Dedicated inverter for refrigerator

ranger42c said:

That'd be a nifty feature. It'd be even niftier if builders of typical AC/DC marine fridges (NovaKool, Vitrifirgo, Norcold, etc.) included both frost-free and a control switch like that. I'm not aware of any frost-free AC/DC fridges...

-Chris

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I am under the impression that "frost free" is actually a heat cycle and that is a fairy high draw which is why it is not included on marine fridges. I guess they could have a frost free cycle on AC power only. That would be nice.

Baker said:

I am under the impression that "frost free" is actually a heat cycle and that is a fairy high draw ............. .

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Yep.

makobuilders said:

However using simple logic, during time away from the boat the refrig may operate for only a few hours per day. During the rest of that time the inverter is in idle yet the big unit is burning 1/3+ kilowatt per day in idle alone! The small, dedicated one about 1/10 kw..........

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That's what I keep trying to tell people.

A marine refrigerator is built to be as efficient as possible for the price. Spend more and you can usually find a slightly more efficient model.

A residential refrigerator is not usually as efficient because there's an endless supply of electricity.

makobuilders said:

I looked at the 800w and 3000w models. The specs sheets show maximum efficiency (low 90%'s) and no-load power draw (about 8 and 20 watts). I don't see anywhere in their specs about sweet spots. Maybe a quick call to tech support can answer that.

However using simple logic, during time away from the boat the refrig may operate for only a few hours per day. During the rest of that time the inverter is in idle yet the big unit is burning 1/3+ kilowatt per day in idle alone! The small, dedicated one about 1/10 kw.

I think I just answered my own question

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Its a lot like an internal combustion engine. If you're idling, the smaller displacement the better. Otherwise best run at peak torque.

"I am under the impression that "frost free" is actually a heat cycle and that is a fairy high draw ............. ."

And due to some bucks spent on K street , the melt cycle is not counted in the KW per year on the info sticker.

Baker said:

I am under the impression that "frost free" is actually a heat cycle and that is a fairy high draw which is why it is not included on marine fridges. I guess they could have a frost free cycle on AC power only. That would be nice.

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Yep, agree, when AC is available from shorepower or genset, feeding the frost-free feature would be "cheap" in the grand scheme of things.

-Chris

Seen many leave the 12v/120vac frig/freezer to go with a basic household unit and run an inverter while cruising etc, they price difference was substantial and quality not much different.
Our boat frig/freezer was only 110vac, we installed a inverter so when we are on long runs the frig is kept up, then while on the hook it runs off gen when that's on in morning and evening.

Mako, I think I understand what you are trying to figure out but it's a little more complicated. I have the data from victron but see no way to upload it from this phone. It's all on the website. The toroidal transformers have less loss at the low end of the output scale. Whether it allows you to overcome the idle losses is going to require you to do a more complete energy use audit.

Marlinmike said:

Seen many leave the 12v/120vac frig/freezer to go with a basic household unit and run an inverter while cruising etc, they price difference was substantial and quality not much different.
Our boat frig/freezer was only 110vac, we installed a inverter so when we are on long runs the frig is kept up, then while on the hook it runs off gen when that's on in morning and evening.

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I went the other way. I got rid of two household fidgerators and replaced them with 12V only Vitrifigos with no freezer compartment. The old units were working fine but when I removed them to rebuild the cabinetry housing them I found their sides almost too hot to touch. These units dissipated heat through their side panels rather than their bscksides, not a good thing for efficiency. Perhaps there are 110v household fridges that have their coils in the rear rather than embedded in side panels. My advice, then, if one chooses to use household fridges make sure the coils are in the rear, a much more efficient design for the small enclosures often found on boats and also often not well-ventilated. I won't get into the 12v only vs 12V/120v discussion. I see pluses and minuses for both.

Good point about the condensing coils. I've read threads where the guy opened up the case and relocated the coils outside the cabinet, which required soldering and recharging. That's too much work!

I am currently running a Magic Chef 4.6 cuft fridge from Home Depot that replaced my old Norcold that died. So far I'm very happy with the install. I also replaced a dead U-Line ice maker with one from Home Depot. I have them both wired to run off my refrigerator AC breaker. In order to run these while on 12v I installed a Kisea 2 KW inverter. We anchored out with this setup a couple of weeks ago and everything worked well. The new fridge pulls less power than the old NorCold did and the inverter pulls .25 amp per the paperwork. We even ran some 120v fans during the night to circulate air and all was well. (The digital amp display on the inverter didn't even register the draw of the little Walmart fans). To say I'm happy with the cost and performance of this set up would be an understatement. Oh yeah, the fridge sometimes has quite a power use surge when starting up after being without power awhile. Maybe because it was new as it hasn't done it again for a while but the 2 KW inverter handled it OK.

