# 1999 Miata conversion



## evmetro (Apr 9, 2012)

Welcome. I will throw in my 2 cents on the charger. I picked out a manzanita charger because of its ability to handle any ac volts input, and you can dial in how many amps you draw. Fast charge with high amp 220, then stop by your buddy's house and plug into his 15 amp 110 volt extension cord.


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## evmetro (Apr 9, 2012)

My build is with an ac35 as well. If you are running that many volts, make sure your controller is the 7501 or the 7601. My ac 35 kit is dated back a few years and came with the 6501 controller that won't take more than 96 volts. I had to buy a new 7601 since I already built the car with 108 volts. It looks like the new kits now come with the 7601.


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## geosynch (Oct 30, 2012)

evmetro said:


> My build is with an ac35 as well. If you are running that many volts, make sure your controller is the 7501 or the 7601. My ac 35 kit is dated back a few years and came with the 6501 controller that won't take more than 96 volts. I had to buy a new 7601 since I already built the car with 108 volts. It looks like the new kits now come with the 7601.


Hi. The controller that came with the motor is the Curtis A1238. It is supposed to regulate up to 130 V. I bought it new just a few months ago.

What brand controller are you referring to?

Thanks!

geosynch


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## drgrieve (Apr 14, 2011)

Consider the well beaten track.

A123 20ah pouch cells or the new Calb grey cells which have a much better C rate than the blues.

Both will give you plenty of amps at a low enough sag rate, the A123 being better.

A123 can be made into a light pack, and can be brought cheaply, and there are 2 or 3 recent build threads on these in the forums,

But I'd use the Calb grey for ease of install. I would go with 36 180ah cells, but you could go with the 60ah in 2p36s.

http://blog.evtv.me/store/proddetail.php?prod=CA60FI

If you buy from Jack, let him know your build details, and he can give you invaluable advice for a good set-up.


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## Yabert (Feb 7, 2010)

geosynch said:


> Haiyin 5000mAh-22.2v-30C
> 25 cells in parallel in a pack, 5 packs in series. 111 V, 13.8 kWh,..... The wiring would be a headache


Absolutely!
You don't have a high performance motor/controller, so why build a complex high power battery pack??
I second Calb gray cells choise. 36S 2P of the 60Ah will be perfect for the performance your motor/controller can supply and easy to connect.

As BMS, you can look for Mini BMS. Simple and work well.


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## jeremyjs (Sep 22, 2010)

could you drop some weight? With how strict you're being on weight if you were able to drop about 200 lbs you could use 180 AH cells without breaking your weight limit. Probably the easiest would be CF hood and trunk lid. With a quick look I saw CF doors and even a carbon fiber hardtop, but they were pricey. I'm sure with a little looking and some cash you could get the weight down that much.

I second the calb CA suggestion. Everything I've seen indicates they're much better than the SE blue cells. Not as powerful as haiyin or a123, but they would last a very long time and be much easier to put together into a pack.


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## geosynch (Oct 30, 2012)

I can't thank you all enough for the advice. This is exactly the kind of feet on the ground experience I simply don't have.

I will definitely go with the CALB cells then, and like the suggestion of the 60ah in 2p36s. I'm going to mock them up this weekend and see how they fit.

I do think I will also relax my weight limit a little bit and think of ways to reduce weight on the car. CF hood and trunk and some light weight wheels might do it.

geosynch


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## evmetro (Apr 9, 2012)

The 6501, 7501, and 7601 are all 1238 controllers. Sounds like you will be ok since it was recently purchased. If you want to make sure, read the model # off of the controller and see what #'s come after the 1238. Best of luck on your build!


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## geosynch (Oct 30, 2012)

evmetro said:


> The 6501, 7501, and 7601 are all 1238 controllers. Sounds like you will be ok since it was recently purchased. If you want to make sure, read the model # off of the controller and see what #'s come after the 1238. Best of luck on your build!


Ah. 1238-7601, then. I can be a bit thick at times 

geosynch


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## dtbaker (Jan 5, 2008)

I dunno about the '99, but my '94 has an AL hood stock, I don't think you'll drop much weight going to CF. Perhaps changing stock seats out to 15# fixed back would take out 30#.  High dollar pounds though. There's not a lot of fat on these cars...

go with Aluminum/plastic racking over steel, etc, shave a little....

