Two questions re: refrigeration use when cruising & Novakool specific ?

[O C Diver]

Ted,



Thanks. I read through that set of posts. Looks like a great solution for the somewhat anemic refrigerators in the RV/Marine market. I assume the fridge is still providing good service after 4 years?

The refrigerator is great. Really prefer the larger compressor that makes stuff cold quickly like a home refrigerator. If I had to do it over, I might have bought it with the optional ice maker for eventual resale bling. I don't use ice, so I'm happier with the extra freezer space, but....

The short coming to most of these apartment and RV / marine refrigerators is the thermostat. There not the best quality. Fortunately on mine it's easy to access and replace.

I ended up replacing mine with an electronic one and couldn't be happier.

https://www.trawlerforum.com/forums...-thermostat-another-project-thread-62905.html

Ted

 

[Slowmo]

We have a Novacool 9000 as well. We do not change the temperature setting while running and it seems to work OK. They do require good ventilation. They have a fan to pull air over the condenser but there needs to be a vent at the top of the cabinet, as well as adequate space behind the unit, to ensure good airflow. Ours has cabinet vents top and side.

 

[Helmsman]

We have a Novacool 9000 as well. We do not change the temperature setting while running and it seems to work OK. They do require good ventilation. They have a fan to pull air over the condenser but there needs to be a vent at the top of the cabinet, as well as adequate space behind the unit, to ensure good airflow. Ours has cabinet vents top and side.

The new Helmsman has a vent at the top, which will help for those of us buying the newer models. I suspect it would not be too big a deal to put a cent at the top of the older models are set up with the same headroom.

 

[Barrie]

Okay, let me say this out loud so my dear wife can hear: IT IS NOT A FRIDGE! You should not think it will perform like the fridge at home. Think of it as a cooler. Don't stuff with food. Buy enough for a couple of days dear and then go shopping again.
An extra 12 volt computer fan will also help if installed at the back to move air around the cooling coils. Easy.
And yes, these wan-a-be fridges run a lot. Mine is on every other minute. So was the one on my old boat.
(I was so bothered by it running all the time that i physically removed it and took it to an AC/DC service dealer and had him check it for a month last winter. He said two words - it's fine.)
A lot of good tips written before me that will help.
Barrie

 

[rslifkin]

Okay, let me say this out loud so my dear wife can hear: IT IS NOT A FRIDGE! You should not think it will perform like the fridge at home. Think of it as a cooler. Don't stuff with food. Buy enough for a couple of days dear and then go shopping again.
An extra 12 volt computer fan will also help if installed at the back to move air around the cooling coils. Easy.
And yes, these wan-a-be fridges run a lot. Mine is on every other minute. So was the one on my old boat.
(I was so bothered by it running all the time that i physically removed it and took it to an AC/DC service dealer and had him check it for a month last winter. He said two words - it's fine.)
A lot of good tips written before me that will help.
Barrie

I disagree that it's not a fridge. It'll happily keep a full load of food cold. But it has limited excess cooling capacity, especially in hot weather. So if you use it like a drink cooler and open it all the time, or are adding lots of warm items to cool down, it won't stay cold enough. But if most things go in pre cooled and you don't open the door too much in hot weather it'll cool fine given good air flow over the condenser. More insulation will reduce running time and therefore power use.

 

[HTurner]

Okay, let me say this out loud so my dear wife can hear: IT IS NOT A FRIDGE! You should not think it will perform like the fridge at home. Think of it as a cooler. Don't stuff with food. Buy enough for a couple of days dear and then go shopping again.
An extra 12 volt computer fan will also help if installed at the back to move air around the cooling coils. Easy.
And yes, these wan-a-be fridges run a lot. Mine is on every other minute. So was the one on my old boat.
(I was so bothered by it running all the time that i physically removed it and took it to an AC/DC service dealer and had him check it for a month last winter. He said two words - it's fine.)
A lot of good tips written before me that will help.
Barrie

I agree, my experience from a couple of boats has been the same.

 

[O C Diver]

Okay, let me say this out loud so my dear wife can hear: IT IS NOT A FRIDGE! You should not think it will perform like the fridge at home. Think of it as a cooler. Don't stuff with food. Buy enough for a couple of days dear and then go shopping again.
An extra 12 volt computer fan will also help if installed at the back to move air around the cooling coils. Easy.
And yes, these wan-a-be fridges run a lot. Mine is on every other minute. So was the one on my old boat.
(I was so bothered by it running all the time that i physically removed it and took it to an AC/DC service dealer and had him check it for a month last winter. He said two words - it's fine.)
A lot of good tips written before me that will help.
Barrie

I used to have that problem (mine was a Norcold [never cold]). See the link in post #54. This is a fixable problem. Frankly I don't understand how Helmsman builds that quality of boat and installs such a low quality appliance.

