Solar powered chargers require light and take too long to provide a charge, and battery-based chargers are bulky and are never charged when you need them. The most "reliable" solution to the extra-battery whenever you need it problem may be the human-powered YoGen ripcord charger.
The YoGen ripcord charger is ready whenever you need it, as long as you have the energy to pull a string. Plug it in and give it a couple of pulls and it immediately brings your mobile device to life, and then charges it like any other charger.
One of our favorite features is that the plug-in device cords, rather than being yet another proprietary plug format like most charging stations are standard USB mini cords. Therefore, you are not tied to YoGen to purchase additional device cords.
Unlike the creative YoGen Youtube videos, this charger hasn't saved any of our lives or marriages yet, but I'm gonna throw one in the car just in case, because you never know when you are gonna need it.