AC powered refrigerators

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
Captain K

Captain K

Senior Member
Joined
Mar 19, 2012
Messages
315
Location
USA
Vessel Name
GITANA
Vessel Make
Sea Ranger 47 Pilothouse
When the time comes to replace our old Norcold AC/DC refrigerator, I'm considering following the lead of several friends and going with an AC powered unit designed for home use. Any thoughts, experience along these lines out there? Suggestions welcomed!
 
I think it depends on how you plan to use the boat. PO of our boat installed a 120v. fridge, apartment size, probably about 12 cu.ft. We are marina rats, so do not worry about power use on the hook. We have a Honda 1000 gas genset that keeps it cold under way, but I would not want to run a genset or inverter all the time to keep it cold 24/7.
 
My fridge (full size) is 120 v only. It runs on a 2000 watt inverter and a battery bank of 4 6V golf cart style.
We had no problems running it 24/7 on our summer long cruise.
 
Greetings,
Same set-up as Mr. jleonard but 3Kw inverter, 110 amp Balmar and 6 golf carts. No problems what-so-ever.
 
RT Firefly said:
Greetings,
Same set-up as Mr. jleonard but 3Kw inverter, 110 amp Balmar and 6 golf carts. No problems what-so-ever.
Click to expand...


3100W inverter, (10) 6V cart batteries running a 110V fridge and a 110V ice maker 24/7 = no problems. What you save on the fridge would buy you many additional batteries.
 
For those of you that are using batteries. What is the draw with your inveretors?
 
meridian said:
For those of you that are using batteries. What is the draw with your inveretors?
Click to expand...

The draw is going to be specific to the fridge, how full it is, how often the door is opened, if there is adequate cooling for the coils, etc. There is no magic in 110V vs 12V. It takes power of either variety to produce cold. 12V in general tends to be slightly more efficient but the conditions I just sighted will trump unit efficiency. Insulate and fill any fridge and the efficiency will go way up
 
I don't see any reason not to use a 120 volt AC fridge, as long as its not a cheapo cheesee looking unit.

If you have the space for a regular household fridge that fantastic. Most boats seem to have good house battery banks and inverter setups so it should be no problem.
 
With all those batteries what size/type charger system do you have?
 
Andy G said:
With all those batteries what size/type charger system do you have?
Click to expand...

I don't know who you are directing the question to, but we have a
3100W-160amp Magnum inverter/charger. We also have a 7.7KW Westerbeke genset and two 108amp alternators on one engine and one 70amp alt on the other. Fortunately power just is not much of an issue for us anymore.
 
One thing to remember about inverters, they don't last forever. I run a 16,000 btu AC unit off a 5,000 watt inverter in my charter boat. The AC draws around 10 amps running with a 80% duty cycle 4 to 10 hours a day 5 days a week for 4 months per year. The system is powered by a 240 amp Leece-Neville alternator and works very well. The system only runs when the engine runs or the boat is tied to shore power. My inverters usually last 4 or 5 seasons and then catastrophically dies. If I was going to run a fridge off an inverter and didn't have a generator, I would definitely think about a back up inverter or plan B for the eventual failure while cruising.

Ted
 
My approach to the refer/fridge problem will almost certainly NOT appeal to members here.

Refer

I need cold beer. And frozen steaks.

Works for me, under 50 amp/hrs a day at anchor. I’m going the solar panel route this year as a back up. I may never need to come back to land.

Ah, except where do I get the steaks? And the beer, and the diesel, and this stuff the Admiral calls salad?

Mike
 
Vixen II has a 11.5 cu. ft Fridgidare household 120 V. unit. The inverter is a 3Kw Charger/Inverter. This coupled with our 8 Kw Northern Lights genset and substantial battery bank has provided seamless power either at the pier or out and about. I find this combination works well. The little Norcolds and their ilk just do not provide enough cold space for full time living aboard (my opinion - when steak and chicken are on sale - fill the freezer...) Also have changed out the dinky alternator on the genset to a delco 105 Amp alternator - this helps speed the recharge times.

