12V Conversion for Vintage 110v Fridge

[AndrewM]

My Cruiser was most likely a park model being entirely 110v. I am not sure (as many on this forum probably are) when 12v systems were introduced into Airstreams, but I know mine had nothing of it.

A few months ago my original refrigerator gave up the ghost. It in all purposes is not a well designed fridge just a glorified ice box with a condenser unit. But it is original, and has a great feel and look to it. It is a Marvel, as seen below:



Since that fridge stopped working I have been considering my options. I do not like a propane option because I do not want to add another vent on the street side, but I would love a 12v mode for camping and on the road. But then I really wanted to keep the fridge, but I believe our sailing friends have an excellent solution actually produced by Dometic.

Custom Cooling Kits - Dometic

Dometic bought the Adler Barbour company, which has been around for many years now and are known for their reliability, especially the units using the Danfoss BD50F compressors. These systems run exclusively on 12v and for a 4.5 cubic ft. space use about 40-50 amps per day (varying on application and evaporator unit)

I will probably do this conversion for a number of reasons:
1. it uses quick connections that allow for DIY install and you can even disconnect the unit from the evaporator without losing charge
2. it uses r-134a so if it ever needs recharged it will be a quick run to autozone
3. They are made for boats so they can handle movement and will work on a tilt.
4. it comes pre-charged

Now the cost will range from $800 to $1000 but for a r-134a 12v fridge that I can install and service myself, with a large community of support and parts, and that saves my original fridge; I find that to be a mighty good deal.

I still have a few questions to answer but I am pretty excited about the alternative. I know a few of the Cruiser guys may be excited to hear about this.

[ventport]

So you could easily run 3-4 days without charging the batteries, sounds good.

[HowieE]

That is a great idea. The CS NC 15 unit

As long as you have the space behind or along side the box you are home free.



.

[RickDavis]

40 to 50 amp hours per day is a pretty good load when boondocking. Normal power consumption for us is in the 30 to 40 amp hour range which is pretty typical. Add another 50 amp hours to that and you would pretty well discharge a 1 battery system in a day.
Thats assuming that the 100/120 amp hour rating per battery is honest and the batteries are fairly new.
It will take a fair number of hours of generator time or a large solar system to keep up with it.
I can understand you not wanting to cut another vent, but the other side of the coin is a 30 lb bottle of propane will run a fridge and cooking for around 3 weeks for about the same weight as the battery that discharges in one or 2 days at best

If you usually have hookups, no problem. If you frequently boondock for long periods as we do I don't think it would work out too well

[Jammer]

Hi Andrew

First of all you want to be absolutely sure that any of the existing coils you're planning on reusing don't leak. Leaks are the main reason really old fridges fail. You, or a refrigeration tech you trust, should pull vacuum on the system and observe that it will hold it overnight with no measurable loss. If there are leaks you want to be sure either that they can be fixed or that you do not reuse that part of the system.

Second of all if the original compressor failed you will want to be sure that it did not contaminate the sealed system. It is common for there to be substantial debris introduced into the refrigerant during catastrophic failures. There is no 100% effective way of cleaning the sealed system once this happens. Techs used to use R-11 as a flushing agent but that's not permissible under the current laws. Other methods pose fire hazards, as even compressed air can cause the remaining refrigerant and oil to form a flammable mixture. Strategies vary. In any case you will want to add a filter/dryer to catch anything that never got flushed out.

Finally even though the Danfoss parts come pre-charged you will want to pull a vacuum on the existing system before releasing refrigerant into it as the air and water vapor that are present will pose problems for thermal performance as well as leading to premature compressor wear.

I think the old fridges are well worth keeping. You're on the right track but be sure you don't skip any important steps.

[Jammer]

Finally you may want to see what the Marvel originally used for refrigerant and how its thermodynamic properties compare to R-134a. If it originally used R-12, then R-134a will work fine although the amount of cooling will drop by about 10%. If it originally used R-11 then R-123 may be a better choice. Most compressors will work with either, I'm not sure what Danfoss says about theirs.

[pbearsailor]

I'd sure second what Rick posted.

I've used 12 volt units on our boat for over 20 years. They are reliable, easy to install, and last a long time. But, the power requirements are large. We run a 12 volt system with a cold plate instead of evaporator, so it's more efficient, but still it uses around 40 amps a day for a very small, top opening box with no freezer. We have 6 inches of insulation around the box. We cruised fulltime for years, unplugged, and it took 200 watts of solar and a wind generator to keep up.

Don't think a large, front opener like the Marvel can approach our efficiency.

