Converting to dc fridge

[scottykrug]

Ok, been perusing the threads on this topic but want to toss this out to the group to see if there is anything I have missed. All thoughts welcome...

Backstory.. our 5 year old dometic reefer has slowly lost its ability to keep our food cold. Fridge temps now go into the 50° F range which is unacceptable. I have cleaned the coils, added fans, straightened up the ductwork, and while all this originally helped, the fridge IMHO has failed. We have looked at rebuilding the ammonia system (between $400 and $700) to full fridge replacement which can go up to $2000 depending on the system. I am strongly leaning towards a dc based system as it does not have to be level, reduced fire hazard, and we never go off grid. Last time we boondocked was in our last camper almost 10 years ago. Even if we did, I can tie in a second group 31 battery backed up by a 2000 wt genset. I am reading between the lines that my truck will be able to carry the load when driving. I found a company that makes a compressor rebuild that replaces the ammonia system completely and draws less than 1 amp. I love the idea that it is the old fridge where I don’t have to rebuild my kitchen. The cost is almost exactly what it would be to rebuild the ammonia system. To me this looks absolutely perfect.

What if anything am I missing? Fire away!!!

Thank you for your reading this and your potential input.

Scooter

[Jframpey]

I switched to a dc frig 9 month ago - works great. I started with 2 6 volt deep cycle batteries which can run it for 24+ hours plus other loads. I’ll not go back to a temperamental ammonia frig.

I got my frig at Home Depot. Here’s the link. Unique 12 volt frig

[ScottG]

Looking forward to it Scotty!

Scott

[scottykrug]

A wealth of information. Thank you all for the input. I will keep checking back here in case of anything also but it looks like that JC-refrigeration compressor kit is the direction I will be going. Will post latter on the install and operation.

[ScottG]

FWIW, JC refridgerations DC compressor draws about 3.2A @12VDC and 400mA for the 120VAC models.

[Lwiddis]

“I can tie in a second group 31 battery backed up by a 2000 wt genset.L

Why is a generator your “backup” for a one amp draw? Why don’t you ever “go off grid?” It’s a new world OP...solar panels, batteries. Come join us in Century 21.

[theoldwizard1]

wa8yxm wrote:
(Danfoss is one of the companies that makes DC compressors ...

The Danfoss company has been bought and sold a couple of times in the past 10 years or so.

2008 - merged with Suaer to form Sauer-Danfoss
2010 - the compressor portion of Sauer-Danfoss was sold off. The new company name is Secop
2017 - Nidec acquired Secop
2018 - Nidec also acquire Embraco compressors from Whirpool

There are some effort to "kill off" the old Danfoss brand name, but the Secop name seem to be staying.

For all of you "techies", the key to the success of the Danfoss DC refrigeration compressor is that it doe NOT use a real DC motor. It is actually a 3 phase AC motor front ended by a dedicated 3 phase DC-AC variable frequency inverter. VERY efficient !

[ajriding]

It would be easier to visit Homedepot and get a $200 dorm fridge, or bigger and just plug it in. Sounds like you go from house to campground and rarely anything in between.
House fridges are not built for the trailer bouncing, but many do it and are fine.

You might need to run a generator for power on drives longer than a few hours, but still this is cheaper than a new (and soon to fail) propane fridge.

The Danfoss electric fridges really are the best option for many RVers. They use very little power and can run 30 degress off level (propane is 3-6 degrees).

Most of these are "chest" type units, so convert your old fridge space to a closet, and make room for a cooler style chest.
They are expensive.
If you live in CA and the power goes out for the next ten years, then this will run off solar, or a car battery.

There are conversions available to turn your existing propane fridge into a danfoss unit. It will work on some models, but not all.
This would be the ideal solution.

[DownTheAvenue]

If you never boondock, the perhaps a residential refrigerator would be a better choice for you. I have a 12 volt/120 volt Nova Cold refrigerator and find it to be far superior to the gas absorption models. Two batteries keep it running unril I drive or run the generator.

[naturist]

Are you meaning something like this? https://www.ganderoutdoors.com/dometic-coolfreeze-cfx-65w-portable-compressor-cooler-and-freezer-53l-101687.html

[cavie]

scottykrug wrote:
Ok, been perusing the threads on this topic but want to toss this out to the group to see if there is anything I have missed. All thoughts welcome...

Backstory.. our 5 year old dometic reefer has slowly lost its ability to keep our food cold. Fridge temps now go into the 50° F range which is unacceptable. I have cleaned the coils, added fans, straightened up the ductwork, and while all this originally helped, the fridge IMHO has failed. We have looked at rebuilding the ammonia system (between $400 and $700) to full fridge replacement which can go up to $2000 depending on the system. I am strongly leaning towards a dc based system as it does not have to be level, reduced fire hazard, and we never go off grid. Last time we boondocked was in our last camper almost 10 years ago. Even if we did, I can tie in a second group 31 battery backed up by a 2000 wt genset. I am reading between the lines that my truck will be able to carry the load when driving. I found a company that makes a compressor rebuild that replaces the ammonia system completely and draws less than 1 amp. I love the idea that it is the old fridge where I don’t have to rebuild my kitchen. The cost is almost exactly what it would be to rebuild the ammonia system. To me this looks absolutely perfect.

What if anything am I missing? Fire away!!!

Thank you for your reading this and your potential input.

Scooter

What is the location of the thermister on the inside fins? top or bottom? Top is cooldest.

[wa8yxm]

There are two basic options.. One may be hard to find.
Many have converted to residential fridges. 120 volt (Fed via an inverter) these often suck 100-300 watts running and abou a 50% duty cycle (That's a target for all fridges)

The other, and both Dometic and Norcold made these at one time. are what I call "Danfoss Class" (Danfoss is one of the companies that makes the compressors they use. I do not know what make Dometic and/or Norcold use).. These are very high effiency compressor fridges,, meat all your requirements (off level and such) and draw (Door closed seems strange to have to say door closed) Less than 50 watts.. How does this compare? A pair of 1136 lamps is 50 to 60 watts.

[scottykrug]

Yep, that is where I found out about this. A sort of epiphany moment as I was ready to replace the whole fridge with a Furrion or one of the yacht designed units for much more money. As for fans.... I have enough fans now to fly it around the camper. One of the steps to try and help the old system limp along. I am quite excited about this but will wait to order. I want to see all comments here to cement the decision. I really don’t need this functional until spring.

[ScottG]

Have you seen this couples videos link?
Seems like the only problem they ran into was a lot of ice forming on the fins inside. They added interior fans to solve the issue.

Scott

[scottykrug]

Yes that is the company. Thank you for the reply.