V supply, but torque starts dropping at about 2200RPM, and peak power is at 3600 RPM. So I can see that being an issue with the low pack voltage - I'll need to do some more math...


The Netgain performance charts are... "interesting". It appears that they spin the motor up without load, then progressively apply resistance with a brake setup to measure torque, and quit when it stalls. I think this would be a good high school science project, but is laughable for a 21st century motor supplier. They have no data below the peak torque point, but presumably if you maintain current below that speed you'll get roughly constant torque.


----------



## WattsUpDoc (Sep 25, 2019)

major said:


> Hi Watts,
> 
> I assume you're referring to the series wound motor. As such it has a variable Kv. Unlike PM motors, the series motor flux varies with load. And its series resistance is likely on the order of 10 milliohms or less.
> 
> ...


I'm actually looking at the Hyper9 SRIPM motors. From what I understand, those are not series wound, so should be constant Kv. Happy to be corrected, as I'm still finding my way around. 



brian_ said:


> The Netgain performance charts are... "interesting".


Agreed, the performance charts are a creative representation. I'd be interested in trying to extract some standard motor parameters from a few points in the chart data to make useful comparables to other motors.

I'll take further discussion on this to the https://www.diyelectriccar.com/forums/showthread.php/anyone-heard-hyper9-187593.html thread instead of cluttering up this battery thread further .


----------



## Duncan (Dec 8, 2008)

WattsUpDoc said:


> Good point! Were you running a single speed, or with a transmission? I'm planning on keeping a 5 speed manual in this setup.
> 
> I've been trying to find the motor constant (Kv) and resistance specs on the Netgain motor that would let me model maximum speed vs pack voltage under varying load, but haven't come across them. Trying to estimate that from their power performance charts, I see them running up to 7200RPM on a 120V supply, but torque starts dropping at about 2200RPM, and peak power is at 3600 RPM. So I can see that being an issue with the low pack voltage - I'll need to do some more math...


I am direct drive - no gearbox and a 4.1:1 diff

Gearboxes are reduction units - in the old 4 speeds top gear was 1:1 
In modern 5 speed top may be a slight overdrive 

So if you are rev limited a gearbox does not help!

In my case I calculated that I would be able to spin the tyres in top gear - so the other gears would be useless - so I was able to put the motor where the gearbox would have gone and free the entire "engine bay" for batteries


----------



## WattsUpDoc (Sep 25, 2019)

Duncan said:


> I am direct drive - no gearbox and a 4.1:1 diff
> 
> Gearboxes are reduction units - in the old 4 speeds top gear was 1:1
> In modern 5 speed top may be a slight overdrive
> ...


Good point! In my case, I have a bit of overdrive in 5th gear (0.84:1), so there's some improvement. But even so, running 2P 30S chains and being able to hit highway speeds comfortably may be better than the increased capacity of 4P 24S chains.


----------



## brian_ (Feb 7, 2017)

WattsUpDoc said:


> I've been trying to find the motor constant (Kv) and resistance specs on the Netgain motor that would let me model maximum speed vs pack voltage under varying load, but haven't come across them. Trying to estimate that from their power performance charts, I see them running up to 7200RPM on a 120V supply, but torque starts dropping at about 2200RPM, and peak power is at 3600 RPM.





brian_ said:


> The Netgain performance charts are... "interesting"...


I was assuming that you were referring to Netgain's usual series-wound brushed DC motors, for which this is the only performance data provided.



WattsUpDoc said:


> I'm actually looking at the Hyper9 SRIPM motors.


That motor is another matter entirely. Netgain publishes more useful performance data, which is provided by the motor's manufacturer. But that's a subject for that other thread...


----------



## Duncan (Dec 8, 2008)

Hi Guys

I weighed my modules when I had the whole pack apart - and now I can't find the results!

Has anybody got the weight of the 2 kWh and 1 kWh modules handy?


----------



## arber333 (Dec 13, 2010)

Hi

Can anyone measure Ri, internal resistance of couple of Chevy Volt gen 1 cells and provide reference to milage? I would like to compare with my pack. I have 180000km pack with 2.1mohm Ri. I saw some conflicting values online. I use SM8124A device.

tnx


----------



## swoozle (Nov 13, 2011)

Duncan said:


> Hi Guys
> 
> I weighed my modules when I had the whole pack apart - and now I can't find the results!
> 
> Has anybody got the weight of the 2 kWh and 1 kWh modules handy?


