Norcold vs. regular refrigerator

Greetings! Thes is my first post, although I've been searching the forums for a little while now. Bought my 45' Hershine about a year and a half ago--my first boat.

It's a 1987, and the appliances could use replacing--#1 is the Norcold refrigerator/freezer (model 461). Boy are they expensive...I know...I'd been warned about the whole BOAT acronym.

I'd love to be able to consider a regular AC refrigerator, since I'm usually plugged in or on my way to be plugged in somewhere. First question please: Has anyone else done this?

The drawback of course is that it doesn't work as long as I'm out on the water. Made me wonder about the possibility of an inverter for this. Would an inverter work on something like a big fridge/freezer? Additional info: I have an Onan 8KW generator.

I appreciate any kind assistance that is offered! Thanks,

Deb

M/Y Quijotesca

Yes.

You want an inverter. Aside from the reefer question, which you will soon figure out, there are simply too many of the things we take for granted in daily life that want 110 AC. If you had a 27 foot sailboat, the answers would be different, but in your class, get the inverter and then assess your power needs from there.

Welcome aboard.

Do you ever want to anchor out?
If not, carry on.
If so, you need to educate yourself about all of the power consumers on your boat, starting with your Norcold ac/dc fridge.
If you will absolutely, never, ever want to spend the night anchored out, you can populate your boat with all manner of ac only appliances.
If you will ever, even just for one night, want to anchor out, none of that AC sh*t will help. You will need bigger batteries, a big inverter, a big generator, and even with all of that, you will still wake up in the morning with flat batteries and will wonder why you ever wanted to try anchoring out.
Once you have a domestic fridge, or freezer, the necessity to keep it turned on and happily consuming huge amounts of AC power will rear its ugly head and keep you happily tied to docks wherever you go, even at wonderful resorts where you will happily pay their $3.50/ft/night.

Or you could go DC only, cut your house bank in half, anchor in free, quiet anchorages for weeks on end.

Wow, Keith! Quite the rant. I would suggest there is a middle course:

I claim no original inspiration; the energy philosophy of my boat was established when I bought it, and I have only extended those concepts.

I cook with a Wallas diesel stove and oven, heat with a cheery passive diesel parlor stove, and have two substantial isolatable battery banks, no generator. My lights are LED, and my major consumer is a dual-current Norcold. (Oh, yeah, phone/data chargers)

I am currently anchored out for the fourth night, with a total of six hours of run/charge time. The only inconvenience is that my hot shower has to wait until engine shutdown.

But I am looking forward to the Ketchikan Yacht club day after tomorrow.

Welcome DR.

Options:

1. Don’t anchor as kolive mentioned and get a nice domestic fridge.

2. Up your battery bank and get an inverter and get a nice domestic fridge.

3. Run your generator any time you are away from the dock and shore power. Lots of big boats do this and an 8kw genset will keep an AC fridge happy as well as most of the other AC appliance you may have on the boat. At 8kw, you will need to think carefully about which are running at any given time.

4. Spend the money on an AC/DC fridge and still likely need to up the size of your house bank.

An inverter would seem to be a standard item on a 45 ft boat even if the owner does not anchor out routinely. Just traveling from place to place the inverter would provide options for electrical use.

As to a residential AC refrigerator, most of the objections to their use do not apply to a boat which lives in marinas with shore power.

The battery bank should be sized to give at least four hours of power for the refrigeration. Shore power is not entirely dependable and it is nice to be able to continue to the refrigeration while shore power is being restored.

Bay Pelican said:

An inverter would seem to be a standard item on a 45 ft boat even if the owner does not anchor out routinely. Just traveling from place to place the inverter would provide options for electrical use.

As to a residential AC refrigerator, most of the objections to their use do not apply to a boat which lives in marinas with shore power.

The battery bank should be sized to give at least four hours of power for the refrigeration. Shore power is not entirely dependable and it is nice to be able to continue to the refrigeration while shore power is being restored.

Click to expand...

What he said.

Just a comment ref the thread title: there are several other AC/DC fridge brands... Norcold isn't the only one. NovaKool, Vitrifrigo, Frigoboat, etc. In case that matters.

-Chris

Deb, how will you use the boat? The fridge?

Getting back to the OP, I strongly urge you to get a copy of Nigel Calder's "Boat Owner's Mechanical and Electrical Manual". It will walk you through this whole topic. in detail, and in easy to understand language. Plus a wealth of other things. Much better place to start than random opinions of strangers on the internet. Then you can come back here better educated and understand and evaluate our responses much better.

