Refrigeration

[R Hutcheson]

A couple of weeks ago someone started a thread where they made a good case for a household style refrigerator in a sailboat. I know Bali Catamarans come standard with what appears to be a household type unit, though they might be marine units. I don't know.

Does anyone on the forum have experience with these units?

What are they like to use underway? Does everything come flying off the shelf if you open the door in a seaway?

[sailorboy1]

Power boaters have lots of experience.

[chris mac]

I don't know what Bali has, but on our catamaran I swapped out the built in marine unit for 2 bar fridges from home depot.
The old unit was 30 years old with soaked and moldy insulation. And didn't seal properly due to several holes from previous owners doing modifications. It desperately needed replacing.
I went with 2 units because of the hull shape. This maximized the cubic footage. I wired to a dedicated victron 1200 watt inverter. Total cost for fridges, inverter, wires, and some starboard to build a frame for it cost just over $800
We are 2 years in with the new fridges and they are working flawlessly. Power consumption is very similar to what running the old unit was. Food keeps much longer now, temp is way easier to adjust, easier to defrost too.
It worked out well for us and I wouldn't hesitate to do it again

[shmorrell]

I’m starting down that road too. Old fridge boxes with questionable insulation and broken AC water cooled compressor makes a full redo necessary. Marine DC unit $1400. Same size Home Depot unit $200ish. I have a 3000 watt inverter, brand new so I’m gonna try a domestic fridge. Glad to hear you’re having success with yours

[Greg Brannon]

My trawler came with a household 18+ cubic ft freezer-over-fridge and a 3,000 Watt inverter for the whole boat that put out a modified sine wave - not an especially pretty one. I don't have measured data to prove it, but I never felt the fridge did as well on the inverter as it did on shore power. I'm not even sure what I mean by 'not as well,' but it seemed to run longer and work harder to maintain temperature when running on the inverter. It wasn't just the fridge that wasn't happy with the inverter. All appliances with an AC motor seemed to not do well.

I replaced the original inverter with a pure sine wave inverter after a few years and am satisfied that it made a significant difference in the original fridge. At that point, the original fridge was 10+ years old, and I suspected it had suffered from the years run on the modified sine wave, so I replaced it with a similar model shortly after the inverter. While the fridge may be my largest load on the inverter, it's worth it. I even added an ice maker to it this year, and it's a joy having a constant supply of ice that isn't a chore to maintain.

The moral: Get an inverter that puts out a good AC signal for major AC appliances.

Good luck!

Greg.

[bensolomon]

Do any of you know how many DC amps your fridge draws while cycling from the inverter?

[Simi 60]

Originally Posted by bensolomon

Do any of you know how many DC amps your fridge draws while cycling from the inverter?

Depends on the size and make

[chris mac]

Originally Posted by bensolomon

Do any of you know how many DC amps your fridge draws while cycling from the inverter?

The running draw is about 5.5 amps at 12 volt per fridge(I have 2) the startup surge is somewhere in the 40's. It happens just long enough for the digital readout to run up and immediately fall to the running draw.
But make sure your inverter can handle the startup surge. The first inverter I got was a pure sine 1500 watt Amazon special. It worked fine except couldn't handle the startup of both fridges together. A victron pure sine 1200 watt handles it fine
The watt draw should be listed in the specs for any fridge you look at

[akopac]

My 12V box uses 28-34 Amphrs a day and has radiant barrier , R36 insulation and good lid seal. 7 cubic foot fridge/1.4 cubic foot freezer. I am solar independent. In the tropics. Papeete now, previously stress tested at 100 air/ 90 degree water in Mazatlan. It’s an isotherm SP system, but doesn’t matter. It’s the insulation and door seal that does.
I would like to know the daily Amphrs for any store bought 110V box system with inverter combo to compare.

[GordMay]

Mini-fridge [< 5 Cu Ft] wattages vary [due to: ambient temperature, temperature setpoint, usage patterns, model efficiency, and storage capacity], but most [newer ‘Energy Star’] products require somewhere between 50 and 100 watts of power, and run for one third to half of the time [8 - 12 Hrs/Day].
However, during the startup process, the mini fridge may have a momentary spike in power usage, ranging from about 300 to 600 Watts.
This power usage, and daily usage duration, translate to about 400 – 1,200 Watt-hours, of daily energy consumption.
YWMV, so look on the specification plate/sticker.
Rated Power in Watts = Rated Voltage [Volts] x Rated Current [Amps]