Fun with Fans and Fridges
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Category: R-pod Discussion Forums
Forum Name: Podmods, Maintenance, Tips and Tricks
Forum Discription: Ask maintenance questions, share your podmods (modifications) and helpful tips
URL: http://www.rpod-owners.com/forum_posts.asp?TID=12075
Printed Date: 02 May 2024 at 8:12am
Software Version: Web Wiz Forums 9.64 - http://www.webwizforums.com
Topic: Fun with Fans and Fridges
Posted By: fwunder
Subject: Fun with Fans and Fridges
Date Posted: 19 Aug 2018 at 7:39pm
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by fred... OK, so I got OCD. Can't help that. I am obsessed with getting as much cold out of my fridge as I can. I really like steaks I can freeze and eat a week to ten days into trip. And we consume an above normal amount of cold milk and white wine, cheeses and spreads and jellies and jams (not at the same time). I prefer running fridge on propane and am a pro at disassembling, cleaning and reassembling the propane system. Still, when ambient temps reach 90+ and I'm not using the AC, it struggles. If sun is hitting pod in those temps it struggles even with the AC running. By that I mean, fridge rises above 40 (42-45) and freezer about 15 or so or even 20. Opening frequently, of course, makes it much worse. At night, it's never really a problem and by AM the fridge is back down to mid to upper 30's and freezer 5-10 or so. This past summer I have been watching and documenting closely (see OCD above). BTW, the above observations are all @ 4 bars (hot weather setting for us). BTW, I do carry a Coleman thermoelectric (12volt) cooler which works great for storing 12 oz. adult beverages and other frequently requested items. Sooo, it's obvious that ambient temp has a lot to do with fridge efficiency. After all, the fridge is absorbing heat from inside the fridge and dumping in back outside to the back of the fridge. The hotter the back of the fridge, the less room for heat to be dumped and the warmer the fridge gets. Simplistic, but makes sense to me. That's why it works better at night - because there is more room for the hot air to dump and because my frequent trips for adult beverages are made to the cooler. Yep, we pulled off the vent covers to make it easier for the absorbed hot air to escape and have even played with "heat shields" to try and block sun from heating compartment. Both help, but still not the solution I think I have been looking for. About a year or so ago I was reading all these people on the internet saying that circulating air in the fridge was *the* solution. Sorta made sense and since everything on the internet is true I bought one. Didn't make any difference as far as I could tell. Maybe in a larger fridge, but I didn't see any difference in the little pod fridge. I put the fan(s) in one of my gadget boxes. (Cleverly hidden from OCD wife who suffers from anti-clutterism!!). You've seen them  Repurposed as...  Cool, huh? Get it? Cool. The last four days have been perfect testing right here in my driveway. First day was sunny and mid 90s. Started up the fridge about midday and put a bunch of bottles of cold water, a half gallon container of water and half a dozen freezer packs. About as full as we would have it camping. I did leave the freezer empty. The fridge and freezer temp @ start were both about 87. I started the vent fan above as well as jumping the pancake fan to circulate as much air as possible. Slideout was in, AC off. Windows closed. Alec Guinness would appreciate the conditions in the pod (any Bridge On The River Kwai fans?). I turned off the pancake fan and left my new vent fan on late afternoon. I left the vent fan on for the duration of the test. Day two and three were ridiculous. Pod in full sun. Daytime highs 92-95 and high humidity. I still can't believe I lived in Florida for 25 years. Nuts. I closely monitored fridge temps. I use one of this AccuRite things that seems to be pretty accurate. So both mornings I started out with 2 and 6 in freezer and 36 in fridge. Surprisingly close and pretty encouraging. During the day, the temps rose. I did open the fridge for about thirty seconds or so both days just cuz I want to stick my finger in the water to see if it really was that cold. When I saw freezer hit 12 degrees and fridge about 38, I jumped the pancake fan to move some more air. It helped and temp dropped back a couple of degrees. I could feel the hot air pouring out of the top vent. Interestingly, I measured the switch that is supposed to kick on the pancake fan