12 volt DC Fridge or 110 Volt - is the latter a viable option?

[themexicandoctor]

Just saw this link & wanted to get answers from those of you who are far more technically competent whether or not this is a viable option looking at a 2, 5 or 10 year & beyond investment, in a RV.

Perhaps its an ideal option for Van Owners on a budget?

But not RV Owners?

I did not understand the description of the Battery Brand he purchased (probably cheap, low quality compared to Lifelines, etc).

In fact budget might have been his driving factor in his component choices versus the longer term choices RV owners typically make.

And are the rigors of the road the reason we don't see longer term comparisons between traditional home units & those designed for the RV & Marine needs?

[booster]

Originally Posted by themexicandoctor

Just saw this link & wanted to get answers from those of you who are far more technically competent whether or not this is a viable option looking at a 2, 5 or 10 year & beyond investment, in a RV.

Perhaps its an ideal option for Van Owners on a budget?

But not RV Owners?

I did not understand the description of the Battery Brand he purchased (probably cheap, low quality compared to Lifelines, etc).

In fact budget might have been his driving factor in his component choices versus the longer term choices RV owners typically make.

And are the rigors of the road the reason we don't see longer term comparisons between traditional home units & those designed for the RV & Marine needs?

Cheap Electric setup (How and Why) plus what fridge is better #VanLife#CheapElectric#MiniFridge

We have had a bit of discussion on the "dorm frig" possibilities on here. It use to be they used way more power than the marine frigs, but if you believe the current energy ratings they are pretty close now to being the same.


Concerns have always been with durability on the road from bumps, etc, with some reporting problems on other sites, and some not.


Another concern is how well they will work in the widely varying conditions and temps of an RV. Residential frigs most likely are optimized to be efficient in a pretty narrow band of temps, maybe 50-85 degrees? If so, they might get overheated when they see 100+* or get very inefficient. No testing on that stuff that I know of.


I can't really say they are good or not so good with any certainty, but they are inexpensive by a long ways compared to a marine frig. With the improved power use, may be an option for some users, especially that have shore power most of the time and/or shorter stays off grid.



I always am a bit skeptical of the utube "experts" as you don't know what background they have or if they are being paid to push stuff. The flashing graphics and zooming are kind of put off to me most times.

[themexicandoctor]

Thank you.

With this guy I believe he isn't pushing any brand name, just the concept & using his info share to gain an income, that is why I submitted the video.

However there are many full timers out there seemingly discarding tried & proven "systems" as something to be replaced with their sponsored items that are also, big ticket investments ie; toilets, fridges, etc.

I am sticking with my yet to arrive Novakool DC unit.

Yet its very tempting when for the optionsl AC, I am investing $1200 for the above, based on the presumption that there is a better, long term reliabity & support with an RV Engineered design.

But for many, I can see why $1200 is the equivalent of 6/Six replacement units not including the Warranty return option.

Especially if you already have a quality solar system in place.

[Winston]

We found Vanlife's video more entertaining than useful - - especially his sales pitch on why you need a refrigerator.

Vanlife is a DIY'er. DIY'ers come with a variety of motivations including "we can't buy what we want, so we'll build it" and, the more common motivation seems to be "we don't have enough money to buy a commercial unit, so we'll Do It Ourselves and save loads". For this latter group you will often find price dominates over quality and longevity.

We fall into the former category of 'building our own as we couldn't find a commercial model we liked' . . . with quality and capability being more of the motivator than cost. Incidentally we ended up with a Novacool R4500 that can be purchased either as a straight 12 volt DC model or as a combo of 110 VAC/12VDC. We bought the latter and use the 110 volts when on shore power and the 12 volts otherwise.

[booster]

Originally Posted by Winston

We found Vanlife's video more entertaining than useful - - especially his sales pitch on why you need a refrigerator.

Vanlife is a DIY'er. DIY'ers come with a variety of motivations including "we can't buy what we want, so we'll build it" and, the more common motivation seems to be "we don't have enough money to buy a commercial unit, so we'll Do It Ourselves and save loads". For this latter group you will often find price dominates over quality and longevity.

We fall into the former category of 'building our own as we couldn't find a commercial model we liked' . . . with quality and capability being more of the motivator than cost. Incidentally we ended up with a Novacool R4500 that can be purchased either as a straight 12 volt DC model or as a combo of 110 VAC/12VDC. We bought the latter and use the 110 volts when on shore power and the 12 volts otherwise.

