Photovoltaic Systems > Solar Regulators > PWM

A PWM (pulse width modulation) controller can be thought of as an (electronic) switch between the solar panels and the battery. The best panel match for a PWM controller is a panel with a voltage that is just sufficiently above that required for charging the battery and taking temperature into account, typically, a panel with a Vmp (maximum power voltage) of around 18V to charge a 12V battery.