Battery not charging? My grinder is dead in the water.

Hey everyone, new here. I've got a 20V cordless angle grinder that's been reliable for a year, but now it won't charge. I plug it in, the charger light blinks red (not solid green like before), and after a few hours it's still blinking. I tried another battery, same thing. Is my charger dead? Or is the tool toast? Any advice appreciated.

Sounds like a charger issue if both batteries fail. Check the charger contacts for dirt or corrosion - a bit of rubbing alcohol on a q-tip can clean them. If that doesn't work, sometimes the charger's internal fuse blows. Does it have a replaceable fuse? My old one did. But if it's under warranty, might be easier to get a replacement charger. Cheap fix usually. Also, make sure your batteries aren't completely dead - some chargers won't initiate if the battery is too low. Try 'jump starting' with a known good battery if you can.

I've seen that blink pattern before. On my DeWalt, it means a defective battery or too hot/cold. Since you tried another battery and it still blinks, I'd suspect the charger. But also check the battery terminals on the tool itself - sometimes the pins get bent. I had a grinder where the battery wasn't making full contact, caused intermittent issues. Also, if the charger has a fan, make sure it spins - if not, it might be overheating and shutting down. In my experience, chargers are the weak link. I've gone through 2 chargers for my grinders but the tools last.

What model grinder and charger? DeWalt chargers have a specific blink code. If it's blinking red fast, it's a temp error; slow blink means battery needs charging. But you said it doesn't charge. Have you tried a different outlet? Sometimes the charger is fine but the outlet is bad. Also, if you have a multimeter, check the charger output voltage. If you're using an aftermarket battery, that could cause issues - stick to OEM. My 20V XR grinder is a beast, but I've learned to keep an eye on the charger. If it's under warranty, call DeWalt, they're pretty good.

I'm a Makita guy, but this sounds universal. I had a similar issue with a Makita charger - turned out the spring-loaded contacts in the charger were worn out, so they didn't make good contact with the battery. A quick fix was to gently pry them up with a tiny screwdriver. Also, check if there's a fuse inside the battery itself - some have them and they blow. If you can, test the battery voltage with a multimeter; if it's super low (like below 5V), the charger might refuse to charge for safety. In that case, you might need to use a 'manual' charge mode if your charger has one, or get a new battery. My advice: don't toss the tool yet, it's probably fine. Batteries and chargers are more likely to fail.