12 volt or mains power fridge?

[mikedefieslife]

Residential/commercial inverter tech fridge rated A+++ and suitable for tropical climates. you're not going to improve upon it with some home-brew insulation. An inverter large enough to power it (start up current) is likely to consumer 0.6a at idle and less in standby.

Front opening is of course less efficient than top opening, but much more practial I find. Also you don't lose the counter space of top opening unit.

[davenrino]

Originally Posted by flagatorclearwa

My question is what extra value does the 110v have? Looking at sources like Defender many of the marine fridges come in either 12v only or 12/110v. The latter are often pricier. What is the value of having the 110v rather than just 12v?

I have both a 12/110 fridge and 12/110 freezer. My boat lives in a marina with shore power. The 110 advantage for me is saving my batteries for the bilge pumps when I am off the boat with the battery switch off in case 110 is accidentally disconnected or the power goes out. It has only happened once and the bilge pumps still protected the boat while the fridge and freezer defrosted (they needed it anyway). The beer, water, and mixers didn't spoil and the bag of cocktail ice was replaced for $2.

[Dsanduril]

Our inverter uses 0.25A in idle/no load, so 6Ah/day. It is ~87% efficient in use (Victron claims higher, but....). That equates to another 6-8 Ah/day in energy "waste". But, the fridge and freezer are so much more efficient than at least 90% of marine fridge installs that the waste is acceptable and still keeps our usage under that of any even remotely comparable marine unit.

[wingssail]

Originally Posted by s/v Jedi

After having used the marine units from Frigoboat for many years, we have now switched to SnoMaster Expedition units.

The biggest unit is 95 Liters one compartment or 85 liters two compartments (each with it’s own thermostat). These can be set as fridge or freezer
https://www.snomasterusa.com/product...fridgefreezer/

These can be a good solution if your boat has the volume to install it. Many people who have become enamored with Engel units wound up putting them on the settee or on the cabin sole, in the way. I don't think that is a good solution.

Next, given the thickness of the insulation I wonder about the efficiency. 66watts is 5.5 amps at 12 volts, and the AH usage will depend on the compressor operation cycle. Running 50% of the time results in 66AH, not bad. If the duty cycle increases to 75% of the time, you get 100AH, or pretty typical. We find that the duty cycle of refrigerators depends on the insulation, and ambient temperature. Even our air cooled unit (we have 6" insulation) performs much better in cooler water areas, and it is marvelous if the water is below 65degrees F, running less than 50%, but in water over 82 degrees (28 C) and high humidity, it runs nearly 100%. I would be surprised if most units, including the Snomaster Expedition (at twice the price of a small marine unit) would not do the same and it won't fit in most boats.

[wingssail]

Originally Posted by Dsanduril

Our inverter uses 0.25A in idle/no load, so 6Ah/day. It is ~87% efficient in use (Victron claims higher, but....). That equates to another 6-8 Ah/day in energy "waste". But, the fridge and freezer are so much more efficient than at least 90% of marine fridge installs that the waste is acceptable and still keeps our usage under that of any even remotely comparable marine unit.

" the fridge and freezer are so much more efficient than at least 90% of marine fridge installs"

I don't find that entirely believable.

[tangara]

The question no1 is power consumption if you are not plug to shore power.
#2 isolation is critical a boat fridge box have 4 inch min on side compare to résidentiel unit with 2 inch max.

If you must run a generator to run your fridge it is costly.

Your boat fridge will last 10 year plus if it is well isolated and maintain.

[Dsanduril]

Well, you said it yourself, you have 6" insulation and find tropical running you get 100% duty cycle. Our 5-year-old 150l (5ft3) fridge runs less than 30Ah/day in the tropics, has walls about 2.5-3" thick, and has a newer cousin that is rated to use two-thirds as much energy.

Our freezer (104l, 3.5ft3), kept at -18C has ~4" walls, uses about 40Ah/day in the tropics. And it too has a more efficient newer cousin.

All-in in the tropics, including all inverter inefficiencies, we use less than 70Ah/day for fridge+freezer, our temperature control is better, and our freezer temperature is lower than nearly every boat we meet.

[ThereAndBack]

Originally Posted by wingssail

" the fridge and freezer are so much more efficient than at least 90% of marine fridge installs"

I don't find that entirely believable.

I think he just made up the percentage.

However, in my case he was correct. The old units on the boat when I bought it were AB/Dometic compressors and were not very efficient. I tore into my boat to see if the insulation was dry/good and it was. Replaced all seals. Ran big gauge wire to the compressors. And still, they used as much or more power for the same volume as the cheap ass dorm style fridge/freezer I use now.

I also have an inverter that is on 100% of the time so that isn't a concern for me.

I have not been plugged into shore power in 6 months. I have approx 500 watts of solar and good batteries.

Earlier in the thread you mentioned that "skimping" on a boat is a bad long term decision and will yield poor results, but I'd like to offer a point of view to you that you may not have considered...

Given that we all have a limited amount of money, we MUST cut costs and live within our means *somewhere*. I'd rather take the 5000 USD that it would take to repair/replace all my marine reefer gear and invest it into solar + inverter and run a cheap energy efficient dorm fridge for a while. And really, if your fridge dies it isn't the end of the world so long as you have canned/dry foods aboard or are near civilization.

