Here is a link for a light weight charger. It takes about 6 hours to fully charge. Once charged you then need to plug it into your phone to charge your iphone. I have it mounted it to my backpack. Bought it from L.L. Bean for $59. Works on an Iphone but not sure about anything else.
http://www.bushnell.com/all-products/outdoor-technology/powersync/solarwrap-mini
http://www.bushnell.com/all-products/outdoor-technology/powersync/solarwrap-mini
