I have been playing a little with some second-hand Li-ION cells from an old laptop in the form of 18650 cells. I have an Adafruit MCP 73833 charger that is LiPO/Li-ION capable in 3.7 and 4.2v with variable charge rate.

Nice little board but it is exposed to the world, and anyone who knows 18650s, knows they are frequently referred to as terrorist cells, they get nasty really quickly for no seeming reason. A short across the connector block, for instance, can very frequently result in much heat, fire and in some cases lots of sparks. Not so long ago, I managed to make the connection between  one of these cells and a set of LED’s using just my thumb, and it gave me a very detectable kick. Ferocious little animals indeed.

So a nice cover for the charger was in order. The box is friction fitted, has all the appropriate openings and even has pieces printed to make contact with the on-board LED’s. The print isn’t perfect so the contact isn’t great. The next version of the top should be better. STL’s can be found HERE.

Some more images below: