If you're looking for a versatile battery booster, this DIY 3-in-1 solar/usb/wall current charger known as the MightyMintyBoost will top of your phone, mp3 player, and other gadgets with ease.

Instructables user Honus didn't just build the MightMintyBoost to geek out and show off his electronics project skills (although it's certainly a nifty little project to do so), he's serious about solar power and the impact clean energy has:

Apple has sold over 30 million iPodTouch/iPhone units- imagine charging all of them via solar power.... If every iPhone/iPodTouch sold was fully charged every day (averaging the battery capacity) via solar power instead of fossil fuel power we would save approximately 50.644gWh of energy, roughly equivalent to 75,965,625 lbs. of CO2 in the atmosphere per year. Granted that's a best case scenario (assuming you can get enough sunlight per day and approximately 1.5 lbs. CO2 produced per kWh used.) Of course, that doesn't even figure in all the other iPods, cell phones, PDAs, microcontrollers (I use it to power my Arduino projects) and other USB devices that can be powered by this charger- one little solar cell charger may not seem like it can make a difference but add all those millions of devices together and that's a lot of energy!

His MightyMintyBoost is a battery booster for devices that can charge via USB and it accepts incoming current from the solar panel on top (or, on cloudy days can be charged via a wall charger or the USB port on your computer). Hit up the link below to see his full build guide and create your own MightyMintyBoost.

MightyMintyBoost [Instructables]