Kevin

Marlinmike said:

Seen many leave the 12v/120vac frig/freezer to go with a basic household unit and run an inverter while cruising etc, they price difference was substantial and quality not much different.
Our boat frig/freezer was only 110vac, we installed a inverter so when we are on long runs the frig is kept up, then while on the hook it runs off gen when that's on in morning and evening.

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Even the low end boat manufacturers use 12/120 volt AC/DC refrigerators. They could lower the price with a 120 volt "dorm" refrigerator and a cheap inverter but they don't.

I'll be they have a good reason.

WesK said:

My former boss used to say "Engineers dream things up, technicians make them work."

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Reads like you're a technician

First of all, if you're going to have refrigeration away from the dock and do not want to run a generator continuously, you must solve the battery recharge problem. My solution consists of 4 each 150 watt solar panels plus the running the genny primarily for hot water.

I began using a dedicated 1KW Xantrex sinewave (%$#@*) priced then at $500 for my 8.3cu ft fridge with self defrost. I configured the power circuitry for the fridge to switch (relays) to the inverter whenever dock or genny power was absent. The inverter runs 24/7. The only reason I can think of for not using an inverter directly to power the fridge 24/7 is that if the inverter fails, refrigeration fails even if dock/genny AC is available.

The Xantrex used to belch every time the fridge entered into self defrost mode about 800 watts plus surge. This was ok by me until the Xantrex just quit. Good reason for having auto switching power sources.

I cringed thinking about spending big bucks at that time for a bigger/better inverter and went to a 2KW true sine cheapie from Ebay. This inverter takes care of the fridge, microwave and TVs. I also have an old 1KW Freedom inverter charger for my 24vdc battery bank. That provides power for our lighting......again with relay power switching.


EDIT: My fridge is a $500 Summit apartment size that I purchased to replace an old POS so called marine refrigerator.

Since you are directing this at my quote I'll reply. For a new boat most manufactures want to say its a 12v/110vac auto switching and the $1000 difference in very minor in a NEW boat price.

Now roll the tape to say 20 years later and 3rd owner, refrig conks out, do you want to spend $1000 more for the 12vdc benefit??

My posts is a data point to the original OP, just to give something to think about, I never say this is what you should do, but if you think because it says marine on the label therefore is better, I have a bridge to sell ya!

WesK said:

Even the low end boat manufacturers use 12/120 volt AC/DC refrigerators. They could lower the price with a 120 volt "dorm" refrigerator and a cheap inverter but they don't.

I'll be they have a good reason.

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Marlinmike said:

............but if you think because it says marine on the label therefore is better, I have a bridge to sell ya!

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I said nothing about being "marine", I said that if a dorm or household refrigerator and inverter were equivalent to a dual voltage refrigerator, the low end manufacturers (or all manufacturers) would be installing them in boats.

Marlinmike said:

Since you are directing this at my quote I'll reply. For a new boat most manufactures want to say its a 12v/110vac auto switching and the $1000 difference in very minor in a NEW boat price.

Now roll the tape to say 20 years later and 3rd owner, refrig conks out, do you want to spend $1000 more for the 12vdc benefit??

My posts is a data point to the original OP, just to give something to think about, I never say this is what you should do, but if you think because it says marine on the label therefore is better, I have a bridge to sell ya!

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Wes--- My thumbs were NOT directed at you, they were for support of non-marine products for use on a boat

Still don't understand, you think Searay wants to put all that in, or just slide a unit that is already multi use ready. I've looked at the electronics of a dual mode refrigerator and its truly nothing great. Real details next time rather then "because they do it must be..."

WesK said:

I said nothing about being "marine", I said that if a dorm or household refrigerator and inverter were equivalent to a dual voltage refrigerator, the low end manufacturers (or all manufacturers) would be installing them in boats.

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Marlinmike said:

Still don't understand, you think Searay wants to put all that in, or just slide a unit that is already multi use ready. I've looked at the electronics of a dual mode refrigerator and its truly nothing great. Real details next time rather then "because they do it must be..."

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Following your logic, they could cut the cost of the boat by a thousand dollars and make it more competitively priced.

If you've convinced yourself that a separate inverter, running 24/7 is better than a dual voltage refrigerator, that's fine for you. I don't think that's the best solution and apparently, neither do the boat manufacturers.

