If someone wants to check this out before pulling the plug on it I suggest getting one of the volt meters that plug into the cig socket. That's what I did. Its perfect since the car turns off the power to the socket when you turn the car off.
This looks like the one I have (I don't remember the exact model I have) and its a 4 pack for $12 so a pretty good deal if you have multiple vehicles.
https://www.amazon.com/12V-24V-Digit...983762&sr=8-21