Dewalt drill battery won't charge - blinking red light

Hey guys, my Dewalt 20V max drill battery (5Ah) just stopped charging. The charger shows a solid green for a second then blinks red. I've tried reseating it, cleaning contacts with alcohol, and even freezing it overnight - nothing works. Any ideas? This battery is only 6 months old.

Ugh, Dewalt batteries have been getting finicky lately. Blinking red usually means a cell imbalance or the BMS is tripped. Try putting it on a different charger if you have one, and if that doesn't work, you might need to jump-start it with a 9V battery. I had to do that on my 6Ah and it worked.

I second the jump start method. I've resurrected two old Ryobi batteries that way. But be careful - those lithium packs can be dangerous if you short something. Also check if it's still under warranty, 6 months should be covered.

Thanks guys, I'll try the jump start. I don't have another Dewalt charger but I have a 9V. Yeah it's probably under warranty but I need it for a project this weekend. Will report back.