# Thundersky Bulk Order Next Week



## Powered By DC (Jan 3, 2009)

I am placing a Large order with TS on Wednesday of Next Week. Since there has been so much discussion about group buys I thought I would make you this offer. $1.10/AH plus actual shipping and customs duties. I can get any size cell they carry. Price includes all the hardware ( aluminum plates and straps, copper connectors, bolts and washers) If you are interested in getting in on my order you need to let me know ASAP. I will be placing this order by next Wednesday Regardless. I can accept checks or credit cards as payment but if you want to use a credit card it will be 2.5% extra. I do not need payment by Wednesday just a firm commitment for what you intend to order.

Dave Kois 
Powered By DC, LLC 
www.poweredbydc.com 
[email protected] 
253-988-5020


----------



## speculawyer (Feb 10, 2009)

Damn . . . ~$352/Kwh plus shipping/customs/etc? 

That is a great deal. If you are doing an auto conversion and haven't got your batteries, you'd be wise to get in on this deal.


----------



## 86Honda (Apr 15, 2009)

I'm trying to get in on this, but I'm not sure my PM is working. It shows no messages sent after I try to PM.


----------



## Powered By DC (Jan 3, 2009)

Hey Bob, 
Got your PM and sent you a reply

Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020


----------



## DC Braveheart (Oct 12, 2008)

Dave,

I just e-mailed you.

Regards,
Stuart


----------



## RKM (Jun 9, 2008)

Dave,

Please count me in for two packs of 45 X 160Ah TS LiFePO4 cells (90 total). 

Stuart, that's two Miatas worth of cells. Are you going to make it three?

Rob


----------



## DC Braveheart (Oct 12, 2008)

RKM said:


> Dave,
> 
> Please count me in for two packs of 45 X 160Ah TS LiFePO4 cells (90 total).
> 
> ...


Rob,

You're doing 2 Miata's???? No fair ... <G>. Have I caught up with you yet on at least one of them?

Regards,
Stuart


----------



## RKM (Jun 9, 2008)

Stuart,

I'm doing one for myself and helping a friend to do his (ordering parts for both, making adapters, couplers, batt boxes etc). Both of our Miatas have engines and fuel tanks out as well. Mine is parked outside waiting for mid May when I should have time to go at it almost full time for a while and get it done. I should get the controller and most of the hardware from Belktronix in a month or so and hope to have the cells by the end of June.

Tres, tres cool re the Tesla. Jealous!

Your blog has great detail, nicely done.

Rob




DC Braveheart said:


> Rob,
> 
> You're doing 2 Miata's???? No fair ... <G>. Have I caught up with you yet on at least one of them?
> 
> ...


----------



## EVComponents (Apr 20, 2009)

I am working with Dave Kois on this LIFEPO4 order with Thundersky. 
Here are the details if you are interested.

Delivery is estimated in 8 to 12 weeks. 
Please email the following details to Dave Kois at [email protected] 
He is handling the specifics of the order with TS.

1) Quantity
2) The size that you want (most common are 60 AH, 100 AH and 160 AH).
3) Method of payment. You can do check, Visa, MC, Amex or PayPal. However, if you do a credit card or PayPal it requires a 2.5% fee to cover that cost.

We need a strong committment by Wednesday so that we can get the quantities correct to TS. 
50% deposit this week.
50% second payment around May 15th, which is when we make our second payment to Thundersky right before they ship via container.

We estimate that the customs, agent fees and shipping fees will be about 10%. That is due before delivery.

Example:
If you are ordering 50 at 100 Ah then the estimate is as follows:
50 X 100 AH X $1.10 = $5,500
50% deposit is $2,750
50% second payment is $2,750 due May 15th.

Estimated 10% for customs, agent fees and shipping fees. This will be due right before delivery.

Email both of us if you have any questions.

Thanks,
James Morrison
[email protected]
425-677-4359

www.peakoilgarage.com (blog)


----------



## wasabipixels (Apr 17, 2009)

did TS ever decrease the % of bad cells they sell? I remember reading some old posts where it was as much as 20% of the cells delivered not working.

259$ per wK/h is an awesome price how many total do you plan on ordering ?


Wish I could join in this time around, maybe next year.


----------



## Powered By DC (Jan 3, 2009)

We have been using the TS LFP cells for 2 years without a single bad cell. They have performed flawlessly. I have not heard of a single person having problems with the LFP cells.

Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020

Our current order is over 100,000ah




wasabipixels said:


> did TS ever decrease the % of bad cells they sell? I remember reading some old posts where it was as much as 20% of the cells delivered not working.
> 
> 259$ per wK/h is an awesome price how many total do you plan on ordering ?
> 
> ...


----------



## CroDriver (Jan 8, 2009)

Hi.

I would like to buy 50 X 160 Ah.

I'm located in Croatia. Is that a problem?

I can pay via PayPal.


----------



## Powered By DC (Jan 3, 2009)

no problem we can have it shipped to your nearest port

Please email me or my partner James Morrison for payment info:
[email protected] or
[email protected]




Thanks
Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020





CroDriver said:


> Hi.
> 
> I would like to buy 50 X 160 Ah.
> 
> ...


----------



## DC Braveheart (Oct 12, 2008)

RKM said:


> Stuart,
> 
> I'm doing one for myself and helping a friend to do his (ordering parts for both, making adapters, couplers, batt boxes etc). Both of our Miatas have engines and fuel tanks out as well. Mine is parked outside waiting for mid May when I should have time to go at it almost full time for a while and get it done. I should get the controller and most of the hardware from Belktronix in a month or so and hope to have the cells by the end of June.
> 
> ...


Rob,

I just e-mailed Dave my order. 

Thanks for the kind words on the blog - figure at least someone will learn from my mistakes!

Stuart


----------



## dtbaker (Jan 5, 2008)

Powered By DC said:


> We have been using the TS LFP cells for 2 years without a single bad cell. They have performed flawlessly. I have not heard of a single person having problems with the LFP cells.


...jumping into this thread late...

I am planning for my next car already, and leaning toward Li... but still nervous about BMS and charger off-the-shelf solution. seems like a 120v system with 90 or 100AH would be comparable to what I have and need.

with the *TS-LFP90AHA, *the listed operating voltage is 2.5-4.25... so to end up with a 120v system (to not fry a 120v rated motor like the ADC 8") would I use
a nominal voltage of 3.0 and use 40 cells?