Ted

 

[Helmsman]

I used to have that problem (mine was a Norcold [never cold]). See the link in post #54. This is a fixable problem. Frankly I don't understand how Helmsman builds that quality of boat and installs such a low quality appliance.

Ted

Well, the fridge has a use case which should match the boat. One thing I have learned in dealing with Helmsman is that they are constantly improving the boat. If customers are concerned about something, and they see a better solution, they fix it. Many times they fix issues with little customer input

There are two issues here, from what I can see. Cooling capacity, and storage capacity. Solving the cooling capacity by going straight AC works for you. I want DC for the redundancy. If the inverter goes, I want the imperfect DC cooling. No need to shut down a great weekend because the inverter struggled.

Capacity is the other issue. But that is an issue with the manufacturer of the fridge, the customer demand for alternatives, and the space/layout of the boat.

I really like what you did with the apartment fridge. I am not sure I would go that way, but if the fridge is a problem (I have had one, and it worked fine after I corrected an electrical failure on it), I will certainly consider it!

 

[O C Diver]

Well, the fridge has a use case which should match the boat. One thing I have learned in dealing with Helmsman is that they are constantly improving the boat. If customers are concerned about something, and they see a better solution, they fix it. Many times they fix issues with little customer input

There are two issues here, from what I can see. Cooling capacity, and storage capacity. Solving the cooling capacity by going straight AC works for you. I want DC for the redundancy. If the inverter goes, I want the imperfect DC cooling. No need to shut down a great weekend because the inverter struggled.

You don't have a generator?

One of my considerations when deciding on electrical supply, was whether to have it run on it's own inverter or the main boat inverter. A pure sine wave 500 watt inverter would probably have been ample. Then the redundancy would have been the main boat inverter. In reality, using the main inverter and having a 500 watt back up to plug the refrigerator into would be normally more seamless. My inverter is pretty bullet proof, so chose the generator as a back up.

Ted

 

[Helmsman]

You don't have a generator?

One of my considerations when deciding on electrical supply, was whether to have it run on it's own inverter or the main boat inverter. A pure sine wave 500 watt inverter would probably have been ample. Then the redundancy would have been the main boat inverter. In reality, using the main inverter and having a 500 watt back up to plug the refrigerator into would be normally more seamless. My inverter is pretty bullet proof, so chose the generator as a back up.

Ted

Yes, I had a generator. Thanks for asking. That redundancy works when you are on your own. Bothers others all night though. We were attending the Vol Navy at Neyland Stadium for the Tennessee Florida game a few years ago. The inverter acted up and was discovered at around five in the morning. Tailgate stuff in a cooler and the fridge. Surrounded by about 500 of my “best friends” sleeping. Fridge was fine. Worked with the inverter for a few minutes, figured it out, and got it up and running.

Didn’t miss a lick. Our little bedroom clock/light was flashing 11:30pm. Averaged twenty tailgaters on the boat throughout the day, though there were about 50 that came through over 6 of 7 hours. Wife said later that having the DC power saved the food. Could have been alright, I guess. But, why guess with food?

Edit to add: the Vol Navy have rows of boats from the dock to the navigable waterway. You have neighbors rafting to you.

 

[O C Diver]

Yes, I had a generator. Thanks for asking. That redundancy works when you are on your own. Bothers others all night though. We were attending the Vol Navy at Neyland Stadium for the Tennessee Florida game a few years ago. The inverter acted up and was discovered at around five in the morning. Tailgate stuff in a cooler and the fridge. Surrounded by about 500 of my “best friends” sleeping. Fridge was fine. Worked with the inverter for a few minutes, figured it out, and got it up and running.

Didn’t miss a lick. Our little bedroom clock/light was flashing 11:30pm. Averaged twenty tailgaters on the boat throughout the day, though there were about 50 that came through over 6 of 7 hours. Wife said later that having the DC power saved the food. Could have been alright, I guess. But, why guess with food?

Edit to add: the Vol Navy have rows of boats from the dock to the navigable waterway. You have neighbors rafting to you.

I tend not to raft up or anchor in close proximity. That and my generator is very quiet.

In your situation, I would have a backup inverter as outlined earlier and a simple alarm system to notify me of 120 VAC power failure.

Once a person commits to a 120 VAC refrigerator, it's pretty easy to work out an acceptable redundancy power source and alarm system if necessary.

