I’ve always thought Gills would be perfect of it has a rechargeable battery like how Synthstrom Deluge has a 18650 battery inside that you can charge with the USB port.
is it possible to mod the Gills PCB and make a new enclosure to fit a rechargeable battery and charge the battery with the USB port?
Sounds possible! It would require one of those battery management boards, and maybe a cut of a trace on the Gills PCB. Not familiar with DIY battery stuff so I’m afraid I can’t give any solid advice!
I sometimes just use a power bar (though one user seemed to have problems with the power bar output jumping up to 12V which would fry your Core board! Some power bars seem to have this high voltage feature nowadays)
You could use a 12V (or anything starting from 7.5V) battery and feed it to the DC input (sort of bypass the DC input jack) but I don’t know how USB recharging works