What BMS and charger are you guys using? The BMS from thundersky? cost for cells + charger + BMS ?


----------



## ClintK (Apr 27, 2008)

dtbaker said:


> ...jumping into this thread late...
> 
> I am planning for my next car already, and leaning toward Li... but still nervous about BMS and charger off-the-shelf solution. seems like a 120v system with 90 or 100AH would be comparable to what I have and need.
> 
> ...


Nominal voltage is 3.2 per cell, 40 cells would do 128V nominal, 170V peak. On the other hand, 30 cells, 96V nominal would be 128V peak - probably kinder for a 120v motor.

I'd recommend finding a balance between the two.


----------



## Powered By DC (Jan 3, 2009)

use 3.2v as the nominal voltage so you would need 38 cells

For a 120v system I would probably go with a zivan charger

For a BMS it depends on what you are looking for. Are you looking for something just to balance the cells or do you want something more sophisticated that can manage the controller and charger ?


Dave Kois
Powered By D, LLC
EV Components, LLC
253-988-5020




dtbaker said:


> ...jumping into this thread late...
> 
> I am planning for my next car already, and leaning toward Li... but still nervous about BMS and charger off-the-shelf solution. seems like a 120v system with 90 or 100AH would be comparable to what I have and need.
> 
> ...


----------



## dtbaker (Jan 5, 2008)

ClintK said:


> Nominal voltage is 3.2 per cell, 40 cells would do 128V nominal, 170V peak. On the other hand, 30 cells, 96V nominal would be 128V peak - probably kinder for a 120v motor.
> 
> I'd recommend finding a balance between the two.


excellent info.... various posts mention running the ADC 8" at 144v, even though rated at 120v. Sounds fairly safe to compromise with a 35 cell setup, which would yield a 112v nominal at 3.2v per cell. Probably could be pushed to 40 cells, but I'd want to hear from a couple other people who had done it without smoking motors....

...any comments about BMS? chargers designed for Li ? Hopefully with over/under v protection and balancing?

d


----------



## ClintK (Apr 27, 2008)

dtbaker said:


> excellent info.... various posts mention running the ADC 8" at 144v, even though rated at 120v. Sounds fairly safe to compromise with a 35 cell setup, which would yield a 112v nominal at 3.2v per cell. Probably could be pushed to 40 cells, but I'd want to hear from a couple other people who had done it without smoking motors....
> 
> ...any comments about BMS? chargers designed for Li ? Hopefully with over/under v protection and balancing?
> 
> d


I like the principle behind the Volt Blochers for balancing http://www.voltblocher.com/Home.html and will probably use them for my own vehicle. Charger I'm still shopping.


----------



## creative1 (Apr 6, 2009)

Count me in. 200AH x 45.
Sending an email to you and James now.
Thanks again for all your help.


----------



## JRP3 (Mar 7, 2008)

ClintK said:


> Nominal voltage is 3.2 per cell, 40 cells would do 128V nominal, 170V peak. On the other hand, 30 cells, 96V nominal would be 128V peak - probably kinder for a 120v motor.
> 
> I'd recommend finding a balance between the two.


As far as I've seen you don't charge the cell to 4.25 or even close. 3.8 max and they drop down quickly around 3.2 as soon as load is applied. I'd go with what Dave says.


----------



## dtbaker (Jan 5, 2008)

Powered By DC said:


> use 3.2v as the nominal voltage so you would need 38 cells


...any great risk in rounding up to 40? I would think that I'd rarely be a full voltage for very long...



Powered By DC said:


> For a 120v system I would probably go with a zivan charger


ok. I think they will preset charging curves as desired... and there are ports in the back to maybe feed back to the BMS, but I dunno...



Powered By DC said:


> For a BMS it depends on what you are looking for. Are you looking for something just to balance the cells or do you want something more sophisticated that can manage the controller and charger ?


I would want whatever would take the best care of the batteries. Not so much from an informational readout, but to actually prevent damage from over/under voltage, balancing, thermal issues, or whatever else needs to be controlled.

I keep poking at this to try and put together a 'complete' system, to get a complete cost for the Li route. I am not an electrical whiz, and need this part of the system to be off-the-shelf and well documented.


----------



## JRP3 (Mar 7, 2008)

dtbaker said:


> ...any great risk in rounding up to 40? I would think that I'd rarely be a full voltage for very long...


Depends on the upper limit of your controller, it might end up being too high for it.



> I keep poking at this to try and put together a 'complete' system, to get a complete cost for the Li route. I am not an electrical whiz, and need this part of the system to be off-the-shelf and well documented.


That's hard to find since this is all fairly new technology, and you'll end up paying a premium for it.


----------



## ClintK (Apr 27, 2008)

dtbaker said:


> I keep poking at this to try and put together a 'complete' system, to get a complete cost for the Li route. I am not an electrical whiz, and need this part of the system to be off-the-shelf and well documented.


Elite Power Solutions offers packages for EVs. http://www.elitepowersolutions.com/products/ They don't necessarily list the vehicle packages on the website, but if you contact them they'll tell you. They're among the cheapest for American based sellers but still quite a bit higher than direct from China.


----------



## RKM (Jun 9, 2008)

Dan,

I'll be using an integrated system from Belktronix (controller, charger, BMS and vehicle integration unit). Contact Bryan at Belktronix to see if he can help you out.

Rob


----------



## dtbaker (Jan 5, 2008)

ClintK said:


> Elite Power Solutions offers packages for EVs. http://www.elitepowersolutions.com/products/ They don't necessarily list the vehicle packages on the website, but if you contact them they'll tell you. They're among the cheapest for American based sellers but still quite a bit higher than direct from China.


...I still have cold feet mostly because there doesn't seem to be a de facto package solution... The ordering from China part I can handle. As a matter of fact, once I figure out what to order I may be able to help with more big orders. My cousin is a metal recycler, and ships containers back from China monthly... and usually is interested in new opportunities.

what I am hearing between the lines is that with a good charger, with good curves, and a long slow trickle from 3.4->3.6 v, that the balancing probably takes care of itself. true?

so, what more does a BMS do? why do you need one?


