Rotary tool battery won't charge - anyone else had this?

Hey all, I've got a Dremel 8220 that's about 2 years old. Battery won't charge at all - the light on the charger just blinks red. I've tried cleaning the contacts and leaving it on charge overnight, but no luck. Any ideas?

Hey Chris, I've seen that blinking red issue before. It usually means the charger can't communicate with the battery. Could be a dead cell or the battery's BMS is fried. If it's out of warranty, you might need a new battery. But before you buy, check if the charger is the problem. Try borrowing a known good battery from a buddy to test.

I had a similar thing with a different brand. Turns out the battery was just completely drained and the charger needed a 'wake-up' - I had to use a paperclip to momentarily short two of the terminals. Worked like a charm. But be careful, not all batteries like that. If it's still under warranty, I'd go that route first.

I've also had luck with freezing the battery. Sounds weird, but put it in a ziploc bag, leave it in the freezer for a day, then let it warm up and try charging. Resets the internal protection circuit sometimes. But if that doesn't work, it's time for a replacement. Make sure you get a genuine one, not a cheap knockoff.