The right solar charge controller is an important part of any solar system. It helps extend the life of your batteries by preventing over- and undercharging, and it also regulates voltage to ensure your batteries are properly charged. The main difference lies in the two types available：PWM or MPPT Charge Controller.
PWM (Pulse Width ModulaTIon) controller is the classic technology for controller.MPPT（Maximum Power Point Tracking）is the most efficient types,the PV input efficiency can be up to 99%.
More expensive to purchase, but much more efficient. With an MPPT charge controller, you can harvest almost all the electricity from your solar panel, whereas with a PWM charge controller this will be about 70%.An MPPT is thus more future-proof: if you upgrade your solar panel later, or add another one, you do not have to replace your charge controller.Choosing a charge controller can be a complicated process.