----------



## dtbaker (Jan 5, 2008)

RKM said:


> Dan,
> 
> I'll be using an integrated system from Belktronix (controller, charger, BMS and vehicle integration unit). Contact Bryan at Belktronix to see if he can help you out.
> 
> Rob



...I am interested... you wanna post more in public here so LOTS of people can learn at the same time? We don't wanna swamp Bryan with too many repeat calls... !

I would be very interested to see a list of what is IN a complete system, what each piece does (why you need it), and how much it costs.


----------



## 86Honda (Apr 15, 2009)

I plan on using my old K+W BC-20 charger from my FLA pack. Because it can be adjusted for current and voltage and tapers near full charge, Dave thinks it will work just fine with Li. Also looking at VoltBlochers.


----------



## RKM (Jun 9, 2008)

Dan,

Sorry for my lack of detail. Too busy to post a long reply. Here is a link to Belktronix. Wander around the site, it pretty much explains the components. Pricing is on site too. I'm going with his new 800 amp controller with dual 120V chargers (can use one or both to cut charge time in half, 2.4Kw combined). The BMS protects individual cells from over charge or discharge. 

http://www.belktronix.com/sysoverview.html

Rob


----------



## rmay635703 (Oct 23, 2008)

86Honda said:


> I plan on using my old K+W BC-20 charger from my FLA pack. Because it can be adjusted for current and voltage and tapers near full charge, Dave thinks it will work just fine with Li. Also looking at VoltBlochers.


Wow, that would be good news and motivation to get my BC-20 repaired


----------



## Powered By DC (Jan 3, 2009)

Even though TS cells can go to 4.2v per charge it is wise to cut off the charge between 3.6v and 3.8v If you end up getting the blue cells it is wise to cut it off at 3.6 

As far as BMS is concerned I am looking at several different solutions. The guys that make our controllers are in the process of building a nice BMS but they are probably a few months away from getting the design finished. 

Combining Brian's Volt Blochers with the TS BMS is a good option 

And I am going to try to put something together with www.elithion.com for those that are interested. These are a top of the line BMS systems but a little pricey if your buying in small quantaties. 

Chargers there are many options : we use the Manzanita Micro chargers but many other chargers will work.

Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020


----------



## bblocher (Jul 30, 2008)

Hey guys,

Just thought I'd chime in with my LiFePo4 experience. Definately calculate your traction packs based off the nominal voltages. Don't let the 4.2 max fool you, even 3.6 or 3.8v.

I charge my cells to just under 3.7v (seems to work best with my balancers shunting at 3.6v so I don't waste too much energy and still keeps them balanced). After the charge is complete the cells will slowly drop in voltage and settle between 3.3-3.4v. My motor and controller are rated for 144v (the controller I think says 160, maybe a bit higher, max). I'm probably probably typically at 150v resting on a fresh charge but after the first 10% or so of the pack you'll see closer to 144v where it will stay until the pack is nearly drained. I've never seen this and you shouldn't either, it's very hard on the cells. 

Try to size your packs so you only need 60-70% of them. Based off the cycle lifes posted this should really extend their life and make it worth the cost.

The Thundersky system doesn't have LVP, and is far from perfect...a little buggy at times, but is doing the job. You're looking at about $3k for the BMS and charger. I see no reason you can't use the BMS on the Zivan HV circuit though. I mention this because the TS charger is huge and onboard mounting is challenging.

You really should look for a charger that has a high voltage circuit. The benefit of having this circuit in your charger is that when a cell reaches your cutoff (I use 3.8v) the charger doesn't just turn off. The charger will continue to ramp down the amps until the cell is within safe limits again and can even ramp back up. Typically it's not much longer, however, and the cell won't stay below 3.8v at which point the charger shuts down completely as the amp output nears zero. This was the behavior I witness so I designed the Volt Blochers. Throw those on to burn off this extra power and keep the charge cycle going longer and bring all the cells up to around 3.6v or higher and you're good. 

It's really not worth pushing them up to the higher voltages (above 3.8). If you look at the TS charging curves you can see you only can a couple percent capacity and stress the cells further to get it.

Hope this info helps guys and good luck on the purchase!


----------



## JRP3 (Mar 7, 2008)

Powered By DC said:


> Even though TS cells can go to 4.2v per charge it is wise to cut off the charge between 3.6v and 3.8v If you end up getting the blue cells it is wise to cut it off at 3.6


I notice on the Sky Energy site they show the TK cells going from 2.5-3.9 while the SE cells are 2-3.6, but they are both blue cases.
http://www.skyenergy.com.cn/EnProduct.asp
But here on their alibaba page they show some of the TK cells going from 2.5-3.6 and others going from 2.5-3.9, so it's confusing.

http://skyenergy.en.alibaba.com/pro...or_electric_car_energy_storage_equipment.html
http://skyenergy.en.alibaba.com/product/212902341-200299010/Lithium_Ion_Power_Battery_160Ah.html


----------



## notnull (Jul 30, 2008)

Good discussion and great prices, so far.

I would still like to get a better feel as to how much current these cells can handle. My feeling is that the 100ah cells would not be able to handle the current required for the typical car conversion and the 160ah are probably the minimum size you would use for a car.

Anyone have a definite number on the lowest voltage under load you would want to see from the cells, my vote is 2.5V per cell under load. It would be nice to have some tests that explicitly show the voltage under load at 3c and 10c bursts. I know they rate the cells for this load but they still don't show you what the voltage is at that load.

My experience is based on A123 cells, I can run these at 10C continuous and don't drop below 3V per cell until about 80% of the capacity has been used. I set my LVC at 2.7V and have only hit it once in about 100 trips. 

Obviously, I can't get this level of performance with the TS cells, but what is the consensus on what the cells can handle. It would be great to get some info from the guys running the cells. Like the lowest voltage the pack hit and the maximum current you pulled during a trip.

Steve


----------



## Powered By DC (Jan 3, 2009)

Thats why I dont recomend charging above 3.6v with their cells. There is really no reason to go above 3.6v in the first place since you gain very little from it.

Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020


----------



## JRP3 (Mar 7, 2008)

notnull said:


> I would still like to get a better feel as to how much current these cells can handle. My feeling is that the 100ah cells would not be able to handle the current required for the typical car conversion and the 160ah are probably the minimum size you would use for a car.


I've seen a number of car conversions using the 90ah cells successfully.


