A PWM solar charge controller acts as the intermediary between solar panels and batteries. When the batteries are lower, it allows full current flow to quickly recharge. A Pulse Width Modulation (PWM), pulse-duration modulation (PDM), or pulse-length modulation (PLM) controller is a device that generates and regulates a PWM signal. But how exactly do PWM solar charge. From the point of view of the power grid, electricity generated by photovoltaic panels is free (it is the prosumer who pays for the entire system), and when the sunlight intensity is high, huge amounts of energy ensure more flexible operation of large conventional power plants and at the same time.