Compressor Fridge Info Thread, for those of us considering switching

[John E Davies]

Overland and SeaDawg, and anybody else who has knowledge or first hand experience, please comment. I am interested in plugging the two gaping holes in the side of the hull and also eliminating one potential fire hazard, the propane line into that area. I would love to see more pics like this from Overland:

 

 

Please talk about what you learned from:

 

Initial research

 

Problems during the installation

 

Tips for an easier installation

 

How to neatly block off the outside openings

 

What you have learned AFTER installing it - using the fridge

 

What brands/ models work best in an Ollie,

 

What brands to avoid.

 

I have owned a portable ARB fridge for several years and like it a lot, so this is not completely new territory. I just hope that I can become educated here.

 

I am currently interested in the Nova Kool F5800, mostly because it will fit nicely in the existing opening. The required cutout is 32 H x 23.25 W x 23.25 to 22" D (adjustable support frame).

 

The Dometic RM2454 (my unit) opening: 36.5 H x 24.01 W x 23.7" D.

 

So the new unit is shorter by 4.5 inches but otherwise really close. The Dometic is 4.0 cu ft, the nova Kool is 5.8 Cu ft, a huge incrrease.

 

Parts diagram:  ... http://novakool.com/products/single_doors/documents/PartsListF5800ACDC.pdf

 

Installation and Owners Manual: .... http://www.novakool.com/support/documents/manualnkf-049revdec2013.pdf

 

Cost is around $1350 plus shipping, warranty is two years, it works at 30 degrees off level, and the venting needed is 30 sq inches above and also below the compressor. ... And that is about the extent of my knowledge about Nova Kool.

 

For those of you wondering why we are even interested in this stuff, please watch: ... 

 

Please discuss.

 

Thanks,

 

John Davies

 

Spokane WA

 

 

 

 

[John E Davies]

Long Nova Kool install thread at the Escape Forum, no pictures for some reason.

 

http://www.escapeforum.org/forums/f8/nova-kool-rfu-8320-refrigerator-installation-4741.html

 

John Davies

 

Spokane WA

[SeaDawg]

John,

We're not home right now, but I'll add a link to the discussion on replacing our dometic with an isotherm truck fridge.

Our oliver hasn't been out of the storage slot, as we're once again delivering a stick built RV to Alaska, but I have extensively tested it in our side yard, in the shade, and I'm really happy with the results.

We've used the compressor fridges in rentals in Australia and New Zealand, and were very happy with the results, even with no solar, but smaller fridges.

I'll be able to give you real world camping results later in the year, but I'm confident in our new danfoss/secop type fridge from at home testing.

I not only got a slightly bigger capacity fridge that should run on solar (if we have sun), but I got a drawer beneath it, too. Ah, the luxury.

Lots of photos.

 

http://olivertraveltrailers.com/topic/legacy-elite-ii-dometic-rm2454-refer/

[SeaDawg]

As far as sealing the now superfluous exterior vents, we've just closed them in with some plastic. We'll figure out something better later....

[John E Davies]

John,

We’re not home right now, but I’ll add a link to the discussion on replacing our dometic with an isotherm truck fridge.

SNIP

http://olivertraveltrailers.com/topic/legacy-elite-ii-dometic-rm2454-refer/

 

Thanks for the link, I somehow missed most of that conversation, probably because of the very misleading title.

 

I do hope that we can gather up as much info and pictures about compressor fridges as possible in this thread so that anyone who may be interested can easily find it. I really think this Forum has enough members and activity now that a FAQ section would be a great benefit.

 

I have some thoughts on doing a permanent patch over the two big outside openings, but it would depend on what fridge I chose, in terms of leaving good access to the compressor and electronics. The Nova Cool F5800 looks very good because all that equipment is up high in the left rear (as viewed from the front of the unit) corner, so a large vent opening in the entry wall there could provide excellent access. If that turns out to be true, then doing a permanent patch job on the unused outside holes would be a good thing.

 

Is there any market for a lightly used year-old absorption fridge? Maybe $400 on Craigslist? Being able to get some cash for the old one might help me sell the idea to my Personal Banker....

 

John Davies

 

Spokane WA

 

 

[Rumline]

I do hope that we can gather up as much info and pictures about compressor fridges as possible in this thread so that anyone who may be interested can easily find it. I really think this Forum has enough members and activity now that a FAQ section would be a great benefit.

