>>899770Sounds horribly inefficient, but then most human powered charging devices are. Reminds me of the power peg, it was a linear induction generator that was supposed to unthrone solar chargers. Problem was it took about 45 minutes of vigorous shaking, I mean VIGOROUS shaking, to get a few minutes worth of power to a smartphone. I was working at REI when it debuted, we had them in the clearance bin after four months.
Hand crank dynamos are more efficient, but you're still looking at a lot of physical effort for not a lot of output.
Thermal generators like the power pot and biolite are probably the most efficient. Solar may be slow as fuck, but it's passive so you don't have to expend energy or fuel.
Like others have said, solar works best if you pair it with a power supply since you can pre-charge it and it discharges to your device faster.
But really, unless you're going to be away from power for a weeks at a time, a pre-charged power bank is all you really need to keep a small device like a phone or GPS charged. Bigger devices like a DSLR it's better to just bring an extra battery or two.