3-way refrigerator

I'm picking up a new 2014 181-G from our local dealer this Saturday and had a question about the efficiency of the 3-way refrigerator in 12V mode.  Or previous TT (27' Salem) worked great on propane, but I always felt a little nervous driving down the highway that way.  Does it cool as well on 12V as it does on 115V or propane?

Originally posted by CharlieM The short answer is no. The Dometic is rated at 132 Watts (12V x 11A) on DC and 144 watts (120V x 1.2A) on AC. More watts means more cooling so DC is slightly less effective than AC. Propane is usually about equal to or somewhat better than AC. That's by the numbers, but experience has shown the DC operation is noticeably worse than on AC or propane. Not sure why, but I think some earlier Dometics were rated a bit lower on DC. That said, the fridge will really suck the battery and, depending on how well the TV is wired, may actually discharge the trailer battery while towing. At best you will only trickle charge the TT battery since most of the current is going to the fridge. Due to the design of the flow limiting safety valves on modern propane tanks there is little danger of operating the fridge on gas while towing. Larger fridges in RVs do not even have a 12V option. It's either propane or shore power and nobody thinks a thing about it.

Originally posted by furpod Ours does fine on 12v. It's the mode we run in when towing, and at full hookups have just left it there on occasion, and no issue. The important thing to know is it WILL drain your battery in 3 hours or so if you leave it on 12v without being hooked up to shore power or a tow vehicle that is charging the pod.

We use the 12v when ever towing and have had no problems, (after the first time we used it). 
It was 95 above and I'm not so sure we cooled it down long enough and we over loaded it.
This weekend will be trip # 9 or 10 since July of 2013. (It's nice to loose track of such things).
Haven't lost track of how long I've been retired yet though!   Monday, this is day four!

Safest bet is to use propane mode, since most factory TV wiring, and most aftermarket installations use 12 gauge wire.  I ran the numbers here before and bottom line the fridge is such a large load you will discharge the battery as mentioned above.  You need minimum 10 gauge and much better 8 gauge wire.

Just curious.  Has anyone used a vessel near or about the size of the freezer and created an ice bank.  This could be done at home before leaving and maintained once AC is available again.