A gross lie has been perpetrated upon the RV community. The lie is: “Your trailer umbilical cord will charge your RV house batteries. You don’t have to do anything but drive!”

The full width and breadth of the myth goes something like this:

1. You plug your towable RV into your tow vehicle with the 7-way* umbilical cord connector.
2. There’s a wire (of undetermined gauge) between the 7-way receptacle and the tow vehicle alternator.
3. When you turn on your tow vehicle, it kicks on the alternator.
4. The alternator charges both the tow vehicle’s starter battery and the RV’s house battery.

But here’s the truth of the matter: