This battery charger circuit is used to recharge the rechargable lithium battery. The circuit comes from Molicel.
Charging is accomplished with a constant current of 60 mA for AA cells to a cutoff of 2.4V per cell, at which point the charge must be terminated.
The charging system shown is designed for multi-cell battery pack of 2 to 6 series connected cell or series/paralel arrangements. It is essential that all cells assembled in the pack are at an identical state-of-charge (voltage) before charging. the maximum upper cut-off voltage is 15.6V (6×2.6V). The ICL7665 from Maxim is a voltage monitor with dual over/undervoltage detection.