A battery question, a friend knocked his goggles battery into hot water, literally. A pint mug waiting for a tea bag.

[Yorkshire_Pud]

Overall the battery is dead but the cells themselves seem fine. I guess something on/in the control board threw a hissy fit.

Having looked at the battery I am wondering if it would be possible to connect the cells from the dead battery to and in parallel with, the cells in the new battery pack.
In general terms I see nothing wrong with the idea and it should double the capacity of the modified battery. He does gripe a bit about the battery life but he often is using the goggles to drive a phone and the phone probably draws the Android 500mA.
My concern is I have no idea if this could damage or screw up the control board in the new battery.
I assume the connections would have to be made with the new battery's cells still connected to their control board.

Any thoughts?
Thanks

 

[EpicFlight]

Toss it.

The casing is not sealed, any one of the cells can be non-visibly damaged. Unlikely, but there is a real risk of explosion and fire while charging – the issue is now you don't know.

Seems a really unnecessary risk for $35 to replace.

 

[Yorkshire_Pud]

OK, I won't suggest it but I am still curious, are these boards designed for a specific battery capacity?

 

[EpicFlight]

it's a 2S1P setup, 7.2V pack. Capacity is printed on the case.

The capacity is wimpy... nothing concerning about taking the BMS board out and attaching it to 2 new cells, any capacity you want... if you know what you're doing.

 

[Yorkshire_Pud]

Are you saying the control board is concerned solely with the number of cells in series and their voltage and that the number of cells in parallel and capacity is irrelevant?

 

[EpicFlight]

Yes – you can attach any capacity LiIon or Lipo cells to the BMS, so long as they're the same.

Of course, I'm making all sorts of assumptions here based on the general nature of a BMS and having a ton of experience with them. Having NOT actually examined, tested, and experimented with the BMS in question, all of this could be inapplicable – though, that would surprise me.

Play with this stuff at your own risk.

 

[Yorkshire_Pud]

Thanks, after the first response I won't be playing but was just curious.

 

[Harro]

If the voltage is correct, then the current drawn from any device depends on the load connected.