Help! My circular saw won't charge and smells like burnt wires

Hey everyone, I've got a problem with my cordless circular saw. It's about 2 years old, worked fine until today. I went to charge the battery and it won't charge. The charger just blinks red and the battery got hot and smelled like burnt wires. Is it the battery or the charger? Any tips?

Sounds like it could be a few things. That burnt smell is never good. Could be a short in the battery or a bad cell. If you have a multimeter, you can test the voltage on the battery. If it's below a certain level, the charger might refuse to charge it. Also, check the contacts for corrosion. If it's the battery, sometimes you can replace the cells, but if you're not confident, maybe just buy a new battery. What brand is it?

I had a similar thing with my drill. It was the charger that went bad, not the battery. The charger would get hot too and the light would blink. I opened it up and found a swollen capacitor. Replaced it and it worked again. But if you're not into electronics, maybe test the charger by trying it on another battery if you have one. Or test the battery on a known good charger.

I'd be careful with that smell. Could be a sign of a damaged battery that might catch fire. If you have a lithium-ion battery, and it's swollen or hot, don't mess with it. I'd dispose of it properly. But first, check the charger: does it have a loose connection? Sometimes the charging contacts get dirty and cause arcing. Clean them with a bit of alcohol. And check the battery terminals too. If all else fails, might be time for a new battery – or a new saw if it's under warranty?