Caravans and moose (XC90)

Hello, after a few months of moving in with us an XC90 D4 has now been added to the caravan. Despite Arctic cold, we have left the camping site and immediately an important question arises. If I am in the caravan and the 12V supply runs over the car, it becomes dark after 15 minutes in the Wowa. Apparently the XC90 then switches off the permanent increase of the ahk. can you confirm it? In the manual there was nothing, can I change it? If we are standing somewhere, it would be great to use the toilet and a LED lamp. That consumes both as well as nothing. The rest goes on gas. Would be very grateful about your experiences / solutions. Otherwise only an expensive Autark package helps for the WOWA, which I actually wanted to avoid. Ps: What happens if I go with hanger in the Eco mode. Then the height of the trailer coupling and the bottom of the trailer is reduced, or is that? Is that still Eco, or should I forget the mode with a hanger?