I'm out of town right now, can do it tomorrow if you still need it.


----------



## WattsUpDoc (Sep 25, 2019)

Duncan said:


> Hi Guys
> 
> I weighed my modules when I had the whole pack apart - and now I can't find the results!
> 
> Has anybody got the weight of the 2 kWh and 1 kWh modules handy?


So, I'm now the proud owner of a Chevy Volt pack .

Duncan, I weighed the packs, assembled as they are. The 4kWh pack is 82.8 lb, and the 5 kWh pack is 103.2 lb. So I'd say the 2 kWh submodule is about 41.5 lb and the 1 kWh submodule is about 20.5 lb (depending how much coolant is left in there ).


----------



## WattsUpDoc (Sep 25, 2019)

inwo said:


> I use cheap Chinese bms up to 32s. After that I've been using a super cheap 7s cascadable "bms?" to monitor with bluetooth. I have that on my Miles truck using 8pcs on 40s LTO. 2 boards for every 10s module.
> Up to 24s I often forgo bms and use 24s active balancers. They can also be cascaded by overlap. Boards are available that were custom made for a boat builder. Connects 3 x 12s = 36s Volt to 3 active balance boards.


Inwo, I'm interested in wiring up either 4p 24s, or 3p 30s, from the Volt battery modules to an Orion BMS. It looks like your harness adapters would do the trick. Would you be willing to share your design, or sell a few cable assemblies and boards?


----------



## inwo (Oct 19, 2017)

I'm out of harness until I get a big order again.


These do a really nice job.
You can reuse the oem sockets or order for a few bucks from mouser.
Keyed "C" dor 12s or "D" for 6s. Boards work on either and fit in the oem housing.


$10 for bare board. Only have a few left as I'm shipping 22 completed boards today. 

Two weeks to get more.


----------



## inwo (Oct 19, 2017)

ps.
Also have a jst-xh version.


----------



## joekitch (Sep 13, 2013)

WattsUpDoc said:


> So, I'm now the proud owner of a Chevy Volt pack .
> 
> Duncan, I weighed the packs, assembled as they are. The 4kWh pack is 82.8 lb, and the 5 kWh pack is 103.2 lb. So I'd say the 2 kWh submodule is about 41.5 lb and the 1 kWh submodule is about 20.5 lb (depending how much coolant is left in there ).


so one full pack is like ~400 pounds..?


----------



## brian_ (Feb 7, 2017)

joekitch said:


> so one full pack is like ~400 pounds..?


The complete pack (with housing) weighs

first generation: 196 kg (432 lb) 
second generation: 183 kg (403 lb)
VOLT_BATTERY.pdf


----------



## streber (Nov 30, 2019)

lobrien said:


> If you are talking about the conenctors on the front of the pack interface (alongside HV connectors) then someone else posted that a standard 3/4in US hose fitting will screw in place of where the fancy locking connectors are now, you just need to unscrew them


They are a 3/4" ORB fitting. I'm using two of these: Meziere Barb to Male AN Fittings WP12034S
Meziere Barb to Male AN Fittings WP12034S

Standard 3/4" pipe will screw in, but won't seal without a ton of tape. It really wants the o-ring to seal.


----------



## brian_ (Feb 7, 2017)

streber said:


> They are a 3/4" ORB fitting.
> ...
> Standard 3/4" pipe will screw in, but won't seal without a ton of tape. It really wants the o-ring to seal.


Pipe threads seal on the thread itself - the thread is tapered so that the fit gets tighter as the parts move together with fitting rotation. O-Ring Boss (ORB) fittings seal with an o-ring outside of the straight threads between the boss around the female port and a matching face on the male fitting, and the threads are just to mechanically hold it together. Please don't ever try to fit any tapered thread into or around any straight thread, and don't try to seal the threads of anything other than a pipe thread fitting.


----------



## swoozle (Nov 13, 2011)

Whether or not they are supposed to work, I'm using nylon US garden hose thread (3⁄4-11.5NH ) to hose barb fittings on those threads and they have performed without leaking for more than a year now.