I'd vote for the new CALBs. If you really want 80 miles, and are limited to 120v, you are going to have a hell of a time though unless you are willing to pack every cubic inch... and go over stock weight. You'll need at least 20kWhr on board, and that will put you over target weight unless you go crazy expensive/light/painful pouch cells.


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## geosynch (Oct 30, 2012)

More stupid questions from a noob:

I've decided to go with the CALB cells, and am leaning to the 60 Ah solution on a xp3ys pack. Otherwise, I'll go with 3y 180 Ah CALBs. I'm going to mock up both configurations this weekend and see how it works out.

Now for my questions:

1- What's my maximum for "y"? I'd like to get the voltage up as high as possible for best performance. I read one place who sold the motor controller I'm using (AC-35 & Curtis 1238-7601) say I could use up to 36 cells (y=6). The place I bought my motor from told me to not go above 34 cells (y=4) because during regen, I could go over voltage and the controller will stop regulating. OK, I get this. I drive a BMW AE and I love the strong regen, and, want to have a strong regen in the Miata. Here's my problem: I started reading the documentation (I know, dangerous ) which said don't go above 96V (which would be 30 cells). The documentation seems to be outdated, and it seems others on this forum have gone up to 34 cells.

Help? Anyone *actually *have the same setup and *know* I can use 34 or 36 cells?

2- If I go with the 60 Ah cells, I would start with a x=1 config (1p3ys). This would get me on the road fairly cheaply ($3k-ish for batteries) for further development that will surely come as the nears "the end." Then, as the project gets more mature, I can add another 1p3ys pack for further range and performance. If I can determine this weekend that I can actually make a 3p3ys fit, then this will be my first choice because that give me ultimately flecxibility for future growth. Now for my question on this config:

Can any of the BMS systems handle this type of configuration? I'm thinking either miniBMS or Orion. Sorry if this is an obvious question. See self-inflicted noob comment.

Ciao!

geosynch


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## geosynch (Oct 30, 2012)

So, I made mock ups of cells and made a decision.

I'm going to go with the "new" CALB 60 Ahr cells in a 3p33s config; but initially, I'll start with a 1p33s config and expand as cash flow allows and as the project gets more mature.

Now, I need to find a BMS that will grow with me.

Ciao!

geosynch


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## evmetro (Apr 9, 2012)

I don't have all the info on max voltage, but if you wind up getting the orion, you can track my build thread entitled "the metro". I am learning as I go, and using 34 cells and the orion. Frodus has been there everytime I get in too deep on the wiring. I have seen a lot of our 7601s wired up to 36 cells on evalbum, but I wanted to play it safe with 34.


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## geosynch (Oct 30, 2012)

evmetro said:


> I don't have all the info on max voltage, but if you wind up getting the orion, you can track my build thread entitled "the metro". I am learning as I go, and using 34 cells and the orion. Frodus has been there everytime I get in too deep on the wiring. I have seen a lot of our 7601s wired up to 36 cells on evalbum, but I wanted to play it safe with 34.


Thanks. That's helpful. I have taken a look at your build thread, but confess that most of the threads I have studied were other Miatas. I'll take a closer look.

I'm aware that some folks are using up to 36 cells with this controller, but I'm guessing they aren't using regen....? Just a guess.

I wrote to the place that sold me the motor and controller and explained what I'm looking for (Max voltage, strong regen) and they suggested 32 cells.

I've decided on 33 because first, I figure if the controller goes out of regulation during regen, I'll pull out a cell. Meh. But most importantly, for the CALB 60 Ah cells, three rows of 11 cells creates a very nice almost square footprint that nicely fits where the gas tank used to be in the Miata.

Bliss.

geosynch


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## evmetro (Apr 9, 2012)

I think that if 33 cells makes for a nice fit, then that would be the deciding factor for me as well. Nothing like the right fit!