It would be interesting to see if the new more efficient home frigs have native 110v AC motors on compressors, or some ECM or other method that might be more efficient. Our new home furnace has an ECM blower motor instead of PSC and it is much more efficient and consistent in airflow (more constant torque)

[GeorgeRa]

Originally Posted by Winston

..................DIY'ers come with a variety of motivations including "we can't buy what we want, so we'll build it" and, the more common motivation seems to be "we don't have enough money to buy a commercial unit, so we'll Do It Ourselves and save loads". For this latter group you will often find price dominates over quality and longevity.

We fall into the former category of 'building our own as we couldn't find a commercial model we liked' . . . with quality and capability being more of the motivator than cost. Incidentally we ended up with a Novacool R4500 that can be purchased either as a straight 12 volt DC model or as a combo of 110 VAC/12VDC. We bought the latter and use the 110 volts when on shore power and the 12 volts otherwise.

I agree with the categorization, indeed there are 2 distinct groups. Our DIY decision was driven by lack of specific features in Camper Van market such as not enough windows and lack of VW Westfalia like layout for camping. The Safari Condo company had some but not available in NA.

[themexicandoctor]

Winston & Booster,

I didn't want to put "too fine a point on the motivations of such youtubers as I was looking to bring forth the qualified answers of the Giants amongst us.

And yes I see the DIY, bare bones,, let's get through the next 6 months Focus of that video.

Booster* you & others like Davydd have the ability to create your own income helping others, with the amount of effort you invest in answering & opining on these forums, you could have a new video everyday simply on what is already archived.

*Winston I haven't seen enough of your posts yet

I purchased the AC option in the DC unit for the possibility of changes in my use of the van in the future ie; taking six months off or RV Repair & of course, when running only shore power or the generator, the latter not a long term option.

The understanding I have is not that the unit performs better when on shore power but that when hooked up, why not get as much juice to the batteries ie; 1- 2 month 4 hour equalization maintenance & general speed & ease of said battery charging.

I do find, via the Magnum ARC Remote, that irregardless of when I did the equalization last, within 12-24 hours of being hooked up to shore power that my unit reads FULL, when using the 20amp setting.

[themexicandoctor]

Originally Posted by booster

It would be interesting to see if the new more efficient home frigs have native 110v AC motors on compressors, or some ECM or other method that might be more efficient. Our new home furnace has an ECM blower motor instead of PSC and it is much more efficient and consistent in airflow (more constant torque)

Its evolving, new information like this that adds to the discussion also.

It's finding the best solution now, focused on future needs, based on present knowledge, for us as Owners, WITHOUT an Outfitter's Pencil Pusher nixing the idea.

[avanti]

Originally Posted by booster

It would be interesting to see if the new more efficient home frigs have native 110v AC motors

Is that even possible? If you want a fully-sealed compressor, you need a brushless motor (so as not to contaminate the works with brush wear). I thought that that pretty much implied a DC controller.

I am no expert, though.

[booster]

Originally Posted by avanti

Is that even possible? If you want a fully-sealed compressor, you need a brushless motor (so as not to contaminate the works with brush wear). I thought that that pretty much implied a DC controller.

I am no expert, though.

I am no expert on motor designs, either, but I looked and ECM motors don't have brushes but seem to run on SCR switched winding control, so probably could be used for a sealed compressor. Whether or not anyone is doing it, or not I have no idea, thus the question. The Danfoss is probably something similar as they do go from native DC to some sort of AC variable drive, I think.

[avanti]

Originally Posted by booster

I am no expert on motor designs, either, but I looked and ECM motors don't have brushes but seem to run on SCR switched winding control, so probably could be used for a sealed compressor. Whether or not anyone is doing it, or not I have no idea, thus the question. The Danfoss is probably something similar as they do go from native DC to some sort of AC variable drive, I think.

I guess it depends on how you define "AC". The Danfoss motor is certainly EC -- it works by having a controller start with DC and then using a special controller to generate many (something like a dozen) modulated currents, each fed to a different stator winding at just the right phase to turn the motor at the desired speed. In a sense, this is "AC", but it is nothing like what you get from a wall plug. My understanding is that if such a motor is powered by 120VAC, the first thing that happens is that the AC is rectified.

It is true that there also exist so-called "synchronous" brushless motors, but their speed range is very limited and more-or-less locked to line frequency. (That is how most mechanical electric clocks used to work).

