No More Off-Grid Worry Each battery can provide 25 hours battery life at 40 Degree F set temperature or 8 hours battery life at 4 Degree F set temperature, keeping the fridge running when external power is not available, such as after turning off the vehicle or at night when the solar panels can not work. Space saving The battery can be fully installed in EENOUR refrigerator, taking no extra space in the car and leaving more space for other essentials. The wireless design ensures no more hassle of organizing wires. Solar Charging Instruction plugging the solar charging cable into the refrigerator’s /SOLAR/ input port can keep the refrigerator running and charge the battery at the same time. The maximum output voltage of solar energy cannot exceed 30V, and the charging input power should be higher than the working power of the refrigerator (38~40W), otherwise the battery cannot be charged. It is recommended to use 90~120W solar panel.