Updated: Jan 10, 2020
What Is A Charge Controller?
A solar charge controller or charge regulator, as implied in the name, is a voltage and/or current regulator which serves to keep the batteries in a solar panel-deep cycle inverter system from overcharging. A charge controller may be a stand-alone device which has to be bought and installed separately or it may be a control circuitry integrated within a battery pack, battery-powered device or charger.
Stand-alone charge controllers or solar regulators.
Stand-alone charge controllers are bought and installed as separate devices, often in conjunction with the solar panels, for uses such as RV, boat, and off-the-grid home battery storage systems.
Integrated charge controller circuitry
A charge regulator may be encapsulated in a single microchip, an integrated circuit, an integrated circuit (IC) usually called a charge controller IC or charge control IC. It may also consist of several components integrated within the circuit. Charge controller IC are used for rechargeable electronic devices such as cell phones, laptop computers, portable audio players, and UPS.
Solar charge controllers are available in different specifications according to features, costs and sizes. The range of charge controllers are from 4.5A and up to 60 to 80A.
A solar charge controller is needed in virtually all solar power systems that utilize batteries.
HOW DOES A CHARGE CONTROLLER WORK?
It regulates the voltage and current coming from the solar panels going to the battery. Most 12V solar panels put out about 16 to 20 volts. Most batteries need about 14V to 14.5V to get fully charged. Therefore if there is no regulation, the batteries will be damaged from overcharging.
Since solar panels can only work during the day, a solar charge controller will ensure that the deep cycle batteries are not overcharged during the day, and that the power doesn’t run backwards to the solar panels overnight and drain the batteries. This is called ‘reverse current protection’ or ‘electronic blocking’.
Some charge controllers are available with additional capabilities, like lighting and load control, but managing the charge that flows from the solar panels to the batteries is its primary job.
Many controllers are configurable, allowing settings for a few hours or all night, or somewhere in between.