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## geosynch (Oct 30, 2012)

evmetro said:


> Welcome. I will throw in my 2 cents on the charger. I picked out a manzanita charger because of its ability to handle any ac volts input, and you can dial in how many amps you draw. Fast charge with high amp 220, then stop by your buddy's house and plug into his 15 amp 110 volt extension cord.


Which Manzanita charger are you using? I really want to purchase a BMS and a charger soon, as I anticipate having a block of time to really start work again. (My AC35 is in the car, battery boxes are built, cell selection has been made, but cells have yet to be purchased).

I was seriously considering the EMW charger "kit" but I then learned it's a 80 hour job putting it together.... I'd rather spend the cash and get one that's assembled. Plus the kit sounded a bit more beta than I have the stomach for.

I've narrowed the BMS down to either the Orion or the Lithiumate Lite. 

My head is spinning with the choice of a charger.

I have a L2 J1772 CoulombTech CT500 EVSE that I use with my BMW ActiveE. I want to be compliant with that (240V, dedicated 40A circuit). Really, that's my primary requirement for the charger.

Suggestions are welcome!

geosynch


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## TEV (Nov 25, 2011)

I got a Manzanita Micro PFC-40, 80V-240V input, adjustable output voltage and amps.

Last year on Cyber Monday they offered a 10% discount.


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## dtbaker (Jan 5, 2008)

I have a manzanita pfc-20 for sale (see details) at a 20% discount ($1800) w/ free shipping in US.... they are a great charger, especially if you will be adding cells or want some flexibility in setting final voltage and how much you can pull from the wall.... i.e. if you have a dedicated 220v circuit in YOUR garage, you can crank the amps up, and then if you are charging somewhere else on 110v house circuit you can back it down.


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## geosynch (Oct 30, 2012)

I've been away for awhile and am ready to roll up my sleeves. I've been tinkering with crimping v. soldering, and see a lot of discussion on this topic.

I've done a fair amount of soldering and thought I knew how to do it. But that was always on a circuit board and with 16 ga (or smaller dia) wire. Every test cable I made with 6 ga and 2/0 gauge has been horrible. I've tried torches, rosin paste big guns, etc.

So, based on my research in the EVDL sections, I'm going to go to Harbor Freight tomorrow and buy this:

http://www.harborfreight.com/hydraulic-wire-crimping-tool-66150.html

And will forgo soldering completely. Comments appreciated.

geosynch


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## Ziggythewiz (May 16, 2010)

Crimping's definitely the way to go. And that one's even on sale! (At least online)

Don't forget to take your coupon!


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## dtbaker (Jan 5, 2008)

geosynch said:


> So, based on my research in the EVDL sections, I'm going to go to Harbor Freight tomorrow and buy this:
> 
> http://www.harborfreight.com/hydraulic-wire-crimping-tool-66150.html
> 
> And will forgo soldering completely.



you do NOT want to solder main traction pack lugs.... crimp is way to go. big greenlee manual crimper is around $200, hydraulics are more... the one you linked to is not big enough for 2/0 I don't think.


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## TEV (Nov 25, 2011)

geosynch said:


> I've been away for awhile and am ready to roll up my sleeves. I've been tinkering with crimping v. soldering, and see a lot of discussion on this topic.
> 
> I've done a fair amount of soldering and thought I knew how to do it. But that was always on a circuit board and with 16 ga (or smaller dia) wire. Every test cable I made with 6 ga and 2/0 gauge has been horrible. I've tried torches, rosin paste big guns, etc.
> 
> ...


Unfortunate that's useless :

http://www.diyelectriccar.com/forums/showthread.php?t=30951&highlight=harbor+crimping


I got one of those instead :

http://www.ebay.com/itm/190743364984?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I paid $65 with free shipping.


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## geosynch (Oct 30, 2012)

TEV said:


> I got one of those instead :
> 
> http://www.ebay.com/itm/190743364984?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
> 
> I paid $65 with free shipping.


Thanks! You just sold one of those eBay crimpers. I looked at the HF website, and even though the thread you posted was from 2+ years ago, it looks like the tool they are selling is still shipping with undersized dies (based in listed specs and user reviews).

geosynch


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## geosynch (Oct 30, 2012)

Thanks again for the sage advice. I haven't received my new crimper from eBay yet, but I have a somewhat related questions on Anderson connectors.

