If you don't already own a backup battery, then the SOScharger is likely going to be the best way for you to foray into the wonderful world of never needing to search for an outlet again. Featuring a crank to easily charge your cell in the event of a power failure or other scenario, the SOScharger also features a built-ion battery, which can serve as your first defense against a dead smartphone.
While the majority of products on the market are going to offer one feature or another, the SOScharger is the perfect marriage of both. Simply select the feature you'd like to use and away you go. Best of all, the SOScharger's internal battery will offer about 100% power for most phones.