A smartphone is great because it does so many things: phone, camera, email, web surfing, music player, blogging..........

You can power it in lots of ways: dynamo; solar cells; or just use an external battery. I can recharge my iPhone 5 times from the external battery I carry and I will also plug in when I stop for lunch or stay in a motel.

All my other electronics....basically lights work off AAAs.

PS when I was in Iceland I used wifi exclusively and managed to blog email etc without trouble of an international data plan.