SUUNNY solar charge controller is controlled by CPU, According to the voltage ofbattery, controller will adjust the charge current and decide if to supply the loads electricity. The following is the detailed performance: ?Generally keep the battery on full voltage condition. ?Prevent the battery from over-charging. ?Prevent the battery from over-discharging. ?Prevent supplying electricity from the battery to solar panels during nights. ?Reverse Polarity Protection for Battery ?Reverse Polarity Protection for Solar panels ?When the current of load exceeds the rated one of controller, the controller will turn into the self-protection state and is automatically locked up, the screen shows 揙verload? ?Short Circuit happens; the Controller will turn into the self-protection state and is locked up, the screen show 揝hort circuit?