Whenever there is a battery in your solar panel system, a charge controller
is a must. Its role is to protect the battery from high voltage of panels, as well as from overcharging and deep discharge. If you simply hook up a battery to panels, it will overheat and might explode.
There are two types of charge controllers:
- PWM-regulators are cheap, but they are suitable only when the voltage of panels is slightly higher than the voltage of a battery. They simply cut down the voltage to the level of the battery.
- MPPT-controllers are more sophisticated and expensive. They convert extra voltage to electricity, so you barely lose any of the generated energy.
The size of a controller is measured in amps. To figure out the power level of a regulator that you need, divide the combined power of your array by the voltage of the battery. For example, if you have two 300 W solar panels and a 12 V battery, then the size of your charge controller should be bigger than 300W * 2 ÷ 12 V = 50 A.
It is necessary to first connect the controller to the battery and make sure it works. Follow the instructions for your model of charge controller. For this task you would need a stranded copper core wire. Don't mix up the positive and negative current: connect the negative terminals of your battery and charge controller with the black wire, and the positive terminals using red wire. Screw the wires tightly into the charge controller and check the battery connections.