Ted

 

[OldDan1943]

I have a NovaKool 9000 12vt.
Let's all agree, humidity is our enemy. Every time we open the doors, moist air enter the boxes and encourages ice to build up on the coils and eventually insulates them from efficiently providing additional cooling. Yes, I did change the door gaskets.
I have made many incremental changes, resulting incremental improvements. Now I have run out increments so unless a miracle occurs, I have learned to accept and live with the end results.
Do be afraid to put some insulating board on 3 sides. I used 1/2" foam board. Realize, adding the board may very well hinder the natural exhausting of the heated air. I added a lower vent, 2 pancake fans there and a vent high out the back. I added a Stainless Lobster. The advantage of that is, it shut the compressor twice every 12 hours, in my case, for 20 minutes each time. The SL has a thermostat, allowing me to set the high and low temps (38/35f) It displays a number of things including humidity, current temp in the box, a graph run time and a few more graphs. It also has a pancake fan inside the fridge. Yes, I removed the drip pan.
Remember what your mama said, "Dont stand there with the door open."

 

[catalinajack]

"This is a new to us boat, and we are currently at a dock until noon on the 30th. trying to get someone out to check and service but very worried about heading out and draining the battery with a fridge that isn't working right. Hot days like this are unusual but do happen occassionally."



Are you identifying a fridge operational problem, a battery and power system problem or a fridge/power consumption problem?

You haven't given enough clues to know which, as you don't tell us whether your Novacool is DC, AC or AC/DC. Nor di you tell how old it is, how old your battery bank is or its capacity. All of that information would help identify the problems.



When our boat was new to us, the fridge was a Norcold AC/DC that performed much the same way as you have described. A local "Freddy Freezer" correctly diagnosed and fixed the problem. Out came the internal inverters , internal to the fridge, and the rest of the AC/DC fridge systems went into his garbage, as they consumed an excessive amount of power, that our house batteries failed to properly support. In went a DC only Danfoss unit, reducing daily power need to so far below our capacity that on the next battery replacement the house bank was reduced to 1/2 of its former total amp capacity. Since then, even after adding a DC freezer, our house bank has an new average of over 10 years between replacements, 4x6v Golf Cart FLA batteries. The fridge is performing flawlessly, as is the freezer. Those changes were done roughly 24 years ago. ymmv.

I could never understand the reasoning of an AC/DC fridge since the fridge inverts AC to DC anyway. The modules that do so sometimes fail (not inexpensive). Then there are the ineficiencies of inverting from the house bank to supply AC to the fridge and then the fridge does what? Yup, it changes the AC back to DC for the Danfoss compressor. Senseless, absolutely senseless.

We have a pair of Vitrifrigo 4.2 cf units in a custom-made enclosure. I built it with at 1.5 inch space underneath and two large vents, one on each side located up high on the sides. I added four-inch computers fans at the vents that are powered from the control module that come on when the compressor comes on which promotes air flow from underneath and out the vents. In the hottest of weather, we cannot set the fridge to max temp without freezing more delicate items in the fridge. I added no additional insulation but, in retropect, I could have for additional efficiency.

By the way, if anyone has one of those AC/DC modules fail, I would replace it with a DC-only module. I do not know but perhaps an AC/DC module can be wired to use only DC.

 

[catalinajack]

I don't know the setup of Novacool fridges, but we do a couple of things that would be universal for lowering electrical use. I bought "fridge organizer" bins like these.
They come in many shapes and sizes, so it takes some time to get the right size for a particular fridge. They serve several purposes. First, when the door is opened, the bins limit the amount of air exchange (cold in, warm out). Second, if they are really used to organize, they can save door openings and time searching by having all "sandwich condiments," for instance, in one bin. Mustard, ketchup, mayo, dill pickles, etc. all out on the counter in a single bin with one door opening.

We have a circulation fan installed on the back of our fridge. I also put in a new vent so that the area behind the fridge has good circulation. I set it up so that the fan exhausts warm air into the cabin and draws in cold air from outside. Obviously, that works in the PNW. In hot climes that could be reversed.

We keep our freezer section completely full of blue ice blocks. That allows us to turn off the fridge for 24 hours after a long day's cruise. We also turn it off at night. I've never been comfortable using my freezer section for meat, etc. Too much chance of undetected partial/total thaw and refreeze. We've figured out simple work-arounds to avoid using the freezer qua freezer and instead use it to reduce the electrical draw of the fridge.

Ketchup should not be refridgerated.

 

[rslifkin]

By the way, if anyone has one of those AC/DC modules fail, I would replace it with a DC-only module. I do not know but perhaps an AC/DC module can be wired to use only DC.

