Arduino Energy Shield
Energy Shield is a LiPo battery based power shield that keeps your project alive. It keeps its battery charged whenever an available power source exists. It accepts a wide range of power sources, from common solar cells via JST connector and USB via USB port on microcontroller, to 9V and 12V DC adapters via DC Jack on your Arduino. Meanwhile it can not only provide power for your Arduino project, with a standard USB port populated on the shield, it's also capable of rescuing your mobile electric devices from dying batteries, such as mobile phone, mp3 and tablet.