Need help: Saw battery won't charge and makes strange noise

Hey everyone, new to the forum. I have a DeWalt 20V circular saw, but the battery won't hold a charge. When I try to charge it, the charger light flashes red and there's a high-pitched whine coming from the battery. Any ideas? I've only had it for 6 months.

That high-pitched whine could be a capacitor or a cell going bad. Don't try to force it—sounds like the battery's BMS is shutting it down. Do you have another battery to test the charger? If it's only 6 months, it should still be under warranty. Contact DeWalt support.

Agreed with Wendy. Flashing red usually means a fault. I'd also check the contacts on the battery and charger for any gunk. But if it's whining, one of the cells might be toast. Under warranty? Send it back.

I've seen this happen when a battery gets dropped. Could be an internal short. If you're out of warranty, you can try prying open the case and measuring each cell. But honestly, for a 6-month-old battery, just get a replacement. Not worth the fire risk.

Welcome to the club of dead batteries. I'd say recycle it and buy a new one. But def try warranty first. Also, check your charger on another battery to rule that out. Good luck!