and it never seemed to get much above 130 (IR and Thermopen). Over the first two days the fridge maxed out @ 40. Considering the "I'll tell you anything!!" conditions inside the pod, I was impressed. BTW, I put the AccuRite sensor below the metal shelf and on top or the crisper in the center of the fridge. Last night was cool and today the temps were mid-seventies and overcast. Measured temps were 1 in freezer and 32 in fridge this AM. By the time I concluded test this afternoon, temp in freezer was 2 and fridge 32. If you got this far, cheers!! I'm pretty comfortable in concluding that the most effective way to make your fridge more efficient is to get rid of the hot air behind it. And, maintain it, of course. If your ambient temps don't exceed mid seventies and your having a problem, there are other issues. I also ordered a switch that supposedly opens @ 125-130 instead of the 158 that come with the fridge. Might be better than putting a manual switch on pancake fan. We'll see. Pod On!! fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Replies:
Posted By: fwunder
Date Posted: 21 Aug 2018 at 8:43am
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Just to followup. Received and replaced fan limit switch (thermo disc). The package I ordered: https://www.ebay.com/itm/Dometic-3850306063-RV-Refrigerator-Thermal-Switch-repl-Exhaust-Fan-Instruct/121639099462 - https://www.ebay.com/itm/Dometic-3850306063-RV-Refrigerator-Thermal-Switch-repl-Exhaust-Fan-Instruct/121639099462 With some minor modifications I pushed out the old (158 degree) switch and replaced it with the new 122 degree disk.  Cut and replaced fan wire spade connectors and put it back in place  Of course, now it has cooled down here considerably so I may have to wait until another hot day to really test. fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: mcarter
Date Posted: 21 Aug 2018 at 8:50am
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fwunder,
looking at pic of switch in cooling fins. I moved my switch from the space provided out to the elbow area, to right of fins. It's a least 40 degrees hotter out there, measured at the tube. My fan runs more often and I didn't change temp switch. ------------- Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability." |
Posted By: fwunder
Date Posted: 21 Aug 2018 at 8:58am
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Hi Mike, Yep, that's an option and it's the first thing I did also. I found on my box that when on propane that area pretty much stayed above 160 degrees and thus the fan stayed on pretty much all the time. If it works for you, great! I am thinking I will use the old (158 degree) disc in that area to control the exhaust fan. Thanks! fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: mcarter
Date Posted: 21 Aug 2018 at 9:01am
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Good advice, I will watch also. ------------- Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability." |
Posted By: Subzilla
Date Posted: 21 Aug 2018 at 9:41am
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I had been very frustrated with our fridge temps so I took it some steps further than you! I not only added 2 computer fans at the top exhaust but added 2 on the bottom intake to push the air up plus added (molded) a piece of aluminum to force the air from the bottom up and directly through the cooling fins. I also added a separate switch to turn the fans on anytime I wanted. So I have 5 fans running.....maybe overkill... I also have the little battery operated circulating fan inside. Would like to get the hardwired version. Our temps had been getting to 50 prior to this. A week in 95 degree Florida last month and it stayed below 42ish in the hottest part of the day. We opened the fridge at meal time more than once but were always quick when we did. I decided just recently to remove the freezer part and will test that here in a few weeks. LOTS of internet info on this and website businesses devoted to this problem. I was even considering an electric only Danfoss compressor type fridge....very energy efficient but won't work on gas. ------------- Mark Concord, NC 2017 RP 179 "Podzilla" 2011 Silverado 1500 4X4 |
Posted By: mjlrpod
Date Posted: 21 Aug 2018 at 10:40am