If you're plugged in all the time, it'll work great. It'll do fine, fairly quiet, and very reliable. If you boondock, I seriously doubt how you can do it.

cheers,
steve

[AndrewM]

If I wasn't so committed to the original fridge I believe a Norcold would definitely be the way to go. The option to do propane is the best way to go when boon-docking, I wasn't trying to argue against that. I think the 12v refurb is only for those who do not wish to let go of antique appliances.

But for now I am full timing and the the next year or two my setup will be mainly for full-timing. As I say that it may seem useless to go for 12v at all; and it may be, but the ability to keep the fridge cold during transportation and a 2 day boon-docking seems like a good deal to me. 40 to 50 amps per day is no small pull, you're right; but it is doable. If I was to get serious about boondocking in a few years, which I hope to, I would like to get two solar panels on the roof that would let me extend my boondocking into a week or two.

Jammer, your concerns are valid if I were to use some of the existing components; but I do not think I would if I were to do the conversion. That means that both the original condenser unit; piping, and evaporator are being removed and I will install either a new evaporator or 'cold plate' in its place. The main concern is for releasing the r-12; I will need a pro to come evacuate it so as not to kill the enviroment. Otherwise from my current understanding, both the evaporator and the unit come sealed and filled ready to be hooked up with 'quick-connect fittings'

So while it is not perfect; I believe the 12v marine option is the best for those trying to preserve the antique feel of 50's appliances while updating to 12v/modern guts

[ekstarr]

Originally Posted by AndrewM

If I wasn't so committed to the original fridge I believe a Norcold would definitely be the way to go. The option to do propane is the best way to go when boon-docking, I wasn't trying to argue against that. I think the 12v refurb is only for those who do not wish to let go of antique appliances.

But for now I am full timing and the the next year or two my setup will be mainly for full-timing. As I say that it may seem useless to go for 12v at all; and it may be, but the ability to keep the fridge cold during transportation and a 2 day boon-docking seems like a good deal to me. 40 to 50 amps per day is no small pull, you're right; but it is doable. If I was to get serious about boondocking in a few years, which I hope to, I would like to get two solar panels on the roof that would let me extend my boondocking into a week or two.

Jammer, your concerns are valid if I were to use some of the existing components; but I do not think I would if I were to do the conversion. That means that both the original condenser unit; piping, and evaporator are being removed and I will install either a new evaporator or 'cold plate' in its place. The main concern is for releasing the r-12; I will need a pro to come evacuate it so as not to kill the enviroment. Otherwise from my current understanding, both the evaporator and the unit come sealed and filled ready to be hooked up with 'quick-connect fittings'

So while it is not perfect; I believe the 12v marine option is the best for those trying to preserve the antique feel of 50's appliances while updating to 12v/modern guts

What an interesting approach! Did you end up doing this? If so what were the results?

[AndrewM]

Originally Posted by ekstarr

What an interesting approach! Did you end up doing this? If so what were the results?

I did end up doing this! I did the 12v conversion to a Dometic/Addler Barber system about 6 or 7 years ago. For most of that time I was full timing and had hook ups almost the entire time. However we just got back from our first camping trip without hookups and tested it all out.

My overall experience with the system has been very positive. My only complaint is I have had two electronic modules (computer module that controls compressor) go out on me. One was covered by warranty, the last one cost me about $140. Other than that the system has been very reliable.

I recongize this isn't a perfect solution. The temperature isn't too even inside the unit, and the front door is ineffecient. I do have dreams of using the original door and making a chest style fridge out of it...but that would mean a larger renovation of the cabinets.

To the concerns of effeciency and boondocking. We just got back from a 8 night trip where the first 5 nights we did not have hookups.

I have 300ah of batteries. And a 200w solar setup with an MPPT charger. The first two days of the trip we were driving most of the day so the TV charges the batteries and essentially runs the fridge. The first two days were also very cloudy so my solar didn't really start kicking in until the 3rd full day. The lowest I ever saw the battery voltage on the trip was 12.3 which is awesome. My solar was putting back 70-75ah on sunny days so almost fully recharging the batteries.

Right now in my family life we aren't going to be going more than 5 days without hookups and I have no doubt that we will be just fine on the current setup. Honestly if I had sunny weather during the summer I could probably go almost indefinitely with our electric needs.

[Foiled Again]

Before refrigerators there were iceboxes. To double your capacity, get a Yeti, or similar brand, precool with ice/dry ice, dump 2/3 of the ice and fi with frozen food. HEAVE it into your truck or trailer. keeps food for 5-7 days easily if kept in the shade.

[FlyinCloud57]

Andrew, We’ve got a ‘57 Flying Cloud and have been searching for a solution to keep the (still functioning) original fridge while undergoing a complete 12v conversion to the trailer, adding solar, batteries, etc. We really wish to preserve the period correct aesthetic of this wonderful vintage trailer and your incredibly helpful post has given us great hope!

