The working principle of the solar lamp is simple. The solar cell is made by the principle of photovoltaic effect. During the day, the solar panel receives the solar radiation energy and converts it into electrical energy output. It is stored in the storage battery through the charge and discharge controller. The open circuit voltage of the solar panel is about 4.5V. The charge and discharge controller detects this voltage value, and the battery discharges the lamp head. After the battery discharges for 8.5 hours, the charge and discharge control action is completed, and the battery discharge ends. The main function of the charge and discharge controller is to protect the battery.