My drill's battery won't charge after dropping it

Hey guys, I dropped my Makita 18v drill off the workbench yesterday and now the battery won't charge. The charger just flashes red. I've checked the contacts and they look fine. Any ideas what might be broke inside? I'm a apprentice carpenter so still learning.

Ouch, drops happen. That blinking red usually means a dead cell or a broken BMS board. If you've got a multimeter, check voltage at the battery terminals. If it's below like 12v, one of the cells is toast. Also look for any cracked soldering on the BMS. I've fixed a few by replacing individual cells, but it's not trivial. Might be cheaper to just buy a new battery if you're not experienced with soldering.

I'd second that. Dropping a battery can crack the BMS board or the cell tabs. Also check if the plastic casing is cracked inside near the fuse - I've seen that cause intermittent shorts. If you're into tool repair, it's a good learning project, but for a work tool, just get a replacement. I've got like 20 Makita batteries so I'd just toss it lol.

Before you give up, try cleaning the contacts with isopropyl alcohol and a stiff brush. Sometimes the drop just lodges dirt in there. Also check the fuse - it might be a glass cylinder type that popped. But yeah, if it's a cell issue, you need to spot weld new ones. I've done it, but it's tedious. If it's still under warranty, Makita might replace it.

Thanks everyone! I'll check the voltage with my multimeter tonight. I'm leaning towards just buying a new one since I need it for work tomorrow, but I might try to fix this one later as a project. Appreciate the tips!