One of the most important and available renewable energy sources is the solar power and it is believed that covering 4% of the Earth’s desert area with photovoltaic cells (cells that convert light into electric current) could provide enough electricity for the whole world. Using it may not be that easy, but solar power can be a viable option for mobile devices such as iPods, cell phones or PDAs.
This project utilizes a modified Adafruit MintyBoost Kit (a small USB charger powered by 2 AA alkaline batteries), a 3.7v 2000mAh Lithium Polymer battery, a Li-Poly battery charger and a solar cell, both from Sparkfun. The solar cell’s maximum capacity is 5v at 100mA in bright sunlight and it is used to make the whole device as compact as possible; a bigger cell could be used if faster charging is required.
The problem with the original MintyBoost is that the two AA batteries, if used to recharge an iPodTouch or an iPhone, are discharged pretty quickly so these have been replaced with the Li-Poly described earlier. The MintyBoost kit used in this project has a JST connector which connects to the Li-Poly charger circuit. The solar cell is connected to the charging circuit using a two pronged connector (you can also use another JST connector). The solar cell is then mounted on the MintyBoost metal case using 2″ wide Velcro.
You charge the whole thing by leaving it in the sun. The charger has a red LED which lights up when charging. After completion, you simply plug in your iPodTouch, iPhone or another USB-powered device you want to use. The author names this project the MightyMintyBoost since it improves the old MintyBoost with higher capacity battery and solar power capabilities. Details and pictures in the link.