Fridge fan photos

[DesertDave]

The back side of my fridge appears sealed completely from the inside, when viewed from the outside. Once I removed the upper vent cover (the lower is hinged and thus easy to see inside) I saw no opening of any kind into the interior.

There is a place below the lower edge of the lower vent, say two or three inches deep and the width of the fridge, that is not in the air path from the lower vent to the upper vent. I store small things there, primarily straps for kayaks and stuff I use to hold the wiring in place when I place my portable solar on the windshield. Air and dust goes there, but not into the camper itself. I've not seen water intrusion either, but I try not to spray upwards with the hose in that area when I am washing the truck, either.

The fixed upper vent part is available in-stock in two colors at my local Orchard Supply hardware store. The painted one I think would match the standard exterior of FWC, while the bare aluminum one would better match those who buy the silver exterior model. It is one of the several covers they sell for crawl space and roof eave venting purposes. They also have models with a finer mesh screen inside, if bug intrusion concerns exist.

 

[SLEDAWG]

Bosque Bill. My mod works great for me. I have a 2013 Fleet too with a 65L 2-way. Adding the small fan and vent was the key to exhaust heat from the coils. I added some screening which keeps the rain and mosquitos out. So far no rain penetration. IMO opinion you may not need multiple fans or a large discharge hole. The existing interior vents are sufficient for me. I've noticed fridge cycles less. I have 200W of solar which works great. Took me three years to fine tune my rig including electrical. I added a manually isolator controlled from the cabin along with 6 gauge wire. No issues with power anymore.


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[Bosque Bill]

Thanks again to DesertDave for starting this topic and Sledawg for info applicable to my 2013 Fleet. You guys got me started.

I unscrewed and pried off the louvered vent cover and then removed the sheet of aluminum that was blocking the vent. The coils were right there and low & behold, there is already a factory installed fan. The fan, as FWC made the installation, is about an inch from the blank panel, so there was no where for the air to go. (I must have a different manual than DD as nothing in it is technical or explains the wiring or the presence of a fan.)

I made the decision not to add an additional fan, but to see if simply unblocking the large external vent will suffice as the air can now flow out the vent. There was unfinished luan behind the aluminum siding which also had a gap between it and the frame. I covered the gap and unfinished wood using gaffer tape (maybe not the best tape for this application, but at hand.) This should help keep any rain that blows in from infiltrating the camper walls. I also covered the terminal block as that didn't seem particularly weather resistant.

I got it all buttoned up before I remembered I wanted to put a piece of window screen behind the louvers to keep out bugs, wasps, mosquitos, etc., so had to take it off again. D'oh! I used adhesive to attach the screening to the back of the louvers and am waiting for that to dry before reattaching the vent cover to the camper (as I don't want to permanently affix the cover to the siding.) I will block the two routed, slot vents above the fridge on the inside to reduce drafts, since they are no longer needed.

 

[SLEDAWG]

Just spent the last 3 nights at Mahogany Flats campground in Death Valley. Fridge set at 3.5. Temp stayed solid at 39 and ice cream and steaks rock solid frozen. 90 degrees at 8100 ft mid-day. 60s at night. First trip after installation of vent fan. Usually, ice cream gets soft and temp in fridge varies during the day. In my opinion, vent made the difference.



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[Will.I.Am]

A couple folks asked me in another thread about the fridge fans I had installed. I thought it best to start a new thread with the photos.

I'd heard from WTW member Dr. J. that he had measured approximately a 30% reduction in electrical useage by his compressor fridge, through the installation of some auxiliary 'pancake' fans that moved air through the condenser coil and out of the vent compartment on the rear (exterior) of his fridge. That sold me on doing something similar myself.

As far as wiring them in, my first thought was to use the existing factory wiring to the back of the fridge area, that was intended for the auxiliary fan for the three way fridges. While easy to find at the back of the fridge, it was not so easy to locate the other end in the battery compartment of my front dinette Grandby.

So I looked at the Dometic wiring schematic from the fridge manual (you read the manual, right?), and tapped into the power wire for the Dometic fan that is on the back of the fridge. It is powered when the compressor runs, which is when I would want the fans to run anyway. You can see my kludgy wiring connection in the photo above showing both fans. I needed to separate out some wiring on the factory bundle to gain access to the wire I needed.

I don't have any of the fancy meters like the Trimetric that Dr. J. used to measure the impact of his install, so I can't verify the results. I do hear the fridge run a lot less, and frequently my AM voltage (before the solar starts charging) sits at 12.9V when I first get up, so I am pretty sure that I have made a large decrease in the electrical draw via this modification.

Hope this helps someone.

Hi DesertDave - any issues with overloading the Dometic 12V supply to the fans? Did you simply split the wires coming out of the panel on the fridge?

 

[Stalking Light]

My 2014 Eagle has the upper and lower vents as well as a single fan. It also has the black and blue 'fan' wires in the upper compartment, but there is just a blank in the fan switch inside the camper. When I metered the wires, however, I found they were always 'hot' so I used them in conjunction with a relay wired to use the negative 'F' connection on the fridge as the trigger to run a second fan only when the first fan is running and not have to worry about the Dometic power supply getting overloaded.

 

[Will.I.Am]

...I used them in conjunction with a relay wired to use the negative 'F' connection on the fridge as the trigger to run a second fan only when the first fan is running and not have to worry about the Dometic power supply getting overloaded.

Thanks Stalking Light, I'm going to work on figuring out how you did you're wiring, that sounds like a good approach. Wish I was better at electrical...

Secondary question: do folks generally wire their fridge directly to the battery..and would this improve fridge performance? I swapped out the orig NorCold 3 way for the Dometic CR-1110, and just used the existing DC circuit for the new fridge. There are hardly any other loads on the system, except at night.

 

[Stalking Light]

Here's a diagram of how the relay is wired

The wire on the right is connected to the 4th wire down on the wiring block of my Dometic 65.

The wire on top is connected to the + side of the fan and the - side of the fan to chassis ground.

 

[JaSAn]

Secondary question: do folks generally wire their fridge directly to the battery..and would this improve fridge performance? I swapped out the orig NorCold 3 way for the Dometic CR-1110, and just used the existing DC circuit for the new fridge. There are hardly any other loads on the system, except at night.

My 2 way refrigerator is on its own dedicated circuit, wired directly to the fuse box. Since my frig can draw 60+ Watts on startup, I thought it was prudent to give it its own circuit. Exhaust fan is controlled by a thermal switch (comes on at 80°F in the condenser plenum) and is on a separate circuit.

jim

 

[DesertDave]

Hi DesertDave - any issues with overloading the Dometic 12V supply to the fans? Did you simply split the wires coming out of the panel on the fridge?

Things still work, so I think the answer is no issues. I added .6 Amps to a circuit that carried less than .5 initially, and the distance was measured in inches. Even with tiny gauge wires the load was a fraction of what it is rated to carry.