Amazon.com: LP 9V Rechargeable Battery Pack, 2-Pack 600mAh Li-ion 9 Volt USB Battery with Micro USB Charging Port for Alarms, Wireless Microphones, Smoke Detectors, Toys, Flashlights, Guitar, Keyboard & More : Electronics
Micro Battery Pak & Charger
Amazon.com: CQRobot MicroUSB Battery Holder (3xAA), Can Hold 3 AA Batteries. Compatible with Arduino Controllers with Micro USB Interface. : Electronics
Overview | Adafruit MicroLipo and MiniLipo Battery Chargers | Adafruit Learning System