A Solar charge controllers or regulator, regulate the battery charge to ensure that batteries are not overcharged. Limits the rate of electric current added or drawn from batteries. It prevents overcharging and may protect against over-voltage, which can reduce battery performance or lifespan, and may pose a safety risk. May also prevent completely draining (“deep discharging”) a battery, or perform controlled discharges, depending on the battery technology, to protect battery life.
Terms “charge controller” or “charge regulator” may refer to either a stand-alone device, or to control circuitry integrated within a battery pack, battery-powered device, or battery charger.
Solar Charge controllers are sold to consumers as separate devices, often in conjunction with solar or wind power generators, for uses such as RV, boat, and off-the-grid home battery storage systems. For solar applications, charge controllers may also be called solar regulators. Some charge controllers / solar regulators have additional features, such as a low voltage disconnect, a separate circuit which powers down the load when the batteries become overly discharged. Some battery chemistry are such that over or discharge can ruin the battery.
Simple charge controllers stop charging a battery when they exceed a set high voltage level, and start charging when battery voltage drops back below that level.
A charge controller with maximum power point tracker capability frees the system designer from closely matching available Panel voltage to battery voltage. Considerable efficiency gains can be achieved, particularly when the Panel Voltage array is located at some distance from the battery. By way of example, a 150 volt PV array connected to an maximum power point tracker charge controller can be used to charge a 24 or 48 volt battery. Higher array voltage means lower array current, so the savings in wiring costs can more than pay for the controller.