----------



## brian_ (Feb 7, 2017)

swoozle said:


> Whether or not they are supposed to work, I'm using nylon US garden hose thread (3⁄4-11.5NH ) to hose barb fittings on those threads and they have performed without leaking for more than a year now.


Sure - it's a low pressure system. You can probably jam a hose in and wrap it with duct tape, and that would work, too. I wouldn't suggest that...


----------



## swoozle (Nov 13, 2011)

brian_ said:


> Sure - it's a low pressure system. You can probably jam a hose in and wrap it with duct tape, and that would work, too. I wouldn't suggest that...


I have to apologize. I was reviewing my setup and realized that I forgot a key part: I did use the o-ring from the original fittings. The nylon thread/barb fitting (Lowe's stock) had a nice shoulder on it that captures the o-ring well enough with the removal of a thread or two (dremel tool). The thermostat/heater housing that the fitting threads into has a recess for the o-ring.


----------



## brian_ (Feb 7, 2017)

swoozle said:


> I have to apologize. I was reviewing my setup and realized that I forgot a key part: I did use the o-ring from the original fittings. The nylon thread/barb fitting (Lowe's stock) had a nice shoulder on it that captures the o-ring well enough with the removal of a thread or two (dremel tool). The thermostat/heater housing that the fitting threads into has a recess for the o-ring.


That's interesting... so it works basically as intended, but limited in engagement force and fit by the thread taper mismatch. Probably just fine for the low pressure.


----------



## swoozle (Nov 13, 2011)

brian_ said:


> That's interesting... so it works basically as intended, but limited in engagement force and fit by the thread taper mismatch. Probably just fine for the low pressure.


 Hmm? Neither of the threads is tapered.


----------



## brian_ (Feb 7, 2017)

brian_ said:


> That's interesting... so it works basically as intended, but limited in engagement force and fit by the thread taper mismatch. Probably just fine for the low pressure.





swoozle said:


> Hmm? Neither of the threads is tapered.


Sorry! I had typical plumbing threads in mind and was thinking of NPT, even though this was clearly about the "garden hose" thread. Of course that's not tapered (it seals with a gasket against the end of the male fitting, like a crude version of an ORF fitting) and there's no issue here.


----------



## cgalpin (Dec 5, 2012)

Hi All. I'm a bit late to the party, but I managed to get a 2012 volt pack for a screaming deal, which I hope to be able to use as a test pack for my current project, and then eventually in another conversion that doesn't need much range.

My goal is to use this as-is initially, although I am not 100% sure it's possible - just keep the entire battery in it's enclosure, hook up ground, 12v, and CAN wires, contactor enable wires, and high voltage cables, cooling lines if in the vehicle, and use it. Is this possible, including getting the bms to self balance? It seems so according to the code on Damien/Tom's AmperaBattery repo in GitHub

It's been sitting for a while and the voltage is currently 348v which I think maybe ok, but would like to charge it up in case it sits for any longer (it might at the rate I am going  ).

So, using the external connectors I hooked up 12v to X2 pins 1,4,9 and ground to pins 5,10. I hooked up X1 pin 1 to CAN high, and pin 3 to CAN low. SavvyCAN reads messages just fine, but I only see one message interpreted showing battery voltage for cells 1-3 (0x460) using the DBC file I got from the AmperaBattery project, whereas it (and Damien's video) shows several others that I should be getting.










I then tried connecting directly to the internal CAN network @125kbps using the slave module wiring harness connector instead of via the BECM per the wiring shown in the repo and video (CAN high, CAN low, Gnd, 5V along bottom row right), but i don't even get any CAN messages that way.

It doesn't matter if I have the service disconnect in or not. 

Two odd things worth mentioning. 

The first is I have another front piece which has the BECM and connections, but nothing ese connected to it, and I get the same set of messages, which is suspicious! Maybe these are cached in the BECM?

The second is the voltage on cell 3 fluctuates from 0 to 3.5ish volts - i am hoping this is not accurate and just my shoddy test wiring or something. For the "head" only it fluctuates but in the 0 - milivolt range.