Many folks soon tire of the dockside Zoo and prefer to anchor out when they can..

If the boat will actually be cruised , anchoring out is the O'nite choice for most.

The quality DC reefers have Danfoss cooling units which is very frugal on DC (battery ) use.

Yes dockside , aground in your own coffee grounds , with a 120 or240 power hose is an inexpensive solution with many dirt house items, but it leaves little alternatives if you wish to use the boat.

A 24-7 noisemaker does work but the lifetime overall cost is almost as much as a dock every night.

M>M,,,, marina to marina is a fine lifestyle some folks choose, eateries , a pool, golf and cable TV as desired.

An inverter will keep a house fridge running , while underway.


Enjoy!

DRocc said:

It's a 1987, and the appliances could use replacing--#1 is the Norcold refrigerator/freezer (model 461). Boy are they expensive...I know...I'd been warned about the whole BOAT acronym.

I'd love to be able to consider a regular AC refrigerator, since I'm usually plugged in or on my way to be plugged in somewhere. First question please: Has anyone else done this?

The drawback of course is that it doesn't work as long as I'm out on the water. Made me wonder about the possibility of an inverter for this. Would an inverter work on something like a big fridge/freezer? Additional info: I have an Onan 8KW generator.

Click to expand...

Congratulations on your boat Deb. That's a beauty, no doubt.
Yes, you can do this (replace your Norcold) with a standard AC refrigerator. Lots of boaters do that.

To power it we use either our batteries connected to an inverter, OR a generator, or plug in at a dock. The generator will also recharge your batteries. Additionally, your own engine's alternator will also put power into the batteries.

I wrote a series of articles on this topic recently that may be of help.
Powering the Refrigerator article on janice142

Now the suggestion to get Calder's is a good one too. He is an amazing guy -- knows loads more than I ever will.

Good luck. What you want to do is being done. It all comes down to money, and how you wish to solve the issue.

A less expensive refrigerator and a larger back-end to supply the power
OR
A more expensive refrigerator that negates SOME of the power supply issues.

Dollars to donuts, it turns out to be about the same $$ either way.

Just a general question....
I've heard house refrigerators don't like the motion on boats. Something about needing to be level to work properly.... I guess 'marine' units might be made differently ??
I do know we used a "dorm" fridge one time. Lasted about 1 season. But it was a cheap one too..
Ideas ??

As others have mentioned, lots to learn about the terminology. Most better units will have a comparable number based on a standard test and measured in kilowatts per day or per year. How you make and possibly store your power is a different subject. The point about comparing units actual power consumption is that while there is a difference in efficiency for most modern units, it's not a multiple.

Where this leads you to is how you generate and store your electricity. As an example, if you plan to anchor for weeks and live off solar and wind generated power, the efficiency of your refrigerator will be critical and can hugely impact your investment in wind, solar and batteries. Alternatively, if you cruise in an area where climate control (air conditioning) is required most of the time, then a continuous supply of generator power when underway means refrigerator efficiency is relatively meaningless. As with many here on the forum, I fall sort of in the middle. While I may anchor out for several days, my normal cruise mode is to only sit for a day or two before cruising a day. My boat is setup with a 900 amphour battery bank. I can usually sit for a day and only recharge the batteries when cruising the next. If I use the microwave (through the inverter) a fair amount, I may need a little generator time to recharge the batteries.

This fall I will likely be switching from my Norcold to a slightly larger apartment refrigerator / freezer ($600). Part of the motivation is frost free and a thermostat that holds temperature regardless of refrigerator contents. While my Norcold still works, it's getting old and the non replaceable door seals leak. While I believe the power consumption with the apartment refrigerator running though my pure sine wave inverter, will be about the same or better than my current refrigerator, I feel I will get a better product (with modern conveniences) for about half the price.

Your situation and parameters will likely vary from mine, so you need to do your own evaluation. For me , the option has some very nice up sides and fits into my boats electrical systems without modification.

Ted

I have no problem with household applicances.

I think the Great Harbors all have household appliances, and noone can argue that they are dock queens.

What you need though is to as AKPROF indicated get an inverter if you plan on being away from shore power for any length of time. Or get a Generator, or both.

DC “marine” appliances are in my opinion over priced for the performance ytou get. They are tied to theold fashioned concept that a boat is a DC system.

