Thinking of getting one and was wondering if it is worth the price and if they worked or not.
I used one when I had my Compact Junior
trailer. The owners manual states that they only cool to 40 degrees lower than the ambient temperature around it. I would carry mine in my air-conditioned tow vehicle, plugged into a cigarrette lighter outlet, while travelling. When camped for the night, I'd move it inside the trailer and use an ac adapter (optional extra) to plug it into a 110 volt outlet.
I once ran it on the trailer's battery
read 12.4 volts at 10:00 PM and 8.0 volts at 6:00 AM!