Solar charge controller helps to prevent your batteries from overcharging. For some good quality solar charge controllers, they will help you lengthen the effective lifespan of your batteries.
A normal solar panel rated at 12V- 14V may be producing 16V to 18V at peak sun. This charge controller helps to regulate the charging process of your batteries, preventing overcharging. It also helps to prevent electricity from flowing from the batteries to the solar panels at night.
Solar charge controller can also help you get the most out of your solar panel. This is by utilising MPPT(Maximum power point tracking) or PWM (Pulse Width Modulation). MPPT solar charge controller monitors the voltage and current output of the solar panel and determines the voltage that the panel will produce at the maximum efficiency. PWM helps to “pamper” your batteries by providing constant voltage battery charging, hence prolonging battery life. The batteries are very expensive. It is not worth it to throw them away due to overcharging.
Hence, do your research and find a good quality charge controller that can save your batteries and work your solar panel to its fullest potential.