Solar Paper: 19cm long, 9cm wide and 4mm thin. There’s an 11mm thick USB charging port at the top, which sticks out of your book like a bookmark that sucks in that precious sunlight. One of these panels weights 128g and equals 2.5 watts, and you can connect more panels with magnets for more power. In good weather, two connected panels can fully juice an iPhone 6 in about two-and-a-half hours. You can connect up to four foldable units for a total of 10 watts, capable of charging an iPad Air 2 to 100 per cent in four hours.
A nifty feature is Solar Panel’s auto restart. With similar gadgets, a passing cloud or sudden shadow shuts the charger down, forcing manual reboot. But Solar Panel resets that automatically. You can use it to charge anything that connects with USB: GoPro, external batteries, Bluetooth speakers, digital cameras, and so on.