----------



## notnull (Jul 30, 2008)

I am sure there are some people using them and I hope they reply with some real data. I just don't want to order them and then have to turn my controller down. Right now I have my controller set for 600A and I use ten 12V AGM batteries. The pack voltage falls to about 105V under this load. I like to keep my lead-acid batteries at about 10.5V per cell under load, so 600A works fine for my pack. If I go to 700A, the pack falls below 100V, which in my opinion is pushing the batteries to hard so I went back to 600A.

Let's say I replace my pack with 40 of the 100Ah cells. Sure the voltage at 1C is going to be about 3.25V*40 = 130V. That is fine and better than what I have now (about 120V) at a 100A load. The question is about power when I want to use it. What happens to the voltage at this 600A load, will the pack fall to 2.5*40 = 100V which is probably lower than I would feel comfortable with. Maybe not, who knows, the graph says 10C pulses which indicate 1000A is possible. I just want someone to verify it before I order. 

Steve


----------



## dtbaker (Jan 5, 2008)

JRP3 said:


> I've seen a number of car conversions using the 90ah cells successfully.


would you say that the 90ah cells hold up to 'continuous' 3c discharge? so... 270 amps for 'a while'? That would be MORE than enough for me. I rarely pull more than 200 (at 96v) for more than 30 seconds at a time. I am not maintaining highway speed though.... just around town accelerations to 35 or 45 mph for a mile or so at most. There are just a couple stretches of 50 for about a mile...

I am guessing if I went with Li in a 120-ish v pack I wouldn't need more than 200 for brief times....

d


----------



## notnull (Jul 30, 2008)

I could probably survive with that as well. Our cars are pretty close in size and weight. I am just very leary of the performance graphs that get posted by manufacturers of these cells. I never pull more than 200A continuous (more than 15 seconds or so) unless it is up a hill. Cruising at 45mph is probably 115ish. 

I just want someone to chime in with their numbers. 

Like, I run a 500A controller and 40 of the 100ah cells. At a 500A load the pack voltage was X, cruising around at 125A load the voltage was Y. That is all I am asking for.

Steve


----------



## JRP3 (Mar 7, 2008)

dtbaker said:


> would you say that the 90ah cells hold up to 'continuous' 3c discharge? so... 270 amps for 'a while'?


I assume so since that's how they are rated but I won't know for sure till I get my batteries and finish my conversion. I'll be using 100ah cells.


----------



## Technologic (Jul 20, 2008)

bblocher said:


> You're looking at about $3k for the BMS and charger. I see no reason you can't use the BMS on the Zivan HV circuit though. I mention this because the TS charger is huge and onboard mounting is challenging.


Geeeez lawheez.

Might I suggest this $177 charger:
http://www.bmsbattery.com/product_info.php?cPath=2_18&products_id=38

And the Goodrum Fetcher $100 24 Cell BMS with current shunt charging, LVP, E-brake set to LV point, etc.

http://visforvoltage.org/forum/5192-4-24cell-battery-management-system-bms

Save yourself a measly $2600


----------



## bblocher (Jul 30, 2008)

notnull said:


> I could probably survive with that as well. Our cars are pretty close in size and weight. I am just very leary of the performance graphs that get posted by manufacturers of these cells. I never pull more than 200A continuous (more than 15 seconds or so) unless it is up a hill. Cruising at 45mph is probably 115ish.
> 
> I just want someone to chime in with their numbers.
> 
> ...


If you're running 144v now, get 45 cells instead of 40. 

I have 45 of the 160Ah cells, so 144v nominal and a 500 amp Curtis 1231C controller. If i'm floored, I've yet to see the voltage drop below 130v (I want to say maybe never below 134v but I haven't monitored it like a hawk) even at about 70% DOD. So that's almost 2.9v @ probably 400-450 amps. Basically I can't even really exceed the 3C limit of my cells. I'm hoping that prolongs their life as well.


----------



## bblocher (Jul 30, 2008)

Technologic said:


> Geeeez lawheez.
> 
> Might I suggest this $177 charger:
> http://www.bmsbattery.com/product_info.php?cPath=2_18&products_id=38
> ...


Perhaps I'm mistaken, but this system only shunts 1A during charging and still doesn't provide HV feedback for the charger. Over voltage is still possible with this setup. 

I don't see much for specs on that charger, but assuming it could charge the voltage I need, it's only 1200 watts. It would take me 20 hours to charge after I got to work. Now that would be a long day at the office!  It's definately a low cost solution for low mileage scenarios though.


----------



## Technologic (Jul 20, 2008)

bblocher said:


> Perhaps I'm mistaken, but this system only shunts 1A during charging and still doesn't provide HV feedback for the charger. Over voltage is still possible with this setup.


I was under the impression to shunt more you only need to change a couple resistors...but I'll need to look at the schematic...


If it's a problem it'd still be well worth anyone's time to just modify the Goodrum a bit with a balancer or higher shunt capabilities... for $2500 
>,>



> I don't see much for specs on that charger, but assuming it could charge the voltage I need, it's only 1200 watts. It would take me 20 hours to charge after I got to work. Now that would be a long day at the office!
> 
> 
> 
> ...


There's plenty of other options... but 1200w-1500w is about the best you can do out of wall 110v outlet ... they sell higher ones which I assume use 220v outlets.

1200w would be a 10 hour charge for my plans (shooting for a range of 150-200miles off a 12kwhr pack or so)... so it's all about efficiency...

but again they do have plenty of cheaper and higher wattage options.


----------



## bblocher (Jul 30, 2008)

Technologic said:


> I was under the impression to shunt more you only need to change a couple resistors...but I'll need to look at the schematic...
> 
> 
> If it's a problem it'd still be well worth anyone's time to just modify the Goodrum a bit with a balancer or higher shunt capabilities... for $2500 >,>


I did miss the last part. "When all channels are in the full bypass mode, the charge current is cutoff, and the main LED turns solid green."

I still don't see anything about over votlage protection. If it has it, that's great! Otherwise, it'll be tough to shunt enough current to make it 100% safe for the cells.

On a side note, grats on your controller progress Tehno!

UPDATE:
This is the link I was looking at: http://www.tppacks.com/products.asp?cat=26
You'd also need to have seperate chargers for each group of 24 cells.