Since the 90 degree hot temps are short lived, (atleast in my area) might it be more convenient to buy a compressor type at walmart, and bring it the few times you need it. Leaving the pod intact, and available for those boondock moments. I supplement mine by using a cooler for meats. I got a Yeti knockoff, Ozark trail 26 quart cooler for 85 bucks at walmart. Worked pretty good. Not quite a Yeti, (i'm guessing) but, like the pod, built to a price point. Sometimes we tend to lose our perspective in our attempt to "fix the damned thing". ------------- 2017.5 Rp-172 2020 R-pod 195 2015 Frontier sv 4.0L 6cyl I'll be rpodding |
Posted By: fwunder
Date Posted: 21 Aug 2018 at 10:55am
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Mark, Shotgun approach! Love it. I think it really comes down to several factors including environment, usage habits, baseline maintenance and moon phase ;), to name a few. The first three years of our use I really didn't notice a big problem. When I look back on all the trips we took and the tens of thousands of miles I noticed that the biggest difference between those years and our trips this year was environment. It's been a hot summer. Heck, it was in the low to mid nineties with 90% humidity on Prince Edward Island! There seems to be a fairly narrow environmental window of operating efficiency for our fridges. I have read many stories of folks insisting their fridges didn't work and the dealer actually removing the fridge, bench testing and telling the client there was nothing wrong with the unit. Of course. They were bench testing in an air conditioned shop! If there was one solution that worked for all of us I would say the closest thing would be a passive solution as suggested by StephenH in another thread - an efficient and easy method of exhausting to outside. I just haven't been able to come up with an easy way to do that with our installations. In the meantime, we'll all just have to MacGyver methods that work for us. BTW, I have looked at several portable compressor options like the offerings from Dometic or Engle and If I was fulltiming it would be a serious consideration along with enough power generation to keep it going. Just doesn't make sense for a few weeks of camping right now. A good cooler and ice is a lot cheaper. Thanks for the input! fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: fwunder
Date Posted: 21 Aug 2018 at 10:57am
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mjrpod, I guess we were posting at the same time. Yep, I agree. fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: DavMar
Date Posted: 21 Aug 2018 at 3:34pm
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+1 fwunder and same for Subzilla. I would though love to see a schematic diagrams of both of your modifications with wiring in all these fans? You are both just pulling air through the outside cooling fins, yes? Did you both just parallel the two additional exhaust fans from your single fan giving you three exhaust fans or maybe I'm missing something? Subzilla where did you tap into for your 12Vdc dual intake fans that are pushing air up? Lastly fwunder your two interior fans are they wired to the interior light or batter to pull 12vdc from? This is all very interesting!
------------- Dave & Marlene J with Zoey the wonder dog. 2017 Rpod 180 2016 Toyota Tacoma SR5 4x4 Lexington, NC |
Posted By: fwunder
Date Posted: 22 Aug 2018 at 11:26am
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Hi Dave, My mod was pretty simple. I tapped the DC power block @ the bottom of the fridge. I used enough wire and a couple of inline connectors so I could remove the top cover and lay on ground or disconnect easily If I wanted to. The fan has a switch on it and a 1 amp inline fuse. It was just something I had in my gadget box that I used a couple of wire ties to attach to grill.  I also switched out the fan limit switch (thermo disc) with a lower temp one. The only wiring difference there was larger spade connectors. Hope that helps. fred ------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: Subzilla
Date Posted: 22 Aug 2018 at 12:30pm
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Ditto to tapping into the power block. These fans don't pull much power so I just wired them all together (upper fans and lower fans) plus threw on an in-line fuse close to the power block tap. I actually replaced the factory temp sensor with one from one of the websites that is suppose to be better.....not so sure....once on, it stays on all of the time and never seems to shut down...hence my switch install. Adjustable ones exist out there.... https://rvcoolingunit.com/-Improve-your-Cooling-Performance-items-C320215.aspx?sid=298 This website also has a similar baffle I made and added. ------------- Mark Concord, NC 2017 RP 179 "Podzilla" 2011 Silverado 1500 4X4 |
