Adafruit Micro Lipo Charger
Available from Mouser Electronics, these Adafruit chargers for Lithium Polymer or Lithium-Ion (LiPoly / Ion) batteries can operate via USB and plugging a 3.7 to 4.2 V battery into the outlet. The circuit has load currents from 100 mA adjustable up to 500 mA using a jumper.
