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2012 Chevy Volt Battery:

330245 Views 663 Replies 95 Participants Last post by  remy_martian
Paid $2000 + $150 shipping from a junkyard.
It is a work of art. I'll be sad to tear it apart for the cells, but that's life.
I'm getting 373 vdc for the battery, and 3.88 vdc per cell.

IF there are 288 cells. Already things aren't making sense. I count 72 modules about 1" thick.



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has anyone tried using one of the many simple bms circuits on ali express? or any of the other sites for their Volt batteries? Im looking for an affortable solution. I want to use 48v modules in parallel to achieve 144v. I find it hard to get my head around how a 144v charger will work with such BMS designs. IVe looked at Mini BMS but it still seems expensive. Using the below I could get by with 6 of them.

44V 48V 50.4V 30A 12S Lithium ion / LiPolymer Battery Pack BMS for E-bike
12S 30A Li-ion / LiPO Battery protection board.

Applicable for
43V (3.6V * 12S) lithium battery & packs
44V (3.7V * 12S) lithium battery & packs
50.4V (4.2V * 12S) lithium battery & packs

Lithium battery (Li-ion)
Prismatic Lithium Polymer battery (Li-Po)

Technical Parameters:
Balanced current: 60mA (VCELL = 3.90V when)
Balanced for: 4.20 ± 0.05 V
Over-charged Protection: 4.2 ± 0.05 V
Over-charged Release: 4.05 ± 0.05 V
Over-discharged Protection: 2.9 ± 0.05 V
Over-charged delay: 5mS
Over-current Protecton: 30 A
Supports Max. Continuing Discharge Current: 30A
Static power consumption: less than 200uA
Short-circuit protection function: disconnect the load from the recovery.

Dimension: 129mm * 53mm

The main functions: Over-charged, Over-discharged protection, short circuit protection, over-current protection, with Balancing function.
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Hi Mate.
Firstly, I assume you mean 48v modules in series, not parallel.

I did look at these BMS but came up with two problems, three if you count cost.
Firstly you need to make a connection to each of the cells, ok if you have access to a Tig welder not so easy if not.
Secondly you also need to buy three chargers, the ones they recommend only charge at 4A (a bit slow I fear) unless you can find one that will charge at 151.2v at, I believe 9/10amps min, not an easy option nor cheap.
Or buy three 50.4v chargers also not cheap, they also need to have isolated outputs otherwise you will get fuses blowing each time you connect them, unless you use relays to break the series connections of the pack when you want to charge (this would need at least two high current relays in the main power lines, not a good option).

A lot of the guy's on here do not think full top and bottom balancing is required, myself included although if all the cells were connected by nuts and bolts it would be easier to implement and an added luxury.
A long time ago, I saw a build on one of the other forums (the one with lots of different conversions of all types) where he made a small and simple controller for each of his cells using zeners and a bit more circuitry, but I have not been able to find it since, that was I believe, a top balancing BMS.

The important thing as far as I am concerned is max and min temperature of the packs and max and min voltages of the cells or pack in total.

My method is to use the three 55v 9A power supplies (which will go up to about 58v) I used to charge my flooded leads and to use an Arduino Nano on each PSU to switch off the charger when the pack (I am using three blocks of 14 cells) voltage reaches 57.4v (4.1v per cell) and switch back on at 54.6v (cell voltage 3.9v) to top it up and keep it fresh. I use 10A relays to isolate the chargers out puts when not charging, to prevent any chance of pack leakage back through the chargers.
I understand it is better to stop at 4.1v per cell to extend life, also I believe the cell voltage continues to rise a little after charging has stopped, although if the charge is slow enough this tends not to happen. I am hoping 9A is slow enough.

I am also using a fourth Arduino Nano to check the temperature of the coolant leaving the pack and delay charging until it reaches 16C ( considered a safe lower temp for charging Li-on cells) and to stop charging if the temp rises to 36C and above(considered unsafe for charging Li-on cells), switching on the pump, heater, radiator etc, depending on the coolant temperature.

I know this doesn't answer your question but I hope it is food for thought.
Good Luck.
Hi John

I was going to use a 144v charger that will auto cut off at that voltage. Would the charger infact need to cut off at 150v?
Also re the tabs on the batteries. Apparently they are soft. Why not gently bend then over and drill a suitable hole for a bolt into it. one by one. with the nearby tabs covered to prevent shorts. then gently bend them back one by one.

