My Drill's Battery Won't Charge - Help!

Hey everyone, I've got a problem with my cordless drill. The battery won't charge at all. I plug it in, the light on the charger comes on, but after 8 hours it's still dead. Any ideas? I've tried cleaning the contacts and even used a multimeter to check the charger output, and it's fine. This is frustrating!

Sounds like you might have a dead cell in the battery pack. Even if the charger outputs correct voltage, a single bad cell can drag the whole pack down. Have you checked the voltage at the battery terminals after charging? It should be close to the rated voltage (e.g., 18V for an 18V pack). If it's significantly lower, that's a sign. Also, make sure you're not using a NiCad charger on a Li-ion battery - that's a common mistake.

I've seen this before. Sometimes it's the charger's fault, even if it has a light. The light might just indicate power, not charging. Try borrowing a known-good charger from a buddy. Also, check if the battery has a thermal sensor - if it's broken, the charger might shut off to prevent overheating. And if it's an older battery, it might just be at the end of its life. You can try a 'recondition' mode if your charger has one, or even carefully apply a higher voltage to jump-start it, but that can be dangerous. If it's under warranty, just return it.

Thanks guys. I checked the voltage at the battery terminals and it's only 12V on an 18V battery. So it's definitely not charging fully. I also tried my other battery and it charges fine, so it's just this one. I guess it's toast. I'll probably just replace it. Any recommendations for a good replacement?

If you're sticking with the same brand, I'd go with a genuine OEM battery. They're pricier but reliable. Third-party ones can be hit or miss, and some have safety issues. Check the amp-hour rating - higher Ah usually means longer runtime, but also heavier. For most DIY tasks, a 3-5 Ah battery is a sweet spot. And make sure it's compatible with your drill's voltage and chemistry.