The biggest problem with the household unit was getting in place - required removal of all of the teak trim pieces IOT provide the 24" width required. Had to buy a new art poster to cover the deep scratch on the panel = wife not happy with that but loves the new fridge.
 
Captain K said:
When the time comes to replace our old Norcold AC/DC refrigerator, I'm considering following the lead of several friends and going with an AC powered unit designed for home use. Any thoughts, experience along these lines out there? Suggestions welcomed!
Click to expand...

My suggestion - Don't do it. Stick with an AC/DC refrigerator. Buy a Nova Kool or Isotherm. These are more efficient than houshold refrigerators and are much simpler to install and operate.

If you run a genset 24/7, then it's not important. If you are counting on battery power, the AC/DC models are your best bet.
 
One of the Norcolds on Gray Hawk died shortly after we bought her. We considered various options and settled on the largest domestic fridge we could physically get onboard. That was hands down the best decision we have made since we bought the boat. At anchor it runs off the Freedom 25 inverter, when we run the inverter, but it will keep things frozen all day with only a couple hours of gen run time, which would happen anyway.

If you only use the boat for weekends and a few weeks of holidays then maybe the Norcolds will suffice but for serious use you can't beat a real fridge and freezer.
 
We have used AC fridges and they are great. This is the second boat with one. We just purchased on at sears for under $500.00 16.0 cu ft with an icemaker. The model we replaced on the boat was 15 years old. it was still working just wanted a black one to match other appliances. Runs on inverter when genset not running. Can't see spending alot more on AC/DC. If it ever breaks any sears repair service can fix. Doubt we will ever need it. A 7.0 cu ft Norcold is $1,300
 
I agree with Baypoint... I can replace/upgrade our Fridge every three years, if necessary, and still come in with lower costs and twice the capacity. If they made an ice maker version in this size unit - I'd be there in the next upgrade. And, I don't think the extra electrical usage of a 120 V. unit via inverter is that signifigant when it is included with all the other stuff we use - ie; sound systems, tv, computers etc. As .an aside... our current fridge runs on about a 30% duty cycle which I think is typical. Even down here in the warm country.
 
Many thanks to all for the very useful comments. I'm going with an AC unit for sure. Thanks again to all!
 
Whatever works for you...I want to switch to a commercial fridge also...not worrying about running the genny as I like pissing off the entire anchorage (which is only me cause that's the point of being in an anchorage)...:D

But space limitations, boat mods, etc....may keep you on the 12/120V track. But is you want to switch...there's no magic buttonthat says one is better than the other.

One day...if I go propane for other reasons...a propane fridge may be in the works too.
 
Captain K - we have the same boat - hope you don't have too much trouble removing the nice little shelf above the Norcold (Nevercold?) Our boat was already equiped with a similar, but very rusty and not working..., unit. Just measure the clearance -trim to trim - IOT install the next 120V. You will be happy!
 
Daddyo said:
The draw is going to be specific to the fridge, how full it is, how often the door is opened, if there is adequate cooling for the coils, etc. There is no magic in 110V vs 12V. It takes power of either variety to produce cold. 12V in general tends to be slightly more efficient but the conditions I just sighted will trump unit efficiency. Insulate and fill any fridge and the efficiency will go way up
Click to expand...

I hate to be a stickler, but I like helping with the right information when I can. Refrigeration systems do not make cold air. The air in the space that a unit is designed to service is drawn into an evaporator, and the heat from that air is given to the refrigerant flowing through that evaporator. That heat causes the refrigerant to flash to a gas, goes to the compressor, then the hot gas is pumped to the condensor where the heat is given off and the cycle begins again. So essentially, we just keep removing heat until the air temperature is where we want it. I have studied Psychrometrics pretty extensively, even in the realm of fluid mechanics, and this is the opinion of all of the professors' and professionals I have encountered. I mean no disrespect, I just like to share the right information. I have had my EPA 608 and 609 refrigeration certification cards for quite a few years and actively pursue refresher training every two years. As for the A/C-D/C issue, like it has been stated, load, insulation, size, frequency of temperature rises, average ambient temperature, even the sun shining on the unit all day can contribute to the amount of amps used per day.
 
