Refrigerator for Vehicles

[Inq720]

I'm starting to go through and recreate the tests

I'll second the Snomaster - They're decent units, and designed for offroad vehicle use.
A comparison video between common offroad/overland fridges. performance, power consumption etc.

There's a series, but here's the first one Engel vs SnoMaster vs ARB vs Waeco Ep 1 of 7 - YouTube

Here are the results of repeating "Expedition Extreme's" test number 2 - Power Consumption.

The conclusion of their tests did indicate the Snomaster was "their" choice as it has two speeds and could let you chill stuff quickly or save energy. The Engel used less electricity, but was far slower chilling. Here is their original chart. It might be easier to read. I've repeated their data below and added the results of the Aspenora. All their data is in metric and I followed suit.

Procedure of the test.

1. Load with 250 ml water raised off the bottom by a box.
2. Set fridge to minimum temperature it supports (Aspenora = -20°C)
3. Measure amps, watts and amp-hours, water temperature, and interior temperature (by different gauge than display). Do this at startup, 1 hour mark and 2 hour mark.

Result and Observations

• The Aspenora started cycling (indicating it had reached its minimum temperature) at the 1:23 mark. They did not indicate whether any of the others did that although the SnoMaster 2 hour temperatures indicate it might have.
• The Aspenora 54 qt, even though larger, chilled the water faster than all others including the SnoMaster 42L that was their winner. The Aspenora was well into icing up at the top of the bottle at the two hour mark where the sensor was located (note below).
• Like the SnoMaster, the Aspenora has two speeds. They liked this feature because it lets you choose to chill thing quickly or to save electricity. The Aspenora out chilled the SnoMaster. Also, in economy mode it approached the Engel's energy efficiency, yet was colder than the Engel (note below).
• Also noted during the tests, the Aspenora has a slow ramping of current during startup. I noted that the current rose over about a sixty second period. No spike!
• Above, I noted that the sides were made of aluminum. I was mistaken, they are steel. Magnets stick.
• I did not see where they discussed construction. Being off-roaders, I suspect they might have had concerns about the plastic of the Aspenora, otherwise, I suspect they would have picked the Aspenora as their winner.
  • SnoMaster 42L, 53 lbs, $1150
  • Aspenora 54qt, 43 lbs, $340

I will be conducting their other test as well.

Water Temp

Fridge Temp

Watts

Amps

Current Draw Amp-hours

Ambient Temp

Start

1 Hour

2 Hour

Start

1 Hour

2 Hour

Start

1 Hour

2 Hour

Start

1 Hour

2 Hour

Start

1 Hour

2 Hour

SnoMaster 42 L

Auto Setting

25.0​

22.2​

8.4​

0.2​

21.2​

-18.0​

-19.9​

46​

60​

59​

3.66​

4.81​

4.77​

0​

5.6​

9​

Low Setting

23.0​

22.4​

8.9​

0.2​

21.0​

-15.0​

-19.4​

40​

33​

31​

3.20​

2.67​

2.50​

0​

3.1​

5.8​

ARB 40 L

25.6​

22.8​

10.9​

0.0​

22.0​

-14.5​

-19.7​

44​

45​

41​

3.50​

3.65​

3.39​

0​

4.3​

7.8​

Engel 40 L

22.7​

22.2​

14.1​

2.7​

21.3​

-3.7​

-12.1​

37​

28​

22​

3.00​

2.33​

2.11​

0​

2.3​

4.6​

Waeco 40 L

26.5​

22.6​

14.3​

1.4​

22.5​

-10.5​

-16.4​

42​

39​

28​

3.50​

3.00​

2.35​

0​

3.4​

6.1​

Aspenora 54 qt

MAX Setting

23.0​

23​

8.1​

-0.4​

20.8​

-13.7​

-19.7​

37.0​

40.9​

44.5​

2.91​

3.22​

3.50​

0​

3.53​

5.96​

ECO Setting

22.3​

22​

8.0​

0.0​

22.1​

-6.0​

-12.9​

35.6​

30.5​

28.6​

2.80​

2.40​

2.25​

0​

2.52​

4.83​

 

[Inq720]

”we” is us, the crew of s/v Jedi. We did a range of tests and posted the outcomes on our Facebook page. Here’s one:

Today we completed the energy consumption testing of the Snomaster Expedition 95 liter freezer. The final test was at a thermostat setting of 6F (-14.4 Celsius). We measured 0.76kWh in a 24h period. We also timed the duty cycle at 42%

This is 10.6% less energy consumption than @3F
This is 20.8% less energy consumption than @0F

The temperature test at the top of the box was stable at 10F which is amazing as with the thermostat at 3F it was ranging between 8F and 10F.

