My Rotary Tool Battery Won't Charge - Help!

Hey everyone, been lurking for a while but now I need some help. My trusty rotary tool (a few years old) just stopped charging. I plug it in, the light on the charger comes on, but after 24 hours the battery is still dead. Is it the battery or the charger? Any ideas? Thanks in advance!

Had the same thing last year with my cordless drill. Turned out the battery was just toast. Replaced it and been fine since. But check if the charger has a reset button or something. Also, make sure the contacts on the battery and charger are clean - sometimes dust or grease messes with the connection.

Could also be the charger itself. Try testing with a multimeter if you have one. Check the voltage output on the charger. If it's 0 or way low, it's the charger. If it's good, then probably the battery. Sometimes cells die, especially if you left it dead for a long time. Also, some batteries have a protection circuit that goes into sleep mode if over-discharged. You might be able to wake it up by jumping it with a spare battery, but that's a bit risky.

Agree with checking the basics first. But if you're using a cheap rotary tool, sometimes the charger is not a smart charger and overcharging kills the battery. A good habit is to not leave it on the charger all the time. Also, check if the battery has any swelling or cracks. If it does, replace it immediately - don't risk it. For peace of mind, I'd invest in a high-quality charger that has a status indicator. It's worth it in the long run.