A charge controller is a device used in solar power systems to regulate the amount of charge sent to the battery bank from the solar panels. The main function of a charge controller is to protect the battery from overcharging or undercharging, which can lead to a reduction in battery life and capacity.

There are two main types of charge controllers: Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT) charge controllers. PWM charge controllers use short charging pulses to regulate the charging rate, while MPPT charge controllers use advanced electronics to maximize the amount of power generated from the solar panels and regulate the charging rate.

Charge controllers are an essential component of any solar power system that uses batteries for energy storage. They are commonly found in off-grid and grid-tied solar power systems, and are used to ensure that the battery bank is charged safely and efficiently.