I reviewed one of these a couple years ago for Macworld, and ended up buying one to take on my camping trips. You don't actually need to charge the power unit

I reviewed one of these a couple years ago for Macworld, and ended up buying one to take on my camping trips. You don't actually need to charge the power unit in order to use the stove; even if you start with a completely run-down battery, the unit will eventually generate enough electricity to start the fan and achieve maximum efficiency. Also, it's always seemed to me that the Biolite is designed primarily as a reasonably efficient biomass stove—a role that, in my experience, it fulfills really well, even with wet wood. I've cooked plenty of meals on it, and it's much more convenient to carry around than a propane or white gas stove (as a bonus, you also don't walk around with explosives in your backpack). The ability to charge devices is a happy byproduct. It's handy when you're cooking up some food and want to power up your phone or GPS receiver. It's probably not as efficient as a solar charges but (a) a solar charger won't cook food, so the Biolite is a convenient multitasker that requires less backpack room, and (b) the solar charger doesn't work at night, when it's cloudy, and so forth. EDIT: FWIW, I also have a PowerPot, which is mentioned elsewhere in this thread. It's pretty cool, and works well; it's also my preferred charging method when I am not cooking, since I can just fill it with water and leave it on the campfire for as long as I need (the Biolite, on the other hand, needs constant feeding of fuel to continue running).