Hello everyone,
I thought I'd share my experience with building and installing an exterior fan mod for my Dometic RM2351 fridge in our travel trailer. I'm doing this in the hopes that it will keep my fridge at a safe temp when the vent side is facing the sun and it's 85F-90F outside (a common temperature range for our trips in the Michigan/Ohio area).
From the factory, it cools great when it's in the shade and it's not more than 70F outside. But once the day starts to heat up, the interior temps have gotten as high as the low 50's - clearly not a safe place to keep food!
Anyway, I looked at various after market 3rd party fan kits already sold, such as the solar version from Camco and a few others. I felt like I could do something much more powerful at a much lower cost with computer case fans, so here's what I did...
For starters, here's the exterior of my TT's vent-side, where the rear of the fridge is located:
Unfortunately, there appears to be some dead space above the fridge, as I discovered when I pulled the panels off. It looks kind of like this:
Anyway, what I intended to build was a 4-fan array supported by two aluminum L-brackets that I got at Home Depot. They would direct air out of the top vent like this:
The computer case fans are standard 80mm, push about 30+ CFM, and draw about .15A each on the 12 volt rail. I decided to do a test run by plugging them into the 120v line (sharing the same plug as the fridge) by using a 12 volt Molex adapter (available at Newegg and/or Amazon, etc). Here's the fans:
So I began to take the panel off by unscrewing it and carefully cutting the silicon seal around the edge. Must be careful - I accidentally gouged out my paint on the top in one small area! 😞
With the panel removed, I discovered that the evaporator cooling fins were placed a lot higher than I originally thought. I was planning to mount the fans pointing up and using directional chute vents to direct the air out at a curved 90 degree angle, but due to space constraints I had to mount them in the front blowing air straight out. I measured about 22" width, cut my aluminum L-brackets to length, and hand assembled them for a trial fit:
I began by setting the fans in the L-Brackets and drilling a marker hole with a bit much smaller than the diameter of the case fans. Then I set them aside and drilled a hole large enough to get a #10 32x1/2" round head screw through the L-Bracket loosely and torquing them down into the fan frames to hold the whole assembly together. One by one I screwed them together - the end result is quite sturdy:
I was going to solder everything together, but decided to use a European-style terminal strip (from RadioShack) so that I could easily replace the fans if one went bad. Initially I just wired them all into one termination point as I didn't want to go through the hassle of doing them one by one for my initial "dry run":
The finished array turned out like this (though I will eventually wire each one into its own terminus in the strip, tidy up the wires, etc, should it work OK:
I mounted it right in front of the fins, with the directional chutes all blowing out and slightly down in an effort to curtail moisture from falling down into the fans when it rains hard. You can see in the second pic that the fan array sits right on top of the cooling fins:
I let it run last night starting at about 8:30 PM, when it was about 82F outside. When I got up this morning, it was a chilly 35F inside:
But unfortunately, when it hit around 2:15 PM today I checked again. The temperature had climbed to 42F, which is unsafe for proper food storage. Hmmmm....
That said, it was about 84F today and sunny. Normally my fridge temp would be climbing closer to the high 40's/low 50's, so it does appear to be aiding in cooling - just not as good as I had hoped. Next I will try filling the dead air space above the fridge, and then adding a second interior fan blowing off of the inside cooling fins.
Right now I utilize one of those battery operated Camco fridge fans, but it doesn't really blow air onto the inside cooling fins.
So... all in all... I'm a little disappointed, but still hopeful. Total cost for building this was under $70 in parts, and I thought that pushing almost 120 CFM in such a small area would definitely solve my issue.... but it didn't.
Oh and, as far as noise - they are barely audible running at full RPM. If I do end up keeping this on and hard wiring it into my 12-volt system, I'll likely just put an on/off switch on the rear when I wire it up. That said... getting power to my interior fan idea is a whole other problem. No internal light or power source, so I'll have to do some drilling into my fridge wall - which scares me.
I thought I'd share my experience with building and installing an exterior fan mod for my Dometic RM2351 fridge in our travel trailer. I'm doing this in the hopes that it will keep my fridge at a safe temp when the vent side is facing the sun and it's 85F-90F outside (a common temperature range for our trips in the Michigan/Ohio area).
From the factory, it cools great when it's in the shade and it's not more than 70F outside. But once the day starts to heat up, the interior temps have gotten as high as the low 50's - clearly not a safe place to keep food!
Anyway, I looked at various after market 3rd party fan kits already sold, such as the solar version from Camco and a few others. I felt like I could do something much more powerful at a much lower cost with computer case fans, so here's what I did...