Nigel Calder has an excellent book "Refrigeration for Marine Pleasureboats" covering all areas, including the most suitable units in terms of usage, voltage, power supply,etc. Anthonyd`s concise description of how it works is good. So is Calder`s, though eye-glazing and helpful for getting to sleep. I got my copy from Amazon.
 
It is thought provoking that a company, Norcold, that had the bulk of the RV and marine markets did not keep on the cutting edge. The old saying: build a better mouse trap , , , , , ,

If there is one product on a boat that I have heard the most complaints on, it is Norcold. Where was their R & D. It seems that they should have been ahead with patents on most of the new technology. Go figure!:confused:
 
My boat has had a propane fridge for 20 years. I'll be replacing it in the spring with a like unit. I get 3-4 weeks on a 20# tank plus no noise.
 
BruceK said:
Nigel Calder has an excellent book "Refrigeration for Marine Pleasureboats" covering all areas, including the most suitable units in terms of usage, voltage, power supply,etc. Anthonyd`s concise description of how it works is good. So is Calder`s, though eye-glazing and helpful for getting to sleep. I got my copy from Amazon.
Click to expand...

Thanks for the title Bruce. I'm going to check that out.
 
Anthonyd said:
I hate to be a stickler, but I like helping with the right information when I can. Refrigeration systems do not make cold air. The air in the space that a unit is designed to service is drawn into an evaporator, and the heat from that air is given to the refrigerant flowing through that evaporator. That heat causes the refrigerant to flash to a gas, goes to the compressor, then the hot gas is pumped to the condensor where the heat is given off and the cycle begins again. So essentially, we just keep removing heat until the air temperature is where we want it. I have studied Psychrometrics pretty extensively, even in the realm of fluid mechanics, and this is the opinion of all of the professors' and professionals I have encountered. I mean no disrespect, I just like to share the right information. I have had my EPA 608 and 609 refrigeration certification cards for quite a few years and actively pursue refresher training every two years. As for the A/C-D/C issue, like it has been stated, load, insulation, size, frequency of temperature rises, average ambient temperature, even the sun shining on the unit all day can contribute to the amount of amps used per day.
Click to expand...

Being a "stickler", you should feel right at home with this bunch. ;)

You are correct of course, you cannot make cold, only remove heat. You are also right on the current used per day on a refrigerator. Without an establiched standard on ambient temperature and door openings, it's impossible to compare the efficiency of one unit to another.

Efficiency is most important when running on DC power (usually 12 volts) so the most efficient units are the ones designed for marine use with 12 volt DC compressors and efficient insulation. Inverters are at best, 90% efficient so any unit that depends on an inverter will be less efficient than one with DC powered components.

The most efficient marine refrigerators use shore or alternator power when available to freeze a cold plate and use the cold plate to absorb heat when on battery power.
 
"If you have the space for a regular household fridge that fantastic. Most boats seem to have good house battery banks and inverter setups so it should be no problem."

Most new house fridges will have a tag on them that gives the KW used in an ideal 365 day year.

Most are not accurate as the insulation heating strips are not factored in by the testing regime.

However it IS a start. Divide the annual KW by 365 , then by 10 (for a 12v system) for inverter feed AH per day.

After most do the math it will be about 100AH of 12V DC , in modest sized boxes, per day.

An inverter just adds 3% to 15% amp load to the total required, that's why DC is preferred.

To use 100AH it requires a 200AH battery to not harm the batt for each 24 hours..

For the hook cruiser the alt energy systems are expensive but worth it.

For the Marina > Marina cruisers or 24/7 noisemaker boats,the house stuff is just fine.
 
Last edited:
You must log in or register to reply here.

Similar threads

Andy G
Eutectic Refrigeration
Replies
9
Views
660
DDW
D
MrJim
Refrigerator misfunction
Replies
4
Views
1K
MrJim
MrJim
T
New OR Members Planning Great Loop Adventure
2
Replies
34
Views
3K
Captain DJ
Captain DJ
H
House battery system too low to charge
Replies
13
Views
2K
hickleyboy
H
ranger58sb
Entry cost
2
Replies
34
Views
5K
waterbound
W

Latest posts

Back
Top Bottom