I know hot weather cooling of the fridge can be difficult so I've modded an upper vent panel to include a fan and a thermostat. I'm hopeful that when the back of the fridge cabinet gets hot the additional airflow will cool it enough to allow better heat transfer though the outer coils. For power I'm running it to a portable battery box I use but there is an easy tap in to 12 volts right at the base of the fridge. From a parts perspective this thing is pretty cheap to build, a Dometic vent panel for $25 (don't want the fan stuff on while traveling), a thermostat controller for $7 and the weatherproof box for the thermostat $22. If anyone is interested I'll link the parts on Amazon.
Mitch
MitchB:
While I have never had a problem with fridge cooling in our NE US climate, I am intrigued by your design. Some questions:
I assume that the spare Dometic panel is so that when you reach your destination you can pull off the existing panel and replace it with this one with the fan and controls, right?'
Why don't you want it on when traveling?
Why do need a thermostat? These small DC fans draw very little current so you could just power it from a switched source in the fridge and leave it on all of the time. Or you might be able to find a DC source in the fridge that is thermostatically switched to power it with. Maybe the burner solenoid valve for LPG use or an AC relay for AC use or both with a couple of diodes.
David
Hey David,
Yes you are correct about installing the modified panel after arrival. In my configuration since I'm using a separate power supply I'd have to manage the wires plus the fan itself isn't really an outdoor type of fan so if I were to hit some wet weather during travel it could be damaging. Everything is pretty secure so it's more about the electronics than the danger of it falling off.
With respect to the thermostat, I had it and it's cheap as sin so I used it rather then tie into something in the trailer itself. Plus, while the draw of the fan is only .25 amps that's 6 amps over the course of the day and I boondock medium to long periods of time so battery is a consideration. I could tap the fridges 12 volt source, it's right there and I might in the future but for the moment I prefer using a different power source.
Hello,
Have a look at the products from arprv.com , they provide fridge protection devices along with a single or dual fan ventilation systems.
Cheers!
Very clever! Replacing the entire vent cover with a fan unit is something I never thought of.
I installed this Valterra fan and have used it for 2 years. I have no data on increased efficiency, but it helps me think I'm improving efficiency whenever I hear its gentle hum as a walk around the back of the camper outside 8)
https://www.amazon.com/Valterra-A10-2618VP-FridgeCool-Exhaust-Fan-12/dp/B002N5YDG2/ref=cm_cr_arp_d_product_top?ie=UTF8
This is mounted inside the external fridge compartment on an existing bracket about halfway between the upper and lower coils. It definitely improves air flow when the included thermostat turns it on. I hardwired it into the 12V available in the compartment.
I've run fans on many fridges over the years- never mounted one outside though- I like it inside the panel out of sight and out of the weather.
12V computer fans work great- I usually use a pair with an mechanical thermostat so no power is drawn when cooling isn't needed.
They are mostly needed because many RV builders do NOT follow the fridge makers instruction on proper installation as to baffling and airflow.
The fridge installs with the upper vent in the wall rather than in the roof usually perform worse and benefit from fans the most.
I could mount the fan on the inside of the vent cover, do you have a thought on whether that would increase or decrease the amount of air moved out of the cabinet? There's not much room between the vent and the back of the fridge.
Quote from: MitchB on July 18, 2019, 11:47:18 PM
I could mount the fan on the inside of the vent cover, do you have a thought on whether that would increase or decrease the amount of air moved out of the cabinet? There's not much room between the vent and the back of the fridge.
Inside and with a clear airflow to the entire fan seems like it would improve cooling the most. Could you mount the fan horizontally at the bottom of the vent and still have clearance with the back of the fridge?
Quote from: Merlin on July 18, 2019, 02:03:05 PM
Very clever! Replacing the entire vent cover with a fan unit is something I never thought of.
I installed this Valterra fan and have used it for 2 years. I have no data on increased efficiency, but it helps me think I'm improving efficiency whenever I hear its gentle hum as a walk around the back of the camper outside 8)
https://www.amazon.com/Valterra-A10-2618VP-FridgeCool-Exhaust-Fan-12/dp/B002N5YDG2/ref=cm_cr_arp_d_product_top?ie=UTF8
This is mounted inside the external fridge compartment on an existing bracket about halfway between the upper and lower coils. It definitely improves air flow when the included thermostat turns it on. I hardwired it into the 12V available in the compartment.
If I were a RV full-timer, I would sure consider these. They are bit too spendy for a casual RV'r like me. Have you installed one in your camper?
