We typically carry an Engel 45qt fridge / freezer in the rear of the tow vehicle when on the road... got tired of running a temporary
12v extension cord from the accessory outlet in the cab, through the rear window, into the bed of the truck, etc... so installed a Victron inverter as a permanent solution.
Used 4ga back to the battery with a 60A fuse, then grounded to the frame near the rear bumper.
I also added a
12v receptacle to the install so I now have 120v outlet and
12v accessory outlet in the rear bed to run the fridge and other stuff while we roll down the road.... super convenient!