It may rank closer to the "inconvenience" end on the post-disaster scale of challenges, but a lack of power for mobile devices certainly didn't help matters in the aftermath of Hurricane Sandy last year. Innovative devices like the BioLite camp stove made appearances on the streets of New York as residents scoured darkened neighborhoods for a chance to plug in.
For accessory manufacturer Etón, which partners with the American Red Cross to co-brand emergency-use chargers, radios and flashlights, flexible charging is a key component of the company's product line. Many Etón products include a handcrank option for quick charging when you're off the grid.
The latest member of the Etón family draws its joules from a new, old source: the sun. The $US99.99 BoostSolar charger includes both a conventional, replaceable 5000mAh lithium battery and a solar panel for walkabout charging. You can plug the battery in to any USB port to charge the night before your hike (7 hours to full charge) and then march on with solar charging to top off during the day (16 hours from zero to full on solar alone).
With a nod towards outdoor and camping use, the BoostSolar includes corner fastening loops for a carabiner or backpack strap. It's also rated IPX-4 for splash and rain resistance -- it might not survive being dropped in a puddle, but short of that it should be good to go.
The BoostSolar can charge both 1A and 2.1A USB devices, so the iPad will fast-charge when connected. A micro-USB input port allows the use of most non-iPhone device chargers to top off the battery, or you can connect a micro-USB cable to almost any iOS device charger and be good to go.