Dremel 4000 not charging? Battery light blinking

Hey everyone, I've got a Dremel 4000 that's about 2 years old. The battery won't charge - the light on the charger just blinks green and red. I've tried cleaning the contacts but no luck. Anyone else had this issue? Any tips before I buy a new battery?

Blinking green/red usually means the battery is too hot or cold, or it's a bad connection. Make sure the battery is at room temp and fully seated. Also check the charger's contacts for any bent pins. If that doesn't work, it might be the charger itself. Can you test with a multimeter? If you're not getting voltage, it's the charger.

I've had this before. Sometimes the battery just goes bad after a few years. But before you buy a new one, try the 'reset' trick: remove the battery, hold the power button on the tool for 10 seconds, then pop it back on the charger. Works for some of my cordless tools. Also, check if the charger is plugged into a surge protector - sometimes those cause issues.

Thanks for the replies! I tried the reset trick and let the battery sit for an hour at room temp. Still blinking. I think the battery might be toast. WrenchWendy, you mentioned checking the charger - I don't have a multimeter, but I have another tool that uses the same charger and it charges fine, so the charger is good. Guess I'll order a new battery. Any brand recommendations? OEM or aftermarket?

For Dremel, I'd stick with OEM - aftermarket ones sometimes don't last as long or have less capacity. But if you're on a budget, some guys swear by the ones from Amazon Basics. Just check reviews. Also, check if the Dremel is still under warranty - some have 2-year warranties, so you might get a free replacement!