For starters, here's the exterior of my TT's vent-side, where the rear of the fridge is located:
Unfortunately, there appears to be some dead space above the fridge, as I discovered when I pulled the panels off. It looks kind of like this:
Anyway, what I intended to build was a 4-fan array supported by two aluminum L-brackets that I got at Home Depot. They would direct air out of the top vent like this:
The computer case fans are standard 80mm, push about 30+ CFM, and draw about .15A each on the 12 volt rail. I decided to do a test run by plugging them into the 120v line (sharing the same plug as the fridge) by using a 12 volt Molex adapter (available at Newegg and/or Amazon, etc). Here's the fans:
So I began to take the panel off by unscrewing it and carefully cutting the silicon seal around the edge. Must be careful - I accidentally gouged out my paint on the top in one small area! 😞
With the panel removed, I discovered that the evaporator cooling fins were placed a lot higher than I originally thought. I was planning to mount the fans pointing up and using directional chute vents to direct the air out at a curved 90 degree angle, but due to space constraints I had to mount them in the front blowing air straight out. I measured about 22" width, cut my aluminum L-brackets to length, and hand assembled them for a trial fit:
I began by setting the fans in the L-Brackets and drilling a marker hole with a bit much smaller than the diameter of the case fans. Then I set them aside and drilled a hole large enough to get a #10 32x1/2" round head screw through the L-Bracket loosely and torquing them down into the fan frames to hold the whole assembly together. One by one I screwed them together - the end result is quite sturdy:
I was going to solder everything together, but decided to use a European-style terminal strip (from RadioShack) so that I could easily replace the fans if one went bad. Initially I just wired them all into one termination point as I didn't want to go through the hassle of doing them one by one for my initial "dry run":
The finished array turned out like this (though I will eventually wire each one into its own terminus in the strip, tidy up the wires, etc, should it work OK:
I mounted it right in front of the fins, with the directional chutes all blowing out and slightly down in an effort to curtail moisture from falling down into the fans when it rains hard. You can see in the second pic that the fan array sits right on top of the cooling fins:
I let it run last night starting at about 8:30 PM, when it was about 82F outside. When I got up this morning, it was a chilly 35F inside:
But unfortunately, when it hit around 2:15 PM today I checked again. The temperature had climbed to 42F, which is unsafe for proper food storage. Hmmmm....
That said, it was about 84F today and sunny. Normally my fridge temp would be climbing closer to the high 40's/low 50's, so it does appear to be aiding in cooling - just not as good as I had hoped. Next I will try filling the dead air space above the fridge, and then adding a second interior fan blowing off of the inside cooling fins.
Right now I utilize one of those battery operated Camco fridge fans, but it doesn't really blow air onto the inside cooling fins.
So... all in all... I'm a little disappointed, but still hopeful. Total cost for building this was under $70 in parts, and I thought that pushing almost 120 CFM in such a small area would definitely solve my issue.... but it didn't.
Oh and, as far as noise - they are barely audible running at full RPM. If I do end up keeping this on and hard wiring it into my 12-volt system, I'll likely just put an on/off switch on the rear when I wire it up. That said... getting power to my interior fan idea is a whole other problem. No internal light or power source, so I'll have to do some drilling into my fridge wall - which scares me.
'tiredTeacher wrote:
One more thought. It is more difficult to PULL air across those coils than it is to BLOW the air. On my Pop up, I put the fan under the coil and blew the air up and out, drawing from the lower vent.
So, your recommendation was stuck in my mind while I was at work today, so the moment I got home and got dinner finished I took it upon myself to try this approach. I had to remove all of my directional chutes and one side of the aluminum L-bar, but I was able to get all 4 fans directly below the evap fins, pointing up. I then fashioned a (temp) upper baffle out of cardboard and duct tape to eliminate the dead space above the food compartment and direct the air out of the entire upper vent cavity.
'tiredTeacher wrote:
I also added a baffle to separate the lower compartment from the upper.
Teach
Curious - could you elaborate more on this? Is it possible for you to take a photo of your setup and post it here? I'm not sure what you mean by separating the lower and upper compartment.
All that said, in a very strange turn of events, this July in lower Michigan has turned out to be unusually cold - as it's currently 64F outside at 9PM and is going to drop to the mid-50's tonight (it's normally mid 80's to lower 90's in this area and mid 70's at night). So I'm not going to be able to get an accurate feel of how this temporary mod works until it heats up again (projecting low 80's again by the weekend).
This is unfortunate, as we are leaving Monday to go for a weeklong camping trip in Ohio and I wanted to have my temporary mod settled into a permanent mod before the trip. :s Guess I'll have to test this setup "in the field"! 😄
Here's new pics of what I did:
I'm almost embarrassed about the cardboard baffle, but it's really just a test run to see if it works. That said, I can't run this off of propane until I wrap at least part of it. The burner stack is just too close for my comfort.
