Grinder battery not charging? Need help!

Hey folks, I've got a cordless angle grinder (18V) that suddenly won't charge. Plugged it in, light on charger flashes red/green, and nothing. Battery is about a year old. Anyone had this issue? Is the battery dead or could it be the charger?

Sounds like your battery might be toast. If the charger is flashing red/green, it often means the battery is too hot, too cold, or has a bad cell. Try letting it cool down if you were using it hard. Otherwise, check the contacts on the battery and charger for dirt or corrosion. If that don't work, might be time for a new battery.

Before you spend cash on a new battery, try a quick trick: sometimes batteries go into 'sleep mode' if they're over-discharged. If you have a multimeter, check voltage - if it's really low (like below 10V), you can try bumping it up with a simple charger or a 12V battery for a few seconds. But do it at your own risk! I've revived a few like that, but if it's a lithium pack, be careful. If that fails, check if the charger works with another battery. If it does, the battery is the issue.

I had a similar problem with my 18V drill battery. Turned out the charger was faulty - it was a cheap one. I borrowed a friend's charger and it charged fine. If you can, ask around to test with another charger. If not, might be cheaper to get a new charger than a battery. But also, age is a factor - a year is not super old, but if you run it hard, could be a dead cell.

Honestly, if it's a brand-name tool (like DeWalt or Makita), their chargers have diagnostics. Flashing red/green usually means the battery can't be charged - it's fried. I'd say try a different battery. If the charger works with other batteries, then it's the battery. Don't mess with trying to revive lithium batteries - it's dangerous. Just buy a new one. But if you're under warranty, check with the manufacturer - some have 2-3 year warranties on batteries.