|Power assisted walking
The trouble with the iPhone is that it gobbles up power and particularly when your using the GPS and it's impossible to get more than a few hours use from the battery. On my trip across Europe on the E4, I had three supplementary batteries (Trent) and got these recharged each night at whatever hotel or refuge I was staying. Although there are some recharging opportunities in Nepal, at the tea houses, these are fairly expensive and unreliable particularly as you get higher up. In Nepal, if you're going to use an iPhone or other electrical devices in an intensive way than you might need to think about your own power generation solution.
|Solar Panel, battery and adapter
As well as being light the panel is also very sensitive and doesn't need full sunlight to generate a charge - it even generated some charge from inside the tent. What I tended to do was attach it to my ruck-sack and have the panel connected to the battery which I kept in the rucksack top pocket. Unless the weather was really bad the battery was charged up after each day's walking and then had more than enough juice to recharge both my iPhone and camera battery. Blessed with surplus power I ended up providing a recharging service to just about the whole group which made me particularly popular. If it wasn't for the fact that the altitude meant that none of us were drinking alcohol, I would have been in free beer for the whole trip.