Quote from: Merlin on July 19, 2019, 05:47:22 PM
Quote from: MitchB on July 18, 2019, 11:47:18 PM
I could mount the fan on the inside of the vent cover, do you have a thought on whether that would increase or decrease the amount of air moved out of the cabinet? There's not much room between the vent and the back of the fridge.
Inside and with a clear airflow to the entire fan seems like it would improve cooling the most. Could you mount the fan horizontally at the bottom of the vent and still have clearance with the back of the fridge?
I did cut away the vent behind the fan so it's unobstructed airflow. We'll see if it works, next week I leave for a 2 week boondocking trip.
One more quick question. How will you keep the sealed thermostat box from getting too hot in the sun and too cold at night? Maybe that doesn't matter?
Quote from: Merlin on July 19, 2019, 08:23:57 PM
One more quick question. How will you keep the sealed thermostat box from getting too hot in the sun and too cold at night? Maybe that doesn't matter?
I'm cautiously optimistic that it won't matter. We'll see.
I was just playing around with cooling on my own fridge last week. In my case I was trying to prevent the existing thermostatic fan from kicking on because it seemed to be running too often. I was planning to either assist with airflow (taking off the cover will stop the fan within seconds), or using a lower power/quieter fan. So my first question to everyone that has responded so far: Do you have a stock fan at all? It doesn't sound like it. My trailer came from the factory with a relatively small Sunon that makes a bunch of noise and doesn't seem to do much. It's mounted on a bracket near the top of the cabinet, but points up. My idea was to install an array of larger, lower power fans (like 120mm Noctua industrial) on a baffle so that the air has to leave the cabinet instead of just swirling around in circles. I was hoping to keep the power the same or lower than the existing fan so that I could just steal its power connection. Any thoughts?
My '15 16TBS with a single door Dometic 3-way fridge did not come with an external fan. The 2 rear- facing vents have what I think is very poor circulation for the cooling fins in the exterior compartment. I like the idea of a baffle in there to force the air up and out. I do think the single fan I added pointing up in the central part of cabinet helps, but for sure a lot of the air it moves just circulates internally. It also runs pretty much all the time, though the thermostat turns it off on cool nights. It is quiet when running. Installing an array of fans pointing out (or a single fan like MitchB) sounds good. That compartment gets HOT!
No fan came on mine either and as Merlin said that compartment gets very hot. There is essentially no air circulation around the cooling fins because they are above the highest vent in the vent panel. I thought about a baffle above the fridge but the available space is small and a baffle would still be above the vents and mounting would have been a challenge. Last year as I was pondering this issue I even thought that perhaps the fridge wasn't installed correctly given the tight space but it is. I think my solution will help, we'll see. It can certainly stand some refinement if I find it's worthwhile.
I put the same fan in as Merlin. We are camped at the beach in Sea Girt, NJ during the "heat wave" and the ice cream in the freezer is frozen.
No data on the fan but our rear with the fridge is pointed into the sun so I believe having some air flow has to help.
The heat index yesterday was 108 F.
Merlin - I like that Valtera fridge fan mod. My electrical abilities are limited to changing out home outlets and light switches. How difficult is it to hardwire that fan into the 12v in the compartment? I suppose I could hire an electrician to do that if it is a really beneficial mod. Thanks
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Last week we were camping in 95 degree and high humidity conditions. Like others here I have added a couple fans inside the outer fridge compartment to move air but sometimes it seems it just needs more flow so this is what I tried. I plugged this fan in and left it running the entire 4 days and all our food stayed good and cold. It moved a lot of hot air out of the compartment.
Now that's a fan! I'll bet you could even turn down the fridge controls a bit!
Quote from: dlb53151 on July 12, 2020, 01:57:33 AM
Merlin - I like that Valtera fridge fan mod. My electrical abilities are limited to changing out home outlets and light switches. How difficult is it to hardwire that fan into the 12v in the compartment? I suppose I could hire an electrician to do that if it is a really beneficial mod. Thanks
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Yours is probably the same fridge compartment as mine. I'll take and post a photo of the wiring. You need to splice into a 12V positive and connect the negative to a ground point, plus add a fuse. One of us on here can talk you through it and it's as easy as changing an outlet or switch and no risk of shock.
Quote from: mojospeople on July 12, 2020, 12:08:23 PM
I plugged this fan in and left it running the entire 4 days and all our food stayed good and cold. It moved a lot of hot air out of the compartment.
To misquote Pinstriper,
you can never have enough fan! :D
This is my first summer since adding 12V squirrel cage fans to the bottom and top fridge vents and controlled by a temp sensor. In western Canadalands, this year we haven't come close to the temps you've encountered, but for the first time, I can run my fridge on the low setting and even then, I've had to increase the temp at which those fans turn
off to keep the inside fridge temp above 37F. Currently, I think it's 95F. GK
Thanks Merlin!!'