I think a wiki would be a great addition to this website; something that all members can contribute to where we can keep information organized.

[Overland]

John, here's my advice -

 

As far as brand goes, the two I found to be most recommended were NovaKool and Isotherm. I went with the Isotherm because I liked the stainless door. In hindsight, the stainless is a pain to keep clean in the trailer, so I think I'd still have gone with Isotherm but they have a new model out now with what is supposed to be fingerprint free stainless. Mainly, I think just getting the Danfoss compressor is the key, regardless who makes the box. I think the Isotherm has a wider cutout but like the NovaKool is shorter so you'll have to figure out what to do underneath.

I found that adding a fan inside the fridge really transformed it. Our first trip out, the temps were up and down and we were always fussing with the temp control and worrying about it, some things freezing and others too warm. But with the fan the fridge has become something we just don't think about. See my Snowball thread for the brand and install. The Isotherm only cools via the freezer coils which is why it was so uneven before I added the fan. Perhaps the NovaKool has a better design in that respect?

I got the ASU unit for the Isotherm but never use it. I should give it a shot again with the internal fan to see if it makes a difference, but the internal temps were too variable using it on our first trip.

I added extra insulation just because. I don't really know if it's made any difference. Couldn't have hurt.

Real life power usage is minimal. It will pull 3.5 amps when starting and then settle down to around 2.5 amps. Probably has a run time around 50%, but that's highly dependent on the inside temp.

Noise is noticeable at times, but never intrusive. I can't hear the internal fan I added at all unless the door is open.

The freezer on the Isotherm is too small for anything but a few ice trays.

The Isotherm comes in both 12/120 and 12 volt only models. I couldn't see the point in the 120 and still don't.

If I remember right, the NovaKool had the compressor located on the bottom, so the internal arrangement was different. And maybe they have a model with an external compressor? That might be a good choice since you have the extra space.

Semi-related - I installed a National Luna in the back of the truck before this last trip and wow, that really changed the way we camp. Three weeks worth of food, no trips to the store, no ice sloshing around in the cooler - heaven.

 

[SeaDawg]

I hope that Randy (trytorelax) will add some real world opinion on his Novakool. I really liked the specs on that, but the fit in our older camper was easier with the truck fridge isotherm compressor fridge.

I will be actually using our new fridge next month. I'm heading north to help my mom pack up her house, as she sold it recently. Later next month, we finally get to go camping in our own Oliver...

Sherry

[sailorashore]

I see there is a strong desire in some quarters to seal the exterior vents on the Ollie, and that is at least in part a motivator to shift from absorption refrigeration to compressor refrigeration. We have had great luck with Danfoss compressor refrigeration on our sailboats and are considering making the change.

 

Of course on the boats the compressor was physically remote from the evaporator plate in the ice box, located in an aft sail locker. The key to efficiency and low amperage draw was being able to move the heat away from the compressor. The compressor had to either be in a very large compartment, be supported by forced air venting of the compartment, or as was the case in our installations, have salt water cooling.

 

The question I want to throw out is this. Why seal off the exterior vents? The unit shown in John Davies photo looks like it is ideally suited for ducting hot air from the fan cooling the compressor directly out the upper vent. That would do a lot to keep the ambient temperature down in the compartment, promote efficiency, and reduce the amp draw.

 

Why not take advantage and duct out that heat? Is there something I am missing? Please advise.

 

John Shkor, SailorsAshore

[Raspy]

I see there is a strong desire in some quarters to seal the exterior vents on the Ollie, and that is at least in part a motivator to shift from absorption refrigeration to compressor refrigeration. We have had great luck with Danfoss compressor refrigeration on our sailboats and are considering making the change.

Of course on the boats the compressor was physically remote from the evaporator plate in the ice box, located in an aft sail locker. The key to efficiency and low amperage draw was being able to move the heat away from the compressor. The compressor had to either be in a very large compartment, be supported by forced air venting of the compartment, or as was the case in our installations, have salt water cooling.

