Lithium ion battery build

[Nickthetaxi]

Hi there, looking for help!. Having converted my Bosch GSB14.4 VE-2 NiMh drills to Lithium-ion batteries, using 'good' reclained Samsung INR21700-40T cells (4000mA 35A Discharge) & 4S 40A balanced BMS (from China!) & using a 2A Li-ion charger. After several months, occasional use, I keep burning out the Mosfets?. I would appreciate any advice?

 

[Alec_t]

I keep burning out the Mosfets?

During charging or discharging?
What is the drill rated running current and rated/actual stall current?
Welcome to maker.pro!

 

[Nickthetaxi]

Hi there, not sure. Can't find any info. online! Will have to buy some more, to run tests. Can only assume 40A is not enough. Not easy to find simple 60A bal bms!.