Here are all results all together:

Thermostat @ 0F: 960Wh/day energy consumption at 57% duty cycle
Thermostat @ 3F: 850Wh/day energy consumption at 48% duty cycle
Thermostat @ 6F: 760Wh/day energy consumption at 42% duty cycle

Our 15 year experience with a freezer aboard is that we did not see any problems with the thermostat at -14 Celsius. When we combine that with the test results, we will be running it at the 6F setting.

Now that I got that last test results out, I've had a chance to study your results. A duty cycle of 57% sounds pretty good. The test in my first posting has a duty cycle of 53% with a delta -72 F°. I imagine if you did your test in the tropics you might have had a higher ambient temperature (unless you A/C your boat ). If your delta is say -85 F°, 57% is really good. Its hard to tell if you don't report the ambient temperature.

 

[DeVerm]

Now that I got that last test results out, I've had a chance to study your results. A duty cycle of 57% sounds pretty good. The test in my first posting has a duty cycle of 53% with a delta -72 F°. I imagine if you did your test in the tropics you might have had a higher ambient temperature (unless you A/C your boat ). If your delta is say -85 F°, 57% is really good. Its hard to tell if you don't report the ambient temperature.

We did the test off the boat in a climate controlled room, temperature 25 degrees Celsius. Also, the freezer was packed with frozen foodstuffs.

We have used these aboard for a 3-month cruise to the Bahamas during the hit hurricane season. Power consumption challenged our custom boxes with 6” insulation and Frigomar K50 keel cooled systems when those were new and was about 25% better than when we retired those 15 years later.

We also have a Dometic unit which is a Waeco as I understand it and it can not keep up when used above 25 deg. Celsius ambient.

 

[HaldorEE]

Are there any serious problems in simply using a very high efficiency house fridge in a RV?
An A+++ rated fridge running off the inverter looks like it would have a low annual kwh consumption. What are the likely problems going this route versus a compressor fridge at several times the cost for the same capacity.

Residential fridges are a bad idea for boondocking. They really don't like not being level.

Chest type fridges are also more efficient if you are going in there a lot since they don't fill up with warm air every time you open the door.

I have been very happy with my Iceco G20. If I needed more space I would definitely move up to an Iceco VL60. A Danforth (now Secop) compressor is what makes the difference. These are significantly more efficient than everything else and they work in an out of level condition. No reason to pay Dometic prices when Iceco has better features (in my opinion).

Dual compartment is very useful. I tend to make the bigger compartment the freezer. You set each compartment individually so you can have all fridge, all freezer, or any combination of freezer/fridge you need. And even my little G20 makes ice which is like gold in the backcountry.

 

[amaclach]

At the end of the day, you don't have to validate performance against other brands. Only 3 things matter:
1) The device performs adequately in the intended environment
2) You have enough battery & solar to power it
3) It's reliable.

An Engle might not have the raw performance or efficiency of the others, but it will run forever in some pretty horrific conditions, but also comes with a pretty hefty price tag. It's all about trading off price v performance/efficiency v reliability. If what you've got works for you, and you didn't have to sell a kidney, then great!

 

[Inq720]

At the end of the day, you don't have to validate performance against other brands. Only 3 things matter:
1) The device performs adequately in the intended environment
2) You have enough battery & solar to power it
3) It's reliable.

An Engle might not have the raw performance or efficiency of the others, but it will run forever in some pretty horrific conditions, but also comes with a pretty hefty price tag. It's all about trading off price v performance/efficiency v reliability. If what you've got works for you, and you didn't have to sell a kidney, then great!

I think I agree... to a point. Maybe its just me. The comparison was mainly... I wanted to know that by getting a cheaper brand, how much efficiency I was leaving on the table. Turns out... none. Yes, there is also the other very important metric of reliability. With the Engle, that is something that has had time to prove itself. This OP model has certainly not done that. Even if it fails in short order... is that a fluke or an indication of the design/make is bad? If it lasts ten years of continuous service in a trailerable sailboat's harsh environment... is that a fluke or an indication of the design/make is good? One data point is not satisfactory to make that judgment call either way. Fortunately, if bad, I can buy two more times and still be ahead on cost.

