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Discussion Starter · #1 ·
Hello! I have been restoring an electric car that's been sitting outside for 5 years and is subsequently rusted and moldy. This is the car: http://evalbum.com/3379


Sadly, the batteries in it were only used about 300 miles before the car was parked. It had 12 Optima D34M for a 144V DC system. I've been trying to resurrect them, but only a few have shown any life and they still won't charge more than part way.


Anyway, I was planning on replacing the system with LiFePO4 batteries, but after reading a bit, I think buying a salvage Chevy Volt pack would be better. It would cost about a thousand less and I'd get about 6kW more than what I was going to order.


Although I have a lot of experience in electronics (computer engineering), I have no experience in electric cars. I would appreciate any help or advice. Here are my current questions:
1. Is this the right decision (getting the Volt pack)?
2. Can I make the pack a 144V system, or do I need to drastically change the car setup?
3. For a BMS, what's the best way to do this? I know people are working on using the Chevy one, but it seems like it isn't ready yet. I also don't know if it works given I change the configuration.
4. Can I use the Elcon PFC 2500 charger in the car, or do I need a different one?
5. Finally, I live in south Texas where it gets really hot (>100F) a lot of the summer. What's the best way to implement some form of simple cooling?


Basically, I'm just overwhelmed by the sheer volume of possibilities and opinions out there. Thanks for your help.
 

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Hello! I have been restoring an electric car that's been sitting outside for 5 years and is subsequently rusted and moldy. This is the car: http://evalbum.com/3379


Sadly, the batteries in it were only used about 300 miles before the car was parked. It had 12 Optima D34M for a 144V DC system. I've been trying to resurrect them, but only a few have shown any life and they still won't charge more than part way.


Anyway, I was planning on replacing the system with LiFePO4 batteries, but after reading a bit, I think buying a salvage Chevy Volt pack would be better. It would cost about a thousand less and I'd get about 6kW more than what I was going to order.


Although I have a lot of experience in electronics (computer engineering), I have no experience in electric cars. I would appreciate any help or advice. Here are my current questions:
1. Is this the right decision (getting the Volt pack)?
2. Can I make the pack a 144V system, or do I need to drastically change the car setup?
3. For a BMS, what's the best way to do this? I know people are working on using the Chevy one, but it seems like it isn't ready yet. I also don't know if it works given I change the configuration.
4. Can I use the Elcon PFC 2500 charger in the car, or do I need a different one?
5. Finally, I live in south Texas where it gets really hot (>100F) a lot of the summer. What's the best way to implement some form of simple cooling?


Basically, I'm just overwhelmed by the sheer volume of possibilities and opinions out there. Thanks for your help.
Everything is known about using the stock Volt BMS. If you want to monitor and balance by sending CAN commands to the BICMs yourself, the info is available. If you want a ready-made solution, use the Volt BMS BICMs (slaves) with Tomdb's SimpBMS to control them.

There are limitations with using the stock BMS and changing the pack configuration. The BICMs get weird if the cell inputs are not completely filled so you are limited to some combination of 30 (BICM 1), 24 (BICM 2/3) and 18 (BICM 4) cells. Secondly, you can't have duplicate BICMs on the same CAN bus. You'll get the cell voltage data but you won't be able to balance.

I run a 42 cell series string (~157V) using a BICM 2/3 and a BICM 4. I have 2 parallel strings which means I have to run two CAN buses to talk to each string separately. I use a raspberry Pi with two cheap CAN bus adapters to monitor and balance every cell in my 84 cell pack.
 

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Discussion Starter · #3 ·
Thanks for the reply. Where is the information for the CAN bus commands? I've only seen some in the forum.



Your setup seems about like what I want to do. How many volts is each cell? Is your setup from one pack? I don't really know specifics of the pack, so I'm not sure how many cells are in one of the modules for a slave/etc.


Does the setup keep any of the cooling system?
Thanks again.
 

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Discussion Starter · #5 ·
Thanks. I read about 10 pages of that thread as well as a couple of others. I'll read through to see what I missed. I was hoping there was some tutorial/wiki type collection of all this information. :p
 

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Thanks for the reply. Where is the information for the CAN bus commands? I've only seen some in the forum.



Your setup seems about like what I want to do. How many volts is each cell? Is your setup from one pack? I don't really know specifics of the pack, so I'm not sure how many cells are in one of the modules for a slave/etc.


Does the setup keep any of the cooling system?
Thanks again.
I've read the nominal voltage for a Volt cell is 3.75, so that's what I used for the 157V number. My 42S2P cell pack ranges from 147V empty to 174V full (depends on how high or low you want to go on charge limits).

The full Volt pack is 96 cells. I have used 84 of them for my pack, which is not a particularly large pack. My range is ~40 miles. I'm looking for room to stick another 42 cell string into my car to get it up to ~60 mile range.

I do still use the liquid cooling capability of the Volt pack but, since I am in Seattle, only for warming the batteries in winter and keeping my Tesla charger cool in the summer. For the latter I can get away with a simple radiator cooling system. You've got quite a bit more of a cooling challenge.


The easiest way to learn the CAN commands is to study Tomdb's code.
https://github.com/tomdebree/AmperaBattery
It gathers together a lot of the work done by Tom and others in deciphering the Volt BMS CAN command set.

There's also my thread if you want to see a discussion of the balancing commands.
https://www.diyelectriccar.com/forums/showthread.php/1st-gen-chevy-volt-bms-balance-200023.html
 

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Discussion Starter · #7 ·
Thanks! I've ordered a 2015 pack, and I'll try to duplicate that setup. I have about 12 Raspberry Pis sitting around for experimenting.



I just removed the old batteries from the car, and will start work on a way to mount the parts of the pack.
 
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