Dremel 4300 battery not charging - any ideas?

Hey everyone, my Dremel 4300 (cordless) just stopped charging. I plug in the charger and the light goes from red to green instantly, but when I put the battery in the tool, it's dead. I've tried cleaning the contacts and even left it on charge overnight, no luck. Anyone seen this before?

Sounds like the battery might be toast. I've had a few that just stop taking a charge after a couple years. But before you bin it, check the charger itself. If you have another battery, try that. If the charger says green on a dead battery, that's usually a sign the battery's not registering. Might be a bad cell.

Agreed with Dan. Also, those lithium batteries can be finicky. Sometimes they go into 'sleep mode' if they're drained too low. You can try a 'jump start' by momentarily connecting to a good battery (if you have one) with some wires, but that's risky. Safer to just get a new battery. And make sure you're using the right charger - I once used a different brand charger and it did weird stuff.

Thanks for the replies. I don't have a spare battery, but I'll try the jump start trick. If not, I'll order a new battery. Appreciate the help!