# 1988 Pontiac Fiero Conversion



## RadioChris123 (Feb 23, 2016)

I got 1 out of about 2000 batteries analyzed - 1988 mAh. I hope they all are like this or better. It definitely took a long time (as expected). I just ordered a 4 battery charger to charge the batteries before and after they are analyzed so I can speed up the process. I wish I could afford 10 more, but one will do for now.


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## RadioChris123 (Feb 23, 2016)

So far I have about 600 cells. I NEED to find a better way to test them because they are taking about 4 hours each. Currently I 'm using a Floureon BT-C3100 ($40 from eBay) battery analyzer. I just ordered a 4way charger ($16 from eBay) to help precharge them for testing.


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## madderscience (Jun 28, 2008)

Hello-

A couple things to be aware of with laptop batteries: Many of these are lithium cobalt cells, which can be dangerous if operated outside of their temperature/SOC range/C rate profile. Unlike the LiFePO4 more commonly used in conversions, lithium cobalt can catch fire. to hedge against this:

1) make darn sure all the cells you get are the same kind, from the same manufacturer
2) Lots of cooling. 
3) a good BMS
4) make sure the cells are packaged in an enclosed metal housing (but with some kind of ventilation)

Also be aware the lithium cobalt cells don't have great cycle life, and you are already starting with used ones. You may want to consider the longetivity of the pack given the amounf of effort you are going to be putting into it.

You might be better off getting a volt pack and reconfiguring it. That will be more expensive initially, but likely less cost in the long run.


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## RadioChris123 (Feb 23, 2016)

Thanks for the info madderscience. I wish I could afford something other than what I'm doing now, maybe after I graduate. I'm taking quite a few precautions when it comes to assembling the packs. I'm weighing different BMS options, fuseable links on each cell, bottom balancing, temperature monitoring, and fan and/or induction cooling. If this doesn't work out, there is always the fail safe - Leadacid Batteries.

Does anyone have experience building such a large bank with used laptop batteries?


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## Moltenmetal (Mar 20, 2014)

By the time you're done with your laptop battery plan, will you have saved anything substantial relative to Leaf or Volt packs from the wreckers?


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## RadioChris123 (Feb 23, 2016)

Maybe, maybe not, IDK, I've never done this before. I suppose I should price out volt or leaf cells again. Does anyone have a suggestions on where to get some (other than eBay)? do you think used junk yard pack or new? 


So far I've tested 80 cells and about half of them are above 2000mAh. I found some that are 3000mAh. that surprised me.


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## madderscience (Jun 28, 2008)

it sounds like there is too much variability in the capacity of those used cells. you are going to have have nothing but trouble trying to build a large pack out of them I am afraid, top or bottom balancing or not.

My understanding is volt packs from wrecking yards run up to a couple thousand, leaf packs a bit more (because they are bigger and easier to reconfigure) but I admit to no direct experience. Availabilty of such postdates my last build, or I probably would have gone that route.

How much time are you going to put into engineering and assembling that pack? could you moonlight for a few months instead, and build up a few thousand $ to throw at a volt or leaf pack?

Lead acid is not cheaper than volt/leaf lithium, if you want it to last at all.

Also, aim for more than 72V if you can. 72V is bare minimum for a roadgoing car, and you won't have freeway capability. 144v or 156v ideally. If you start with 72V now, at least leave physical room for doubling the battery size and installing more powerful motor and other components in the future so you don't have to reengineer everything.

Good luck.


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## RadioChris123 (Feb 23, 2016)

Well I'm getting there, slowly but surely. I have 2 four way analyzers and 1 four way charger. The analyzers seem to get really hot so I augmented one with a computer fan. Check out the hole in the bottom. It seems to check each battery faster because they don't have to stop charging and discharging to cool down.

4 of the 20 cells are done. Each have 72 cells averaging 2300mAh. That is 165 Amp Hours (596 Watt Hours at 3.6 Volts). 20 of these should give me 11.9 KWh. In comparison the Volt has 18KWh. 

Remember, I'm not trying to break any world records here nor is this a daily driver, this is just a budget build for fun.


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## Anthonyelectric (Oct 3, 2013)

This is excellent, I think you are farther along in your conversion than I am (1984 Fiero).

I found a rotted 86 Fiero that was converted a decade ago with dying Pb.

So far (in the 6 ish years this has been going on)....I've only got the motor and transmission in the car. I need pro help as I want this done this summer!


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