12v Refrigeration - What size do you use?

[TimC]

I'm very encouraged with posts I've read here and on other threads on tnttt. I am hoping that other's experience with these types of frig units (they all are very efficient in all capacities I was looking at) and with 108ah and 100 watts I feel I will have a good experience. When I finished the TD I blew off the frig idea thinking I could go forever with ice chests. Well, that experience when ice is just a short hike across a park or I only stay overnight and travel each day or two is fine. When I run to the third day in a remote area I am constantly monitoring ice conditions so my fourth and fifth day of food doesn't go bad and likely spending more time than I care to in my car.

Several have mentioned mounting the panels on the roof of the trailer or TV. I decided I wanted to be less restricted in parking spots and more flexible in pointing the panel in an ideal direction three or four times per day to maximize power gain. So below is my partial solution with my 50 watt panel mounted on it. I will be swapping that panel out with a 100 watt when it arrives. It is roughly twice the height and same width so it should fit my swivel mount. The knuckle on the swivel is a quick and dirty mock up of what I will be making for the final version. It's just scrap and MDF which is a no no as far as weather resistance. I can swivel it 360 degrees and tilt 180 degrees. Got the idea off Google but couldn't find a source to buy it, so, I built it. Easy Peazy!



Close up of the swivel


I've got my finger on the button to order a second, identical 100 watt panel and a charge controller to handle both. I just don't want to spend that extra ~$150 unless I need to. I'll experiment with the first one and maybe add the 50 watt panel to that to see how it goes first (Cosmo's method w/ two ch controllers). I am guessing that I may be better off spending the $ on a few more AHs instead.

Source of inspiration...
https://www.pinterest.com/pin/371828512954340860/?lp=true

Thanks everyone!
Tim

[GuitarPhotog]

Seems to me in that build you could put a 3-way rv fridge and run propane for a lot less money than the batteries, charger and solar panels cost. Cool it down on 110v before the trip, run on dc in transit, and propane at destination. You would still need a battery system to support the electronic control board, but soooooo much less.


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Three-way fridges are expensive because the adsorbtion cooling mechanism, which converts heat from the propane flame to cooling for the fridge is much more complex than a simple compressor-based fridge. And they are bigger, and heavier, and must be vented top and bottom. Not that much gain going 3-way over 2-way (120VAC/12VDC).


<Chas>

[GPW]

And just to mention , on most any independent ( non Factory RV forum ) there were a good many FIRES caused by the 3 way “NoColds “ .. Their solution was replacing the Chinese 3 way cooling unit with an Amish built one ($1K + labor ) and adding another $1K+ Automatic fire extinguisher system … The RV industry ... Sorta' like standing at the edge of a huge hole and throwing Money in !!! … grrrr !!!!
For casual camping , you can buy a lot of ICE for $2K …
I had one , that’s why I’m telling you , don’t make the same mistake ...

[Cosmo]

I am still in awe I am able to even put a fridge in my teardrop. Not too long ago this would have been a fantasy.
I chose an electric fridge because it meets my needs better. I am not a fan of any one technology.

Propane fridges appear to me to be simpler than a compressor fridge. There are no moving parts. Just add heat, keep the system clean and level!
https://www.youtube.com/watch?v=cy1W-uWvR9U

=Cosmo

[dmb90260]

I had a sort of refrigerator in my Teardrop. Sort of because it kept the temperature only 20 deg below the ambient temp. When it was very hot out it was useless, I used the standard cooler with ice most of the time.
When I moved to my standie, Kenskill it had an icebox. That was useless, it was basically a cardboard cube with zero insulation.
I installed a NORCO two-way. In a driveway test it would run on propane for about 30 days with a 20 gal tank.
But one day I was headed to San Diego and pulled over for something and it had a burning smell. Turned it off.
Since then I use it only with on-site 120v electric and that is fine. I never found the source of that smell. When we installed it we put the same insulation over it that is used in your vehicle hood. The counter top inside may get warm but it is never hot. I do have a vented access door behind the fridge which I kept open when I parked originally.
I no longer do that and every thing works fine. I still show up with a cooler full of ice for most of my beverages and big items.
Recently I have added small $100 ice maker from Sam's Club. As long as I keep the water topped off it churns out little ice cubes that keep me just ahead of things
so I do not have to buy more ice for the cooler. The small freezer in the fridge could never keep up with that so my big martini gin bottle lives there.
All of this works fine with only one person accessing things, add another person or two and you may need more ice.
Additionally I do have a Honda generator for power if I need it in remote areas.

[Pinstriper]

You were running a propane fridge in transit ?


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[TimC]

These small fridges do not have a fan in them to circulate air.

https://www.amazon.com/gp/product/B01E5 ... UTF8&psc=1

Cosmo, I like the idea of a small fan. I'm curious if one of the below fans with some fabrication of a case would work to circulate air in the fridge. I get that I don't want massive air movement. This one has 2.3 cfm which is even higher than necessary I think. What do you think? I'm a tinkerer and don't have any problem either wiring with a battery (there are many small 12v batteries on the market) or wiring direct to the input to the fridge, or, there are versions of this that are 5 volt. I've also run an 12v, 80mm case fan on a 9v battery with sucess. This fan runs on 6/100 amp, so, I think it would last quite a while on a charge. Maybe even one of those rechargable battery packs that you use for a phone backup. OK, I'm rambling. Can you tell I like the idea of adding a fan to the fridge?

https://www.ebay.com/itm/12V-25mm-Mini- ... 0047.m2108

Tim

[Cosmo]

Ahhh Tim we are of one mind! I am working on the same problem.

