12volt or 12/110 volt fridge ???

The 12V only one won't run on Shore Power unless your battery charger is running, if its the only thing onboard charging batteries to run it is not the most efficient way to operate, if you have other stuff running off your batteries all the time it probably makes sense if is cheaper.

Actually it'll run until your batteries run down. You really only want 12v when you're hanging on the hook or such with the gen and motors turned off. Otherwise you're better on 110v. If I chose between the two I'd use a straight 110v rather than a 12v. The 110v I can keep closed and the cold in for the little time I have no 110v, but a 12v could kill your battery (and your food) if the shore power cuts out while you're away from your boat. On boats we like redundancy. The 12v backs up the 110v. 12v only is for day cruisers who bring their food each time they're going out (small boats).

P.S. If your boat doesn't have a gen, be very careful with a 12v fridge. I generally shut them off when hanging out unless it's on a seperate battery. Otherwise you could spend the day hanging on the hook only to find dead batteries when you go to head home.

FWIW, our 12V/110V fridges always runs on 12V. When both 12V and 110V are present, the fridges automatically choose 110V. But then when being fed 110V (as from shorepower), there's an internal converter in each fridge that changes it to 12V. The fridges uses a 12V compressor.

-Chris

This is exactly the way a 12/110V. fridge works. The advantage to the 110V. option is that when you leave your boat tied up to the dock and shore power connected, you can turn your battery switches off and still have the fridge running from 110V.

What do those of you who leave your boats tied up with no one onboard do to maintain a bilge pumping arrangement if you do turn the batteries off as suggested above?

Your bilge pumps should have power supplied to the automatic float switch system directly from battery power, before the battery switch. In other words the float switch should have power whether the battery switches are on or off.

Yes, of course. I was speaking to OP's "what is the difference..." question.

FWIW, we leave battery switches on (even though bilge pumps are connected before the switches and so automatically powered), because in our case one of the main battery switches also activates the shower sump... which catches and then pumps overboard condensate from one of our AC units. The AC aren't often on when we're not there, but sometimes they are... and sometimes we run them in the de-humidifier mode... so we've developed the bait of leaving the sump enabled. Not directly relevant to OP's question, but then the kneebone's usually connected to the thighbone, etc...

-Chris

My last two boats have had 110v fridges.
They are considerably cheaper than the 110v/12v versions.
You can buy an under counter 110v or an apartment size fridge to fit in most spaces.
(Sometimes requires a little carpentry)

When not running the generator I can run the fridge off an inverter which shuts down when the voltage drops.
The inverter is not connected to the starting battery or the generator battery.
Also with the 110v only set up you never have to worry about draining the batteries during shore power outages.

Thanks, I was curious as to what the lock it and leave it procedure was.

There's another way to solve that with an AC/DC fridge. We have both DC and AC breakers for each fridge. We usually leave the DC breakers off when we're on shore power... so if there's a power outage, there's no impact on batteries.

Of course, sometimes I do leave the DC fridge breakers on (e.g., when I'm expecting the outside cleaning crew to inadvertently trip the main AC breaker in the cockpit, a not-untypical occurrence, no matter how much "training" I've "offered"), but we're close enough to check the boat daily if necessary, and I can also often tell if there's likely to be a weather-driven power outage, anyway...

-Chris

I purposely didn't mention brands earlier, but it happens out two fridges are NovaKool models, one an R75MT and the other an R2600.

As I described, ours both work with either AC or DC, with a built-in internal AC-to-DC converter, and a 12v (only) compressor. And I have routinely referred to these as AC/DC fridges, although perhaps my terminology needs some help.

Or do you mean the transformer is an option in the RFU9000 and you declined? Or perhaps when you say an "AC/DC version" you mean a model that runs the compressor on AC (not converted to DC) when AC is present, and DC when DC is present? With a compressor designed to work at both voltages?

-Chris

Everything on my boat is 12v and 110v by inverter (5.000/10.000w). I have three 245w solar panels and 4 large 6v Trojan batteries, I run only the 3 aircons on my generator, all in all a bullet proof configuration in a sunny climate!

Galley Fridge is SunDanzer 12 Volt Upright Combination Refrigerator and Freezer - DCRF134

Flybridge Fridge/freezer is Norcold 12 Volt

What you want to ask here about the 12V fridge? What does it mean? And what is concept of using to supplies? Can anybody please help me to understand?

The fridge in your house runs on 110 or 230v depending if you are in the US or Europe, a 12V Fridge runs on 12V which can at a pinch be extracted from a car battery which should be charged at the same time or it won't run for long.