PWM solar charge controllers are the standard type of charge controller available to solar shoppers. They are simpler than MPPT controllers, and thus generally less expensive. PWM controllers work by slowly reducing the amount of power going into your battery as it approaches capacity. When your battery is full, PWM controllers maintain a state of “trickle”, which means they supply a tiny amount of power constantly to keep the battery topped off.

       With a PWM controller, your solar panel system and your home battery need to havematching voltages. In larger solar panel systems designed to power your wholehome, panel and battery voltage aren’t typically the same.  As a result,PWM controllers are more suited for small DIY solar systems with a couple oflow voltage panels and a small battery.