Refer - DC vs AC/DC

[Scott Barnard]

Which is best? DC alone costs less.

 

[SteveK]

DC IMO
It does not need an inverter, most compressors are DC and the AC is converted. The only advantage of AC/DC is art the dock you can switch to shore power AC. I run my ACDC fridge DC all the time.

 

[rslifkin]

My fridge is currently DC-only. However, now that we have an always on inverter setup and AC power is available 24/7, I'd prefer an efficient self-defrosting AC-only fridge over an expensive marine fridge that requires manual defrosting.

 

[Scott Barnard]

At the dock the AC goes to the batteries then to the Refer? Does this have any downside affect on the batteries?

 

[rslifkin]

At the dock the AC goes to the batteries then to the Refer? Does this have any downside affect on the batteries?

As long as the charger is big enough to keep up with the load the batteries never know or care, they just stay at float voltage with the charger supplying power to the DC loads (including the fridge). The batteries will only get cycled if you draw more power than the charger can provide.

 

[Scott Barnard]

Thanks all. Seems saving several hundred bucks for DC only is the route.

 

[Delta Riverat]

I'm quite pleased with my new 8 cu-ft Dometic 12 VDC fridge. Uses very little power and gets plenty cold.

 

[ranger58sb]

I've come to better appreciate the frost-free feature on the AC-only fridge and freezer in our galley, powered by inverter when away from shore power or when the genset is off.

OTOH, our AC/DC fridge on the bridge at least runs from a different battery bank, so switching breakers so that runs on DC only when we're anchored gives us a little more time between re-charge for the inverter bank.

-Chris

 

[Kaniksu]

I too went AC only on a Summit zero clearance fridge w/o a freezer. Wish I did it sooner.

 

[Ithaka7]

AC only is the way to go, as there is much more choice and a lot less expensive. At first, people, especially on sailboats try to go DC only... then the cost adds up quickly. Once you get a good inverter, then you start adding all the typical household appliances and you forget about DC. Leave DC for navigation and lighting.

 

[Delta Riverat]

Yeah, especially the expense. My 8 cu-ft 12 volt RV fridge was $1300. You can get a 10 cu-ft residential for $400. But the securement and the door locks are on you as well as the 15% inverter loss.

The big one for me was I didn't have to modify the opening in the nice teak -

 

[SteveK]

I know there are cheap fridges out there. But they need to fit into the space available and look good in there.
Sure I would get an AC only if the price was sole consideration.

I admit I have not compared fridge battery power consumption on 12V compared to battery consumption thru inverting.

I also look at the power the fridge needs within the inverter capacity that can be used for things that will not run off the batteries.

 

[Datenight]

Which is best? DC alone costs less.

Scott, I went DC only three boats ago in 2003. At the time it was the best choice and I was delighted with my Isotherm. Amp draw was 40% less than the Norcold it replaced. If you are a mostly DC boat it may be the best choice. I think a DC only is better than an AC/DC.

Our NP 45 has an AC 10 cu. Ft. Summit. It has been great. We also have 600 watts of solar which makes a big difference. In my situation the AC fridge is the winner.
Rob

 

[Comodave]

We replaced the refer in our current boat a couple of years ago. The problem was getting the new refer in the door. I had to cut up the old one to get it out. So we didn’t have a lot of choices for the new one. We found an Isotherm that would fit through the door. It is AC/DC but seems to be very efficient. It is also the first refer in a boat that I don’t have to run at full cooling settings. It goes up to 8 and we run it on 3, it freezes ice cream at that setting. Overall we love the Isotherm.

 

[Kaniksu]

Summit is not inexpensive, but as with others, it precisely fit in the space formerly occupied by a Norcold and because it was designed to be an ADA compliant under-counter built in fridge, it breathes through the front bottom and required no clearance.

 

[CaptTom]

AC/DC gives you options. I like options. Plus, in most cases there's an exact-fit replacement available. I ditched an AC-only department-store fridge the PO installed and found a replacement for the OEM fridge which originally came with the boat. Even the screw holes were the same. I always figure it's best to have something specifically designed for the task at hand.

 

[Bmarler]

I think it depends on the situation. If I had a galley that needed an upright fridge I would likely go ac only so I could go frost free. I have a huge house bank and inverter is on 24/7, so would be a nonissue.
But, my galley has a big double door under counter built in. I use an Adler Barbour remote compressor with air and raw water heat exchanger. Super efficient dc only setup.

 

[Kaniksu]

Personally, as 2024 ebbs, my goal is to retain one of you gurus to be my project manager. Since Bmarler lives close by, he may get stuck with me.

 

[Bmarler]

Personally, as 2024 ebbs, my goal is to retain one of you gurus to be my project manager. Since Bmarler lives close by, he may get stuck with me.

lol,
like you really need any help with that...