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Quote from: Merlin on July 12, 2020, 12:26:20 PM
Quote from: dlb53151 on July 12, 2020, 01:57:33 AM
Merlin - I like that Valtera fridge fan mod. My electrical abilities are limited to changing out home outlets and light switches. How difficult is it to hardwire that fan into the 12v in the compartment? I suppose I could hire an electrician to do that if it is a really beneficial mod. Thanks
Sent from my iPhone using Tapatalk
Yours is probably the same fridge compartment as mine. I'll take and post a photo of the wiring. You need to splice into a 12V positive and connect the negative to a ground point, plus add a fuse. One of us on here can talk you through it and it's as easy as changing an outlet or switch and no risk of shock.
Looking forward to that photo Merlin! I want to do the fan mod too!
Thanks
I can't figure out how to post my photos........
@Paul (https://aluminumcamperforum.com/index.php?action=profile;u=1) , is there a file size limit?
Quote from: Merlin on July 12, 2020, 05:19:24 PM
I can't figure out how to post my photos........
@Paul (https://aluminumcamperforum.com/index.php?action=profile;u=1) , is there a file size limit?
@Merlin (https://aluminumcamperforum.com/index.php?action=profile;u=42)
The size limit is hight enough shouldn't be a problem, can you email me the pictures I'll give it a try
Posting for Merlin
Thanks Paul.
The photo of the fan shows its placement in the upper cabinet pointing up. It's the Valterra brand. https://www.amazon.com/Valterra-A10-2618VP-FridgeCool-Exhaust-Fan-12/dp/B002N5YDG2
The photo of the cabinet shows where I tapped into the 12V DC. The red positive wire from the fan goes into the orange wire hole and the black negative wire goes into the white wire hole in the DC junction block. I put a 2A Littlefuse holder (that has a yellow wire in/out) in the positive wire and used crimp type heat shrink connectors to make the connections. After I took the photos I redid the wire ties that normally button everything up.
All told, it was probably an hours worth of fun. The thermostat on the fan works fine; running on warm days or in the sun and turning off at night. I'm convinced the additional air circulation in that cabinet is what contributed to being able to turn the fridge controls down one number and yet maintain proper temps. ( I have a hanging thermometer inside the fridge and check it every opening.)
Thanks for the photos and all the information Merlin!
Merlin,
Do you know at which temperature the fan activates?
On at 100F and off at 80F. So in typical summer temps here in Michigan, it runs afternoon/evening and is off night/morning. Unless the compartment is in the direct sun, then on all but early morning.
The good news about several thermostatically controlled external fans is that I can finally keep the inside of the fridge cool. The bad news is that keeping the inside fridge temp consistent takes day to day adjustment of off/on fan temps. Perhaps this negative is more of a function of camping in northern Canadalands where wild swings of temperatures are commonplace. GK
Quote from: Merlin on July 15, 2020, 07:51:04 PM
On at 100F and off at 80F. So in typical summer temps here in Michigan, it runs afternoon/evening and is off night/morning. Unless the compartment is in the direct sun, then on all but early morning.
Thanks for the great info Merlin. I thought the on/off temperature would be the same. I feel like there is quite a gap between the two temps. Can we adjust the on/off temps?
Quote from: GrampaKilt on July 15, 2020, 08:44:36 PM
The good news about several thermostatically controlled external fans is that I can finally keep the inside of the fridge cool. The bad news is that keeping the inside fridge temp consistent takes day to day adjustment of off/on fan temps. Perhaps this negative is more of a function of camping in northern Canadalands where wild swings of temperatures are commonplace. GK
GK, do you use the same fan?
You are so right about Canadalands GK! A few days ago we had temps of 32'c and very humid. Today it's 18'c and bone dry!!
Quote from: Sylvain on July 16, 2020, 07:27:38 PM
Quote from: GrampaKilt on July 15, 2020, 08:44:36 PM
The good news about several thermostatically controlled external fans is that I can finally keep the inside of the fridge cool. The bad news is that keeping the inside fridge temp consistent takes day to day adjustment of off/on fan temps. Perhaps this negative is more of a function of camping in northern Canadalands where wild swings of temperatures are commonplace. GK
GK, do you use the same fan?
You are so right about Canadalands GK! A few days ago we had temps of 32'c and very humid. Today it's 18'c and bone dry!!
No adjustments and you would not want to. The temp gap keeps the fan from short cycling (frequently starting and stopping).
(Oops, replied to the wrong thread. Oh well)
I have not found a linear relationship between external fan OFF/ON, external air temps, the temp in the fridge coils and internal fridge temps, so that one OFF/ON setting does it all.
