Dual Charging Modes: Solar powered, no extra utility bills, no batteries to replace, just solar panels to absorb the full sunlight; USB charging, can be used during the day or at night by connecting it through the USB port. You can easily switch between 2 modes in different situations. Auto On/Off: Light sensor controls the solar lanterns auto on at auto and dark off at daytime. [NOTE]: The actual working time and required charging time are affected by the intensity of the sunlight.