Help! My Chainsaw Battery Won't Charge – Dead or BMS?

Hey guys, my 18V Makita chainsaw won't charge. The charger shows green light instantly when I pop the battery in, but the saw doesn't run. Battery is about 2 years old. Is the BMS fried? Any way to revive it?

Felix, could be a cell imbalance. Try a 'jump start' with a 12V car battery charger for a few seconds on the terminals – but be careful. If it's a Makita, sometimes the BMS locks up. I've had luck by discharging the battery fully (connect a 12V bulb) then recharging. Let us know if it clicks or anything.

Had this happen on a DeWalt. Try cleaning the contacts with alcohol. Also, check fuses – some batteries have internal fuses that blow. If you're handy, open it up and look for a popped SMD fuse. Otherwise, a new battery might be cheaper than the headache.

Thanks guys. I tried the bulb trick – nothing. I'll open it up this weekend and check the fuse. If that fails, guess I'm buying a new one. Appreciate the help!