That is just not the case any more.

Solar.

We have a apartment sized 10 cu ft fridge with icemaker on the boat. Powered by a 3000 MSW inverter or gen. 3 years in and in violent seas has been perfectly fine. Bought it at HDepot, made by Whirlpool. I installed the optional icemaker. Nice sized freezer on top, cold ice cream and ice.

Before that it was a GE model new in 1985.

A home fridge is not going to be as good as a marine fridge, it will make all sorts of noises, get rusty, spill water out the bottom, pumps will fail and the food get hot, paint will peel off doors, sheet metal is paper thin, have no decent warranty, technician will refuse to work on it cause its not latest model, too old to find parts, or they don't have a clue what they are doing, refrigerant will leak out of the lines, take a very long time to cool down the food, break down when you least expect it, the food will go flying off everywhere, the doors will fly open whacking your kid in the head, it will electrocute you when it gets wet, it will heat up the cabin, inside plastic parts will snap off due to violent boat rocking, no ice maker, no automatic defrosting, food gets buried deep into it and becomes lost. OH WAIT a sec, I am describing a marine fridge with a sea water heat exchanger...

"I've heard house refrigerators don't like the motion on boats. Something about needing to be level to work properly.."

40 years ago Propane reefers needed to be level , but that is long past.

Today if you dont roll lot of bed its levelenough.

Modest motion actually helps this style of reefer to cool.

The big hassle with house boxes is they are built to have the biggest interior , which reduces insulation space and forces the requirement to heat the insulation daily to keep it working.

K street has worked to keep the insulation heating electrical use out of the annual power requirement sheet , stuck on the door of new units.


Caviat Emptor.

One of the difficult things is figuring out exactly what the power consumption will be when operating off the battery.

Some appliances just don't have the amperage so we guess a bit.

12v is pretty simple:
If it's a 10 amp appliance, then you consume 10a running it for an hour.

120 is tricky (thru the inverter)
If it's a 10 amp, it will consume 100a of 12v power, plus the inefficiency of the inverter. How do we figure that?

If your battery is a 200 amp hr battery, you can only use 50% of that before needing a recharge so you have 100 amps to use.

So with the above 12v appliance you can get 10 hours of use.
With the 120v appliance you can get 1 hour of use, less the efficiency loss.

Does this sound right?

====
Now, when we figure out our need, we can figure out how big of battery bank we need to operate between charges.

I'm currently in the process of trying to figure out how to increase my battery bank (different post).

For the OP, once you know your power needs, you'd be able to figure out what supply you need.

FF said:

K street has worked to keep the insulation heating electrical use out of the annual power requirement sheet , stuck on the door of new units.


Caviat Emptor.

Click to expand...

Fred,
The defrost cycles are included in the power consumption for the Energy Star Label. The testing procedures are clearly outlined in this document to include the cost of Frost Free electricity usage in the annual power consumption estimate.

https://www.ecfr.gov/cgi-bin/text-i...a7ce86&mc=true&node=ap10.3.430_127.a&rgn=div9

Ted

Seevee said:

One of the difficult things is figuring out exactly what the power consumption will be when operating off the battery.

Some appliances just don't have the amperage so we guess a bit.

12v is pretty simple:
If it's a 10 amp appliance, then you consume 10a running it for an hour.

120 is tricky (thru the inverter)
If it's a 10 amp, it will consume 100a of 12v power, plus the inefficiency of the inverter. How do we figure that?

If your battery is a 200 amp hr battery, you can only use 50% of that before needing a recharge so you have 100 amps to use.

So with the above 12v appliance you can get 10 hours of use.
With the 120v appliance you can get 1 hour of use, less the efficiency loss.

Does this sound right?

====
Now, when we figure out our need, we can figure out how big of battery bank we need to operate between charges.

I'm currently in the process of trying to figure out how to increase my battery bank (different post).

For the OP, once you know your power needs, you'd be able to figure out what supply you need.

Click to expand...

Unfortunately, that's not how it works.

Some units have very small compressors with low power consumption but run for longer time periods. A unit with a larger compressor and higher amp draw may have a much shorter run time and actually use less power in a 24 hour period. Insulation plays a huge part in total power consumption, but isn't reflected in the refrigerator's voltage or amperage draw.

