Sander Battery Not Charging - Any Ideas?

Hey everyone, new to the forum. I've got a cordless orbital sander (Makita 18V) and the battery won't charge. It's only a few months old. I plug it in and the charger light just blinks red, no green. Any ideas what's wrong?

Dave, sounds like the battery might have a bad cell or the charger is giving up. I've seen this before. First, try cleaning the contacts on the battery and charger with a bit of rubbing alcohol. Sometimes grease or dust messes with the connection. If that don't work, see if you can borrow a friend's charger to test. If it charges with theirs, your charger is toast. If not, the battery is likely the issue. Many times it's just one bad cell and a rebuild is possible, but for a new battery, maybe warranty?

A blinking red light could also indicate the battery is too hot or too cold. What's the temp in your garage? Also, make sure you're using the correct charger for that battery. I once fried a battery because I used a mismatched charger. Check the model numbers. If all else fails, try a hard reset: pop the battery on the tool, pull the trigger for 5 seconds, then try charging again. Works sometimes.

Safety first, Dave! When messing with batteries, make sure you're in a well-ventilated area and away from flammable stuff. If the battery is swollen or smells weird, don't charge it and dispose of it properly. Also, if it's under warranty, contact Makita before taking it apart. Li-ion batteries can be dangerous if punctured. Good luck and let us know what happens.

Thanks guys! I tried cleaning the contacts and checking the temp, still blinking. Bob, I did use the right charger, but I'll try the hard reset. Larry, no swelling or smell. If the reset doesn't work, I'll just claim warranty. Appreciate the help!