I agree, for a boat there's rarely a case that an AC/DC fridge is truly a benefit. Although there's power conversion going on in the module regardless, as the Dandoss/Secop compressors don't just run on straight 12v DC. I'm pretty sure it's actually lower voltage 3 phase AC drive.

As far as the AC/DC modules, you can just leave the AC side disconnected and run it on straight DC. Mine is running that way right now as the AC side of the module is a little flaky (so the AC fridge breaker is off and mine isn't on the inverter panel anyway).

 

[catalinajack]

Keep the drip tray handy. You will need it when you defrost. Even with it, if the ice is thick enough, you will need to towel some of the water out or it may drip out onto the floor.



Good luck with your first trip!

My Virtifrigo fridges do not have drip trays. At the back is a v channel that collects melting water to a fitting to which I have a hose that drops into the engine where I collect the melted water in a bucket rather than letting it go into the bilge. No fuss, no muss.

 

[catalinajack]

Okay, let me say this out loud so my dear wife can hear: IT IS NOT A FRIDGE! You should not think it will perform like the fridge at home. Think of it as a cooler. Don't stuff with food. Buy enough for a couple of days dear and then go shopping again.

An extra 12 volt computer fan will also help if installed at the back to move air around the cooling coils. Easy.

And yes, these wan-a-be fridges run a lot. Mine is on every other minute. So was the one on my old boat.

(I was so bothered by it running all the time that i physically removed it and took it to an AC/DC service dealer and had him check it for a month last winter. He said two words - it's fine.)

A lot of good tips written before me that will help.

Barrie

Uh, Barrie, our fridges keep cool just fine, just like home except for frost-free.

 

[catalinajack]

I disagree that it's not a fridge. It'll happily keep a full load of food cold. But it has limited excess cooling capacity, especially in hot weather. So if you use it like a drink cooler and open it all the time, or are adding lots of warm items to cool down, it won't stay cold enough. But if most things go in pre cooled and you don't open the door too much in hot weather it'll cool fine given good air flow over the condenser. More insulation will reduce running time and therefore power use.

Ah, good point. Perhaps the terrific performance we experience with our Vitrifrigos is at least partially attributable to the fact that we use an Engel fridge-freezer in which to keep beverages. Beer is colder than when stored in coolers on ice.

 

[rslifkin]

Ah, good point. Perhaps the terrific performance we experience with our Vitrifrigos is at least partially attributable to the fact that we use an Engel fridge-freezer in which to keep beverages. Beer is colder than when stored in coolers on ice.

That's probably it. These fridges don't have as much surplus cooling power as a house fridge, so there are some usage patterns they just can't handle.

 

[DrissZougari]

I have added a second quite 12v fan behind my Novakool fridge ( these hardly use any juice). The issue with Novakool refrigerators is that they need good ventilation around the compressor.

 

[catalinajack]

I have added a second quite 12v fan behind my Novakool fridge ( these hardly use any juice). The issue with Novakool refrigerators is that they need good ventilation around the compressor.

I think that air flow is important to all refridgeration, not just Novakool. The only way to be certain that it is not an air flow problem is to pull the unit out of its enclosure and test-run it. If it keeps cool, then you have your answer. How you then solve the problem can be another challenge.

I have often wondered about often-seen Novakool criticism (Neverkool) given that they use Danfoss compressors as do many other brands such as our Vitrifrigos. Of course, seals and box insulation are important but there are no mysteries in this regard. The only thing that comes to my mind is that the model of Danfoss compressor used by Novakool is too small for a given number of cubic feet.

 

[rslifkin]

I think that air flow is important to all refridgeration, not just Novakool. The only way to be certain that it is not an air flow problem is to pull the unit out of its enclosure and test-run it. If it keeps cool, then you have your answer. How you then solve the problem can be another challenge.

I have often wondered about often-seen Novakool criticism (Neverkool) given that they use Danfoss compressors as do many other brands such as our Vitrifrigos. Of course, seals and box insulation are important but there are no mysteries in this regard. The only thing that comes to my mind is that the model of Danfoss compressor used by Novakool is too small for a given number of cubic feet.

Novakool does use a little smaller compressors than some. Even their big stuff has a BD35, while the big Vitrofrigo units (not sure about Norcold) use a BD50. But some of the newer Novakool models offer dual BD35s as an option like the big Isotemp units (more cooling power and separate fridge/freezer thermostats).

I like Novakool's packaging of the systems though. They do a good job of maximizing internal space in a given cutout size and they're easy to add insulation to if you have space. That extra insulation definitely helps hot weather performance with the small compressors.

