Amazon.com: 6pcs 2A 5V Charge Discharge Integrated Module 3.7V 4.2V for 18650 Lithium Battery Charging Boost Mobile Power Protection PCB Board Module : Electronics
Charging protocols for lithium-ion batteries and their impact on cycle life—An experimental study with different 18650 high-power cells - ScienceDirect
Designing an Advanced 2S Li-Ion/ Li-Po Battery Charge System using MCP73844 IC