 

[Sun]

I objectively tested my Dometic 75 dual zone (2 sides) cooler with 24hr tests to determine average watt usage in my usual environments:

For my CFX75DZW (same compressor & insulation as CFX3-75), there are so many possible variables values can vary GREATLY but here are my trials based on ambient temperature 80 Fahrenheit.
Hourly consumption for Fahrenheit temps (on AC pwr, not opening lid):

One side 35 (other side off) 9W
One side 25 (other side off) 13W
Both sides 35 13W
Both sides 25 19W
Both sides 31 16W
Freezer 1 & Fridge 39 38W
Freezer -8 & Fridge 32 55W

-Cooler only takes 1-2 hours to cool to set temperature when empty but adding warm food/drinks will take a day or more to equalize and can double watt usage until equalized.
-Watt usage numbers can be a multiple at one ambient temp compared to another.
-Ambient temp +5F may use 0-5% more watts.
-May use 5-10% less watts when full of cold food/drinks.
-Opening 4+ times/day may use 0-10% more watts.
-Larger compartment can be slightly more efficient if cooler is not well ventilated because compressor generates some heat on the small compartment side.
-CFX75's reported temps are accurate; it’s normal for temps to vary a few degrees throughout cavity in any fridge or freezer depending on types of food/liquid stored.
-Smaller compartment (usually considered the freezer side) however is 5-10 degrees warmer in top section, (it has fewer coils).

 

[ncowan]

The point of the tests are for comparison purposes... not to project my actual usage. If others have or will do tests in the future, you would always want to use a common test. If my "stuff" isn't the same as their "stuff" or I open mine more or less than others the tests are invalid for comparison purposes.

Steady-state means once everything in the fridge is at the same temperature, heat transfer goes to zero... between the stuff, air inside and walls. The only heat transfer will be through the walls. Once reaching a true steady state, and the lid is not opened any "stuff" will affect how it cycles, but the average wattage would stay the same. IOW, any cold stuff would tend to keep thermostat satisfied longer, but once kicked, it would have to run longer to re-cool the interior and stuff. But the average usage would be the same as an empty box test. (There are at least two caveats that come to mind, but they are so minor only lab quality test gear could measure it.)

Also, I stress the delta temperatures... not the actual thermostat settings. If someone were to test a unit in say... Florida while the ambient is 85°F, they could set their unit to 85°F - 72°F = 13°F and directly compare their result to my -4 °F (delta -72 F°) test. I would far rather be doing that test... 85°F is where my boat's happy place will be.

Insulation - Although I mentioned the small vents on three sides, I did not detail my extra insulating. I should have. Of course, I will not cover up the vents. That would totally stop heat transfer and the unit wouldn't cool. Adding insulation is a very common and quite beneficial DIY improvement to any unit... even an Engel.

AC Adapter - I'm sure you're right. And for a Dometic or Engel, I bet they source a high-quality, efficient AC adapter. Based on this being a commodity quality, China product, I wouldn't count on that kemimoto fridge. I'd bet money if someone else bought one, they'd find their AC adapter was the a different one they sourced that week. Mine looks like a commodity laptop adapter - 14.5V, 6.0A.

If someone knows of a test (standard or manufacturer specific) I'd like to conduct it to compare this unit to a Dometic or Engel. My tests so far indicate it compares quite favorably - efficiency wise. With my 272Ah battery build and even without the aid of solar panels, I could last nearly a week while making frozen boat drinks. The only test left is longevity. And I would expect a high-end Dometic or Engel be better... but 3x better!?!?.

I will be doing the same kind of tests once I get my LiFePO4 battery built for comparison. I'll also give some real world results once its in the boat with the insulation and the boat is in its happy place, say mixing frozen Margaritas in the sunny Keys.

We are taking a 6-8 week road trip with our 2022 outback and want to hook up a portable refrigerator. Does anyone have a recommendation? It doesn't have to be large. Freezer may be unnecessary. Will this unit draw off the car battery when the car is off? Would an additional battery be needed? Budget is low. This probably won't be used again. Thanks in advance!

 

[tim0shel]

Can't go wrong with an ICECO! All this heat we have been having and previous summers mine has been running 4years straight in my car on a Solar power station I built with 280ah cells. I have VL60D dual zone run one side as freezer with icecream and the other as fridge.