We have 2 ARB's. 82 qt & a 50 qt. I have not used them both on 12v yet though. Everywhere we have camped so far has had 120v. When we do get to that point, I will have to get 1 or 2 deep cycle 12v batteries for each fridge/freezer. I already have a Cabela's 2 bank Pro Angler charger & can use either our Honda eu2000i generator or our 2000/4000 watt inverter setup. Anyways, they work GREAT. The 50 qt was able to maintain 0*F on 90*+ days. We want to be gone for a month or more at a time, so 1 freezer & 1 fridge in addition to our tiny camper fridge does the trick. We also brought a Coleman cooler (just for drinks) & just kept rotating & refreezing the water jugs. This takes care of any scenario & lets us be gone for a loong time. The price did hurt but i also feel that I got what I paid for. Surprisingly enough, we have used the 50 qt in the back of the 4Runner quite a bit since we got it. Great for doing day trips to far away markets, getting stuff we can't get local & bringing it home.
We have a 2008 Dodge Power Wagon w/ARE MX series cap, roof rack/basket, home made bedslide that the 2 ARB's are in/on. So, while space is always at a premium, the 3/4 ton platform gets the job done for us while pulling our little 18' 3500lb camper.