...
modern smart phones do not charge enough with a dynamo hub, at least off road, maybe on tarmac all day downhill they get some charge.
a simple battery pack 10.000-15.000mA/h does the job.
My phone is off on a bike tour almost all the time. Gets turned on to check e-mail once a day, weather forecast, maybe a few short phone calls, etc. I do not have to charge it for almost a week that way. Battery is about 8 watt hours.
My SP PV8 hub and Cycle2Charge V3 charger puts out this output according to the USB current gauge I used to measure with:
- 6.5 mph to get any power at all, below 6.5 it did not turn on.
- 9 mph was about 0.6 amps, or 2.9 watts.
-11 mph was about 0.8 amps, or 3.9 watts.
-15 mph was about 1.0 amps, or 4.8 watts.
Thus, my phone would need 3 to 8 hours a week, depending on how flat or hilly the terrain is. I put the charger output into a pass through cache battery, then charge things from there.
I use a separate GPS, do not use my phone for that purpose. My phone is 4g. And I use a real camera, not a phone camera.