Fair enough. I'm not too worried about it charging (though I am confident that it will be an enormous amount of work and possibly take multiple passes while leaving the cell phone off). For me, this was more a "throw one more backup layer" on things; when I'm in the car and carrying what I normally lug around, I typically have:
- The ~100Wh car battery and USB adapter off the cigarette lighter.
- A tank of fuel to charge said battery.
- A car jump starter (in case said battery goes dead), with its own battery that can do USB.
- A laptop with its own battery with USB output.
- A tablet with its own battery with USB output
- A small power station.
- A second, 100Wh power station.
- A ~400Wh large power station.
- An unfolding set of solar panels with another small power station.
- The aforementioned solar/crank charger with a very small power station.
Having to actually crank anything is going to be about at the bottom of the list in terms of things that I'm going to be doing in any situation, so this is about 9 things that would have to fail subsequent to my cell phone battery dying in a situation where there's an emergency for this to come up.
I did consider a more-serious charger at one point, but that would have been a pedal power station; it's vastly easier to generate a given amount of electricity with your legs than your arms. If having it in the car or house is all you need, that's probably a better choice if you're worried about it (and you can definitely find video on YouTube of people charging phones with it):
https://www.k-tor.com/shop/generators/power-box/
There's also someone that sells a tiny thermoelectric camping generator that can run on wood. If you're really concerned about needing power, my guess is that it's probably less-work to find something you can burn in that.
googles for the name
"BioLite"
https://www.amazon.com/BioLite-Campstove-Electricity-Generating-Charging/dp/B00FU8RBPE/
EDIT: I also have an AA-battery-to-USB-and-USB-to-AA-battery powerstation somewhere, but I don't know if that's actually in the car. I think that that's at the house.