 

[Comodave]

I think that air flow is important to all refridgeration, not just Novakool. The only way to be certain that it is not an air flow problem is to pull the unit out of its enclosure and test-run it. If it keeps cool, then you have your answer. How you then solve the problem can be another challenge.

I have often wondered about often-seen Novakool criticism (Neverkool) given that they use Danfoss compressors as do many other brands such as our Vitrifrigos. Of course, seals and box insulation are important but there are no mysteries in this regard. The only thing that comes to my mind is that the model of Danfoss compressor used by Novakool is too small for a given number of cubic feet.

The fridge in our new boat doesn’t cool well, we just found out this last weekend. I am going to pull it out of the cabinet and see how well it cools standing in the open air. But right now I have Covid so it will have to wait until I get over it. I don’t see any vents in the cabinet so when I pull it out if there actually aren’t any vents I will have to add some and a fan to help with cooling the cabinet.

 

[Comodave]

Ok, I as feeling a bit better so I pulled the refer out. It is a Norcold (Nevercold). The 2 fans are working. But the cabinet has no air intake or exhaust. I am going to have to figure out how to get a low intake and a high exhaust. But that will be another day, today I am exhausted just getting it out.

 

[koliver]

Ok, I as feeling a bit better so I pulled the refer out. It is a Norcold (Nevercold). The 2 fans are working. But the cabinet has no air intake or exhaust. I am going to have to figure out how to get a low intake and a high exhaust. But that will be another day, today I am exhausted just getting it out.

Dave
Good work, for a guy who should be laying low. Sorry to hear about your Covid. Hopefully you wont get any terrible symptoms, as today's efforts would seem to show a positive outcome. I know how ugly it can get, and hope that you will never know that.
We can all wait a few days for your next report.

 

[BruceK]

The fridge in our new boat doesn’t cool well, we just found out this last weekend. I am going to pull it out of the cabinet and see how well it cools standing in the open air. But right now I have Covid so it will have to wait until I get over it. I don’t see any vents in the cabinet so when I pull it out if there actually aren’t any vents I will have to add some and a fan to help with cooling the cabinet.

Take off your mask and threaten the fridge with Covid unless it co-operates.
And get well,soon and safe!

 

[Comodave]

Thanks for the nice thoughts guys. Appreciate it. Will see tomorrow how cool it is and what happens when I put some things into the refer.

 

[mcboatface]

Old restaurant trick: Freeze a cup of water. Place a quarter on top of the frozen water. Return to freezer. As long as the quarter is still on top of the ice, no thawing has occurred.

We keep our freezer section completely full of blue ice blocks. That allows us to turn off the fridge for 24 hours after a long day's cruise. We also turn it off at night. I've never been comfortable using my freezer section for meat, etc. Too much chance of undetected partial/total thaw and refreeze. We've figured out simple work-arounds to avoid using the freezer qua freezer and instead use it to reduce the electrical draw of the fridge.

 

[Comodave]

An update on my refer situation. I had a troubleshooting flow chart from Nevercold. Following it I found that the compressor resistance was out of the specs. I called Nevercold to ask how bad it was and their answering system said that they wouldn’t help consumers troubleshoot their refers but to call an authorized repair center. I called them all in my area, nobody would work on the freon based compressor, only the ammonia based ones. So the search was on for a new refer. The problem is getting the old one out the door and the new one in the 21.25” door. I ended up cutting off everything on the back of the old refer and some rear feet and then got it out the door. Found a new one from Isotherm that was specified as 20.5”. Ordered it from Defender. Comes truck. Finally ended up driving 2 hours to pick it up in order to get it faster. Open it up and the big front door is damaged. So Defender gave me credit for picking it up and also a couple of hundred dollars for having to mess with the door. However the 20.5” depth is without the doors so I had to remove the doors to get it into the cabin. BUT it cools like a champ now. We have been turning it down since it is too cold even with it packed full. They are shipping out the new door so I will have to swap it out when we get home. But so far we are loving the new Isotherm. One problem was that it is 7” taller so I had to do some work on the cabinet to get it in. But we have a really good working refer now.

 

[backinblue]

Old restaurant trick: Freeze a cup of water. Place a quarter on top of the frozen water. Return to freezer. As long as the quarter is still on top of the ice, no thawing has occurred.

The quarter will eventually work it's way into the ice even w/o thawing. Another trick is freeze something like a small cup of water or an ice cube tray and turn it over after it's frozen. If it's empty when you return you know you lost refrigeration for a decent period of time.