Does anybody make a fridge that maintains even temps?

[Joe & Cherie]

Hi guys,

First I want to emphasize my fridge is not a 3 way, nor is it a 12v DC that uses the heated tube thing (whatever its called)....lol. I have a 12v DC only "truck fridge" that uses a compressor.

So here's my question, while on our 2 week trip to FL, it worked great - I monitored inside temps with a remote thermometer. But I had to adjust the knob to anywhere between 2 to 4 to keep temp at 38* inside depending on the camper temps. I remember with my Casita it was the same thing.

So, why do the RV fridges cool relative to outside temps?? Why cant somebody make one that you set on 38* inside and it stays 38* inside, regardless of outside temps? It seems so simple. Am I missing something?

[The Minimalist]

Is the reefer mounted, per the installation instructions, to allow proper ventilation? When the inside temps rose, was the trailer closed with the AC off. Was there any ventilation to the trailer?

If the inside temperature were held steady, the thermometer shouldn't need to adjusted.

I'm not sure where the condenser coils are in these refrigerators. If they are located on the back and are facing the outer wall as in most RVs, some additional insulation on the wall may help.

Bottom line, if the temp in the trailer is steady, a properly working thermostat should maintain a steady reefer temp. Otherwise, I would suspect a problem with the reefer.

Good luck on this one.

[Joe & Cherie]

Well that's the issue. I think the fridge is working fine as intended and vented fine. During our trip the inside of the camper temps fluctuated all over the place. This came from not wanting to run a/c during the day while outside, not running ac and closing camper while away out running around, sun, etc.

But my thoughts are why not have the fridge design monitor fridge temp on the inside of the fridge? Turn on at 40 and off at 36 for example. Why are these designed that they are relative to outside or camper temps? It seems my home fridge stays steady regardless of house temps.

A simple thermostat inside fridge would do the trick. I could run a/c 24/7 and then camper interior would stay consistent and fridge would stay consistent. But that's not camping to us! We love the fresh air.

[TomandCallie]

Joe, I feel your pain and have had the same frustration. I have a brand new Dometic 1.9 3-way fridge. It cools great on AC and propane (and holds the temp well when driving on DC), but I find I am constantly having to adjust it up or down to keep the temp where I want it. Sometimes in no time it will dip way down below freezing so I have to turn it up. Then after a while I'll find it to be higher than I would like, so down the dial goes again. I'm certain it is working as designed. So why the heck don't they build the thing with a thermostat? How hard would that be???

And what's with the gas valve having not only a temp dial with 1-7 settings, but there is also a separate "low, med. and high" dial. The owners manual does not go into any decent explanation on just how to use this correctly. Frustrating to say the least!

[Casita Greg]

Most RV and trailer fridges are "absorption" systems, as opposed to "compressor" systems typically found at home. On the upside, absorption fridges have no moving parts to wear out, but on the downside, they don't chill as quickly as compressor units. They also require a much longer chill-down time, (usually overnight,) before they reach proper refrigeration temps.
Ambient temperature does have a major impact on the absorption style units and they are known for fluctuating widely depending on the outside temps, the number of times that the door is opened to get things, etc. There are now some newer compressor type units on the market, which a lot of commercial truckers are switching to for their sleeper cabs, in lieu of the absorption units that have been around for decades.
Your absorption fridge's efficiency can be improved to some degree by adding additional insulation on the top and sides of the fridge unit, and many of us have also added home-made sheet metal baffles to concentrate the convection flow across the coils in the back to assist it to cool better.

Below is a couple of pics showing the upper baffling I made from a couple of 2 ft. sections of rolled dryer vent sheet metal from the "Big Box" store, a pair of tin snips, some aluminized duct tape to seal gaps, and a few rivets. The view is looking into the upper vent with the grill removed. Besides filling all the void spaces around the fridge on the top and sides, (don't cover the rear of the fridge where the coils and piping are.) There is a curved baffle installed above the cooling coil, and a lower baffle attached to the outer trailer wall. I used 1 rivet and a Snap Cap to secure the lower outer baffle and attached it to existing holes in the upper fridge vent to secure the top of it.