----------



## Technologic (Jul 20, 2008)

bblocher said:


> I did miss the last part. "When all channels are in the full bypass mode, the charge current is cutoff, and the main LED turns solid green."
> 
> I still don't see anything about over votlage protection. If it has it, that's great! Otherwise, it'll be tough to shunt enough current to make it 100% safe for the cells.
> 
> On a side note, grats on your controller progress Tehno!


Thanks... I should have a tentative PSU and charger together sometime in the next couple days (finally have some time to work).

The overvoltage is current shunting... which is the bypass mode... and it uses the current shunting to autobalance the cells.

I don't think the 1A current shunt makes a difference if you're charging at 10A-15A at all. it seems to simply bypass that cell and shunt the current while the other cells balance.

Here's the discussion... I'll look at the schematic myself when I have time:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=5416&start=15

They specifically mention it's use with a TS 90Ahr x 144v pack...

My suspicion is using a large shunting resistor (say 2ohm and 10w) would work just fine to keep the voltage down.


----------



## notnull (Jul 30, 2008)

bblocher said:


> If you're running 144v now, get 45 cells instead of 40.
> 
> I have 45 of the 160Ah cells, so 144v nominal and a 500 amp Curtis 1231C controller. If i'm floored, I've yet to see the voltage drop below 130v (I want to say maybe never below 134v but I haven't monitored it like a hawk) even at about 70% DOD. So that's almost 2.9v @ probably 400-450 amps. Basically I can't even really exceed the 3C limit of my cells. I'm hoping that prolongs their life as well.


Thanks Brian, that is what I wanted to know. Hopefully, someone using the 100ah cells will reply.

My plan would be to use 44 cells and charge them with individual 12V sla chargers in 4 cell blocks. I have done this with my A123 cells in the past and it works fine. I would still incorporate the blockers to keep from overcharging.


----------



## bblocher (Jul 30, 2008)

Technologic said:


> The overvoltage is current shunting... which is the bypass mode... and it uses the current shunting to autobalance the cells.
> 
> I don't think the 1A current shunt makes a difference if you're charging at 10A-15A at all. it seems to simply bypass that cell and shunt the current while the other cells balance.
> 
> ...


I honestly didn't read more than a few pages (it's 75 long!).

The 1A shunt is the bypass current. So for example with a 10 amp charger current on the cells, any cell that has reached the bypass stage still sees 9 amps, 10 gets to the terminals, but 1A of it is turned into heat before making it into the cell. The cells not in the bypass stage, of course, receive the full 10 amps. Looks like they do offer two shunting options. Looking at the PCB I saw 2W and 5W where the power resistors go.


----------



## bblocher (Jul 30, 2008)

notnull said:


> Thanks Brian, that is what I wanted to know. Hopefully, someone using the 100ah cells will reply.
> 
> My plan would be to use 44 cells and charge them with individual 12V sla chargers in 4 cell blocks. I have done this with my A123 cells in the past and it works fine. I would still incorporate the blockers to keep from overcharging.


I think you have a really good idea there, but the only unknown for me is what is the maximum voltage of a SLA 12v charger? I'm trying to figure out what voltage the pack would actually get charged to. 13.6v?


----------



## Technologic (Jul 20, 2008)

bblocher said:


> I honestly didn't read more than a few pages (it's 75 long!).
> 
> The 1A shunt is the bypass current. So for example with a 10 amp charger current on the cells, any cell that has reached the bypass stage still sees 9 amps, 10 gets to the terminals, but 1A of it is turned into heat before making it into the cell. The cells not in the bypass stage, of course, receive the full 10 amps. Looks like they do offer two shunting options. Looking at the PCB I saw 2W and 5W where the power resistors go.


That's not what it appears to be at all actually

It appears that a zener switch or something is used to detect the cutoff point, then activiating a sufficient voltage to turn on the PNP... which then shunts the entire charge into the resistor... the lower the resistor value the higher the shunt current...

That simply isn't how you describe at all... at 6.8ohms it shunts everything but 500mA unless I misunderstand this... (which makes perfect sense IMO)allowing for balancing.

Check out the schematic on that page and tell me I'm wrong... this is the designers exact wording:

"At a maximum 20% duty cycle per cell as I jump from cell to cell, this is plenty to keep the high cells down when charging at up to 7-8 amps. So 500 ma of shunting current per cell should be plenty."

"
Today my plan is to fully populate a 16-channel board, using the 15 ohm shunt resistors, and do a heat check. I'm also switching to using 2k resistors for the main LED, instead of the 820 ohm versions I have on my test board. This should reduce the current that the FET control logic uses, which may, or may not make a difference in how much "extra" time the first four channels take,in relation to the others. Right now it is about 2 minutes, near as I can tell, and that is with the 20 ohm shunt resistors. Using the 15 ohm versions will boost the shunt current up to about 250-300mA, so that change alone will cut that two minutes in half, maybe more."

The shunt resistor appears to merely be the effective amount of "load" the charger will see and modify the current output accordingly.


----------



## bblocher (Jul 30, 2008)

Is this the quote you're referring to? http://endless-sphere.com/forums/viewtopic.php?f=14&t=5416&start=15#p80953

Is this guy one of the two designers? He mentions adding 1157 light bulbs to the circuit to help burn off the juice.


----------



## Technologic (Jul 20, 2008)

bblocher said:


> Is this the quote you're referring to? http://endless-sphere.com/forums/viewtopic.php?f=14&t=5416&start=15#p80953
> 
> Is this guy one of the two designers? He mentions adding 1157 light bulbs to the circuit to help burn off the juice.


I think he was testing it... the 2nd part was from Goodrum though...

Look at the schematic and follow what I mean here.









R1 and R2 (voltage divider) bring the voltage input down to the detection level at 3.65-3.69v (I haven't looked up the specifics of what the LM431 is, but it's probably an Opamp or something)

This effectively creates a voltage divider again that's only active (ie. none infinite resistance) once the voltage reaches the cut off of the battery.

This effectively shunts all current but 500mA (at 6.8ohms) which passes through to go to the next battery in the series configuration (ie. uping the current of that battery to charge it more quickly back to balance).

Effectively shorting the battery out of the configuration and sending the small amount of current draw to the next battery in series with it.

Here's fetcher's words (one of the designers):
"I did some testing today with a bunch of beat up 11p cell blocks. At first, the charging current was limited by the power supply and was cruising along at about 7 amps. No noticeable heat from the IRFB4110 at all. 

