Power Output (rated) - 15 watts
Integrated Battery / Outputs - No / 2 USB (3 amps total)
Weight - 27.1 ounces
Dimensions (Folded/Open) - 7.5 x 10.1 x 1.3 / 31.25 x 10.1 x 0.6 inches
MSRP - $53
URL - http://www.ravpower.com

The RAVPower offering is powerful and very affordable. Its solar cells aren't as efficient as the Anker, though, given that it's larger with less power output. But it still cranked out nearly 10 watts when charging an iPad in our testing, though via 1.9 amps and voltage a little more than 5 volts. In our cloud cover test, sometimes it recovered and sometimes it didn't, ceasing to charge an iPad — though our test iPhone recovered every time. There are three rigid solar panels about the size of an iPad that fold up; a fourth segment in the case closes the whole thing with Velcro and has a pocket with two USB ports. Like the Anker, the pocket is secured with a small piece of Velcro in the center, putting contents at risk of falling out. There are four eyelets in the corners to secure the unit; conveniently, four carabiners are also included. It's also water resistant, but heavier than other units.