There is two versions of BFN18650 1S1P batteries in Leifheit Dry & Clean:

  • 3.7V 1800mAh – Li-Ion
  • 3.2V – probably LiFePo4 (Li-Po)

Check voltage on device:
Leifheit Dry Clean 51000 Battery 3.7V

Both are 18650 1S1P size. You have to buy version without extra protection pcb because it won’t fit.

If you would like to replace the battery just open case in left back corner. Disconnect the old one and solder connector to the new one.

You can use NCR18650B 3.7V with extra connector it is easy to solder: