The Lithium-Ion battery can be charged through the microUSB port on the top and provides 1.58 Wh (500 mAh @ 4.2 V, model PT802040).

It is connected to the mainboard with a JST plug meaning it can (in theory) be replaced when it has degraded after a few years—no soldering required, yay.

This little 4 Ohm 2.5 Watt driver seems to have a lot of "oomph" for its size compared to the Eneby Portable.