The link you provided to the cooling kit appears to be outdated, are you able to tell me which specific kit you used? Dometic offer a number of kit variations and I’m not sure sure which one is most appropriate for this project. I’m thinking maybe this one is best but I’m not positive: https://www.dometic.com/en-se/outdoor/boat/boat-refrigerators/dometic-coldmachine-kit-cu-55--vd-07-64410

However, they currently offer MANY cooling kits: https://www.dometic.com/en-se/outdoor/boat/boat-refrigerators?sortBy=Relevance&count=48

Many thanks in advance! If we ever have the pleasure of crossing paths in real life, I owe you a cold beverage of your choosing! 🍻 🙌

Sean

Originally Posted by AndrewM

My Cruiser was most likely a park model being entirely 110v. I am not sure (as many on this forum probably are) when 12v systems were introduced into Airstreams, but I know mine had nothing of it.

A few months ago my original refrigerator gave up the ghost. It in all purposes is not a well designed fridge just a glorified ice box with a condenser unit. But it is original, and has a great feel and look to it. It is a Marvel, as seen below:



Since that fridge stopped working I have been considering my options. I do not like a propane option because I do not want to add another vent on the street side, but I would love a 12v mode for camping and on the road. But then I really wanted to keep the fridge, but I believe our sailing friends have an excellent solution actually produced by Dometic.

Custom Cooling Kits - Dometic

Dometic bought the Adler Barbour company, which has been around for many years now and are known for their reliability, especially the units using the Danfoss BD50F compressors. These systems run exclusively on 12v and for a 4.5 cubic ft. space use about 40-50 amps per day (varying on application and evaporator unit)

I will probably do this conversion for a number of reasons:
1. it uses quick connections that allow for DIY install and you can even disconnect the unit from the evaporator without losing charge
2. it uses r-134a so if it ever needs recharged it will be a quick run to autozone
3. They are made for boats so they can handle movement and will work on a tilt.
4. it comes pre-charged

Now the cost will range from $800 to $1000 but for a r-134a 12v fridge that I can install and service myself, with a large community of support and parts, and that saves my original fridge; I find that to be a mighty good deal.

I still have a few questions to answer but I am pretty excited about the alternative. I know a few of the Cruiser guys may be excited to hear about this.

[Jcondon]

Originally Posted by FlyinCloud57

Andrew, We’ve got a ‘57 Flying Cloud and have been searching for a solution to keep the (still functioning) original fridge while undergoing a complete 12v conversion to the trailer, adding solar, batteries, etc. We really wish to preserve the period correct aesthetic of this wonderful vintage trailer and your incredibly helpful post has given us great hope!

The link you provided to the cooling kit appears to be outdated, are you able to tell me which specific kit you used? Dometic offer a number of kit variations and I’m not sure sure which one is most appropriate for this project. I’m thinking maybe this one is best but I’m not positive: https://www.dometic.com/en-se/outdoo...5--vd-07-64410

However, they currently offer MANY cooling kits: https://www.dometic.com/en-se/outdoo...vance&count=48

Many thanks in advance! If we ever have the pleasure of crossing paths in real life, I owe you a cold beverage of your choosing! 🍻 🙌

Sean

We have installed a few Isotherm units. They are easy to install yourself.https://www.suremarineservice.com/Is...-Sizing-Chart/

[Bubba L]

Originally Posted by FlyinCloud57

Andrew, We’ve got a ‘57 Flying Cloud and have been searching for a solution to keep the (still functioning) original fridge while undergoing a complete 12v conversion to the trailer, adding solar, batteries, etc. We really wish to preserve the period correct aesthetic of this wonderful vintage trailer and your incredibly helpful post has given us great hope!

The link you provided to the cooling kit appears to be outdated, are you able to tell me which specific kit you used? Dometic offer a number of kit variations and I’m not sure sure which one is most appropriate for this project. I’m thinking maybe this one is best but I’m not positive: https://www.dometic.com/en-se/outdoo...5--vd-07-64410

However, they currently offer MANY cooling kits: https://www.dometic.com/en-se/outdoo...vance&count=48

Many thanks in advance! If we ever have the pleasure of crossing paths in real life, I owe you a cold beverage of your choosing! 🍻 🙌

Sean

Sean, like Jconson said, the Isotherm works well. We completely gutted a 1956 Dometic for our 55 FC and converted it to a 12vdc compressor unit using an Isotherm with a Danfoss compressor. It works great. Our fridge work starts around post #234. Good luck

[amschind]

Isotherm also makes standalone units designed as a "bring your own insulated box" setup.