Now you can take your Arduino anywhere you wish with Adafruit PowerBoost 500 Shield - Rechargeable 5V Power Shield. This stackable shield goes onto your Arduino and provides a slim rechargeable power pack, with a built in battery charger as well as DC/DC booster.
Compatible with Arduino Uno, Duemilanove, Mega, Leonardo and Due - basically any Arduino-pinout-shaped Arduino as only the GND and 5V pins are used. Please note that Adafruit PowerBoost 500 Shield - Rechargeable 5V Power Shield does not pass through the ICSP headers (the battery is in the way) so if your stacking shield uses ICSP for data transfer (like the Ethernet Shield), you'll need to stack the PowerBoost above it!
Adafruit PowerBoost 500 Shield - Rechargeable 5V Power Shield can run off of any Lithium Ion or Lithium Polymer battery (3.7/4.2V kind). Plug in the battery and recharge it via the microUSB jack.
The onboard boost converter can provide at least 500mA current, and can peak at 1A. There's an onboard fuse to protect against higher current draws which could damage the boost converter or battery.
Adafruit PowerBoost 500 Shield - Rechargeable 5V Power Shield comes as a kit of parts, some light soldering is required to attach the stacking headers and switch! Battery is not included.
Adafruit Website: https://www.adafruit.com/products/2078