The Energizer Powerkeep Wanderer is a backpack that not only captures solar power to charge your devices, but keeps you hydrated and stores other essentials on your hikes. For minimalists it is not. But consider that you can charge up a lightweight battery before you hit the trailhead and keep it charged during your hike with the attachable solar panel. And a water packet and drinking hose keep you hydrated along the way. It comes with plenty of interior pockets for stashing snacks, even a change of clothes. Retails at about $160.