My Impact Wrench Battery Won't Charge - Help!

Hey everyone, I've got a DeWalt 20V max impact wrench that I've had for about a year. Yesterday I went to use it and the battery was dead, so I plugged it into the charger and the charger just blinks red and green and won't charge. I tried a different battery and it works fine, so the charger is ok. Any ideas what's wrong with the battery and how to fix it? Thanks!

Had the same thing happen with one of my Makita batteries. Sometimes they just need a little 'jump start' if they've been fully drained for a while. Try putting it in the freezer for a few hours? Actually, no, that's for old Ni-Cads. For Lithium-ion, you might have a dead cell. But first, check the contacts on the battery and the tool/charger - make sure they're clean. Use some contact cleaner or just a pencil eraser on the metal strips. If that doesn't work, you might have to pry it open and test the cells with a multimeter. Could be just one bad cell causing the whole pack to fail.

I agree with Carl on checking contacts. But also, some chargers have a reset function - unplug the charger for a minute, then plug it back in. Also, if the battery has a little button to check charge, press that - if no lights, it's totally dead. You can try to revive it by putting it on the charger and giving it a few seconds, then remove and repeat a few times. If it's still blinking, it might be the battery's internal protection circuit. That's harder to fix. Sometimes you can find replacement batteries on sale - might be cheaper than messing with it. But if you're handy, you can buy a balance charger and try to bring each cell up individually - but be careful with lithium cells!

I'm not as technical as you guys, but I had a similar issue with a Ryobi battery. I took it to a local tool repair shop and they said the battery was 'over-discharged' and the charger couldn't detect it. They used a special mode on a high-end charger to wake it up, and it worked! So maybe you can find a hobby shop or battery store that can do that. But also, check if your battery is still under warranty - DeWalt usually has a 3-year warranty. If it's less than 3 years, just call them and they'll send you a replacement.

Thanks for the tips! I tried cleaning the contacts and that didn't help. I also tried the unplug trick. I think it might be the over-discharge thing. I'll check the warranty - it's been about a year and a half, so might still be covered. If not, I might take it to that shop. Appreciate the help!