Check out the #pilet, SoulsCircuit’s very cool retro-futuristic handheld tablet/console.
Designed with Free Software, the pilet runs #Plasma and a full range of KDE software.
More at
https://soulscircuit.com/pilet
Follow SoulCircuit and the progress of the piet here:
For the clockwork pi uConsole, which is a similar product and also uses two batteries, that seems to be the case