Also instead of Arduinos why not just use simple temperature control circuits that are a dime a dozen on the various electronics websites. Would seem a cheaper easier option? Thats what I plan to try along with a suitable relay and either blow air down the water channel or pump coolant.
There is built-in easy access to each cell for BMS purposes (not high current, though). Just use the existing BMS connector. I cut one end off the BMS cable and wired it to my Elithion BMS boards. The other end attaches to the batteries.
Hi Dave.

If you use that connector in that manner does the charging go through those BMS's also how are the batterys connected out for the high current "main line" to the controller? I want to have 3x48v modules in the trunk and the other three up the front under the hood. ie 144v
n parallel jointed at the front then feed to the controller. Excuse my ignorance. Ive been doing my best to read up on this but still find it confusing.

with fans i was thinking one fan pushing on one end and on the other end another one sucking the air out. A filter is a good idea.
In NZ it doesnt get more than say -4 where I am and thats during the middle of the night when I will have it in my garage which doesnt tend to go below zero. I may put warm fuzzy blankets over the batts when i charge them after getting home in winter. :) Or prehaps ill just have some insulation around them. Undecided. Right now trying to find someone in the USA willing to take my money. Its hard as they want a US credit card. Ill keep trying.
Re the temp control boards I was merely making the point they are less than 10 usd each vs whatever a audiweno or however its spelt costs. I dont quite follow what defines a smart vs dumb charger. I do not have a lot of money so I am sailing close to the wind as they say but trying to achieve an acceptable result. Hense I am going to use a motor and controller and charger from china that are far cheaper than the mainstream choices on this form. Of course I cant have my cake and eat it so things like regen are not available to me. The controller will be locked to the motor settings wise. The charger is non adjustable once it leaves the factory. They will program whatever voltage cut off I want but again its locked after that. That may seem annoying but the charger is far less than half the price of the usual type of charger quoted here. It will cut off at whatever voltage I ask them to set it to. I dont see how I can have a BMS make the charger do anything?
And that's the reason why every OEM car has a ground fault detection. The contactors will not close if there is any low-ohmic connection between chassis and anywhere in the HV system.
A solution for ground fault detection gave me a headache. Im currently planning on installing a secondary DC motor (powered by the drive battery) to spin my air compressor with the bonus benefit of hopefully allowing me a waiver on ground fault detection because of the fabulous brush dust the motor will generate. (NZ guidelines are vague, they stipulate install if its practical.)

Anywaaaay Eldis do you know of any ground fault detector thats not the hugely expensive thing from Germany?
Not from top of my head. There should be quite a few such devices available. I'm planning on adding the ground fault detection directly on PCBs of some of my toys later on.
If you find anything thats not expensive let me know. Home based RCDs are not able to be used.
I'm not sure if this has been talked about yet or not, it didn't come up in search. (I'm not sure why it took me so long to figure this out!?!)
Thank you. This is very helpful.
Re: 2012 Chevy Volt Battery: hmmm

I have a question. Well a few. With these cells to baby them a little is 4.2v ok or is that stretching them. Better to go to 4.1? 4.0?
Lastly using 4.2 as the example do you set your charger to stop at 168volts for a setup of 144v motor and controller? 6 (3x12 in parallel) of the 12 cell modules split front and back for a 144v nominal setup.
Im not a bms person, BUT, if you are going to push 4.2 it gets dicey because some cells will eventually go over on charge. That is where you need a bms. I stop at 4.07 mainly bcause it works out to be 195 on half a pack on my equipment. I was running 196/197 until i smelled the electrolyte smell one sunny morning. Havent smelled it since.

Remember all your measuring equipment has tolerances unless they have been calibrated against a standard.

I would stop at 164 without bms run that for a bit, see if some cells run high, then adjust up or down. I cant give advice abojt using a bms. You also need to see what the controller max input is and back off a bit from that.
The cheaper chargers are factory locked. What should I set the voltage to for 4.0 volts (4.0 best for long cell life?) per cell on a setup with 6x 12 chevy cells setup as 144v nominal parallel?
Personally, I charge my top balance pack up to 4,06v since more than half a year now with great success.
I'm very happy with my top balance pack, but as I wrote on my build thread, I will use the chevy Volt bms to charge at higher voltage when I need a bit more range.

