I installed a solar power station in my shed for lighting and a small inverter to run some power tools. Since there is no environmental control in the barn, I needed this ACOPOWER battery temperature sensor to have the charge controller charge the batteries at the correct voltage, which is compensated according to the temperature of the batteries, as temperature ranges can be extreme here. I checked that the temperature sensor is working properly with the charge controller as my batteries were cold this morning and the charge controller charged them at a higher voltage than it should. When your solar panels are not in a temperature controlled environment, this battery temperature gauge is an essential addition to your solar array. For the price it offers exceptional value.