Surfr ($100) is EnerPlex’s iPhone 5/5s battery case, set apart from the crowd thanks to its self-contained solar panel. Inside, there’s a standard 2000mAh battery, which should provide a full recharge to a fully depleted handset.
While micro-USB is certainly the faster method for juicing up the case, the sun can also be used when needed. The case supports this feature without much added bulk; it’s about the same size as most batteries of similar capacity.
After roughly an hour of direct sunlight, Surfr can provide enough of a charge for a 10 minute phone call. Consider the solar panel a backup for emergency situations, not the main charging method.