One cell came up before the others and the LED for that cell gradually got brighter. Before the current started throttling, a second cell came on. As soon as the first cell reached set point, I could see the charge current start to taper down and it eventually settled at the shunt current, about 500ma. Shortly afterward, all but one cell was lit. The low cell was measuring 3.5v and climbing slowly. I'm sure it would have eventually caught up, but I had to dismantle the test setup before I could finish. More testing tomorrow."

I'm 99.9% sure the Goodrum/fetcher is the best BMS on the market for balancing, charge cutoff and LVC (you could do a 3.4 ohm resistor if you wanted 1A for faster charging and higher current, just need a good sink on the transistor etc.)


----------



## CroDriver (Jan 8, 2009)

Technologic said:


> 1200w would be a 10 hour charge for my plans (shooting for a range of 150-200miles off a 12kwhr pack or so)... so it's all about efficiency...




You think that 12kWh is enough for 150 miles?! 

The Tesla has an 30kWh pack and a controller/motor with an efficiency over 90% plus regen and has that range


----------



## Technologic (Jul 20, 2008)

CroDriver said:


> You think that 12kWh is enough for 150 miles?!
> 
> The Tesla has an 30kWh pack and a controller/motor with an efficiency over 90% plus regen and has that range


My car plans should have like 1/3rd the Coefficient of Drag and 1/4th the weight of the Tesla...

Also the Tesla's pack size is 56kwh last I heard. With a range of 256 miles.

All calculators and intuition says 150miles is an underestimate with regen. 90% efficiency isn't anything special ... 97% would be 

Amazing what a Cd of 0.15 and a weight of 800lbs does to all of the "facts and figures" companies use to claim how difficult it is to get their range... fiberglass + aluminum and a sleek small profile beats everything


----------



## bblocher (Jul 30, 2008)

I didn't realize they are actually charging through the board. So they are able to bypass (almost) the cell from the charger.

This looks like a good EV solution. You'd need a charger for each group of 24 cells still, not a big deal.

For someone looking into this as an option my other question would be how much current can you charge through it? Just to make sure it can handle some high amp chargers.


----------



## Technologic (Jul 20, 2008)

bblocher said:


> I didn't realize they are actually charging through the board. So they are able to bypass (almost) the cell from the charger.
> 
> This looks like a good EV solution. You'd need a charger for each group of 24 cells still, not a big deal.


No, you'd just have to switch the charger part to a single set and hook up more to it 
At least this appears to be the way to do it...



> For someone looking into this as an option my other question would be how much current can you charge through it? Just to make sure it can handle some high amp chargers.


Fetcher says 20-30A which is the limit of some of the components they're using (the ICs for instance).

He recommends using smaller cells though or higher shunt capacities .... or wait a longer time for higher Ahr packs 

I suppose though you'd still want a timer on the pack... 500mA-1A is still enough after LONG periods to overcharge a pack if one cell does in fact die.


----------



## notnull (Jul 30, 2008)

bblocher said:


> I think you have a really good idea there, but the only unknown for me is what is the maximum voltage of a SLA 12v charger? I'm trying to figure out what voltage the pack would actually get charged to. 13.6v?


Brian,

I bought 12 of these chargers for my project and am currently using 10 since I only went with 120V. They are cheap and very fast chargers. They have been working perfectly for six months. I have indidual wires running from each poistive and negative terminal of my AGM batteries that terminate into Anderson Power Pole connectors, which I put together to form one large connector at the front of the car for six batteries and one big connector at the back of the car for four batteries. Then I have a bank of six chargers at the front of my garage with one connector (basically 12 pins, big pins) and one bank of four chargers at the back of my garage. When I come home from work, I pop the gas cap and plug in the rear plug then plug in the front plug through the grill opening, takes about 30 seconds. I can see all the lights from the chargers and they are usually done in about 3 hours and all flashing green. I just unplug before I go to bed although leaving it running doesn't hurt anything it just waste energy.

The chargers deliver 10A initially until about 14.4V then it slowly drops the current while pushing the voltage up to 14.7V, at about 1A and 14.7V it is done and goes into a trickle mode, which typically won't happen on the LiFePO4 batteries bacause the voltage doesn't drop back down low enough. So, it charges a 4 cell LiFePO4 pack to 14.7V or about 3.7V per cell which is perfect in my experience. I am very happy and the whole setup ran me just under $400. I am not sure they are rugged enough to mount in a vehicle, but I just leave mine in the garage.

I got them here, http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4506

Also, they will draw too much current for a typical 110V outlet. I have two separate 20A - 12Gauge runs from my panel. I run six one leg and four on the other. The one with six chargers will pull 10A during the first phase.

Steve


----------



## EVComponents (Apr 20, 2009)

Technologic said:


> My car plans should have like 1/3rd the Coefficient of Drag and 1/4th the weight of the Tesla...
> 
> Also the Tesla's pack size is 56kwh last I heard. With a range of 256 miles.


The Tesla Roadster has a 53 kwh battery pack with a range of 244 miles.
The weight of the Roadster is 2,700 lbs with a Cd of 0.35.

The Tesla Model S Sedan has three different battery sizes with different estimated ranges. The base model is 42 kwh with an estimated range of 160 miles. The Sedan will have a Cd of 0.26 and the car will weigh approximately 4,000 lbs.

James (Tesla fanboy) 

www.peakoilgarage.com


----------



## Technologic (Jul 20, 2008)

EVComponents said:


> The Tesla Roadster has a 53 kwh battery pack with a range of 244 miles.
> The weight of the Roadster is 2,700 lbs with a Cd of 0.35.
> 
> The Tesla Model S Sedan has three different battery sizes with different estimated ranges. The base model is 42 kwh with an estimated range of 160 miles. The Sedan will have a Cd of 0.26 and the car will weigh approximately 4,000 lbs.
> ...


Yeah I'm shooting for 800lbs... and the safety of your average formula 1 car 

4000lbs is such a huge waste.


----------



## EVComponents (Apr 20, 2009)

Technologic said:


> Yeah I'm shooting for 800lbs... and the safety of your average formula 1 car
> 
> 4000lbs is such a huge waste.


The Model S is a sweet ride. It is designed to have the luxury of a BMW 5 series and be pure electric.

