Battery not charging on my new circular saw - is it the charger or the battery?

Just got the new XYZ 18V circular saw and the battery won't charge. I plug it in, red light comes on, then blinks after a few seconds. Batteries are brand new. Anyone had this issue? Is it the charger or the battery?

Sounds like a defective charger or battery. I've been using XYZ tools for years, never had that issue. But when I did, I called their support and they sent a replacement charger next day. Check the warranty, they'll take care of you.

Before you call, make sure the contacts are clean. Sometimes they get a film. Also, try a different outlet. Could be a bad ground. Blinking red usually means communication error. If it's new, I'd just exchange it where you bought it.

I've seen batteries that are cold cause issues. It's winter, maybe you left it in the truck? Let it warm up to room temp and try again. Also, if the saw was left in a hot garage, could affect it. But yeah, could be a lemon. I prefer DeWalt myself, but XYZ is okay.

Check the battery terminals for any bent pins. I had that happen once. If they're fine, try another battery if you have one. If the charger works with that, then battery is bad. If not, charger. Process of elimination, you know.