Posted By: Wood River Pod
Date Posted: 22 Aug 2018 at 9:40pm
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Mark, Would you please post some pics of your fan (in & out) mod along with your "channel" to route the air though the fins. I and I'm sure others would be most appreciative. Thanks Jeff ------------- Smith's in Hailey Early 2017 179 HRE http://www.rpod-owners.com/forum_posts.asp?TID=9134&PN=1&title=wood-river-179-mods - Wood River Mods |
Posted By: DavMar
Date Posted: 22 Aug 2018 at 10:21pm
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Hey Fred, When I saw your photo where you tapped in for voltage for
you fan I had to just smack my forehead and go dahhh, along with how stupid can I be! But
thanks so much for sharing the photo! Hi Mark, So, you too also wired all your air intake fans and exhaust
fans from the same point that Fred did? Guys, please understand I’m just trying to help understand how
you made your modifications not only for myself but anyone else who maybe
interested on improving the refrigerator cooling. Fred, As for the fans inside the refrigerator did you wire directly to the interior light and if so do you have a photo or can describe how you wired these fans? Did you both or anyone else know that with at least in the Dometic RM 8501 model if you converter dies then you loose all control over switching your refrigerator over to gas or battery power? Sad but true since there is no battery back up that powers the refrigerator controller board which allows you to switch. I contacted Dometic about this and they said this model has no battery backup control despite their own parts diagram showing this battery backup in their schematic, so all I can say is go figure? All in all very interesting guys and thanks for sharing your information on these modifications.
------------- Dave & Marlene J with Zoey the wonder dog. 2017 Rpod 180 2016 Toyota Tacoma SR5 4x4 Lexington, NC |
Posted By: fwunder
Date Posted: 03 Sep 2018 at 1:06pm
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I wanted to follow up on my latest mod for this cooling thing. I bought this little gizmo: https://www.ebay.com/itm/232605014144?ViewItem=&item=232605014144 - https://www.ebay.com/itm/232605014144?ViewItem=&item=232605014144  The probe fits nice and snugly under the new 50 degree celsius switch (122 fahrenheit) .  The thermostat is wired to exhaust fans with start temp set to 45 degrees C and stop set to 35 degrees C. I did test the thermostat calibrating it against my Thermopen. It seems very accurate. I added a simple push-button switch to power off the thermostat and fused the power feed with an inline spade fuse. I used spade connectors on everything so I could easily disassemble and/or try the thermostat with upper or lower fan. First impressions (in driveway): Both fans start at their set temperature and stop at their set temperature. With outside temp at 85-90, slide in, four bars on panel and empty fridge/freezer - no problem maintaining 0-5 F in freezer and 36-38 F in fridge. The fans definitely make a huge difference. It's going to take some more playing around to determine optimal cut in/cut out temps for either fan. Since I'm just testing in the driveway at the moment I can't really say if the fans are cycling at all. Monitoring as much as possible, it seems the tube temp does not drop to cut out temps (35 C). We will be camping soon, so I should be able monitor closer. My gut feeling is that the fixed thermal switch @ 50 C (122) is a bit lower than it needs to be. The stock thermal switch is 70 C (158) seems too high. Somewhere in between is probably optimal. I may just end up wiring both fans to same thermostat. We'll see. Happy Labor Day! fred
------------- 2014 RPod 178 => https://goo.gl/CV446f - MyMods and Buying Habits 2008 4Runner Limited 4.0-liter V6 Yes, those are wild ponies dining on grass while dumping tanks! |
Posted By: DavMar
Date Posted: 04 Sep 2018 at 4:14pm
I'm impressed and intrigued! Fred, please let us know how all your Labor Day testing went and how your experiments are turning out. Hopefully the end result of all your work will be a separate tutorial for others like myself to follow. ------------- Dave & Marlene J with Zoey the wonder dog. 2017 Rpod 180 2016 Toyota Tacoma SR5 4x4 Lexington, NC |
Posted By: backin15
Date Posted: 12 Sep 2018 at 9:48pm
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Which taps on the power block would I connect to if I wanted the auxiliary fans to come on with the main fan? ------------- 2015 179 2013 Xterra Pro 4X |