Abstract: The supply of power from a battery to a load is controlled by the charging current output status of a solar cell, such that when the solar cell receives light, the load is cut off; and once the solar cell no longer receives light, the battery is charged to a preset saturation level and the solar cell no longer supplies charging current to the battery, or the charging current falls short of a predetermined level, the battery will revert to an output mode with suspension of the charging function.