Battery not charging? Help!

Hey all, my cordless mower's battery won't charge. It's a 40V lithium-ion, only a year old. Plugged it in, light blinks red, and it won't take a charge. Any ideas?

Had that issue with my drill battery. First, check the charger contacts for dirt or corrosion. Clean with a cotton swab and alcohol. If that doesn't work, might be the battery's internal balance. Sometimes they go bad if left in extreme heat or cold. Try leaving it on the charger for a while, but if it's got a warranty, might be time to use it.

Also, make sure the charger is plugged into a working outlet. Sounds dumb but happens. And check the battery's voltage with a multimeter if you have one. If it's super low, the charger might not recognize it. Some chargers need a minimum voltage to start charging. You can try 'jumpstarting' it with a different battery if you have one, but be careful.

I've seen this before. Sometimes the battery's circuit board detects a fault and won't charge. Try pressing the battery's reset button if it has one. Also, if you have another compatible battery, swap to see if the charger works. If the other charges, it's the battery. If not, it's the charger. Process of elimination.

If it's under warranty, call the manufacturer. I've had luck with that. But also check if the battery terminals are bent or pushed in. Sometimes they get bent and don't make proper contact. Use a small screwdriver to carefully bend them back if needed. Also, store the battery at room temp before charging - cold batteries can be finicky.