Voltage Converter For Refridge

[scarlet]

We just bought a 2011 Lagoon 450, and the refrigerators will probably need replacing as they barely keep things cold, and it takes close to 8 hours to freeze an ice cube in the freezer compartment. I've been looking at the marine variety, and they are outrageously expensive, and some of them look like they are cheaply made... So, I got to thinking... Why can't I go out and buy a nice undercounter one for the home?

We've had one in our home for over a decade... it is beautiful quality... and under $300. The only issue I see is the 110 vs. 12 volt issue. So, I'm wondering whether I can use a 110/12v converter to plug in the refridge?

https://www.sears.com/isaddle-110v-a...1&blockType=G1

Full disclosure, I'm not very knowledgeable about anything electrical, but we use converters all over our boat (because it's European wired), so I'm thinking, why not for the refridge, too? I haven't pulled the refrigerators out yet, so I don't know if they are hardwired, or if they plug in, but if they do plug in... wouldn't this work? And, if they get hardwired... is there a way to use a converter to somehow step it down?

At the cost difference, I could buy a half dozen home refrigerators for the cost of one marine one, (plus I just like the home ones better.. they just seem to be much better quality.. )

Can someone advise me if this would work?

[tkeithlu]

We use an ordinary apartment sized refrigerator/freezer. It runs off the inverter at night, and has been the source of problems for us. The startup of the compressor motor tends to drop the battery voltage below the minimum for the inverter, it cuts off, and the alarm then interferes with our sleep.

So, the concept works, as does the broader matter of having a 120v AC circuit in the boat. Our AC can be supplied by shore, genset, or inverter, but what can come off our inverter is limited; no air conditioning, for example.

Do explore your battery capacity, inverter size, wiring gauge, and any other issues regarding current draw in getting into this, but yes, you can use home and RV appliances in a boat.

[sailorboy1]

have you done the simple common things like checking your seals and cleaning filters and condenser coils

[capt jgw]

The 12 volt marine refrigerators draw around 5 or 6 amps when they are running. A 120 AC under counter fridge might draw 1.5 amps at 120 volts which sounds good until you do the math. 5 amps at 12 volts is 60 watts. 1.5 amps at 120 volts is 180 watts, so three times the draw. An inverter can easily output 180 watts but it will have around 10 percent loss so call it 200 watts. Divide by 12 to get the running amps, it comes out to 16.6 amps. When the compressor starts up it takes two or three times the running amperage to start, so call it 48 amps start up for about a second, then 16 amps continuous after that. And it will be running most of the time. So it can be done with a moderate sized inverter, but the power draw is significant. The only other way to power it is to have a generator running or be plugged in to shore power 24/7, and who wants to do that. That's why the boat builder installed marine units instead of household ones. I looked at doing this, but I can't afford the power drain.

[john61ct]

Soon as you're off grid unless you like running the genny a lot,

energy efficiency is a huge priority in selecting appliances.

Spend a couple grand on a good 12V compressor fridge,

or if you have spots for a couple matching Engel portables, can choose / switch whether in freezer or fridge mode.

Yes some Euro or Aussie mains-powered units are as efficient, but not available in 120V since industry captured our regulators.

And need full sinewave inverter sized for the compressor startup surge, good ones cost more than the fridge, and do add to the energy draw in conversion.

There are threads on converting to a 12Vdc thermostat to power the inverter up/down as needed, but bit of a science project compared to just getting a good native DC setup in the first place.

[tkeithlu]

There is a big energy budget question here, and I ignored it, for which I apologize. I forgot that while I have a budget, my energy resources are greater than those of a Lagoon 450.

[a64pilot]

You can do it, and they aren’t as inefficient as many suppose.
There is an efficiency loss in conversion and 10% is a pretty good number to use, you can do better with a single specific inverter that is high quality and sized correctly but there will still be a loss.
DC is not more efficient than AC, if your drawing more power, it’s because you getting better cooling and or you have poor insulation.

If your mostly in Marina’s no problem, it will work great, if your mostly at anchor you can still do it, but how much Solar do you have?
If you spend significant time at anchor your going to need Solar anyway.

[Big Joe Bob]

[QUOTE=scarlet;2958454]We just bought a 2011 Lagoon 450, and the refrigerators will probably need replacing as they barely keep things cold, and it takes close to 8 hours to freeze an ice cube in the freezer compartment.

Have someone take a look at it, we had a similar problem and found out our fridge was OVER gassed, now it works perfectly.

Cheaper than a new fridge

[alamoana]

I would check the gas as others have stated, you may have too much, too little (a leak), or not enough insulation or for gaskets not sealing.
And a household fridge via inverter will work perfectly, just a matter of wiring for start up loads.
Good luck

[stormalong]

Another negative of house type refrigeration is self defrost. This periodically turns on a heating element to melt any frost that has accumulated on the evaporator. That uses a lot of power and adds heat to the refer.

[accomplice]

Another thing to consider is how you can keep a land-fridge latched shut while underway.

[scarlet]

Originally Posted by sailorboy1

have you done the simple common things like checking your seals and cleaning filters and condenser coils

Not yet. We closed on the boat at the end of July, spent about 5 days on it, then had to come back to Kansas. I'm going back this weekend, and I'll take a look at the maintenance above whilst I'm out there.