In this video, the author is going to show you how to make your own solar USB charger using the following items with inbuilt battery backup.
Materials:USB female end,5V regulator, 2 diodes, Black and red wire, Altoids tin, Solar panel (greater than 9V), Switch, 9V rechargeable battery, Solder and soldering iron.
Schematic: click here
Courtesy: bluepapercanoe