There is a huge market for people who want to go EV, but they don't have the mechanical aptitude to handle a custom EV conversion. I am really happy that a company like Tesla Motors is trying to bring EVs to the masses. They just broke 1,000 pre-orders for the Model S Sedan in less than a month. $5,000 deposit required for a car that might be delivered in late 2011. Most likely in 2012 though.


----------



## Technologic (Jul 20, 2008)

EVComponents said:


> The Model S is a sweet ride. It is designed to have the luxury of a BMW 5 series and be pure electric.


Well IMO luxury doesn't mean 2000 lbs of leather and poorly appointed interiors... stark high contrast minimalist interiors can be more attractive


----------



## EVComponents (Apr 20, 2009)

Technologic said:


> Well IMO luxury doesn't mean 2000 lbs of leather and poorly appointed interiors... stark high contrast minimalist interiors can be more attractive


It sounds like you might appreciate the Tesla Roadster, which is based on the Lotus Elise. It is definitely more minimalist in terms of interior.


----------



## JRP3 (Mar 7, 2008)

Techs idea of luxury is a go cart with a suspension


----------



## bblocher (Jul 30, 2008)

Technologic said:


> No, you'd just have to switch the charger part to a single set and hook up more to it
> At least this appears to be the way to do it...
> 
> Fetcher says 20-30A which is the limit of some of the components they're using (the ICs for instance).
> ...


There is a different diagram on the website that is newer and seemingly easier to understand. 

It appears it doesn't bypass the charger around each cell. Each cell circuit can trigger the main mosfet reducing or stopping the charging current for the entire pack. They shunt 500ma or 1A depending on the resistor used and once that cell drops below the threshold the mosfet goes full on again. So basically it's exactly like all the other BMS options out there that are talking directly to the charger (except cheaper). Again, if I'm looking at this new schematic correctly.


----------



## Technologic (Jul 20, 2008)

JRP3 said:


> Techs idea of luxury is a go cart with a suspension


Maybe you'd call the original Aptera that... but I wouldn't 

If a car was made out of diamond and weighed 1/8th as much as your average sedan with equal or better strength... would you claim it was a go cart with a suspension? Or just good engineering


----------



## JRP3 (Mar 7, 2008)

Technologic said:


> Maybe you'd call the original Aptera that... but I wouldn't


I'm not a fan of the Aptera. I think a much more useful vehicle with 4 wheels could be made to perform almost as well concerning distance.


> If a car was made out of diamond and weighed 1/8th as much as your average sedan with equal or better strength... would you claim it was a go cart with a suspension? Or just good engineering


I'd probably consider it too damn expensive


----------



## Technologic (Jul 20, 2008)

JRP3 said:


> I'd probably consider it too damn expensive


Carbon is cheaper than iron last I saw 

I was merely analogizing something like an aluminum foam extruded car body, which would be way stronger than steel, but would weigh like 1/16th as much.


----------



## aeroscott (Jan 5, 2008)

carbon fiber is under 1.00 / lb . oh that would be great .


----------



## Technologic (Jul 20, 2008)

aeroscott said:


> carbon fiber is under 1.00 / lb . oh that would be great .


I meant the element carbon... 

BTW to calculate the cost-effectiveness of a material you calculate it's volumetric stiffness/g then calculate the thickness needed... then divide by the price per lb... since aluminum foam takes up 6-16 times more volume per lb than steel.

Don't forget to calculate stiffness (for now let's not include plastic/metallic deformation upon impact), you take the GPA to the power of the thickness... so 2mm thick Aluminum vs 1mm thick steel is 1/2 the weight, but 1.7times as stiff (or so)... this is based upon a 80GPA Young's Modulus for aluminum and a 120 GPA for steel (tops for cold rolled bodies)... Usually cold rolled steel bodies are less stiff than aluminum though (around 70 GPA).

Carbon fiber is significantly overrated for structural applications ... try some elastomer Akulon with a GPA (stiffness) over pure tungsten (4 times higher than steel) at 1/10th the weight  

http://www.dsm.com/en_US/html/dep/akulon.htm

Be sure to use the one with fiberglass reinforcement  stuff is a mere 2.7g/cc same as aluminum thereabouts. But has a Young's Modulus around 320GPA (only a few ceramics are higher, like Tungsten Carbide, Silicion Carbide, Aluminum Oxide (sapphire/emerald), Diamond)

Can be hot molded, sheets, heat pressed, pellet injected, etc etc. Also has amazing sound dampening characteristics, displays characteristics of both high plastic deformation absorption (crash energy absorption) and ceramic fracturing (displaced energy removal from substructure).

Carbon Fiber's current $30/yard price for the good stuff is beyond wasteful unless you intend to use it on it's strongest axis, stretching out the fibers to breakage.

So yes... to return to the original point. A 4000lb car in this day and age for $50k? no thanks. Injection mold the entire body/frame out of Akulon and get back to me. It just might show a little bit of inventive spirit  and concern for future battery replacement costs by using a far far smaller battery (ie. cheaper servicing)

I wonder if Munk was in love with a pigeon a few years ago, maybe that's why he named it Tesla Motors? Certainly would explain a lot.

"One night as he was lying in bed, she [the pigeon] flew in through the window and he knew right away that she had something important to tell him: she was dying. “And then, as I got her message, there came a light from her eyes - powerful beams of light”. “…Yes,” “…it was a real light, a powerful, dazzling, blinding light, a light more intense than I had ever produced by the most powerful lamps in my laboratory.”
~Nikola Tesla


----------



## AndyH (Jun 15, 2008)

bblocher said:


> I didn't realize they are actually charging through the board. So they are able to bypass (almost) the cell from the charger.
> 
> This looks like a good EV solution. You'd need a charger for each group of 24 cells still, not a big deal.
> 
> For someone looking into this as an option my other question would be how much current can you charge through it? Just to make sure it can handle some high amp chargers.


Brian - You're looking at the V1.3 schematic - the board on the streets is V2.3 and controls the charge input.

Here's the store: http://www.tppacks.com/products.asp?cat=26 
Here's the instruction sheet with schematic: http://www.tppacks.com/documents/4-24%20-%20Cell%20LiFePO4%20BMS%20Kit%20Assembly-Test%20Instructions%20-%20v2.3.pdf 

One doesn't need a charger for each group of 24 cells because the boards can be daisy-chained together. One can also build partial boards for each subpack. Connect the 'brake inhibit' outputs together to activate the chosen LVC alarm.

