Other than for extended stays in the wilderness, why would you buy one of these?
Takes days to charge and is weather dependent.
It seem that for the cost and size/weight for almost every scenario you would be better off buying a few AA Eneloops (
Amazon.com: eneloop Power Pack Kit: Electronics) and the iGo powerXtender (
Amazon.com: iGo powerXtender Universal Battery Operated Charger:…) and carry that, maybe with a spare set of batteries or two.
Am I missing something?