I have the T-31 (the smallest one) Truck Fridge (Indel B) and I have a 100W portable solar to keep my camper battery charged. The battery is a brand new high quality deep cycle battery. If camped with reasonable exposure I have more than enough power to run the fridge, charge camera batteries etc, indefinitely. Camped in shade covered sites with overcast skies it's borderline. After 2nd day or so I have to run the tow vehicle for a bit to back up the solar.
Regarding the fridge, works great at freezing, I'm finding it tricky to hit the sweet spot setting where it keeps frozen stuff on the bottom frozen, while not also freezing my eggs, cheese etc that is sitting on top.
But still the way to go IMO