Charge Controllers

This is an essential component in a solar electric system is the charge controller or regulator. The basic function of the controller is to prevent the PV array from overcharging the batteries. Excess charge will damage batteries. A controller provides overcharge protection by disconnecting the PV array when the batteries reach a set voltage and reconnects when a lower voltage occurs.

Controllers are rated by the maximum continuous PV charge current they are able to support.

Most controllers offer Pulse Width Modulation to provide more precise and complete battery charging. Maximum Power Point Tracking controllers ensure delivery of the maximum possible PV power into the battery bank.

Controllers can also include additional features such as low voltage disconnects and alarms and remote reporting functions.

Temperature compensation is a highly recommended feature since batteries and modules behave differently under particular temperature conditions. Temperature compensation modifies the solar charging voltage in response to battery temperature. A warm battery undergoes faster chemical reactions and needs less voltage and current to fully charge. A cold battery needs more robust charging since cold temperatures rob a battery of its capacity.