Comment on solar portable charger / device of http://autochargers.soup.io/post/319856495/Discover-Why-People-Like-The-Smart-Battery

First of all, be careful with these batteries. I used older packages of battery-operated Cordless 18-Volt tools you get at Harbor Freight, and if you're not careful you can zap yourself good enough if they still hold a charge. If you have access to new batteries Ni-Cad (glance at eBay) I would go that route, although $ is always a limiting factor.