DeWalt cordless drill won't charge - any ideas?

Hey all, my DeWalt DCD771 drill battery won't charge. It's the 20V max battery, green light on charger blinks once then goes solid red. Tried different outlet, no luck. Any suggestions before I toss it?

Sounds like a dead cell. DeWalt batteries are generally solid, but they do fail sometimes. Have you tried a hard reset? Sometimes you can jump start them by touching the terminals with a 9V battery for a sec. Google it if you're brave. Otherwise, just buy a new battery – OEM only, don't cheap out.

Before tossing it, check the contacts on both battery and charger for corrosion. I've revived a few with a pencil eraser and some rubbing alcohol. Also, if it's an older battery, the BMS might have locked up. Try leaving it on the charger for 24 hours – sometimes the balancing circuit resets. If that fails, it's probably toast.

I had the same issue with a Ryobi battery. Turned out the charger was bad. Try borrowing a charger from a friend to rule that out. Otherwise, look for a refurbished battery on eBay – half the price of new and works fine. Don't pay DeWalt prices if you can avoid it.

Thanks all! Tried the 9V trick and no luck, contacts look clean. I'll try leaving it on charge overnight. If that doesn't work, guess I'm buying a new one. Appreciate the help!