Refrigerator for Vehicles

[Inq720]

I'm renovating a small sailboat and will be installing a full solar system from what I'm learning on this forum. For this post I wanted to show-and-tell what I came up with for a small refrigerator/freezer. I probably should have asked for advice first, but made the jump without a net. I started out looking at Dometic, Waeco or Engel in the 50 quart range based on advice from this forum. However, the sticker shock drove me to Amazon and many hours of comparing. I finally picked an Aspenora 54-Quart Portable Fridge Freezer. Some of my criteria:

1. Of course cheaper - Amazon had it 15% off for $340. https://www.amazon.com/gp/product/B082YWHMCY After the fact, I think it is possible to get it off the company site for cheaper... not sure. https://www.aspenoras.com/
2. I wanted it relatively square - Many of the brands had "Ergonomic" shapes. I plan to build it in and will be adding 2+ inches of rigid insulation around to help the efficiency. The ergonomic ones make that a serious PITA!
3. Having the handle removable - See 2 - Also it allows me to mount the freezer to boat structure.
4. Having two compartments so freezer and fridge could be used simultaneously. This one does, but it is not regulated independently. Its simply the fridge area is over the compressor and must get slightly heated.
   
5. Has controls and displays on top - Didn't want to have the insulation interrupted and will only have access to the top once installed.

I finally ran into this one and what synched it was a customer review - that did his own detailed testing with graphs and all. Appealed to my engineering anal-retentiveness. It also showed that the unit was more efficient than the Dometic equivalent. https://www.amazon.com/gp/customer-revi ... B082YWHMCY

Anyway, I just received it last week and started testing it with the included AC laptop type power supply. Once I finish my LiFePO4 / Overkill battery, I re-run the tests with 12 VDC. Since the ship has sailed, I'm not likely to get something else, but I would be interested in feedback about the efficiencies I'm finding with this unit and/or other tests that might be enlightening.

Some Observations - I see the Dometic / Engel are more industrial and built like tanks and that the Engel even requires freight charges. This is certainly a lightweight item made mostly of plastic, aluminum walls a came by FedEx for free on Amazon Prime. I'll be building it into cabinetry, so I'm not too worried about it taking abuse from movement. It has more bells and whistles leaning toward home fridges.

PRO:

• Has a nice interior light in the door that shines down.
• Display temperature, mode is always showing.
• Soft close - I'm betting they needed that to protect the lid electronics from people who slam it down.
• Latch - Not sure if pro or con. Keeps closed, but won't fully close from a dropped lid.
• Noise - Quieter than my desktop computer and I don't think I'll be able to hear once built-in, but don't think I'd want it next to me while sleeping if not enclosed. Have nothing to compare it to, to know if its better or worse than say a Dometic / Engel.
• Vents are on three sides - 2 appear to be intake, 1 exhaust. Very slight heating of air. Not worth noting.
• Has two speed compressor - Max, Eco.

CON:

• The fridge section is 1/4" too short to hold my long-neck beer bottles! DAMN!!!
  
  
  D.A. Engineer!
• Is lightly build. Will not take abuse like a blow-molded cooler or steel cooler.
• UI Menu is a little awkward and button presses don't always recognize. Once set up, I doubt I'd ever change it unless I want to change the main compartment between freezer and fridge temperatures.

Testing Conditions
Ambient Room Temperature: 68°F
Using smart plug watt-meter. I'm sure not super accurate, but I've run the tests for at least 24 hours to reduce error.

Test 1 - Maximum Rate Freeze - This is to simulate turning on the freezer and dropping a 2.2 pound of fish fillets.

• Start at room temperature
• Thermostat set to -4°F (delta -72°F)
• Mode set to MAX
• Pyrex 8"x8" pan with 1.06 quarts (1 liter) of water at room temperature.

Results:

1. It took 1 hour, 57 minutes for the thermostat to reach -4°F and pause for its first cycle.
2. Took 89.0 Watt-hours
3. Took another 7 hours to freeze the ice solid.
4. Took another 196.0 Watt-hours

Test 2 - 4 - Steady State Usage

• For three tests set thermostat temperature to simulate freezer, fridge and fridge in the islands.
  • -4 °F (delta -72 F°)
  • 20 °F (delta -48 F°)
  • 37 °F (delta -31 F°)
• Mode set to ECO
• Empty contents.
• Door is not opened during test - Although not realistic for usage, I couldn't think of a quantifying opening schedule to be more real world.
• Start test once interior reaches a steady state.
• Run the test for 24 hours.
• In ECO mode the compressor, when running, draws 32 to 38 watts.

Results: The average watts (based on duty cycle). Note: Again this is AC wattage. DC should be better. Internet says AC adapters have 50% to 90% efficiencies. And for my situations, I'll be adding 2" of insulation on sides and bottom.

1. -4 °F => 20.0 watts average over 24 hours, (481 Whr)
2. 20 °F => 14.8 watts
3. 37 °F => 9.0 watts

 

[snoobler]

Musings:

The quantity in the fridge directly impacts how much power it uses. I suggest you repeat the tests by filling it with something representative of typical use and open it for 30 seconds, 10 times in a 24 hour period. You may find dramatically different results.

If the unit has any installation spacing requirements, I would respect those and not insulate it. If you insulate the entire unit, you're putting a box around the heat exchanger. It's moving heat from the inside to the outside, so you need to allow the heat to escape from the unit. Insulation may reduce efficiency because the heat is escaping into an insulated volume that just keeps getting hotter.