Measuring actual power consumption over a standard time period is the only reliable way to know how much power a unit will consume. Clearly RV and boat appliance manufacturers need to be required to provide an Energy Star Label like home appliance manufacturers.

Ted

Seevee said:

12v is pretty simple:
If it's a 10 amp appliance, then you consume 10a running it for an hour.

120 is tricky (thru the inverter)
If it's a 10 amp, it will consume 100a of 12v power, plus the inefficiency of the inverter. How do we figure that?

If your battery is a 200 amp hr battery, you can only use 50% of that before needing a recharge so you have 100 amps to use.

So with the above 12v appliance you can get 10 hours of use.
With the 120v appliance you can get 1 hour of use, less the efficiency loss.

Does this sound right?

Click to expand...

The same appliance, using the same amount of energy over a given time period, will draw 1/10th the current at 120VAC than at 12VDC (in a perfect world), so absent the losses of the inverter, the energy drawn from the battery bank will be the same. So 1A at 12V for one hour is 1 amp-hour (1Ah - voltage is implied), or 12 watt-hours (Wh) of energy. The same unit in an AC version would draw 0.1A at 120V (perfect world), which is also 12 Wh, but reflected back through the inverter, it will be 10 times the current at 1/10th the voltage from the batteries for 1Ah; still 12Wh of energy, too.

Inverter losses depends on the unit, but a conservative number would be 80% efficiency, so divide Wh or Ah by 0.8 to bump up the actual draw from the batts accordingly.

Deb:

Our boat came from the builder with a 14 cu ft, 115V AC "domestic" fridge. A few months ago we went thru the same exercise as you, to answer the question, should we replace our 12 year old fridge and if so with a 12V or a new 115V. We tested our existing fridge, and found that it was using an average of 1.7KWH of power per day. Because our inverter is 90% efficient, if we power it from the batteries it uses 1.9KWH per day. In a previous thread on this subject, I asked if anyone had tested their 12V fridge to determine how much energy it was using, but didn't get a reply.

115V domestic fridges sold in N. America have an "Energy Star" rating. www.energystar.gov. When choosing a new fridge, you can use this data to decide which size, features, configuration, etc you prefer. Energy Star is a voluntary program, and 12V fridge makers have chosen not to participate.

When deciding on a new fridge, there is a few principals to keep in mind.
1. All fridges, regardless of voltage, require defrosting. A buildup of frost on the coils will drastically reduce efficiency. Defrosting costs energy, either by briefly heating the coils as happens in a "frost free" fridge, or by leaving the door open until the frost melts in a manual defrost version.
2. From the Energy Star data, you will see that the amount of energy used by a fridge is in direct proportion to the size of the fridge. A 14 cu ft one, will use approx twice the power of a 7 cu ft. Also from Energy Star data, you will see that new fridges use much less energy than ones manufactured even ten years ago.
3. There is no free ride. All fridges use a compressor turned by either a 12V DC or 115V AC electric motor. The only difference is the 10% energy loss if powering a 115V fridge from batteries thru an inverter. A small motor/compressor that needs to run nearly continuously will in the end use just as much power as a large motor/compressor which runs only briefly. Where there is a difference is in the thickness of insulation, quality of the door seal, and its ability to keep frost off the coils (which is why all the top Energy Star rated fridges are "frost free" models).
4. As you have noticed, there is a huge difference in price and features between 12V and 115V fridges.

If you don't already have an inverter, I suggest that you install a pure sine wave one. Besides a fridge, they will also power a coffee maker, toaster, microwave, TV etc.

"Some units have very small compressors with low power consumption but run for longer time periods. A unit with a larger compressor and higher amp draw may have a much shorter run time and actually use less power in a 24 hour period"

The DC fridge folks all agree that as the heat slowly enters the box , the best way to remove it is about the same rate. Pro Boat Builder,

If it were up to the DC fridge builders the unit would operate 24/7 , at a very low pulse rate , for best efficiency.

They tried but were hit with too many calls "this thing is broke , it never shuts off".

A big hammer of a unit is only efficient at air cond , taking a warm box down to refrigerator or freezer temps.

Then the slow release of heat from foodstuff and the insulating value of water making ice slows the cooling process a great deal.

Even eutetic systems will use more energy with a big compressor , and not freeze faster because of the ice forming on the internal tubing.This has been solved , but it is too expensive to manufacture in tiny quantities..

The pulsing DC units that learn the box are the most efficient in power use today.

Even the off grid folks with the bucks and room for a Sun Frost usually choose DC .