My first fan iteration of 2-5" computer fans exhausting at the upper vent was ineffective. I finally used the idea found here https://www.arprv.com/rv-fridge-fan.php , that of installing 4" squirrel cage fans, one at the lower vent, one at the upper. Pricey ARPRV's fans (proprietary?) were to tough to spec online (0.2A draw and 1800 rpm) but I finally found something close in Aliexpress. The fans are controlled by this inexpensive temp controller https://www.amazon.ca/dp/B07VRNM9FS/ref=dp_prsubs_2 . The sensor is attached to the bottom coil per ARPRV's recommendation. Currently the OFF/ON differential is set for 15 degrees with OFF being 95F.
This fan configuration really moves the air! Lately, I've experimented with the COLD to COLDEST temp button instead of adjusting external fan OFF/ONs. This is working most of the time.
A second controller (same brand) regulates the fans inside the fridge https://rvcoolingunit.com/Norcold-Evaporator-Fan-Greater-inside-Cooling-Custom-Deluxe-wGrill-P3239953.aspx . The OFF/ON differential for this one is 5 degrees, OFF is 37F.
A couple of asides.
1. I left the 5" fans insitu which happen to be lighted, one red, the other green. If the fans are running in the evening, the glow emanating from the upper grill is pleasantly eerie.
2. I struggle mightily with English translations of Chinese instructions so that once I finally 'get' it, I rewrite them for future reference. If any are interested the temp controller above, FWIW, here is my rewrite. https://drive.google.com/file/d/1htdPDo9QEqIGwLUx2WZ8PJyweebgNwWv/view?usp=sharing
Regards, GK
Quote from: Merlin on July 16, 2020, 09:20:45 PM
Quote from: Sylvain on July 16, 2020, 07:27:38 PM
Quote from: GrampaKilt on July 15, 2020, 08:44:36 PM
The good news about several thermostatically controlled external fans is that I can finally keep the inside of the fridge cool. The bad news is that keeping the inside fridge temp consistent takes day to day adjustment of off/on fan temps. Perhaps this negative is more of a function of camping in northern Canadalands where wild swings of temperatures are commonplace. GK
GK, do you use the same fan?
You are so right about Canadalands GK! A few days ago we had temps of 32'c and very humid. Today it's 18'c and bone dry!!
No adjustments and you would not want to. The temp gap keeps the fan from short cycling (frequently starting and stopping).
(Oops, replied to the wrong thread. Oh well)
Ok! Thank you so much Merlin.
Quote from: GrampaKilt on July 17, 2020, 01:14:19 PM
I have not found a linear relationship between external fan OFF/ON, external air temps, the temp in the fridge coils and internal fridge temps, so that one OFF/ON setting does it all.
My first fan iteration of 2-5" computer fans exhausting at the upper vent was ineffective. I finally used the idea found here https://www.arprv.com/rv-fridge-fan.php , that of installing 4" squirrel cage fans, one at the lower vent, one at the upper. Pricey ARPRV's fans (proprietary?) were to tough to spec online (0.2A draw and 1800 rpm) but I finally found something close in Aliexpress. The fans are controlled by this inexpensive temp controller https://www.amazon.ca/dp/B07VRNM9FS/ref=dp_prsubs_2 . The sensor is attached to the bottom coil per ARPRV's recommendation. Currently the OFF/ON differential is set for 15 degrees with OFF being 95F.
This fan configuration really moves the air! Lately, I've experimented with the COLD to COLDEST temp button instead of adjusting external fan OFF/ONs. This is working most of the time.
A second controller (same brand) regulates the fans inside the fridge https://rvcoolingunit.com/Norcold-Evaporator-Fan-Greater-inside-Cooling-Custom-Deluxe-wGrill-P3239953.aspx . The OFF/ON differential for this one is 5 degrees, OFF is 37F.
A couple of asides.
1. I left the 5" fans insitu which happen to be lighted, one red, the other green. If the fans are running in the evening, the glow emanating from the upper grill is pleasantly eerie.
2. I struggle mightily with English translations of Chinese instructions so that once I finally 'get' it, I rewrite them for future reference. If any are interested the temp controller above, FWIW, here is my rewrite. https://drive.google.com/file/d/1htdPDo9QEqIGwLUx2WZ8PJyweebgNwWv/view?usp=sharing
Regards, GK
Thanks for sharing GK! This might be very useful!
Thanks Paul and Merlin. If I understand correctly I just need to buy that one Valtera fan (versus dual fans and other fancy setups) and position / wire it like you showed. I'll plan to get that done this summer and will let you know if I have any questions.
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