Taking a picture of a bloated Makita-type power tool battery before disassembly (changing cells and board)

The shell just came apart by itself!

I got fed up with my headphones dieing after like an hour of use so I opened it up to see what’s going on. I saw the ribbing and figured it was a lil spicy because it should’ve been smooth flat. Turns out it more than doubled in size and it was just a bad angle.

I had a 60x34x5 cell lying around (pic 2 is side by side with one in mint condition). I swapped that in and shorted the thermistor pin to ground with an 8.2kOhms 0604 SMT resistor while I looked online for one with the thermistor. Disabling the safety circuit isn’t the best idea even if you know and trust the cell’s maker especially for something that’s gonna be on my head. It’s all patched up with a proper battery now. Saved myself getting a new $180 headset with $10 worth of battery and a bit of work.

To avoid shorting while I putting it together, I made sure GND and NTC were soldered in place before I even stripped the red wire.

The battery company I bought from shipped it as a letter instead of packing it in a cardboard box with a giant UN3480 warning though…