12/24/120v fridge freezer power draw/efficiency comparison

[LocalmotionSC]

I've been researching fridge/freezer efficiency, I know its a topic of interest (and confusion/debate) for many people.

I came across a series of tests (link) done by expedition extreme on youtube (and a pdf spreadsheet (link) of their findings).

They performed 1 and 2 hour cooldown, cycling, insulation, and 12, and 24 hour power draw comparisons. With 4 fridges (Snomaster, Arb, Waeco, and a 26 yr old Engel) and ambient temps in the mid 70's [73-78].

Set to 0c (32 fahrenheit), the fridges consumed between 24 amp hours on the low end to 30 amp hours on the high end, over a 24 hour period (290-360 watt hours).

The best performing in this test was the Waeco and the worst performing was the 26 year old Engel, strangely, in the 12 hour test the Engel tied for best performance.

 

[john61ct]

The unit lasting 26 years will outweigh any piddling differences in energy efficiency even if you needed to spend a bit more on your solar

 

[LocalmotionSC]

The unit lasting 26 years will outweigh any piddling differences in energy efficiency even if you needed to spend a bit more on your solar

Definitely, but in some cases, cost efficiency and energy efficiency are separate considerations (i.e. some might opt for the most energy efficient unit because they are extremely limited in square footage available for solar or payload available for batteries, even at the expense of cost efficiency--though in this case the difference in energy use (20-25%) is small enough that I doubt that would make sense). To bad we can't buy 26 year old Engels or they didn't add a newer model egel to the comparison.

On a totally unrelated note, you and I were just discussing the pros/cons of LFP/Lead Acid batteries, on another forum (I go by dzl there). Its a small world

 

[john61ct]

I think Engels currently still make best value reliability longevity.

I rarely look at handles, usually dunno which forum I'm in, doesn't matter, focus on info / substance

 

[LivinDaDream]

Those numbers align very well with what I've measured on my 4.2 cu.ft. Vitrifrigo unit the I installed in my Lance 815 about a year and a half ago. When the unit first starts up, I see about 4.1A current draw and within a couple minutes, it drops to around 3.7A until the end of the cycle.

Depending on ambient temps and how often I'm in it, I see about 300± Wh/day in power usage and it's near silent in operation. I can now get 3 days of operation out of my 100AH LiFePo4 battery without any charging if I'm judicious with my other power usage. Time will tell as for the longevity of the Danfoss compressors all these units use (BD35 seems to be most common). The item I suspect will be the first to fail would likely be the cooling fan, but that seems a very common 12V item...in fact I may go ahead and purchase a spare to keep on-hand.

 

[john61ct]

electronic controls, PCBs are the biggest failure points

compressors very rarely fail, any brand

 

[Josie'slandcruiser]

Thanks Local MotionSC.

Link to the test you are referencing?

I've been researching fridge/freezer efficiency, I know its a topic of interest (and confusion/debate) for many people.

I came across a series of tests done by expedition extreme on youtube (and a pdf spreadsheet of their findings).

They performed 1 and 2 hour cooldown, cycling, insulation, and 12, and 24 hour power draw comparisons. With 4 fridges (Snomaster, Arb, Waeco, and a 26 yr old Engel) and ambient temps in the mid 70's [73-78].

Set to 0c (32 fahrenheit), the fridges consumed between 24 amp hours on the low end to 30 amp hours on the high end, over a 24 hour period (290-360 watt hours).

The best performing in this test was the Waeco and the worst performing was the 26 year old Engel, strangely, in the 12 hour test the Engel tied for best performance.

 

[LocalmotionSC]

Thanks,
Link to the test you are referencing?

The links are in the original post (expo, makes it hard to see links if you don't hover your mouse over the text, its kind of irritating).

Here they are (click LINK):
This LINK is the spreadsheet
This LINK is the video where they discuss/compare 24 hour power draw
This LINK is to a video where they explain their methodology

 

[Ducky's Dad]

The item I suspect will be the first to fail would likely be the cooling fan, but that seems a very common 12V item.

When my Indel B 50 failed a couple of years ago, it turned out to be the fan. Fridge was throwing a code that nobody recognized so suspicion was a bad PCB, until the tech got into it. Every time the fan came on, unit would throw code and shut down. New fan solved problem.

 

[realsystem]

Hello. I'm just curious anybody used regular home fridge in a camper/van/RV? I mean small one AC 110V like in motel. Are there any difference in internals between special fridge(ARB, Engel) and regular simple home appliance(in terms of compressor only, besides electronics)? Of course this is about AC from inverter in the camper/RV setup and I understand that special fridge will convert 110V AC to 12V DC(some has this option). But my question mostly about mechanical parts. DC->AC->DC is not efficient, I know. Anyway, why not to use regular fridge with inverter? It's one way of current conversion.

 

[LivinDaDream]

If you look at individual mtbf values on most equipment as an overall system, it's the mechanical items that generally have the lowest mtbf values of all the components that make up a system. If I get a wild hair I may see if I can get a glimpse of the mfr and model number of the fan in use on my system to see if it's a cheap POS or not. The Vitrifrigo line seems to be mostly sold into the marine market and one would think that a more hostile environment would be considered when choosing components, but you know how that goes. The 12V/120V control module that powers the unit is enclosed in metal, so that's a plus, but the fan and the condenser are open to whatever might blow in through the vent panel in the side of the camper. I may partially close that vent area to reduce the likelihood/amount of road spray or salt spray entering that space.

 

[LivinDaDream]

Hello. I'm just curious anybody used regular home fridge in a camper/van/RV? I mean small one AC 110V like in motel. Are there any difference in internals between special fridge(ARB, Engel) and regular simple home appliance(in terms of compressor only, besides electronics)? Of course this is about AC from inverter in the camper/RV setup and I understand that special fridge will convert 110V AC to 12V DC(some has this option). But my question mostly about mechanical parts. DC->AC->DC is not efficient, I know. Anyway, why not to use regular fridge with inverter? It's one way of current conversion.

It's hard to find power consumption values for the small 110V units, but the one I did find was 150 watts for a 3.2 CU.FT. model. That's 3x what my 4.2 CU.FT. unit draws. If you have the power to spare, it's certainly not a bad way to go, given that most of these type units sell for $200 or less, compared to $900 for the one I bought. While they don't come with trim or bezel to provide a solid mounting method in a panel, I'm sure that for the extra $700, you could work something out. Even though I'm very "value oriented", I value my time very highly, so I didn't want to fool with all that...and being in a truck camper, I don't have the space to have 2x or 3x the battery bank that serves me very well as I'm now set up.

 

[realsystem]

Sure, value is a key, not a question. I like to build things from scratch, re-purpose and build something that people usually just buy and mount. And I have small fridge 0.9A 110V AC and am thinking about re-purposing it. At least to feed brain with ideas.

 

[realsystem]

Its entirely possible, as you know, it will be a powerhog compared to a designed for the purpose AC/DC ’fridge.
If you try it, suggest use a real sinewave inverter. Induction motors are not happy running on modified squarewave.

How to understand that my particular compressor is unhappy with my inverter? I just did a quick test and it's immediately start freezing inside, powered by factory Tacoma inverter.

 

[john61ct]

The efficiency of 240Vac fridges made for well-regulated countries in Europe and down under, is often as good or better than 12V compressor fridges, even with inverter overhead added.

But in the 120Vac markets, industry's capture of the agencies has led to relatively much less efficient units, so in using a cheap dormfridge your Ah per 24 hours will be much much higher, by a panel or two on good days.