Review on Charging Controller Protection Undervoltage Automatic by Ans Brownlee

I purchased this unit to switch off loads connected to my solar powered shed when the main batteries run low. My goal was to turn off the power at 55% battery voltage (12.15V) and resume operation when the battery voltage exceeds 12.8V (30°C) to +113°F (45°C). Adjustment: There are several ways to calibrate; I connected an AC voltage source and a multimeter to the input. In any case, it is important that the desired on/off voltage is available so that it can be set "out of the box", which was far from what I wanted. Once the desired voltage was applied to the input, the potentiometers could be slowly adjusted to turn on and off at the desired setpoints. Temperature Sensitive: This is a cheap controller and I expected it to be temperature sensitive. However, it turned out to be even more sensitive than I expected (hence only 4 stars). I ended up calibrating at -23F so I wouldn't over discharge or freeze the batteries. With DC applied for the duration of the test, the following PCB temperatures (temperature measured between relay and PCB) resulted in the following on/off voltages without adjusting the potentiometer between temperature changes: -23F 12.15 (OFF) 12.79 (ON) ) 70F 12.27 (OFF) 12.90 (ON) 113F 12.33 (OFF) 12.97 (ON)