Any thoughts? Is it just that mine is sending different message ids and I need to get/use another dbc file (or figure the messages). I don't want to try enable the contactors and charge it until I understand it's condition better.

tia,
charles


----------



## swoozle (Nov 13, 2011)

cgalpin said:


> Hi All. I'm a bit late to the party, but I managed to get a 2012 volt pack for a screaming deal, which I hope to be able to use as a test pack for my current project, and then eventually in another conversion that doesn't need much range.
> 
> My goal is to use this as-is initially, although I am not 100% sure it's possible - just keep the entire battery in it's enclosure, hook up ground, 12v, and CAN wires, contactor enable wires, and high voltage cables, cooling lines if in the vehicle, and use it. Is this possible, including getting the bms to self balance? It seems so according to the code on Damien/Tom's AmperaBattery repo in GitHub
> 
> ...


To my knowledge nobody knows how to get the BECM to balance the pack. But we do know how to command the BICMs to do so:








1st Gen Chevy Volt BMS Balance Commands Found


Here's how to command your OEM Chevy Volt BMS BICMs (slaves) to bleed charge off of specific cells in order to keep them in balance. This does not involve the BECM (master). I wasn't able to figure out the command(s) to send the BECM to get it to initiate this work. This is a more manual...




www.diyelectriccar.com




Tom's code implements those commands.

I don't know why you aren't seeing traffic on the BICM CAN bus. As noted in the thread above, there should be constant polling of the BICMs by the BECM once it is powered up. Did you disconnect the BECM to connect to the BICMs? If so, you can shoot a 0x200#020000 CAN frame and all of the BICMs will dump their cell voltages and temps.


----------



## cgalpin (Dec 5, 2012)

First, thanks for taking the time to reply, and confirming the balancing can be achieved with Tom's code. I should have chosen my words better - having to have some code to send CAN commands to achieve this is perfectly fine if I can get it to work! And thanks for linking to the other thread. Despite searching and reading for hours I clearly haven't found all the info out there on this 

When I was using the BICM CAN bus I had it disconnected from the BECM. I was expecting a burst when it got 5v, like Damien observed. But your hint of sending the 0x200 message makes perfect sense so tried it, and initially did not get any results (but was only sending 4 bytes instead of 8 at the time - i thought savvycan will fill in the rest). So I hooked up both buses at the same time and sending the 0x200 with 8 bytes and then started fiddling around with the wiring and started getting sporadic results. I'll try explain what I am seeing, but I think I have a bad BICM, or maybe a wiring harness issue.

This is with the BICM harness connected to the BECM, the BECM getting 12v and ground, and the 500kbps CAN connected. I see a 0x460 there all the time with inn-accurate voltages. I also get a 0x200 there all the time, but with different data and several other messages shown above I haven't tried to decode.

Along with the above, I connected to the back side of the 125kbs CAN pins of the BICM harness while still connected to the BECM.

Initially I was getting nothing. I do not think me sending the 0x200 was actually doing anything, but in this configuration I see a 0x200 on the bus with a data payload of 52 C0 00

Looking at the front of the battery (so it looks like a T) If I disconnected the front BICM connector closest to the front cover I get the 0x300, and 0x310 messages (all others connected). I got a lot of these so maybe they just started at some point and continued - not sure now  It was acting "flakey" at best for a while.

If I disconnect the middle BICM connector (2nd furthest from the front) with all others connected I get 0x460-0x463, 0x470-0x473, 0x4e0-0x4e3, 0x7e0-0x7e3. They stop as soon as I reconnect. The temps seem inaccurate at -25c - -27c when it's in the 60+F range here, but that could just be the dbc file.

So it looks like the middle module is causing a problem and not only breaks the chain, but stops other traffic too.

I tried plugging in the left rear and right rear connectors to the middle BCM there was no change, but if I plug the left rear connector the to right rear BICM the messages stop again (although this might have been during the next step - lost track, sorry).

Interestingly if I take the middle connector and plug it into the next BICM in the chain (left rear) I then get 0x465, 0x475, 0x7e5. But nothing if I try do the left rear into the right rear (next connector in the chain). Maybe this is due to the module size differences and the BICM has to match the connector position (middle and left rear are the same size modules).

So really confused, but at least all the cells appear to be a healthy 3.52 volts so far!