I bought a used Manzanita charger (this one in fact, from member dtbaker). It came with an Anderson SB-50 already attached.

So, I ordered another Anderson SB-50 to mate with it from a reputable vendor. 

But they don't mate. They are both marked Anderson SB-50. I bought a few SB-50 from the vendor and they all mate with each other (no snickering).

Did Anderson change the design? Do I need to order another type of connector? Or, should I simply ditch the old one?

Mostly, I'm trying to understand why the difference more than I'm looking for advice. Thanks for tolerating the n00b questions.

here's a photo. The new one is the red one. The gray one is still attached to the charger.










geosynch


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## dtbaker (Jan 5, 2008)

geosynch said:


> Did Anderson change the design? Do I need to order another type of connector? Or, should I simply ditch the old one?



looking thru my pile of stuff.... I have the mate.  I'll snip the sucker off the unused cable and send to you so you have a pair. You'll need to get 2 new little connector ends, or splice to the stubs of the wires. I'll leave a couple inches on there for you to work with.


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## z_power (Dec 17, 2011)

Aren't Anderson connectors "color coded" for for different voltages? They also have some kind of mechanical "code" to avoid accidental use for example 80V charger on 24V battery.


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## TEV (Nov 25, 2011)

geosynch said:


> Thanks again for the sage advice. I haven't received my new crimper from eBay yet, but I have a somewhat related questions on Anderson connectors.
> 
> I bought a used Manzanita charger (this one in fact, from member dtbaker). It came with an Anderson SB-50 already attached.
> 
> ...



You need to get another SB50 gray , they don't match if they are not the same color. If you allready got the red ones and you have 2 reds , just change the gray housing of the charger with a red one (20 seconds of work) , the terminals are the same.

Just make sure when you put them back together to insert the pins in the correct position and push until they "click"


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## geosynch (Oct 30, 2012)

TEV said:


> You need to get another SB50 gray , they don't match if they are not the same color. If you allready got the red ones and you have 2 reds , just change the gray housing of the charger with a red one (20 seconds of work) , the terminals are the same.
> 
> Just make sure when you put them back together to insert the pins in the correct position and push until they "click"


Thanks everyone for the replies. I suspected that the color was the issue, but there was no such information on the vendor's website that I had ordered these from.

Dan, thanks for the offer to send me the other half! I really do appreciate it. Let me know if I can send you a few $ for shipping.

I'll need several more Anderson connectors, so, I think I'll keep the one on the charger there; even if it is 20 seconds. 

geosunch


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## geosynch (Oct 30, 2012)

Hello folks! I've started to install my batteries and I have a question for the collective wisdom of this forum.

I am installing Sinopoly 180's and have a question regarding the mechanical integration.

I'm building 3 packs of 8 on one pack of 9. These are assembled in one long row so that the pack of 9 is just over 25 inches long and the packs of 8 are just 22 inches. The cells are compressed fairly tight together, but the cells on each end of the packs are held in place with two long bolts.

Mechanically, it is very solid, but the cells on the end could expand under internally pressure with just the bolts resisting - nothing to to keep the exposed face from deforming under pressure.

A picture is worth a thousand words, so, below are four to describe what I mean.









Above is a photo with 8 of 9 cells in place. You can see one of two long bolts that are used to keep the cells in place. The idea is when the nut is tightened, the angle iron along the bottom compresses the cells against the back of the rack.









All 9 cells in place.









The cells are in very tight.









Another view showing the end of the row. The bolts are tightened to about 30 ft-lbs, keeping the cells tightly compressed in one direction. Outward expansion, along the axis parallel to the row of cells, isn't quite as tight. 

I read a lot about the importance of packing cells in tight. Do I need to provide something on that exposed face (the face that just was the two long bolts keeping it in place)? This would be to keep the pack in compression along the axis parallel to the row of cells.

Thanks for any insight.

geosynch


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## dtbaker (Jan 5, 2008)

My personal conclusion from available data is that end plate compression is irrelevant under normal conditions as the cell case itself is stiff enough to hold internal pouches.