 

John Shkor, SailorsAshore

 

I have some experience with sailboat refrigeration too. I went from ice to a Danfoss 12 volt compressor system that was built into a highly insulated, top loader box. The box was much better insulated than anything in an RV. The compressor was 12 volts in, but it had it's own inverter system and was actually an AC hermetic motor. The compressor and condenser package was mounted under the galley sink and the lines went to an evaporater plate in the box. It got rid of it's heat with a typical air heat exchange coil and it was remote enough to have no affect on the box. This system worked well as far as keeping the box cold, just as a home refrigerator does, but it used a lot of power over time. IIRC, it took about 3.5 amps and ran about 30% of the time. This meant it ALWAYS had to have power, 24 hours a day, and that is a problem on sailboats. It's also a problem in RVs. Solar works during the day, but having enough to dedicate to the fridge and keep it going reliably all night, every night becomes a problem.

 

A fan in the box really helps cool everything down, but it's not always the best thing, or has to be sized right, because it tends to make everything the same temp, including the freezer section.

 

My next home built system, on the boat, was a holding plate system with a true 12volt motor and belt driven compressor. I mounted a skid with the equipment in a locker near the fridge box and got rid of the waste heat with a heat exchanger cooled by sea water. This was much more efficient, but the water cooling system was troublesome because it required a thru-hull fitting below water level that was also not likely to get air bubbles while sailing. Plus the pump used power and did not last long in that situation. So I went back to the drawing board and designed a submerged heat exchanger for the fuel tank. This delivered all the waste heat to the fuel in the tank and required no pump or sea water system. Excellent! It reduced the power draw and eliminated all the associated other problems. I was also able to manage the power use because it only needed to run about 15 minutes every six hours or so. This meant I could time it to run when hooked to shore power or with the engine running, a lot of the time. No more near constant draw.

 

The difference was a relentless, but low power draw that always had to be on vs a manageable, occasional draw. The constant low draw is much harder to deal with and is the way it is in RVs, unless you have relaible solar and batteries or a shore tie.

 

Absorption has it's shortcommings too, such as slow operation and a lot of waste heat, but I can't see how 12volt systems are enough better to warrant the change. Before deciding on a truck fridge, look at a small office fridge or your home fridge. They run a lot because they don't store cold. And they make noise. Consider how a constant energy draw will be managed in poor weather, or at night or in the shade. Those passive condenser coils are a poor way to get rid of heat, are mounted right on the fridge and must have ventilation.

[Overland]

I understand the concern and even had in mind that we might have Oliver add the top vent back if needed. I’m sure that, depending on the relative temps inside and out, there would be an efficiency gain at times with an open vent to the outside. In practice however, we’ve had no issues with the fridge keeping cool. I even kept the fridge running for a week here at the house with the temp topping 95 degrees inside the trailer and the fridge never struggled. In fact, before I added in the interior fridge fan, our main trouble was keeping things from freezing inside the fridge.

 

Maybe if I could find a vent that could be manually opened and closed, then I might be tempted to give it a shot, but at the moment it works so well that there’s no real motivation to make any change.

[SeaDawg]

I'm guessing John wants to seal the outside vents to eliminate dust. That, and wasp nests, are some of my motivation. I happen to like 12 v Danfoss better than the 3 ways as (hopefully) we can run on solar and battery power, without propane/ fossil fuel being part of the mix.

Our truck fridge says it needs 24 square inches of venting... I can accomplish far more than that by opening the lower drawer, if necessary. But, we still have the exterior vents for the 3 way if needed.

I am thinking we can manage shoulder season camping with our isotherm truck fridge. I'll certainly let you know if it doesn't work on 200 watts of solar.

Sherry

[SeaDawg]

BTW,we've had cold plate systems on the sailboat for over 40 years. Very reliable. Just very inefficient for us as both systems have been engine driven. Most of the hours on our new engine are likely from charging the refrigerator and batteries. Our original refrigerator on the boat is huge. Fine on long trips with crew, wasteful with two or four people and a shorter sail.

Another motivation is testing the Danfoss on 200 watts solar. We have far more battery storage on the boat than in the trailer. With a smaller, more right sized refrigerator...

Sherry

[Overland]

I think you’ll be fine with 200, but of course it depends on how much you consume otherwise. I mentioned above that we added a National Luna 60 liter fridge freezer to the truck for extra storage. It uses the same danfoss compressor and I run it off a single lifeline battery and a 200 watt portable panel. Over our three week trip I never saw the battery dip below 80% but we were lucky and saw very few cloudy days. I have the option to charge the battery via the alternator but I disconnected that after a few days since the panels worked so well.

