Solar seems like a great way to charge your mobile devices, but many solar chargers are not exactly portable. The 11.7-oz., 6 x 6 x 0.75-in. BoostSolar, however, is light enough to slip into a laptop bag or tablet case.
The solar panel charges the backup battery, which has enough juice to fully recharge most smartphones from a zero state twice via the USB port. In my tests, a solar charge took about 16 hours; once the battery was fully charged, it easily powered up my iPhone 5 twice. The BoostSolar can also charge a tablet (once), but not a laptop.
The $100 BoostSolar is water-resistant to light splashes, and its rugged design can withstand some abuse, including jolts and short drops.