Go Power! Solar Regulators GP-PWM-25 Solar Regulator Most solar charging kits need a solar regulator to prevent over-charging. The NEW Go Power! GP-PWM-25 is a 25 Amp Pulse Width Modulated digital charge solar regulator. The GP-PWM-25 regulates the current-flow from the solar module(s) to the batteries, keeping them balanced and at peak performance. Click here for more information.