[booster]

Originally Posted by avanti

I guess it depends on how you define "AC". The Danfoss motor is certainly EC -- it works by having a controller start with DC and then using a special controller to generate many (something like a dozen) modulated currents, each fed to a different stator winding at just the right phase to turn the motor at the desired speed. In a sense, this is "AC", but it is nothing like what you get from a wall plug. My understanding is that if such a motor is powered by 120VAC, the first thing that happens is that the AC is rectified.

It is true that there also exist so-called "synchronous" brushless motors, but their speed range is very limited and more-or-less locked to line frequency. (That is how most mechanical electric clocks used to work).

It is interesting terminology for sure. What is usually see about ECM says they are AC sometimes and DC others, probably because they are trying to not confuse purchasers and have the buy the wrong input power motor.


My guess, based on not much of anything, is that is a more pole motor similar to a 3 phase AC motor but they control the windings with square wave pulses in stead of frequency shift like a variable frequency drive. A would think a pulse square drive would be able give a bit more torque than a truncated sine wave, but that is also a guess.


I did look at the Carrier home AC/heat pump literature and in the high end ones that are very efficient they talk variable speed compressors with slow ramp up speed, so certainly sound like that is some sort of ECM control motor.

[themexicandoctor]

Maybe this is where the Refrigeration background of Idleup & Chicago Tom would be valuable input.

I am going to pm them both.

[GallenH]

So an observation and a question.

OB: It appears to me that the biggest question has to do with the adaptability of a unit intended to be stationary and in a relatively controlled environment to a situation (RV) which has neither of those. That concerns me but perhaps it's less of an issue than it appears.

Q: I seem to recall earlier discussions about buying a RV/marine fridge where it was observed that the 120vAC portion was merely a transformer of sorts that just reduced the 120v to the 12v native to the fridge compressor. So the argument was that it really didn't make sense to buy one which was 2-way but rather just stick with the 12v. Is this correct?

[GeorgeRa]

Reciprocating compressors are suspended on springs inside their housing, I would assume that these suspensions are tuned for stationary use for homes and dynamic use for mobile application. See this video how soft these suspensions are.

https://www.youtube.com/watch?v=15VOMei7awo

[themexicandoctor]

Originally Posted by GallenH

So an observation and a question.

OB: It appears to me that the biggest question has to do with the adaptability of a unit intended to be stationary and in a relatively controlled environment to a situation (RV) which has neither of those. That concerns me but perhaps it's less of an issue than it appears.

Q: I seem to recall earlier discussions about buying a RV/marine fridge where it was observed that the 120vAC portion was merely a transformer of sorts that just reduced the 120v to the 12v native to the fridge compressor. So the argument was that it really didn't make sense to buy one which was 2-way but rather just stick with the 12v. Is this correct?

Good question.

When I asked Novakool about adding the AC Option in the future they said that adding that option can be done later but that the cost of the separate components & labour would be $400 plus.

Sound correct?

[avanti]

Originally Posted by GallenH

Q: I seem to recall earlier discussions about buying a RV/marine fridge where it was observed that the 120vAC portion was merely a transformer of sorts that just reduced the 120v to the 12v native to the fridge compressor. So the argument was that it really didn't make sense to buy one which was 2-way but rather just stick with the 12v. Is this correct?

Yes, it is correct. Fridges with Danfoss compressors are native 12VDC as you say. The "120VAC" option is just a wall-wart-style DC adaptor. Makes no sense at all in an RV.

[GeorgeRa]

I have ACDC compressor fridge and use it often. When we come back from a trip and I want everything off except fridge. On my easily accessible control panel I have 2 CBs, Fridge AC or Fridge DC. I would not use this option of my van would be wired for easy AC <> DC change. So, for a commercial van I would agree with Avanti, AC has a limited value.

If you choose to add AC the cost would be about $20-25 for a quality ACDC 12V 10A converter brick.

[GallenH]

So. If you had the AC option would that mean that the fridge would be operating off of AC while your charger was dedicated to charging your battery and not dealing with the fridge demands?

[GeorgeRa]

Originally Posted by GallenH

So. If you had the AC option would that mean that the fridge would be operating off of AC while your charger was dedicated to charging your battery and not dealing with the fridge demands?

On camping with shore it can run on AC or DC but I tend keep it on DC.
No shore camping DC only.
After a trip for unloading period with house shore all systems off and the fridge on AC. If we need more fridge room we occasionally use van's fridge on AC.