Unfortunately, the Iphone 3G is not efficient as far as battery life is concerned. Compared to the original iPhone, the battery drains more quickly during a day of typical use. To solve this problem a new solar powered case has been launched. This new case is compatible with all iPhones.
It comes in white and black leather so in addition to providing power the case also protects the phone. The solar panel is mounted to the front of the case. In direct sunlight, the charger provides enough power for the phone to function in less than 3 hours. After 10 hours the phone is fully charged. If you are in a badly lit area, the phone can also be charged via a mini USB.