I hope to release here more details about the Volt bms in the next months.
Hi Yabert

I would be very interested if you can find a way to make the existing BMS modules work. I read online today they may function on some level if you feed 12 volts into the right pins but I dont know if thats true?
I posted these on my build thread but I thought they should go here as well

The Battery bracket/holding tray is made from the Chevy bits and weighs 5kg

- This is my way of getting the air out
With the current forecast I have a couple of days before I will need to ensure I have anti-freeze in there

I was even able to re-use the rubber sheets that Chevy used in the battery mountings
Hi Duncan

Love your pipe work. Very cool. Can you please tell me the gauge of the pipes as I want to do something similar between my batteries under the hood and the rear ones in the back. What pump do you think will have enough grunt to push through my three front batteries and three rear batteries with the length of pipe under the car as well? :)
I see this mention of vacuum filling. Not sure how that would work. It does sound expensive. At this stage I dont think ill put a heater into the loop at least initially.
Ive read online that 4.2 volt per cell is actually 80% charge in these cells as per Chevy factory settings? Is that right?
Hi John
The pipe is standard plumbing pipe - the type you solvent weld together - I think its 15mm

The reason for the vacuum fill is that the inlet and outlet are at the bottom - with the cooling passages above them - so it's difficult to get the air out

I fixed that by filling mine with the battery on its end - so the water outlet was above the cooling passages
Then I ran a hose through it for about an hour - then when it was all full of water I dropped it back down
And added some antifreeze mixture - just in case

As far as flow rate and heating cooling I have just ordered a "solar pump" from Banggood
12v Solar Hot Water Pump
About $30NZ delivered
How much heat do I need to dissipate???- say its 3Kw - at 8 liters/min the temperature rise will be about 6C

So the water coming from the batteries will be 6C warmer than the water going to the batteries
Sounds OK to me - I will find out when I use it

As far as heating v cooling - the battery wants to be 25C - 30C - here in Southland the air temperatures rarely reach 25C
I think I will be heating a LOT more often then cooling
HI Duncan. My understanding and correct me if im wrong is the battery is damaged from getting too warm but if its too cold its not damaged but range drops. Is this correct? Or does driving it cold cause damage too?
I will have to google how vacuum fills work. Wouldnt your fluid just run out again as soon as you lowered the battery back down and if you capped it then it would still run out when you went to connect the hoses up? For my setup I wasnt planning on heating the batteries but I am interested in insulating them so they might warm naturally under use.
In my 3 year , 8000 mile, 750 charge experience: you are being too paranoid.

I pull 400 amps for 6 minutes on monster hill. Longer if I get caught at the red light 1/2 way up. The pack temp rises ten degrees.

Figure 10% reduction in everything when they are below 60 f. I DONT cool when ambient is below 60f seems like a waste.

My $0.02 YMMV
Hi Piotrsko

:) We are probably paranoid due to the trouble getting these batteries across the ocean to us. They are pretty much our "precious". :)
Do you know if the cold affects the batteries in a damaging way or just lowers the range on the day?

Also can someone please tell me once and for all what i need to get a factory locked charger set to for my 144 (72 cell) volt setup? Ie final voltage and any other relevant instructions to pass to the agency who will configure the charger for my situation. Different people say different things lol. Id like to keep it conservative ie around 80 percent charge maybe slightly more. 4 volts a cell? :)
HI Duncan do we need to put diodes on our contactors?
Ive tried to search but cannot find a answer. What is the short circuit rating of a chevy volt gen 1 battery? I thought two times 225 amp 250v or 500v dc fuses (positive and negative) would be good but now im thinking maybe I am incorrect. In New Zealand we are required to fuse as per the below. If anyone knows what fuse would match these specs I would be grateful. My installation is 3x12s Chevy volt modules in Parallel for a total of 96 cells. My inverter is relatively low powered at a max rating of 120amps input. But the rules are quite specific in the reference to "maximum battery short circuit current. The cable I am using is 184amps continuous rated.

"Overload protection 2.2(5) The electrical systems within an electrically-powered low volume vehicle must have over-current protection devices that: (a) are an appropriate selection for the design of the electrical system; and (b) are mounted as closely as possible to both poles of the power source, but not within a compartment containing venting batteries; and (c) are designed to protect the wiring and electrical components of the electrical drive from over-heating following an over-current situation; and (d) have between 20% and 40% overload capacity, in order to protect the electrical wiring and components of the electrical drive from damage; and (e) are DC-rated for the maximum battery voltage and capable of interrupting the maximum short circuit battery current; and (f) protect all connections to the high-voltage traction battery and motor wiring, which must include ammeter shunt wiring, volt meter wiring, battery management systems, chargers, and heaters; and (g) in the event of deployment, are not likely to cause themselves, or any surrounding components to ignite."
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