A Solar Regulator AKA Solar Charge Controller could be considered the backbone of solar electric systems. Almost every system requires a solar regulator or charge controller. A solar charge controller limits the rate at which electric current is added to or drawn from electric batteries. A solar charge controller will protect your batteries from being overcharged by your solar panels and it will block any reverse current (from the batteries) as well. Solar charge controllers will actually protect every aspect of your solar power system from your batteries to your solar panels. The charge controller is an absolute necessity for big solar systems.