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Tesla Battery Module from PW1
#1
Hi all, 
Got my self a old 2016 Tesla Powerwall 1, for a decent price (if it is not stuffed)
Got several sites on Solar/AGM with Victron kit, so new the lithium game.

Connected up a few things and couldn't see voltage. got the system hooked up to the mains and still couldn't see the pack getting charged.
Decided to finally crack this baby open and get to the modules. Found one of them at 2.8v and the other at 1.5v, from what I can see the nominal is 22v...

What would the recommended steps and products to at least see if these are still viable. What type of charger / charge volt/rate should i aim for?
I don't want to dismantle the pack (yet) down to the cell level, hoping to try and recover the entire pack.

If successful then I'll get the BMS setup and boards ect

ASY,HVBAT,MODULE,TT, 22V01,POD,SSTR
TPN: 1063198-00-a

Cheers in advance
Ben

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#2
Hi Ben,

I'm in the same situation right now. Both modules were at <2V.

I started charging them outside the house with a few hundred mA charge current through a lab power supply.
During charge I monitored the voltage of every single cell group and took temperature measurements periodically.

Stop charging if one cell behaves differently (voltage not rising or getting warm)!!

Once the pack voltage reached about 20V (all cells at >3V),
I used my rc charger with higher current to charge and balance them to 4.1V.

After a few days, one pack was still at 4.1V and perfectly in balance, but the other had cell groups with high self discharge.
The following discharge test of the good pack showed a total capacity of 160Ah which is the rated capacity of 74x samsung ICR 18650 22 cells. 
Perhaps you are lucky.

The next step is to find and permanently disconnect the cells with high self discharge.
For this purpose I disconnected the fuses of the problematic cell groups.

Do you plan using them with the Tesla Wallbox?

best wishes
Thomas
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#3
Thanks Thomas, Sounds like there is some hope for these cells after all. I'll go pick up a bench power supply and thrown them on there for a few days.
Did you start off at 20v with a few hundred mA or 12v with a few hundred mA?

I don't plan on using them with the Tesla Powerwall again (You practically need to destroy the PW to get the modules out).

*edit* How do you identify hot cells? Just by hand?
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#4
It would be a good idea to start with 12V or even lower voltage and increase when the current drops towards zero.
I checked the temperatures by hand and with an infrared thermometer.
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#5
It took about 6 hours to get from 1.5v to 12v @ 200ma-250ma. I'll leave it overnight at that and ramp it up to 18v then 24v.
Then measure cell packs to ensure that they are somewhat balanced.

Any recommendations from people out there about the best BMS for theses?

  
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