Compression may or may not prevent 'swelling' in over-temp situations, but that just means cells would vent out the top in that case rather than swell, so I don't think the cell is any better off.

I guess you could try to slip a 1/8 plate of steel or AL in there on the faces, but I don't really see what good tight compression does under normal operating conditions.

that being said.... hold the cells from jiggling around IS important to reduce stress on the terminals and bolt loosening


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## geosynch (Oct 30, 2012)

dtbaker said:


> My personal conclusion from available data is that end plate compression is irrelevant under normal conditions as the cell case itself is stiff enough to hold internal pouches.
> 
> Compression may or may not prevent 'swelling' in over-temp situations, but that just means cells would vent out the top in that case rather than swell, so I don't think the cell is any better off.
> 
> ...



Thanks, Dan! I always feel better when I can stand on the shoulders of those who have already been down this road.

Best,

geosynch


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## Coulomb (Apr 22, 2009)

geosynch said:


> Do I need to provide something on that exposed face (the face that just was the two long bolts keeping it in place)?


Well, here's a different answer. In our experience with CALB SE cells, we find the cells swell just with ordinary charging. We have 10 (ten, yes, ten) battery boxes in our Miata/MX-5, and go to some trouble to clamp the cells in all of them.

Our cells actually came with clamping bars and threaded rods, so if your cells don't come with them (or they aren't available as an optional extra that you are supposed to make your own version of if you don't buy theirs), then maybe these newer cells don't need them.

If you or others that use these cells don't notice any swelling with ordinary charging, then it seems like a fair bet that you don't need clamping. However, I don't think that the cells have changed all that much in three or so years, i.e. my suspicion is that clamping is still a good idea.

Here is an idea of what we did; this is one of only two boxes where the cells are at right angles (not just in parallel rows):










These are 40 Ah cells, but we have 218 of them. [ Edit: that box and its mirror image cousin have just 7 cells in each. ]


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## MN Driver (Sep 29, 2009)

It probably is important to keep the Sinopoly cells compressed. Every Sinopoly pack at EVCCON 2012 had some swelling, most packs had at least an 1/8 inch or so amongst about 1/4 to 1/2 of the pack. As far as I can tell they were fine even in that condition but once swelling is to a certain point the voltage sag will get to a point where the cell is useless, although that might be mutual symptoms(clamping the cell may or may not prevent a cell failure). I haven't heard of any Sinopoly cell failures though.


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## Ziggythewiz (May 16, 2010)

Coulomb said:


> In our experience with CALB SE cells, we find the cells swell just with ordinary charging.


Interesting, how long did your cells take to swell? 
What do you consider ordinary charging? A&V?
How long have you had them? 

I've only had mine for about a year, but no issues.


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## dtbaker (Jan 5, 2008)

Coulomb said:


> Well, here's a different answer. In our experience with CALB SE cells, we find the cells swell just with ordinary charging. ...
> These are 40 Ah cells, but we have 218 of them.



ok.... couple interesting things to consider here. with 40ah cells, some in parallel, then blocks in series, I'm wondering what you are doing to balance the system either initially, or with some kind of cell-level BMS?

what really surprises me is that you think charging is causing swelling rather than potential hot spots during heavy discharge under high-amp draw? The key here is that *most* builds gravitate to straight series connections of cells, simplifying connections and balancing.

so, while I remain open to new info, I am inclined to say that with a straight series pack, well balanced initially, you'd be unlikely to see any swelling since there will not likely be a internal hots spots during normal charge or discharge at less than recommended 3C.

now.... if you're NOT balanced, or pulling 10C from cells intended for 3C or 5C max... all bets are off!


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## electro wrks (Mar 5, 2012)

"The bolts are tightened to about 30 ft-lbs, keeping the cells tightly compressed in one direction. Outward expansion, along the axis parallel to the row of cells, isn't quite as tight."


If the cells do swell, in your current design, they'll push mostly against the sides of your tension rods. Possibly, with enough force to make it very difficult to remove the rods and the cells, even with the nuts loosened. One better option would be to run the tension rods 90 degrees to the area of the major swelling force, the largest flat surface of the cells. When the tension rods are loosened, the cells would be free to slide out.