Any ideas on what's going on here? Since the middle connector works on the next module, I am assuming the harness is ok, and its the BICM.

thanks,
charles


----------



## swoozle (Nov 13, 2011)

cgalpin said:


> First, thanks for taking the time to reply, and confirming the balancing can be achieved with Tom's code. I should have chosen my words better - having to have some code to send CAN commands to achieve this is perfectly fine if I can get it to work! And thanks for linking to the other thread. Despite searching and reading for hours I clearly haven't found all the info out there on this
> ....
> 
> Any ideas on what's going on here? Since the middle connector works on the next module, I am assuming the harness is ok, and its the BICM.
> ...


I can only offer minor comments (subject to remembering correctly; it's been awhile):
Yes, it does sound like the #2 BICM is bad. 
Yes, the CAN bus goes through each BICM so you won't see downstream BICMs if you disconnect one in the middle.
To make sure the #2 BICM is bad, you can swap it with #3 and see if the symptoms follow. BICMs 2 and 3 are completely identical. They take their identity from which pins are shorted in the connector (there's a little loop of wire).


----------



## cgalpin (Dec 5, 2012)

swoozle said:


> To make sure the #2 BICM is bad, you can swap it with #3 and see if the symptoms follow. BICMs 2 and 3 are completely identical. They take their identity from which pins are shorted in the connector (there's a little loop of wire).


Aah I was wondering how they could be identical but give different messages - makes sense.

I just physically swapped them (although its essentially the same test I did before, and I get the 0x465, 0x475, 0x7e5 messages.

I'll try get a replacement. Anyone have one they don't need? It's the one numbered 22911432

thanks again,
charles


----------



## swoozle (Nov 13, 2011)

cgalpin said:


> Aah I was wondering how they could be identical but give different messages - makes sense.
> 
> I just physically swapped them (although its essentially the same test I did before, and I get the 0x465, 0x475, 0x7e5 messages.
> 
> ...


See my PM


----------



## cgalpin (Dec 5, 2012)

Thanks for the BICM @swoozle ! I am back home and trying this again.

I'm hoping it's just something I am doing wrong, but I am unable to get any CAN messages on the 125kbps bus again like when I first tried this. At some point I realized I had the 5v and GND wires swapped, long enough for the wires to start warming up. Can anyone tell me if the BICM has circuitry to protect itself from idiots, or could I have damaged them? And how can I test they are still ok other than trying to get CAN messages directly off the BICM harness?

tia,
charles


----------



## remy_martian (Feb 4, 2019)

"At some point I realized I had the 5v and GND wires swapped, long enough for the wires to start warming up."

🤦‍♂️

Now it comes out.

Brave to finally admit a little fact that should have been the first sentence in this thread.

I doubt it. If it had protection, the wires wouldn't have gotten warm.


----------



## cgalpin (Dec 5, 2012)

Thanks. Sorry I took two sentences to mention it, I’ll try start with it next time .

Anyone know for certain, and/or how to tell?


----------



## remy_martian (Feb 4, 2019)

"If it had protection, the wires wouldn't have gotten warm."

Um...it no longer works?


----------



## cgalpin (Dec 5, 2012)

The reason I am asking is because I was having trouble getting it to work before, so don't want to rule out doing something else wrong as well, with the BICMs actually being ok. I don't think it's quite as simple as it worked before, and now it doesn't. Previously it didn't work, then started to partially work, without me being fully sure what changed in between. I tried to describe this in my 2nd post above.

I also don't know if this affects just the first BICM or all of them, or if they could even be repaired. There are no signs of damage on the board, but I am not an EE. 

I will likely end up buying at least another BICM #1 to see if perhaps just one is damaged, if anyone has one, but I feel like I should try prove I damaged these first. no? 

thanks,
charles


----------



## swoozle (Nov 13, 2011)

cgalpin said:


> The reason I am asking is because I was having trouble getting it to work before, so don't want to rule out doing something else wrong as well, with the BICMs actually being ok. I don't think it's quite as simple as it worked before, and now it doesn't. Previously it didn't work, then started to partially work, without me being fully sure what changed in between. I tried to describe this in my 2nd post above.
> 
> I also don't know if this affects just the first BICM or all of them, or if they could even be repaired. There are no signs of damage on the board, but I am not an EE.
> 
> ...


