Adafruit PowerBoost 1000 Charger - Rechargeable 5V Lipo USB Boost @ 1A - 1000C

Perfect power supply for your portable project Safe for all 5V-powered electronics like Arduino, Raspberry Pi, or Beagle Bone 2A internal switch means you can get 1000m A+ from a 3.7V Li Poly/Li Ion battery. Low battery indicator LED lights up when the voltage dips below 3.2V, optimized for Li Po/Li Ion battery usage Boost converter chip extras: synchronous conversion, excellent efficiency, and 700KHz high-frequency operation