There's about a 100V limit, though, but that's based on the charge control portion of the circuit, not the shunt and LVC portion for each channel. Charge current thru the board is reported to be 'about 30A'.

One also doesn't need to charge thru the board.

For example - I'm using these boards with a 21-cell pack of TS60s. (Thread on E-S.) I use the TS charger on pack positive/pack negative for most of my charges. The control circuit for the BMS is not energized. The shunts still work when cells get to the 3.65 to 3.72V range. The TS charger will not completely fill the pack - it's only set to about 3.65V per cell.

When I want a full pack, I connect a power supply to the BMS after the TS charger is done with it's 15A main charge. The 5A power supply is set to take each cell to 3.7V, the shunts keep things in check, the BMS control circuit throttles the charge current as more shunts activate, and the board shuts the charge off when the pack is full.

Here's what end of charge looks like for the V2.3 BMS. The far left LED is the bicolor red/green. The orange LEDs indicate when the shunts are modulating in and out.


----------



## Powered By DC (Jan 3, 2009)

We have some extras that we ordered and we have one person who asked to back out.
Here are the quantities and sizes of the remaining extras.

129 of the TSLFP 100 AHA 
(specs)
http://www.thunder-sky.com/pdf/20092201189.pdf

40 of the TSLFP 160 AHA 
(specs)
http://www.thunder-sky.com/pdf/200871782241.pdf

The total order was over 150,000 AHs. Delivery is expected in 8-12 week (July).
If you didnt get your order in before I placed the order and you need one of these sizes contact me ASAP
Dave Kois
Powered By DC, LLC
EV Components, LLC
253-988-5020


----------



## CroDriver (Jan 8, 2009)

Technologic said:


> I
> 
> "One night as he was lying in bed, she [the pigeon] flew in through the window and he knew right away that she had something important to tell him: she was dying. “And then, as I got her message, there came a light from her eyes - powerful beams of light”. “…Yes,” “…it was a real light, a powerful, dazzling, blinding light, a light more intense than I had ever produced by the most powerful lamps in my laboratory.”
> ~Nikola Tesla


Nikola Tesla was a genius. He invented the AC motor/generator (that's probably why Tesla motors is named after Nikola Tesla), AC current, wireless transport of electric energy and many other things...

And the most important thing, he was form Croatia, just like I am


----------



## EVComponents (Apr 20, 2009)

FYI... The 150,000 AH order to Thundersky has been fully committed to individuals. In fact, it was oversubscribed at 157,000 AHs. 

We are putting together the last minute orders and getting another 52,000 AHs.This includes extras in the sizes of 60 AH, 100 AH and 160 AH. So if anyone else is looking to get Thundersky or Sky Energy cells at $1.10 per AH please contact Dave Kois ASAP. 

The bulk of our requests have been for 60 AH, 100 AH and 160 AH, so that is what we include in our container for extras to fill it up. 

If you want the smaller 40 AH cells or the larger 200 AH and 260 AH cells, we need to know specifically. We only order the 40 AH, 200 AH and 260 AH cells when there is a specific customer request for that size.

Here is the contact info for Dave Kois:

Dave Kois 
Powered By DC, LLC 
EV Components, LLC 
www.poweredbydc.com 
[email protected]
253-988-5020 

My email is [email protected]

Thanks,
James Morrison


----------



## EVComponents (Apr 20, 2009)

Powered By DC said:


> We have some extras that we ordered and we have one person who asked to back out.
> Here are the quantities and sizes of the remaining extras.
> 
> 129 of the TSLFP 100 AHA
> ...


We completed the ThunderSky LIFEPO4 bulk purchase last week for 153,000 AHs. 
The other orders have been shifted to a Sky Energy order that is being organized right now.
Most of that Thundersky order is committed to companies and individuals. 
Delivery to the port in Seattle is expected in June or July. 

There has been some juggling of requests and last minute changes from several people. 
Here is the resulting effect on the extras that are underway. 

There are still 101 of the 60 Ah cells available. 
If you have an interest in any number of those cells, please let Dave Kois know ASAP. 
(specs) 
http://www.thunder-sky.com/pdf/TS-LFP60.pdf

Dave Kois 
Powered By DC, LLC 
EV Components, LLC 
253-988-5020 
[email protected]


----------



## lorraine (Feb 11, 2009)

JRP3 said:


> As far as I've seen you don't charge the cell to 4.25 or even close. 3.8 max and they drop down quickly around 3.2 as soon as load is applied. I'd go with what Dave says.


yes, 4.25V is for Li2MnO4 battery cell, LiFePO4 cell is about (3.65+-0.05)V. so Normal voltage is 3.2 per cell,40 cells would do 128v,148V peak.

Lorraine
www.xhnykj.com
(38120S/3812P/38105S cylindrical LiFePO4 cell manufacturer,10C max discharging current)
[email protected]


----------



## CroDriver (Jan 8, 2009)

lorraine said:


> yes, 4.25V is for Li2MnO4 battery cell, LiFePO4 cell is about (3.65+-0.05)V. so Normal voltage is 3.2 per cell,40 cells would do 128v,148V peak.
> 
> Lorraine
> www.xhnykj.com
> ...


So that peak voltage can be reached if the cells are charged with an higher voltage...? Is it shortening the battery life if we charge them above 3,2V? 

I will have an 111 cell pack, so that would be 355V nominal, peak =....?


----------



## EVComponents (Apr 20, 2009)

CroDriver said:


> So that peak voltage can be reached if the cells are charged with an higher voltage...? Is it shortening the battery life if we charge them above 3,2V?


It is shortening the life if you charge them to the listed max (2.5V～4.25V) every time. 
Our testing shows that it is a waste of energy to go above 3.8 V. 
You don't get much more range compared to the amouont of energy used.


----------



## lorraine (Feb 11, 2009)

yes,it will shortening the battery life,so we have BMS to have over charge and over discharge protect. our 38120 LiFePO4 battery cell max charging current is 3.65+-0.05V, and end-off voltage for discharging is 2.0V

Lorraine
www.xhnykj.com
(38120S/3812P/38105S cylindrical LiFePO4 cell manufacturer,10C max discharging current)
[email protected]


----------

