Summary

This is a rechargeable 400mAhr powerbank for the M5stack Atom Matrix, designed to be FDM-printable and serviceable (no glue!).

Warning: I noticed this warming up while charging, so not yet convinced it is safe for extended charging. I haven't noticed heat issues while in use / discharging.

This needs to be printed with a transparent filament so you can see the charge lights of the internal charging board. Best to print the "side" part on a raft. The spacer and bottom corners needed a little sanding for fit and flatness. Wrap the battery in kapton tape to prevent electrical contact with the charge board. The 4 screws that hold the sides on were heated with a mini blow torch so they could melt their way in, rather than splitting the thin edges.

Parts list:

• 400mAhr lithium battery
• USB C charger board
• USB C male plug with board
• 4x M1.4 4mm screws
• Hookup cable

About AU$10 total for all non-printed parts.