Cutting corners isn't always bad so long as you don't cut the critical ones. I have better power overall and a cheaper freezer. It works for me and has been working for a while now.

[wingssail]

Originally Posted by Dsanduril

Well, you said it yourself, you have 6" insulation and find tropical running you get 100% duty cycle. Our 5-year-old 150l (5ft3) fridge runs less than 30Ah/day in the tropics, has walls about 2.5-3" thick, and has a newer cousin that is rated to use two-thirds as much energy.

Our freezer (104l, 3.5ft3), kept at -18C has ~4" walls, uses about 40Ah/day in the tropics. And it too has a more efficient newer cousin.

All-in in the tropics, including all inverter inefficiencies, we use less than 70Ah/day for fridge+freezer, our temperature control is better, and our freezer temperature is lower than nearly every boat we meet.

OK, so you can get a 150lt refer which will run, in the tropics, at two-thirds as much energy as your existing unit which consumes 30AH/day with 2-3 inches of insulation and I am assuming front opening door. That calculates to 18AH/day?

Well, I cannot say it is impossible without calling you for gross exaggeration, so I'll take that on board, (meaning I'll stick it in my brain for future consideration) because if true, it will be truly miraculous and might be a good thing for me to know at some point. Meanwhile I'll keep watch for some technical specs on such a unit.

[Dsanduril]

Here are the tech specs for the newest units:

Liebherr GP 1486 freezer - rated for climate class SN-T (T=tropical, up to 43C/109F). Standardized testing rated at 273 Wh/day (23Ah/day).

The Liebherr TP 1720 and 1760 fridges are rated SN-ST (subtropical, only 38C/100F max ambient temperature) and 169/173 Wh/day (14.5Ah/day).

There's been a fair amount of argument around here about those energy ratings, I can only report one data point, ours, and we find them to be pretty close in the tropics, and up here in the chilly water we use significantly less. For both units that's 40Ah/day, add another 15Ah/day for inverter idle losses and inefficiency (tech specs Victron Phoenix) and you're still at only 55Ah/day for all your cooling.

[Sternwake]

Regarding a front loading fridge, vs a top loading one, the act of opening the hinged door is going to purge a significant portion of the cold air inside the fridge whether the door is on top or the side.

So in my opinion cold air spilling out, is not the reason they are more efficient. They are more efficient as there is no door seal at the bottom, where it is coldest, and can more effective insulation there.
For the toploader to be even more efficient, then the door would have to slide open, and displace almost no air.

I bought a DC only unit, as when I have AC available my power supply will handle running the fridge too.

The only time this is less desirable than a fridge which can run off AC as well, in my expected usage, is when I am trying to recharge at the highest possible amperage rate, and the fridge's 2.7 amps, are 2.7 amps not helping my charger/power supply to bring the battery to absorption voltage faster.

Pretty much a non factor. The AC/DC unit price increase compared to the DC only unit, paid for a significant portion of my 40 amp adjustable voltage power supply/charger.

With better insulation, and optimized condenser/compressor ventilation, my DC fridge's (50liter interior volume) power draw is basically a non issue as well, averaging 0.43Ah each hour in 75 f average ambient temps, as I use it.

I was able to reduce this average from 0.62ah each hour average, with a secondary D seal inside the provided door seal, so the metal skin of the fridge body could not be exposed to interior cold under the provided door seal.

[Dave22q]

You might consider dual powee or 12v cooler chests. Prices good because more RV/truck than marine marketing, you might need to periodically remove condensation. Chest setup much less convenient storage v. upright mini frige. Prices for 'marine' refrigerators are a joke.

[Simi 60]

We run 2 x 100 litre bar fridge
1 x 100 litre freezer
1 x 550 litre 2 door fridge freezer
All front opening, all household 240v
Haven't been on a marina berth in 4 years - all solar and inverter driven.

The cost of replicating all that in marine 12v would be in the tens of thousands and , being built in I'd be stuck with them and their ongoing issues for life.
Instead, with 240v units available in every port, in most cases its easier and cheaper to replace them if they have issues vs paying for a fridge tech.

[jmschmidt]

You might consider a dual voltage set up if you have a genset. 12v underway, 120v on the genset or dock power.

[waterman46]

When our old Glacier Bay system gave up, and we were in Panama, we bought a cheap dorm fridge. It is tiny compared to the built-in, but worked a small miracle for us as a temporary measure. I had gotten really tired of the trip to town every other day for ice! It includes a tiny freezer compartment (inside the cold plate) which also worked very well.
The dorm fridge, being so small, didn't take even as much power as our old GB unit, even though it ran 24/7 on the inverter. A decent inverter will have a very small current draw when it is in the standby mode, and land based units are quite efficient these days.
The dorm unit made about 12 small ice cubes per day for the Admiral ( I don't mind my G & T with no ice cubes). There were some issues, like making a strap to hold it in place, and to keep the door closed when heeling. And it did create a bit of heat, but we had it in the forepeak where we didn't mind that.
So I think it is possible to use a mid-size land-lubber unit, but with clever ventilation. You'll need to add a convenient way of locking the door, and be sure to mount it transversely if you are on a monohull.