 

Speaking of heat and fridge ventilation, I just went and checked the fridge in the truck. It’s 97 here and the truck has been parked in the sun all day so it’s baking in there. The fridge is indeed struggling a bit but still reads 43 degrees. The freezer is at 8. Not surprising since it’s probably 120 inside the truck.

[Try2Relax]

Novakool observations - model R5810

This was the closest fitting fridge to the opening from the Dometic, there is approximately ½" on either side (½" foam insulation extremely tight fit) and about 2½" both top and bottom, but not having all the propane components in the rear the fridge is actually deeper and this has more interior space.

 

With the extra space above and below I utilized that two area for the ventilation. With the compressor only needing to be cooled and the exchanger in the back being able to exchange the air, unlike a 3-way which actually generates extreme amounts of heat, I decided to keep everything internal and closed off the outside vents. The compressor on it is in the upper left rear corner, which is good as it then keeps any compressor heat generation above the exchanger in the rear, for maximum fridge cooling performance. I blocked off the top area, to control airflow, and installed two 40mm (I think) super quiet computer fans to pull the warm air out, which connects to the OEM fan connector to run whenever the compressor runs.

 

I used reflectix insulation, with the curve of the hull some places are 5 layers deep and the thinnest is 2. In the outside, I have cut to fit vinyl sheet, from some cheap the surround wall, between the tight fit and the stock vent covers it is held in pretty tight. I haven't determined a permanent resolution yet, but this one will last a while.

 

As to performance, the fridge runs on an approximately 50% cycle and the overnight draw is usually 23AH, which is easily recovered by 10-11am most days. The fridge is extremely stable temperature wise, the difference between fridge and freezer is generally 16 degrees so at a 4.5 out of 7 on the dial, it maintains 35 in the bottom shelf of the fridge and 18-19 in the freezer. I do not have any sort of air circulation inside the fridge, everything is stock.

 

I used rectangular aluminum under the fridge, secured to the floor, to lift the fridge 2", for the bottom air intake. I did not want to screw through the face so I drilled holes into the rectangular aluminum and used turn buckles to secure to the screws where the face frame mounts to fridge body. The bottom of the fridge is pulled tight against the cabinet frame and the airflow block on the top is a tee that spans the width of the fridge and is cut to fit height wise which keeps it tight and prevents the ability of tipping (just in case). The vent covers are held in place magnetically, this was an afterthought or I would not have had the screw holes cut.

 

While in dead silence sitting at the table you can make out the sound of a fan hum the only real sound it makes is when the compressor kicks in there is a low vibration hum that fades out once it is going, I figure something I did is slightly loose and could use some padding but unless you're Archie Bunker it wouldn't be an issue.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Overland]

That looks like a nice install. I think both you and Sherry have about twice as much ventilation through those horizontal vents than I have with the ones Oliver installed for me. While I don’t think my compressor runs excessively it does make me wonder how much more efficient it might be if I increased the venting. Or maybe a computer fan at one of the vents would be worth experimenting with.

[SeaDawg]

That's a really nice install, Randy. Thanks for all your photos.

We tabbed in wood for a floor support/ riser/ drawer framing in ours. We also used scrap lumber for the uprights to attach the truck fridge to the Oliver cavity. Some is epoxy only. Some has screws through old holes into the side of the talk drawer cavity.

We're leaving tomorrow for a few weeks. We'll see how it does. At home, we used about 19 to 20 amp hours per day, I think, on average. I think we can handle this. Mostly on solar.

Though I have nothing at all in the drawer beneath the fridge yet, I'm very happy to have it.

My manual says we need a total of 24 square inches of venting. I suspect that the Novakool is similar. You probably have twice that.

Thanks for sharing the photos.

I'll share our experience with the indel truck fridge as we gain some time with it.

Sherry

 

 

 

 

 

 

[Try2Relax]

I will add to anyone considering replacing their current fridge, I don't know about the truck fridge, but the Novakool can be ordered with a left hinge for better in trailer access. I didn't realize it when I ordered mine, so like Sherry, I have a right hinge. I would think the other brands do too, just something to keep in mind.

