A solar charge controller manages the power going in and out of the batteries in a solar power system. It does this by regulating voltage and current. It stops your batteries getting overcharged by controlling the flow of energy from your solar panels. It also stops the reverse flow of power, which can drain and. If you want to have batteries as part of your home solar system, you're going to need a charge controller. The chief function of a controller is to protect your batteries. Since batteries. Unlike batteries or invertersthat have several types, controllers are much simpler in that you have two options to choose from. You either go MPPT or PWM. A solar charge controller is a handy piece of equipment that is almost always necessary as part of a battery bank in a solar system. If you're going to have batteries, you're going to.