Note added on December 17. I forgot to mention below that all my AA and AAA batteries are rechargeable. But if I do not have access to a power outlet, I can as a last resort buy non-rechargeable batteries.

Original post below:

I usually try to carry enough batteries to last a week. Last tour:
- camera, rechargeable Li Ion batteries, carried five but I think I could have gotten by with three.
- android tablet (7 inch), usually it was turned off but used it where I had wifi for e-mail and weather.
- tail lights (2), 2 AAA batteries.
- headlight (for bike), but never used it since my tour was mostly in June. 3AAA batteries.
- headlamp (for my head), 3 AAA batteries.
- GPS, Garmin Vista black and white, 2 AA batteries. This was where most of my battery charging was.
- cell phone, old flip phone, dedicated charger, does not use USB. I left it off the entire trip.

My tablet, I occasionally plugged into an outlet if I was in a restaurant that had an empty table near an outlet when I arrived. Most of my wifi access was in restaurants. Have no data plan.

The photo of an outlet at a empty campsite that was near the hiker biker site I was in I had:
- one AA and AAA recharger loaded up with AA batteries.
- USB charger, my tablet (not shown) was plugged into it.
- Li Ion charger, it also had a USB charger port on it. This was charging my camera battery.
- 3 into 1 adapter that allowed me to plug all of these things into one outlet.



I have a dynohub on a 26 inch wheel, but on that tour I used a 700c bike, thus could not use the dynohub to charge on the road.

For my dynohub, I have soldered up a USB charger, parts were under $10. Have not used it enough to know about long term reliability, but so far it works nice. I think it absurd that people charge over $100 for USB chargers for dynohubs. But it is a tiny market, no economics of scale.