Originally Posted by Bohemian
When the TT is being towed, and the batteries are charging from the TV's alternator, I'm sure there's not a lot of amps involved because the wires in the harness aren't big enough to handle that.
My question is: What is limiting that current? What prevents us from melting wires and blowing fuses? (I know, that's two or three questions.)
Wire length, size and resistance of the connector, from the front of the TV to the batteries somewhere in the AS will limit the tow charge current flow to from 5 to 12 amps in my experience. I have a digital ammeter with shunt on my Argosy 20' and that allows me to see just what charge current I get.
You can put a much larger wire in the TV, and better connector, and larger charge wire in the AS to get more tow vehicle charge to the AS batteries, but it is a royal PITA to do, and every time you change TV's you have to go through it again.
A good Converter/charger such as a Progressive Dynamics 9245 or 9260 and a generator will do the job better, faster, and easier. I still like some charge from the TV, but have resigned myself to it's limits.