The Dometic takes up the space of a beer or two, or a tub of fresh Guacamole, or some other survival essential (if there are any others), so it’s a problem we must solve… Baw haw haw haw!

The Dometic is needlessly large in size. But it is efficient. It runs a month on 2 D cells. It uses a low speed squirrel cage fan. I just measured the draw on the Dometic fan at .02 amps an hour or .48 amps a day which is pretty good! 14.4 amps a month. 3.6 amps a week. 1.5 amps on a 3 day weekend. In the useless data department, for grins I put a wind meter 1 inch away from the output of the Dometic and it measures 5.1 miles per hour. While that might seem like useless data to most people its sure to cause a lot of chin scratching around the campfire. Maybe even diffuse raging arguments about Nitrogen in the trailer tires before they get too violent.

My guess is the low cubic foot of air movement of these fans will work fine. I can compare the small fan with the Dometic air flow with my wind meter once its in my hands (Saturday). This will increase chin scratching and maybe give the arguers a position to defend.

At .06 amp draw at 12V fan that you found is 1.4 amps a day. 4.3 amps for a 3 day weekend. 9.8 amps a week. If that works for you… why not try?

I ordered this one. Will report back. Unfortunately the info does not give an amp draw but I can measure it when I receive it Saturday. I have loads of USB battery packs to learn with.
https://www.amazon.com/gp/product/B07NC ... UTF8&psc=1
If the power consumption of this fan is low, the combination of the fan and USB battery will be far smaller than the Dometic fan.

Maybe the size of a satisfying wedge of ripe Brie!
=Cosmo

[TimC]

[size=150][color=#000080]Ahhh Tim we are of one mind! I am working on the same problem.

OK, this is where you guys with Prime got me. Order an $8 item and have it in two days. I gotta wait until I have $25 of goods and then they ship it when they get to it. I know, I know... I can pay shipping and have it in about a week.

I like that little fan. 25mm is tiny, but, right sized I think for what you (we) are trying to create. I made a rough sketch of 25mm square and measured the diagonal at about 1 3/8". That should fit in a short, or long piece of 1 1/2 PVC. I'm picturing making castle like cut outs on the bottom, much like a castle nut. Mount the fan above that space maybe with a web of stainless or copper wire to hold it up and tie it to. It'd be easy to make one cut out large enough for your USB power cord to exit. Some sort of box to contain the power pack attached to the side or just epoxy or velcro it on the outside of the pipe, or, would it be small enough and non-restrictive enough to just mount inside the pipe? If it wouldn't take up too much room I'm thinking the pipe could go most of the way up the wall of the fridge, just an inch or so short of the cover. The cool air will spill over the top of your food and circulate down between. The pipe would keep items from blocking good air flow.

I'm guessing that fan is 5v due to its USB? Probably burns amps and circulates air about what my suggested fan would. Not a problem to recharge the power pack every couple days. Shoot, just have two small ones. When one is fully charged swap it out. An inside pipe mount would make that easy, maybe.

I gotta try this myself. New project...

Tim

[Cosmo]

Nice! I will finally put toilet paper and paper towel tubes with some tape to use on the "Air Shaft" prototypes!

If it works I look forward to giving all my RV friends "The Shaft" which they may accept with a smile!

SMALLER, CHEAPER, BETTER. You can only pick two.

=Cosmo

[aggie79]

Most 25mm pancake fans, especially one running at 7000 rpm, are quite loud. This may not matter being inside of a refrigerator.

I believe USB voltage is 5 volt. If you want to use 12v, try searching for 25mm computer case fans.

[tony.latham]

Here's a solution if you want to run a 5V fan on a 12V system:

https://www.amazon.com/SMAKN%C2%AE-Converter-Voltage-Supply-Waterproof/dp/B00RE6QN4U/ref=sr_1_8?keywords=5v+transformer&qid=1564761794&s=digital-text&sr=8-8

There are lots of these out there. Just make sure the fan doesn't exceed the amp rating.

T

[Cosmo]

Thanks!

Tim is approaching his idea from the 12V side and I am "going in" with the modular 5V USB power pack experiment. I prefer this approach (until I change my mind).

In my opinion,the small fans make up for size with speed (I have had to do this this myself at times) which uses more energy. We shall see

For my needs, I don't want wires coming into the fridge.

I am planing a removable install for the times I want the fridge stuffed with food. Once I eat a few Artichokes and create some space I can pop in the fan to save energy and provide even cooling. There may be times I prefer the zone effect without the fan too! That's how I use the bulky Camco fan. A friend with a propane fridge is also using the Camco fan and likes it.

All Ideas are welcome from common sense to grandiose schemes. Nothing is impossible for the man who does not have to do it himself! BAW, Haw haw.

=Cosmo

[sherryk]

Regarding a small fan for the fridge, I have had this one for 2 years, Camco Fridge Airator with On/Off Switch - Absorbs Refrigerator Odors and Smells, Space Efficient Compact Design, Maintains Consistent RV Temperature (44124) https://www.amazon.com/dp/B01E5SNB5I/re ... rDbYJMRXKQ

It’s quiet, just takes batteries. And works well I think. I had a cheaper one first, a square blue one..and it didn’t last.

I have a 6+ years old domestic 35 , never had a problem with it.

[TimC]

I think I will be all in with the 5v fan and USB bank system. I don't even have the frig yet so I will be watching for Cosmo's experience. I too can see times with and without the fan's use.

I've found several long, skinny USB banks that would fit inside 1 1/2 PVC and not restrict air flow much.

Tim