1. First check the indicator light of the solar charge controller to see if the indicator light flashes normally. If there is an abnormal situation, check it according to the product manual to determine the fault of the controller.

   2. If the indicator light of the solar controller is not on, you should check whether the connecting wires of the solar panel, the battery, the load and the controller are normal, whether there is any looseness and falling off, and if so, reconnect.

   3. Use a multimeter to measure the voltage of the battery to see if it is in a state of power loss.

In the process of using solar charge controllers, there are several voltages that must be understood.

   One: The high voltage protection voltage is to prevent the battery from being overcharged, generally at 15.5V. Some controllers do not have this function, or this function fails, and the result is that the battery is bulging and even fails.

   Two: The low voltage protection voltage is the voltage set to prevent the battery from being over-discharged. Usually at 11V. Similarly, if this function is not available, or the precision of the components is not enough, the battery will be over-discharged. Usually, the voltage of the battery is lower than 5V, it is difficult to charge it back, and the battery will be scrapped.

   Three: Recovery voltage, which means that after the low-voltage protection of the controller, it needs to recover to a certain voltage value to work normally, usually the voltage is 12.5V, if the low-voltage value is not reached, the controller cannot automatically resume to work.