Rechargeable 9V Battery

This is a small DIY 9-volt rechargeable battery assembled from leftover miniature cells. Four 250 mAh cells provide a total of 1000 mAh without exaggeration. The case is printed with a 0.2 mm nozzle using a minimal layer height of around 0.1 mm, ensuring a clean surface and avoiding the staircase effect.

The top part of the housing is printed from two materials: the main body uses standard filament, while the light-pipe area is made from transparent PLA in several layers to create a clear charge-indicator light guide. Contacts come from a regular disposable 9V battery, which is perfect for soldering wires.

For the charging module, it requires not only a boost converter but also a small custom PCB that can be ordered. If you're planning to build this battery, I assume you're already comfortable with a soldering iron—there are only six components to place and solder, nothing complicated.

You can download the print-ready parts in 3MF format using the provided link. If you liked this model, let me know by giving a like!