A solar charge controller deals with the regulation of power that goes into the battery bank from the panels. It ensures that the cycle batteries do not heat up in the middle of the day and that the power doesn't flow in reverse to the panels overnight deplete the batteries. A significant function of a charge controller is to control the voltage and open the circuit to halt the charge when the battery voltage soars to a particular level. This s helpful in cases when the panels end up giving out more voltage than what is actually required. It is advised that if a solar panel puts out more than 2 watts per 50 battery amp-hours, then enlisting a charge controller is recommended. Some controllers in the market have extra capabilities, such as lighting and load control, yet dealing with power is its essential responsibility. Two different technologies, Pulse with Modulation (PWM) and Maximum Power Point Tracking (MPPT) can be used in a charge controller. Their performance in a system is very different. An MPPT controller costs more than a PWM controller but can repay the money over-time as savings because of their 94-98% efficiency. Often referred to as a solar regulator, it offers a range of other functions as well, like, Charging of batteries at different stages; Safeguards against reverse current flow; Disconnection on low voltage; Data Logging.