Dewalt 20V max battery not charging - any ideas?

Hey guys, my Dewalt 20V max battery (5Ah) won't charge. Light on charger blinks red/green. Tried different outlets, cleaned contacts, still no luck. Battery is about 2 years old. Any fixes before I drop $150 on a new one?

Check the voltage with a multimeter. If it's below 10V, the charger might not detect it. Sometimes you can jump-start it with a good battery. Got another battery? Wire them pos to pos, neg to neg for a few seconds - careful not to short. That's revived a few of mine.

Honestly, just buy a genuine Dewalt replacement. Aftermarket ones are crap and might damage your tools. I learned that the hard way. Check online for deals – sometimes you can find a 2-pack on sale for not much more.

Had the same issue with a Milwaukee battery. Took it apart and one of the cells was dead. You can replace individual 18650 cells if you're handy with a solder iron. Costs like $5 vs $150. Lotsa tutorials on YouTube. Just be safe with Li-ion.

^ That works too, but make sure you match the cells exactly. If you mess up the balance, it could be a fire hazard. Sometimes it's just the BMS board - check that first. Or try the freezer trick? Put battery in a ziplock bag, freeze for 30 mins, then charge. No joke, works sometimes.