> Step 2 of course is figure out how to fashion some sort of charging system so my magical godlike pocket super abacus continues to function after ~days
In the good old days of USB 2 I'm sure you can figure out how to get a stable-enough ~5V power supply that would charge the smartphone.
With USB-C you'd need to reinvent IC manufacturing and figure out a needlessly-fragile and overcomplicated protocol before the phone would even accept any power. Yay for progress!