USB powerbank/handwarmer

EDC Gear for Flashlight Carriers USB Power Devices
1

Hello,

I recently purchased an USB hand-warmer/powerbank for my wife. One came defected due to the USB not working properly but it charges and works well. The company sent me a replacement and told me to keep the defective one. But the battery doesn’t last long on these things.

My question is, can I remove the battery from one and stack it on top of the one that’s working perfectly. Solder the 2 batteries together, then connect it back to the wires according to - and +, will that increase the runtime?

Thanks.

2

There should be no problem

glue the banks together
remove electronics from defective
connect batteries parallel to the other bank

3

Thanks Lexel.

4

One important thing
when connecting both banks together the cells should have the same voltage.
if yot there will be a high current damaging cells

you can connect em with a 0.5-2 Ohms resistor to equal the voltage