If this happened before you received the BICM I sent, you can try it with just that known-good BICM. The BICMs will respond independently.


----------



## cgalpin (Dec 5, 2012)

Nope, after 

But at least with my bad BICM #2 I thought the communication chain broke at the bad one, so I’d need to start with a working #1.

My bad module had water damage. I cleaned off the corrosion and will test with that, in case by some miracle it works now 

thanks


----------



## Duncan (Dec 8, 2008)

Hi Guys
I have just opened up a Volt battery I bought - it took 8 months to get here
Its got 3 off 3.1 kWh modules and 4 off 2.3 kWh modules - so is that a Mk2 Volt?

Does that use the same chemistry as the Mk1?? - the cells are at 3.37 volts to 3.39 volts -


----------



## piotrsko (Dec 9, 2007)

All I know is on a mk2 the pouches are the same but wired different. Might be a cooling plate. Brian should be along soon to sort it out for you.


----------



## brian_ (Feb 7, 2017)

Duncan said:


> I have just opened up a Volt battery I bought - it took 8 months to get here
> Its got 3 off 3.1 kWh modules and 4 off 2.3 kWh modules - so is that a Mk2 Volt?


Yes, the Volt battery with 7 modules is the second generation (2016+). There are four 12S2P (45 V nominal and 24 cell each, so 48S and 96 cells total) and three 16S2P (60 V nominal and 32 cell each, so another 48S and 96 cells total).

https://media.gm.com/content/dam/Media/microsites/product/Volt_2016/doc/VOLT_BATTERY.pdf



Duncan said:


> Does that use the same chemistry as the Mk1?? - the cells are at 3.37 volts to 3.39 volts -


Both generations are described by GM as "NMC-LMO". Cell voltage ranges should be very similar between generations.


----------



## brian_ (Feb 7, 2017)

piotrsko said:


> All I know is on a mk2 the pouches are the same but wired different. Might be a cooling plate.


The Mk2 or second generation modules are similar (including the same internal cooling fin design), but the Mk 2 cells have substantially higher capacity, apparently resulting largely from being thicker - Mk1 is 96S3P and Mk2 is 962P, so there are only 2/3rds as many cells in the Mk2, but with higher total capacity.


----------



## mons2b (Nov 17, 2015)

Ive tried to search but cannot find a answer. What is the short circuit rating of a chevy volt gen 1 battery? I thought two times 225 amp 250v or 500v dc fuses (positive and negative) would be good but now im thinking maybe I am incorrect. In New Zealand we are required to fuse as per the below. If anyone knows what fuse would match these specs I would be grateful. My installation is 3x12s Chevy volt modules in Parallel for a total of 96 cells. My inverter is relatively low powered at a max rating of 120amps input. But the rules are quite specific in the reference to "maximum battery short circuit current. The cable I am using is 184amps continuous rated.

*"Overload protection 2.2(5) The electrical systems within an electrically-powered low volume vehicle must have over-current protection devices that: (a) are an appropriate selection for the design of the electrical system; and (b) are mounted as closely as possible to both poles of the power source, but not within a compartment containing venting batteries; and (c) are designed to protect the wiring and electrical components of the electrical drive from over-heating following an over-current situation; and (d) have between 20% and 40% overload capacity, in order to protect the electrical wiring and components of the electrical drive from damage; and (e) are DC-rated for the maximum battery voltage and capable of interrupting the maximum short circuit battery current; and (f) protect all connections to the high-voltage traction battery and motor wiring, which must include ammeter shunt wiring, volt meter wiring, battery management systems, chargers, and heaters; and (g) in the event of deployment, are not likely to cause themselves, or any surrounding components to ignite."*


----------



## remy_martian (Feb 4, 2019)

Notice they are concerned about overheating, not about protecting your inverter. The rules are concerned about fire, not wallet, protection.

Max short circuit is voltage divided by battery impedance. It's really not something you ever want to do to a lithium battery....a lead acid will tolerate it.

Detailed fuse datasheets give that max short circuit current. Finding the battery impedance could be roughly inferred by voltage sag at high current draw.


----------