Instead of tension rods, jacking bolts (with a suitable tension member nearby), could be used to compress the pack. They could be threaded into the frame of the battery box or you could use some kind of long, coupler nut/bolt combo if there's room inside the box. What ever method you use, you should include a stout plate on the end cells to control the swelling. Check with supplier/manufacturer. 

Don't forget to think about sealing the battery compartment from outside dirt and water. Also, you may need insulating, heating, and cooling of the batteries if you're planning on operating the car in extreme temperatures.


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## Coulomb (Apr 22, 2009)

dtbaker said:


> with 40ah cells, some in parallel, then blocks in series, I'm wondering what you are doing to balance the system either initially, or with some kind of cell-level BMS?


Yes, cell-level BMS, top balanced. This is the top of the above battery box, with the lid off:












> what really surprises me is that you think charging is causing swelling rather than potential hot spots during heavy discharge under high-amp draw? The key here is that *most* builds gravitate to straight series connections of cells, simplifying connections and balancing.


We intend to go to straight series; 218 cells at 40 Ah is 28 kWh. But that's over 700 V, and we don't have a suitable controller yet. So for the time being, we're paralleling two strings of 109 cells.

The reason we don't suspect discharging is a little embarrassing; having had the cells for about 3.5 years, most of them are not discharged yet! We've observed swelling in cells that have only been charged, never discharged.



> now.... if you're NOT balanced, or pulling 10C from cells intended for 3C or 5C max... all bets are off!


We don't do anything without our cell level BMUs on the cells. We do expect to draw 6C from these 40 Ah cells, which is a little high.

Full build thread (warning: very long!) is here: http://forums.aeva.asn.au/weber-and-coulombs-mx5_topic980_page1.html .


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## Coulomb (Apr 22, 2009)

Ziggythewiz said:


> Interesting, how long did your cells take to swell?


We sometimes noticed it on the first charge.



> What do you consider ordinary charging? A&V?


5.5 A (C/7.2) to 3.65 VPC, bypassing at 3.60 VPC. It's at slightly lower voltages now, but those were the settings when we noticed the swelling.



> How long have you had them?


About 3.5 years, but we discovered this inside the first year.


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## Ziggythewiz (May 16, 2010)

Coulomb said:


> We sometimes noticed it on the first charge.


That's what I've heard, that lemons are lemons from the factory. I'm sure they've made lots of QA progress in the last few years. Mine were the scraps from some of the last batches before the CAs were released and while some didn't look great, they've performed well.


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## geosynch (Oct 30, 2012)

I'm surprised it has been so long since I have posted to this thread. I have had loads of questions pop up during my conversion but have been able to figure most of them out on my own by researching on my own. But, I have another one that I'm hoping to get help on from this forum. A little background.

I "completed" my Miata conversion about 6 months ago and have put on about 3,000 miles. As with any project, however, it is never truly complete.

I'm using a Curtis 1238 controller and my pack is about 108V (33 Sinopoly 180 cells). I am using an Elithion Lite BMS.

Refer to the Elithion diagram here, I am using a TE Connectivity relay at position K1. That relay's rated switching load is 30 amps at 28 VDC. I understand I'm abusing the relay, but I had it on hand at the time and the relay has worked for six months. It is time to upgrade that relay to something meatier so I don't find myself stranded one day.

I bought this relay kit for my heater and I liked it enough to buy a second one to use in the K1 position. But I need some help with the circuit.

Now refer to the wiring diagram for the relay I bought for the purpose of inserting in to the K1 position of Elithion's Curtis 123x circuit (below).










The original idea was to simply replace the heater element with the K1 relay, but when I started the work I quickly realized it wasn't as drop in easy I had hoped because the K1 relay is a single pole, switching only the positive leg of the circuit. 

It seems I could simply ignore the negative leg of the circuit between the relay and the what is shown as the (-) side of the heater (shown as the handwritten letter "G"). When the contacts open, there would still be a path available to suppress a spark across the contacts through the power diode shown.

But my "spidey sense" is tingling. I'm not an EE (but took EE classes as part of my ME degree years ago) and confess I'm scratching my head and hoping for help.

Thanks for any advice.

geosynch


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