[drover]

If you have solar on your van its not really needed, mine is 12 yrs old and the batteries are charged from solar all the time, power from the JGC is just for the fridge while running down the road, my 15 doesn't have a smart alternator so the run is from the jumper terminals to an anderson at the back with a fridge switch at back of fridge where it can shut off power to the fridge when stopped, its fitted there where the cable drops to a smaller gauge....

I looked at the fact that if my solar can't keep things going for a few hours driving down the road what chance do I have spending weeks by a creek, its never needed charging from the tug, in fact even in caravan parks the 240v is just for HWS, kettle and toaster, nowadays since I went lithium it doesn't even have a mains charger in van at all, my solar does it all ... running the Grand idling to charge shoudl never be an option though.

But if you need to then just tap into a clearance light circuit and drive with your parkers on, then if you stop the bells will start and remind you to turn the lights off hence the charging unit but really in a modern van set up for off grid its shouldn't be needed ... Im not sure that the 20 has a smart alternator actually.