Greetings from Hilton Head, SC,
When towing for about 3 days, the battery in our Dodge Durango will go dead due to the the Brake Buddy and parasitic loads. We have installed Toad-Charge and the problem goes away.On the car, you attach a small regulator to the battery and run a wire harness to the front of the car. Another wire harness connects the car to a coach harness which connects to 12 VDC thru a thermal circuit breaker. Slick system!
http://www.lslproducts.com/ToadChargePage.html
NOTHING DRIVES LINE AN ALPINE!