[SeaDawg]

Well, I promised some updates after we actually got to use the truck fridge.

Overall, we're very happy after two weeks and some days with only solar and generator. It has taken some monitoring and getting used to.

The first day, from warm to cold, took about 8 hours to cool. I'd have done better to put some ice blocks or cold material in. The extra run time cost an extra 20 amp hours of battery power. Or, of course, cool it at home before leaving, but, I wanted the warm startup test.

Most days, the fridge used between 40 and 50 amp hours. When it runs, it uses 3.5 ah. Most often, it runs 12 to 13 minutes, with a 20 to 25 minutes rest. I found it ran better ( less run time) with a couple ice packs in the otherwise empty freezer.

Parked in dense shade, the trailer was nice and cool, but we didn't generate more than 1 to 1.8 ah in power to compensate for the new fridge with our 200 watts of rooftop solar.

The first week, we ran the Honda 1000 to make up. After that, we mostly used a portable 100 watt panel that we moved around in the spots of sun.

For people who plug in most of the time, the change would not be noticed. For us, it's a new learning curve on solar management, as we don't usually plug in, and have no power on our NC camping property.

In the sun, we'd be fine. Preference is to live in shade, so adding a portable panel and Port will work well for us.

Overall, I really like the fridge. Pretty even temps all around. the fixed door shelves took s little getting used to.

I removed the glass shelf above the produce drawer before we left home. A disaster waiting to happen. I was going to cut a plexi shelf, but I'm happy just moving one of the wire shelves down.

This fridge had a flip up on the top rack to allow for tall items... But not really designed for a full gallon of milk. I can live with that. A quart or half gallon is plenty for a week or two, anyway.

The freezer is small. It does make ice in a few hours. A couple trays, and a few bags of veggies would probably fill it, though.

At camp, we left the original vents open, with screening behind them. Average daytime temp was a high of 86, night lows in the 60s. one (very welcome) night the low was in the 50s.

 

I played a bit with the temp control and two thermometers. It didn't make a big difference in temp turning down the fridge from 7 to 6. Just cut the run time frequency.

I really like the big drawer in the bottom of the fridge for produce, and water bottles. Organization is different than the old dometic, but better for me as far as access.

Randy brought up s good point about the door swing. Our fridge, I think, only can swing right. Which is good for me. We cook outside 96 per cent of the time. Right swing is easier for loading groceries dumped by the door, accessing beverages during the day, and just as easy as the old left to take stuff out and stack on the small dinette table to prep for outdoor cooking. With the left swing, I had to move everything beyond the door for loading.

Sherry

[Overland]

Looking at your earlier photo, your freezer looks a bit larger than mine and mine doesn’t have that plastic shroud around it. I wonder if that makes a difference in cooling.

 

I get 3.5a starting and 2.5a running, but the difference may be in our battery monitors rather than the fridges. Or they might be using a higher RPM on the compressor. I think the Danfoss has three speeds. I’m surprised you said it took 8 hours to get to temp. My experience has been a couple of hours, maybe 4 at the most. But then that’s been in the spring and fall with trailer and starting fridge temps in the 60’s-70’s which I’m sure makes a huge difference. It might be worth plugging in and running the AC while you do the initial cool down if possible.

 

I wouldn’t worry about the glass - we’ve abused ours and it hasn’t seen a scratch. Tempered glass is tough.

 

I agree about the door storage. We still haven’t figured out how to stock it efficiently.

[SeaDawg]

Overland, I think it was around 85 in the trailer when I turned on the fridge. I also had the door open quite a bit as I stocked it at the same time it was cooling down. if I could have stocked it with only cold items, I think that would have made a difference, too. Chilling a bottle of wine and a dozen beers undoubtedly added to the time it took to drop to 40.

I also found later that the bottom of the fridge door wasn't sealing tight unless I pushed in on the corner. There's a metal guide that seems to need adjustment.

I managed to break a tempered glass shelf in the fridge on our last Alaska trip in the RV. It made a huge mess. That's the first time it's ever happened to me, but it's made me gun-shy.

I'm interested in seeing how the fridge performs next trip. It's all different from the old three way, but I'm quite happy so far.

Sherry

[SeaDawg]

We got back last weekend from a couple weeks in Tennessee and  North Carolina.  We're both quite satisfied with our choice of the tf130.