Energy Efficient Refrigerators - SunFrost.com

www.sunfrost.com/all_efficient_refrigerator_models.html


Sun Frost refrigerators and freezers are so outstandingly energy-efficient, powering a home with solar power or other low output energy sources is both feasible ...

We turn our inverter off at night when at anchor. Boy does that cut down on transient 110 draws. God bless our 12/110 V refrigerator which averages less than 4 amps per hour.

But plenty of boats out there that have SubZeros on board and run their genset a lot. There is no magic answer as to how one chooses to power the myriad of reefers available. Depends on how many pounds of fish you carry around too!

Our boat had a Norcold when we purchased it used back in 2005. For our use, it was horrible. Just the remembrance of defrosting, what a BPITA. And a marine fridge may be more efficiencent but of course some of that efficiency is because YOU have to do the defrosting.

I replaced ours with an 8.3cuft Summit which unfortunately is no longer available. It continues to exceed our expectations. OK, as everyone knows, a marine unit may operate with a higher efficiency...maybe! But it still requires power, there are no free lunches.

Before I made the change to Summit, I found that the Norcold discharged 2 huge group 8 batteries while on anchor over a weekend. And yes I ran our generator for what seemed to be hours and hours. So there the marine fridge offered no salvation. More attention to our boat’s system was urgently needed. The first step was to add a modern multistage charger, I purchased a Xantrex 5012 (or is it a 1250?) which out preformed that old style charger that came with the boat.

Moving on with our Summit and the Xantrex, we still could not keep the batteries charged running the genny for hours and hours. So it mattered not which fridge style we used. An improved battery bank and charger was required. As I type, I have a two banks operated in parallel of golf style batteries that provide a total of 860 amp hours plus 4 each 295 watt solar panels capable to provide almost 1200 watts plus a 3KW true sine wave inverter. We rest comfortably on moorings or our anchor for weeks without problems. The genny is used for coffee in the mornings plus to recharge a 24v battery bank which is used for a couple of 32” TVs at night and for our 24vdc windlass. The 24v system uses an old Freedom inverter/charger to make the 120vac.

The 3KW sine wave inverter runs 24/7 although it is toggled on via a relay to the boat’s AC power system only after the loss of dock/genny AC power.

My apartment sized fridge 10.7 cu ft uses anywhere from 0.9 to 1.1 amp 120 vac while running the compressor.
The defrost heater kicks on, not very often and maybe 4 to 6 amps for a short time.

It has been a very nice experience so far. Not an arm and leg to buy and has needed no repairs. I paid $400 for it during a july 4th sale or some other holiday, and it has an automatic ice maker I installed myself which I had from some used fridge of another make. Pretty much those are all the same.

I had to modify the wood cabinet to make it fit, I do all my own work. OEM, the cabinet had been used with some kind of marine fridge long ago, and had lots of wasted interior space with unuseful wood pieces running here and there. Now it can handle many models of fridge about this size. Doors can be set to open either way. But watch out for the delivery guys, they are real rough on stuff. I had it delivered to my house and they had bent the bottom support plate that holds the wheels which I had to straighten. I tell you they don't really care it seems until they show up at your door, then they seem to care.

The new design fridges weigh much less than the older ones. So much easier to move onto a boat.

https://www.homedepot.com/p/Whirlpo...AiKOEALw_wcB&dclid=CLn2st7x59wCFVgLNwodhmoKcA

I made the white metal bracket from my old fridge shelf , welded modified, epoxied and painted or some such. The freezer only comes with one shelf for an ice maker bucket.

Our 6 cf dorm fridge with separate freezer compartment and door* is drawing a little less than 1A right now, with the compressor running. Power is only 100W, give or take a little (PF is 0.85, which is where the discrepency is).

At my marginal cost of $0.10/kWh all-in, it's projected to cost about $3/month, based on run time in a 24 hour cycle and the readings on a Kill-A-Watt. It's in my garage, out of the sun, but into the 80'sF by day, and 60's at night. For island power of $0.65, cost would obviously be 6-1/2 times higher, or $20/mo.

I suspect you dropped a zero or didn't move the decimal point one place.

*no automatic defrost, and not 'frost free', so no heaters.

Just replaced our old Norcold with an Isotherm. Cold-plate technology = 1/3 the power consumption (according to the paraphernalia). Works great AC or DC and draws less current than the old Norcold.