Salvaging cells from battery

[Nealh]

Hi Dave,



I wasn't quite sure what you meant but thought I would open it up again and have a look and decided to test the individual cell voltages to check they were balanced. I found that 14 cells were between 3.55 and 3.58 one cell was at 3.33 and one cell was at 0. This is probably a daft question but would a dead cause the bms to cut off charging?

Not d8veh.
But yes, all the time a bms reads a cell voltage at below the lvc.

 

[Justin.Clements]

Thanks Neal,

I don't suppose a pouch cell can be revived in the same way as an 18650 cell by connecting in parallel? I'm thinking the current would be too high.

It seems really odd that the original bms would allow charging but cut discharge when you increased the load and the replacement (pre-used) bms allows discharge but prevents charging.

 

[Nealh]

Thanks Neal,

It seems really odd that the original bms would allow charging but cut discharge when you increased the load and the replacement (pre-used) bms allows discharge but prevents charging.

Cell voltage would have caused the lvc to shut off so either voltage was getting low or voltage sag came in to play unless of course weak cells just crashed voltage wise.
Used bms mat well have been faulty to start with , where did you acquire it from or was it an old one you had ?

 

[Justin.Clements]

Used bms mat well have been faulty to start with , where did you acquire it from or was it an old one you had ?

I originally bought 2 kits and 2 batteries. One battery failed after a couple of years all the cells puffed up. It was the one my partner used and hadn't been used for for about 5 months. Paul from Em3ev thought the cause was that the battery was over discharged and the cells puffed when it was put on charge.