What's an adventurer to do in such predicament? Well, you can go hardcore and hopefully brag to your friends about how you survived in the wilderness with no signal. Or you can do the smart thing and invest in solar-powered equipment. Harnessing the sun rays, these gadgets of various shapes, sizes, and additional purposes other than charging are able to power your USB devices anytime, anywhere, as long as there's light to soak in (although that's not a prerequisite, either). Some of them will also let you cook a meal while charging, or come with extras such as built-in flashlights, FM radio, AA/AAA battery chargers, and other useful stuff.