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The contactors are INSIDE the pack, and they kill all HV outside the pack when open. And won't close unless the controller is happy with the situation (so, no direct access)


BUT even if you did have direct access, you definitely do NOT want to charge an entire pack blindly with a HV supply. The cells are definitely unbalanced, and definitely will not charge consistently or evenly. You are much more likely to explode a pack trying this than you are to recover even one of the 97 cells in the pack.




Copart auction here

Right now there are 5 for auction. 2 of which I think would be good for battery replacements.
Would be nice to know what signals trigger the relays contactors INSIDE the battery pack. Perhaps then we can try to hoop up to the regular 110v wall charger for slow charge vs the DcC fireball method
 

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Would be nice to know what signals trigger the relays contactors INSIDE the battery pack. Perhaps then we can try to hoop up to the regular 110v wall charger for slow charge vs the DcC fireball method
I can see that you are desperate to try to solve this problem. However, posting replies in a year old thread to a poster who hasn't been on the board for nearly a year isn't very productive.

The answer to your questions is no. The high voltage battery is designed to be isolated behind those contactors embedded in the battery pack. They are controlled by the BMS which is also embedded in the same pack. The system uses CanBus commands, which are the only control signals that come in from the outside.

Literally, all one can do is ask the BMS to activate the contactors. They are programmed not to do that activation if the cells are below a certain voltage.

At this point, no matter how the problem gets solved, it's going to require dropping the pack. There's no way to avoid it.

ga2500ev
 

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Thank you for your words of discouragement 🤓. I was trying to think outside the box because with 2 year+ uncharged batteries, it is most likely that my batteries are shot, and it’s too much wasted effort to do all that work and end up back to square one. My other “out of the box” thought was to tow the car in neutral (since it allows me to switch into neutral with the key engaged) and apply brakes for regen charging. But, as you stated, if the BMS isn’t engaging the battery, then it won’t complete the loop, or even enable the regen braking.
In John’s evolving world video of the battery disassembly, huge relays are clearly visible. There has to be a 12v power source to them somewhere external to the hv battery pack. I’m sure if fiat released a wire diagram it can be done to bypass the BMS/CANBUS.
 

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I'm sorry to be Debbie Downer. Yes 12V does come from outside. However, the control of that 12V to the contactors is the BMS, which is inside the battery container. So, again there is no way to control the contactors without having physical access to them.

ga2500ev
 

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ga2500ev
I'm sorry to be Debbie Downer. Yes 12V does come from outside. However, the control of that 12V to the contactors is the BMS, which is inside the battery container. So, again there is no way to control the contactors without having physical access to them.

ga2500ev
No worries, I am happy/thankful that at least people are responding to my questions. This is a great community, and I want to add learning as I have been for other stuff (for some reason this forum also added my google e-mail account as well as my other Vladifresh account, so I have two accounts on this forum now). But, I digressed...

In any case, I much rather cut out a 2-3" access hole in my car floor (and into the cover) than drop the battery (and everything associated with it, including makeshift chargers). There are 2 cables going into the relay circuit. It would be nice to have the pinout of each connector to know where the 12v signal to activate the clunker goes to. I'm willing to guess its the circled one close to the center as the wire gauge is bigger.

I realize that fiat/bosch put those safeguards in place to prevent cell damage, swelling and fire. I am mainly trying to figure out how much voltage I have on my EV battery, which is probably toast anyway (but it can only be checked with the clunker activated, and at the test point location under the hood). Right now the test port is showing me 5.6v, but the clunker is not activated. Additionally, I have the car sitting outside, away from the house or anything that can ignite. Also, if I can get the clunker activated via the 12v signal, I would temporarily leave the BMS signal floating/cut so that the 12v don't go back to it. Also, IF I can get the clunker activated and check the HV battery voltage, I would hook up my factory 110v charge to try and get the voltage up initially, before reconnecting everything back to stock and proceeding forward with the charge. Assuming that the HV pack will even take the initial charge from my factory charger and not fry it or anything else on the car

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I appreciate your out-of-box attempts, but I believe this is the whole point...:

Assuming that the HV pack will even take the initial charge
The pack's internal BMS prevents it from taking a charge, so the only potential solution is to drop the pack to charge individual cells.

If any one cell is truly permanently ruined, the only solution is to drop the pack to replace every ruined cell.
 
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