Designing a 12Volt DC power supply of lithium ion battery in parallel connection by using one single charge controller

Lithium ion battery is designed to perform as a portable 12Volt DC power supply. This power supply was tested to recharge a parallel of lithium ion battery by using one single charge controller. This experiment aimed to prove the concept of solar photovoltaic to charge a lithium ion battery for water quality monitoring system. This type of system is considered a low voltage application. Charge controller proposed in this experiment will charge a lithium ion battery to their maximum capacity, protect it from thermal hazard and overcharging. A reference voltage of 4.2V as the nominal voltage is set and the methods which are used in this project are constant-current (CC) and constant-voltage (CV). The main idea of this research to show that a charge controller is selected, to perform a charging process, based on state of charge of the charge controller.