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Well my Novakool 3800 arrived last week and I was able to get it installed over the weekend. I have a Palomino SS-1251 that had a Dometic 3 way in it. For whatever reason, the 3 way just could not maintain an acceptable temperature when the outside temperatures got above the mid 80’s. That, and the fact that the absorption units need to be level drove me to the compressor unit. (anybody want the old 3way unit? I’m in Maryland) I’m still assessing the average current draw and how long I can go without sun. I have 2 100 watt panels, Bogart charge controller and battery monitor, and 2 6 volt Crown 230 Amp Hour batteries. Over the last two nights, the battery monitor indicated 94% in the morning, after starting the night with a full charge. That roughly converts to 12 Amp Hours consumed over night, which is pretty promising, I think.
See photos at:https://halethorpephotography.smugmug.com/Truck-Camping/Compressor-Fridge-Install/
Overall, the install went fairly smoothly. When I removed the old unit, I saw that it was woefully under insulated (perhaps part, if not all of it’s cooling problem). I added a significant amount of foil faced, rigid foam board, 1/2 inch on the bottom and 1 inch on the sides and top. I used aluminum tape to tape up the insulation seams as much as possible. I have read that you can significantly improve the efficiency of these units by insulating the crap out of them. Novakool requires ventilation of the compressor and condenser (all in the rear of the unit). I modified the existing refrigerator vents by taping over most of the vents with aluminum tape. This results in about a 1 inch by 16 inch vent at the bottom and the top of the refrigerator compartment. I thought venting to the outside was better than putting that heat into the living space. The unit is super quiet; I have to listen at the vent outside to hear if it’s running.
I did find that the old fridge was not fused (or at least I could not find it). The camper power center had a fuse that was labeled refrig, but when I pulled that fuse, the wire was still hot. Not sure why it was done this way, but at least they had a nice fat 10 gauge wire going to the fridge. I’ll be installing an in line 15A fuse this week. Another general thought is that it would have been better if I could have attached the insulation directly to the refrigerator, as this would have eliminated the gaps that I ended up with between the fridge and the insulation I added to the opening. The trim was in the way of doing this and removing the trim was a can of worms that I didn’t want to open. I plan to chink fiberglass into those gaps as much as possible.
I’ll report back over time regarding the unit’s performance and how well the solar system can keep up.
Joel,
Thanks for posting. I am debating making the switch even though our camper is only a few months old.
Some of the TC manufacturers as well as RV manufacturers do a very poor job of installing the fridge which often accounts for the poor cooling. The air coming in the lower vent is supposed to pass over the cooling coil and nothing else. The factories are not doing this in many cases and air is simply following the path of least resistance bypassing the coils. The installation manual covers this issue and should be online. What really kills it on the pop-ups is locating the upper vent on the sidewall, although no real option there.
As you noted the space around the fridge is often left uninsulated or is insulated poorly. Insulation from batts rather than foam board works well in those situations.
What I have never found a cure for is how easily the flame is blown out when operating on propane. All is well until a tractor trailer approaches pushing a bow wave of air and out it goes. Same thing in a strong storm. Having tried all the suggested fixed on the Internet as well as those proposed in the past by Dometic, I believe it is the nature of the beast or at least my beasts. 🙁
Interested to see a long term follow-up.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCUpdate: I have not turned off the fridge in about 2 weeks. I used the camper while racing last weekend and got the batteries down to about 80%. I came home and parked the truck and left the fridge going. Yesterday I was only up to 94%, so at this point, even with good sun, the 200 Watts of panels are not enough to recover from the weekend (even with the fridge as the only load).
While the compressor might only draw 2.2 Amps, I’m seeing closer to a 3 Amp draw when the fridge is running. Apparently, they don’t include the current drawn by the fan that blows on the compressor. This is important information and should be provided by Novacool. My laser pointer IR thermometer shows the compressor running around 113 F. Not sure at what temperature that fan kicks off, but it was pretty much running whenever the compressor was running.
I had the truck parked such that the fridge side was in the sun. It would likely help to have that side in the shade. I also have brown fridge vent covers. I think changing them to white will reflect the heat and help the situation.
The IR thermometer also shows that the temperature inside the box varies. When the top shelf shows low 30’s I can see 10 degrees higher on the door and lower shelves. Knowing this, I was able to adjust the temperature control a little higher and still have the top shelf around 35 F.
At this point, I’m borderline at best for long term boondocking. But I’m more than fine for a few days between plug ins. I’m hoping some more tweaks will get me power positive, but eventually I may have to add another panel.
My rig come with a Domestic compressor frig. and also 4 AGM batteries, no solar. It’s been trouble free for the 3 1/2 yrs. I’ve had it. As mentioned, my coach builder too did a lousy job installing. I insulated around it and added a LED readout thermometer on the door. It’s a much better unit than the 3-ways I’ve had in other RV’s.
2012 Tiger CX Ram diesel 4x4
Lot of batteries. How are you keeping them charged without solar, genny?
Driving, on board 2.8 Onan generator and shore power. Only draw on them is frig.,led lights, Espar diesel heater fan and water pump. Never had an issue.
2012 Tiger CX Ram diesel 4x4
Makes perfect sense to me. I think there are usage patterns in which a genset is a better solution to battery charging than solar panels. We have just two batteries which are neither pricey or large and have no problem with having adequate power using our genset very sparingly on its ECO setting so it is extremely quiet.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCA compressor fridge will NOT run on propane. It uses a compressor just like your home refrigerator and runs on 12 volt dc electricity provided by your house battery(s). When plugged into shore power, the converter provides the 12 volts needed.
If you’re going to boondock, you probably really need solar panel(s) to keep the house battery topped up.
The good thing about a compressor fridge is they usually need MUCH less electricity than a 3way, since the electricity only needs to run the compressor and not heat the ammonia solution in a 3way in lieu of the propane providing the heat.
So if you ARE boondocking and relying on solar, you won’t need as many solar panels or as big a battery bank.
Regards
John
I don't like to make plans. They cause the word "PREMEDITATED" to get used in court!
DON'T FEED THE VULTURES!
My Body is a Temple! Ancient, Crumbling, Probably Cursed . . .Comparing a compressor fridge to a 3 way operating on 12V is not a fair or realistic comparison IMO. While it’s true that a compressor fridge uses less 12 power than a 3way operating on 12V, I don’t know why anyone would operate a 3 way on 12 volts while camping. Propane is the preferred operating mode for the 3 way when camping as it uses very little 12V. It also uses very little propane.
The main reason I switched to a compressor refrigerator was that my 3 way would not cool sufficiently when the outside temperature was above the mid 80’s.
Comparing a compressor fridge to a 3 way operating on 12V is not a fair or realistic comparison IMO. While it’s true that a compressor fridge uses less 12 power than a 3way operating on 12V, I don’t know why anyone would operate a 3 way on 12 volts while camping. Propane is the preferred operating mode for the 3 way when camping as it uses very little 12V. It also uses very little propane.
The main reason I switched to a compressor refrigerator was that my 3 way would not cool sufficiently when the outside temperature was above the mid 80’s.I agree and even with the fan going, a ammonia absorption fridge is going to track the outside temperature. Our new three-way does a much better job than our old one holding right at 40 degrees in the lower box when the outside runs up into the 90. Best thing is it does not blow out with passing trucks as our last one did.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC
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