Although I did this to my Casita, it can be easily reworked to fit probably just about any of our trailers with minor modifications. The whole key is you want to form a narrowed draft slot in the vicinity of the cooling coil so that more air is funneled across the cooling fin surfaces to help dissipate heat. After I installed this on my trailer, my fridge setting went down from 4 to 2 to achieve the same level of about 35 degrees F, just by increasing the insulation and increasing the efficiency of the cooling air flow. Although I personally haven't found the need for them, some other additions which others have made to increase air flow across the cooling coils included the addition of a few of those 12 vdc "pancake" computer fans, hooked to a switch on the side of the fiberglass cabinet, to use when needed to boost more cooling air across the fins of the cooler. YMMV

[The Minimalist]

Greg, I have done the same mods on my Dometic, plus added a pancake fan to exhaust heat quicker. It is an improvement, though I still have to adjust the settings. I let it get as cool as it can without freezing, knowing that at some time during the day it will tend to warm up.

Note: The OP is referring to a DC truck fridge with compressor.

[Casita Greg]

Originally Posted by The Minimalist

Greg, I have done the same mods on my Dometic, plus added a pancake fan to exhaust heat quicker. It is an improvement, though I still have to adjust the settings. I let it get as cool as it can without freezing, knowing that at some time during the day it will tend to warm up.

Note: The OP is referring to a DC truck fridge with compressor.

True, but several others had inquired as to whether there was anything they could do to improve the efficiency. My post was more directed at helping those.

[Joe & Cherie]

It's ok, I don't mind discussing both types. It will help others. We can maybe specify which type we are referring to in posts. I'm sure some day I'll have another absorption in a different rv. I will say I absolutely love the compressor style. It cools fast and well. And with a good battery bank, long weekends boondocking should be possible too.

But on the compressor type if they would just put a thermostat that reads interior fridge temp.....bam problem solved. I guess it was a $5 cost savings not to do that!

I guess my only solution is not to be so detail oriented and not try to chase the fridge temps to the perfect spot. And of course keep the beer buried under 20 lbs of ice in the cooler!!!

But if I were in the market for a new fridge, I would try to find one that has that internal thermostat feature.

[Gordon in Idaho]

My Edgestar 12V compressor fridge has an internal thermostat and a digital readout on the side, as I think most chest style fridge/freezers do. If I set my desired temp at 40 degrees F, it cycles on at 42 and off at 38.
I think it helps to maintain a "cold ballast" in the fridge to stabilize the temperature. A case of beer works for me (in the pursuit of efficiency, of course).

Gordon

[Timber Wolf]

I have the Truckfridge and leave it set on five and forget about it, works fine. Sometimes the stuff inside may be a little colder than other times, but not enough to worry about.

[Joe & Cherie]

I like that but unfortunately that puts me in the low 20's on a cool night uuggg!

[Harvey]

Can't answer your question re 12v compressor type fridges. I have a friend who is 'into' truck campers. He first owned a Lance high wall truck camper but has since bought a Palomino pop-up type truck camper with bath, shower & water heater. He recently published (on the truck camper forum) a short treatise on how he stabilized temperatures in his Dometic 3-way fridge. Another member on the forum asked a couple of questions & asked for pix of his mods but he hasn't yet responded. If he does provide pix I'll try to post 'em here, with his permission of course. I've asked for his permission to provide copies of his tutorial to interested absorption fridge owners/ His method provides +/- 3 degree stability with a low control number setting. If/when he provides permission I'll be happy to provide his tutorial by PM, or post it here if he gives permission.

[David B.]

Originally Posted by JWScarab

I like that but unfortunately that puts me in the low 20's on a cool night uuggg!

Joe, our Truckfridge also works on "5" keeping a constant temp. Maybe you should contack Truckfridge and explain your problems.
Dave & Paula

[Joe & Cherie]

Originally Posted by David B.

Joe, our Truckfridge also works on "5" keeping a constant temp. Maybe you should contack Truckfridge and explain your problems.
Dave & Paula

Now that 2 of you guys are getting same results - that's a good idea!! Mine is a NorCold (I used truckfridge as a generic term to describe the 12v compressor type) but I think a phone call to Norcold is a good idea to see if its normal! I'll reply back.....