Advice for DIY repair of Portable Power Generator

[ctdctd]

Hi Guru’s

Newbie here – although I used to be an electronic design engineer in a past life and I have a multimeter and a soldering iron!

Anyway, I have acquired a broken 750Wh portable power generator with a 12.8V 60Ah LiFePO4 battery pack and would like to save it from an early death.

As it stands, everything works correctly including the AC inverter but when it is recharged, the charger cuts out when the batteries reach 12.8V and the actual capacity I get is around 100Wh.
The charger is the correct one for the generator and is rated at 14.6V 10A.

The generator has suffered minor impact damage and there is discolouration on one end of the battery pack so I’m assuming that one or more of the cells have taken a whack.

The overall size of the pack is about 320 x 120 x 130h and there is a BMS marked JBD-HP04SK 30A mounted in the middle of the pack. It is not obvious what cells are within.
So questions are:-

• How can I confirm it’s the battery pack that’s at fault
• If the battery pack is faulty, do you think it might be repairable if I strip it down?
• If I do strip it down, how best to wrap it up again!
• Or, any economical suggestions to replace the battery pack with something that will fit in the available space?

It would be nice to keep the 750Wh capacity but I wouldn’t mind a reduction if it was easier to safely package.

Thanks for any advice!

 

[ctdctd]

Somewhat interestingly, I've just tried charging it - thought I see if any area of the battery was getting hot.
After 10 mins, the voltage has reached 12V and the BMS metal plate is getting very hot - almost too hot to touch.
Have stopped it charging - do the BMS modules normally get hot?
Or could it be getting hot trying to control charge to a faulty cell?

 

[ctdctd]

Update for this if anyone's interested!
I stripped the battery pack down and it was obvious there had been some leakage.
Further investigation revealed puncture holes in two of the four cells caused by the battery pack shifting within the power station enclosure and getting impaled on the self tapping case screws! Terrible design.

I don't have the capability to rebuild with two replacement cells - looks like the battery connections are welded?
So, am looking about to see what else might fit in the available space.