WesK said:

Following your logic, they could cut the cost of the boat by a thousand dollars and make it more competitively priced.

If you've convinced yourself that a separate inverter, running 24/7 is better than a dual voltage refrigerator, that's fine for you. I don't think that's the best solution and apparently, neither do the boat manufacturers.

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Yes indeed, they not only could use a separate inverter running 24/7........maybe not cutting cost by $1000 but by providing a better product. The idea of spending $1500 for a run of the mill so called 'marine' refrigerator that lacks basic features commonly found in most homes today is ludicrous! No refrigerator manufacturer would even consider trying to sell units that lack simple interior lighting or self defrost features.

I see two reasons why marine junk commands high prices. First is there is a small market for their products and second because too many believe if it lacks the word "marine" in its nomenclature, many will not purchase the product.

foggysail said:

I cringed thinking about spending big bucks at that time for a bigger/better inverter and went to a 2KW true sine cheapie from Ebay.

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Hey Foggy, how is your cheapo inverter holding up, and for how long has it been operating?

Yes this is where we agree, I didn't say better (relative word) and indeed takes a little more thought on how switches are etc, which when selling a boat (and I'm not talking Flemming or Norhavn) but the vast numbers of production boats keeping operations simple - sells.

I lost count the number of times I helped a fellow dock mate hump his/her Norcold refrigerator off their boat because it crapped out...

There is a very smart group of people on the forum (far smarter then I) and have had great conversations on compressor types/cold plates/insulating/amp hours etc, in most cases these superior systems were not marine off the shelf products.

WesK said:

Following your logic, they could cut the cost of the boat by a thousand dollars and make it more competitively priced.

If you've convinced yourself that a separate inverter, running 24/7 is better than a dual voltage refrigerator, that's fine for you. I don't think that's the best solution and apparently, neither do the boat manufacturers.

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Holding up quite well. My microwave operates as if it was powered from dock power. Microwaves are very sensitive to both waveforms and frequency. This is because most that I am aware of use what is know as a constant current transformer although with the advent of newer electronics, I suspect they may eventually be phased out.

Heck, my fridge operates quietly and reliably! Since my adventure with Xantrex, I understand there are numerous, good quality, reasonably priced inverters out there in the market. This particular inverter has about 3 years of running history so far.

"! No refrigerator manufacturer would even consider trying to sell units that lack simple interior lighting or self defrost features."

House stuff has power on in almost unlimited quantities 24/7/365.

Boats that are untied do not.

FF said:

"! No refrigerator manufacturer would even consider trying to sell units that lack simple interior lighting or self defrost features."

House stuff has power on in almost unlimited quantities 24/7/365.

Boats that are untied do not.

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Sure, your post is absolutely correct. Home style fridges do consume additional power because they provide additional features than those sold under the banner of "marine." But boats with either face the same challenge when untied.

There are choices, one can spend upwards of $1500 for a marine style without self defrost. The benefit here is no inverter is required. The other choice is to spend less than $1000 for a home style including a decent inverter and have the features people consider important in their homes.

It is simply a matter of individual choice.

foggysail said:

First of all, if you're going to have refrigeration away from the dock and do not want to run a generator continuously, you must solve the battery recharge problem. My solution consists of 4 each 150 watt solar panels plus the running the genny primarily for hot water.

EDIT: My fridge is a $500 Summit apartment size that I purchased to replace an old POS so called marine refrigerator.

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" It is simply a matter of individual choice."

And how much you chose to entertain the anchorage with your noisemaker.

Some folks believe a noisemaker has an all up cost of $5.00 to $10.00 per hour of operation ,

so savings from a dirt house reefer could be hard to realize if you spend almost any time on the hook.

EDIT: My fridge is a $500 Summit apartment size that I purchased to replace an old POS so called marine refrigerator.[/QUOTE]

FF said:

" It is simply a matter of individual choice."

And how much you chose to entertain the anchorage with your noisemaker.

Some folks believe a noisemaker has an all up cost of $5.00 to $10.00 per hour of operation ,

so savings from a dirt house reefer could be hard to realize if you spend almost any time on the hook.

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????????????? Did you read my previous response????

MY MARINE GENERATOR-----YOUR REFERENCED NOISEMAKER----operates for about an hour in the mornings to heat hot water. Maybe again during dinner hour if Wifey wants to use our electric stove.

And more general information ,,, my panels start changing at daybreak and continue until sun set. IF THE BATTERIES will accept charge (not in float mode) the panels charge at 23-25 amperes from about 9AM until after 3-4PM. I HAVE NEVER had a battery charge situation since installing solar.