This Li-Po/Li-ion Arduino charger shield is mainly designed to power up the Arduino from single 3.6V Li-Po battery. Li-Ion and Li-Pol Charger/ DC-DC Boost converter Arduino shield provides 6.5V/400mA from single Lithium Polymer battery. The Arduino shield is equipped with BQ21040 battery charger IC and CS5171 step up DC-DC converter. The shield also has prototype area to utilize the maximum area of PCB. LIPO battery can be mounted on the same PCB. BQ21040 IC helps to charge 3.6V LIPO battery and Boost converter IC CS5171 converts 3.6V into approx. 6.5V to power up the Arduino. The CS5171 can continuously deliver 400mA of current. Board requires 5V DC input to charge the battery. Charging current is set to 500mA. However it can be changed as per requirement by altering R3 value, refer to datasheet of BQ21040 for more information. LED D2 indicates when charging cycle is complete. On board NTC is used to prevent over-temperature of battery and is recommended to keep the NTC sensor in contact with the battery while charging.
Li-Po/Li-Ion Arduino Charger Shield using BQ21040 – [Link]