It's really quiet and efficient.  We camped in shade, but gained most of our power from a 100 amp solar panel that I moved around in the best four or five hours of sun. We supplied the rest with a short run of the generator in the morning.

 

Paul likes the molded spaces for beer cans. Up by the freezer, it keeps the beers super cold. I'm figuring out the rest of the space. I love the slide out bin on the bottom. A lot less juggling of bulky items.  The  bottom door rail hold a quart of milk and another of half and half, plus other tall items. I had more than enough  space for our refrigerated food. The freezer is small, but held several bags of vegetables,  a quart size gel freezer pack, and a couple  steaks. I think the fridge works best with a fairly full freezer, for some reason. With daytime highs in the low 80s, nights in the 60s, I could turn the fridge down to 5 or 6 instead of high, and still maintain 40 degrees or colder in the fridge.

 

Sherry

 

 

 

 

 

 

[SeaDawg]

So, I thought I'd update this a little.

This trip, we're camped in a small area surrounded by tall trees. Except for an hour and a half of overhead sun, my fixed panels don't do a lot.

Once again, I ran the fridge empty to cool it down. But, as ambient temp was 60, it took less than an hour for the fridge to hit 39.

Then loaded with cold beverages and food, some ice and frozen veggies in the shoebox freezer. Full, but not packed tight. I don't have an internal fan.

 

I definitely have needed the supplement of the portable panel, and we run the honda 1000 for 30 minutes to an hour each morning, to bring the amp hours down to 20 or 25 hours from full. With a couple moves of the portable panel, I'm back at 100 per cent battery sometime between noon and one. The solar does the rest. By nine pm, I'm down 19 to 24 hours on battery. Fridge doesn't use as much with cool nights, typically 19 to 24 amp hours.

I run the gen in the morning to get the most efficiency from the gas, and bring hours needed down to 20 or 25. (The charge controller sends more power to the battery when it's lower.)

I charge our phones and Dyson vacuum at the same time, while the genset is running. Solar does the rest. And, the weather has been storybook perfect in the NC mountains. 75 to 80 high, fairly clear skies, 50s at night. No need to run fans or furnace.

With a better, more efficient portable than my $100 Coleman 100 watt, we'd not need the genset at all, I think. I rarely get more than two to four amps from it, but, it works.

And, I'm loving the organization and steady operations of the indel truckfridge. It's been a great solution for us. Very quiet.

 

For John -- still haven't done anything more with the vents than cover them with plastic... Maybe we'll think of something this winter. It keeps the bugs and dirt out, so it's ok for now.

 

Sun's getting low. Time to start the campfire.

 

Sherry

[mountainoliver]

I just completed my changeover to a Nova Kool compressor fridge. The model I ended up with is a R5810. These photos show some of the major steps of the installation of the new refrigerator. Because the opening is a little bit too wide, I had to fabricate the four stainless brackets. They are epoxied in place and allow the fridge mounting screws to pull against the fiberglass cabinet front. The outside upper and lower vents are still removable and are sealed with closed cell foam. I used the outside access several times during the installation and can see a benefit to having outside access in the future for cleaning behind the fridge, etc. Because everything associated with the fridge is now inside the camper, it is 100 times easier to remove and replace. I disconnected the gas line outside under the camper and replaced the "T" fitting with a flair union. I plugged both ends of the gas line that runs up to the old fridge so that it'll stay clean for future use if needed. The last things that I have to fabricate are the upper and lower grills. I have 1/8 aluminum stock that I'll cut to size and mill slots in. I plan on painting these gloss white. When running the only noise (and it's very slight) are the fans I added to help remove the heat from the back of the fridge. So far the fridge has been running on battery power from the day I received the fridge now 14 days ago. There have been several cloudy days during this time and the batteries have come back to 100%. The only things running have been the fridge and the Maxxfan on auto mode. There have been temps in the camper of 95 degrees and the fridge has maintained 18-22 degrees in the freezer and 33-35 degrees in the fridge. Testing will continue with a few short trips before we head out to Quartzsite in December or January.

 

 

 

 

 

 

 

 

 

 

[Overland]

Very nicely done. I can’t wait to see the finished product.

 

I’m jealous of your drill press/router. That looks like quite a machine.