Odd battery / 7-pin question

[dkarnes87]

I take a travel trailer out camping often. I have Wi-Fi in my truck, and would like to use it since sometimes campground Wi-Fi is spotty. I know the only way to do this is with the truck in the ON or ACC position, but I don’t want to waste gas or kill my truck battery.
I’m wondering - if I keep my truck plugged into the trailer via 7-pin, and the trailer plugged into shore power, will that 7 pin connection keep my truck battery charged? I’m also thinking I could keep jumper cables connected between the house battery on the trailer and the Truck battery, but I think that could look a bit trashy and may cause issues.
Any thoughts here?

 

[crash68]

Or buy a small battery charger like the Nico Genius 10 that has a 12V supply mode and just plug the truck in:

NOCO - 10-Amp Smart Battery Charger - GENIUS10

The GENIUS10 is a 10-amp battery charger, battery maintainer, and battery desulfator for 6-volt and 12-volt batteries.

no.co

The +12V pin on the trailer plug is fuse from the battery at 30 amps. So it is possible to back feed from your trailer provided the trailer doesn't isolate that wire from back feeding. Check to see if that pin stays hot(+12V) on the trailer side when the shore power is on.