AC-DC adapters are typically 85% or better, particularly on units touted for energy efficiency.

 

[tim0shel]

That one seems to have some thickness to it to help with keeping temp. Pretty good deal.
I've ran ICECO for years, this year I bought another which was bigger. It runs in my car 24/7 but mostly is used as my aid station for when I do loop ultra marathons. ICECO has been a solid fridge freezer. I have the dual VL60 individually controlled freezer/fridge.
It has ran over a week with no solar connected on my 280ah battery and if I recall still had some more juice. But with just 100watt panel depending on ambient temperature I can run it and charge the battery during the day.

 

[Solarfun4jim]

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.

 

[Inq720]

Musings:

The quantity in the fridge directly impacts how much power it uses. I suggest you repeat the tests by filling it with something representative of typical use and open it for 30 seconds, 10 times in a 24 hour period. You may find dramatically different results.

If the unit has any installation spacing requirements, I would respect those and not insulate it. If you insulate the entire unit, you're putting a box around the heat exchanger. It's moving heat from the inside to the outside, so you need to allow the heat to escape from the unit. Insulation may reduce efficiency because the heat is escaping into an insulated volume that just keeps getting hotter.

AC-DC adapters are typically 85% or better, particularly on units touted for energy efficiency.

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. 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.

 

[Inq720]

You travel in style... no doubt! Thank you for posting.
I'd like to see more real world use cases to know if I'm in the ballpark. Right now, I'm planning on only 200W of panels. With your numbers...
That's only 80W for 4 hours... hmmm. Hate to cut back on frozen Margaritas.

 

[DeVerm]

Surprised that you didn’t include what we found was the best performer: Snomaster. I know it’s expensive, it is not a budget choice. Picture is towards the end of the build in our boat.

 

[Inq720]

Surprised that you didn’t include what we found was the best performer: Snomaster. I know it’s expensive, it is not a budget choice. Picture is towards the end of the build in our boat.

Who is "we"? I searched on this forum and found a reference to this test. For instance the "Episode 3 Fridge Cycling" sounds similar to my steady-state, but there are very few conditions listed, so I'm not sure. If I try to interpret that table, -20.4C is the same at my -4 °F test. In it they state an average utilization of 6.7 A/H. And the other units tested even higher (8.1 to 11.7 A/H). The Aspenora above only draws 36 watts (3A at 12VDC) when the compressor is running and averaged 1.7 A/H during my 24 hour test. That big of a discrepancy says we're comparing apples and oranges.

Do you have a link to your actual tests? I'd like to see the conditions and re-create them with the Aspenora so we can do a valid comparison.

Thanks.

 

[Reed Cole]

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.

If your electrical system can power it the only real concern would be the abuse the fridge would suffer in a moving vehicle. Rv/boat fridges tend not to have glass shelves, plus are designed to tolerate plenty of jostling. How big of a concern that is is unknown to me, probably depends on the vehicle and how much you drive to some extent.

 

[yabert]

... after 2 years, it's good. no disasters

Same experience here. I use a cheap 120V mini bar fridge in the van powered by an inverter and after more than 20k miles, no problem.
The price of the fridge + the inverter was still 2 or 3 times less expensive than a 12V fridge.

 

[DeBe]

House hold Inverter fridges are used here in Australia in RVs with out any problems.

 

[Picasso]

I love Engel. I hate my residential fridge and its damn every 24 hour defrost cycle that uses more power vs cooling the damn thing.

 

[amaclach]

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

 

[Zil]

I'm renovating a small sailboat and will be installing a full solar system from what I'm learning on this forum. For this post I wanted to show-and-tell what I came up with for a small refrigerator/freezer.

I want to thank you for the time to post your actual test results. So many just say "I bought this one and it is best." This post is appreciated.

 

[Inq720]

I want to thank you for the time to post your actual test results. So many just say "I bought this one and it is best." This post is appreciated.

I appreciate the comment...

I also was hoping for some data coming back from others. As technical as this DIY site is on the supply side, it doesn't seem to extend to the usage side. Just the mA eeked out of panels, chargers, BMS and inverters.

 

[Inq720]

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

Thank you for the link. This is exactly what I wanted... some way for me to objectively judge this commodity, Chinese fridge. The first thing I noted about in your vid was it recommended viewing a previous vid... so I did. It was a cool down test very similar to the one I did first above.

Before I get started with the testing, I want say, I have no axe to grind. I bought the Aspenora from Amazon and my major driving decision was it was 1/3 to 1/4 the price. However, I did my research and now these tests are hopefully going to confirm I didn't waste my money. If I had a larger budget for the fridge, I probably would have purchased the Waeco or Engel. I had not heard of the SnoMaster before. I would imagine that if I was going to be rough and tumble in a 4WD, the Aspenora would be a questionable choice. I won't be doing any abuse tests. But for sailing... its generally pretty smooth.

As for the test, you can view for yourself, but I'll summarize the key aspects here.

• Start fridges from ambient temperature of 23°C
• Used a (1) 250 ml soda of some sort also at ambient temperature.
• Use max rate cooling.
• Document fridge temperature and fluid temperature at 30 minutes and 60 minutes.

In the video, the SnoMaster clearly was better especially since it was larger at 42 liters. However, I would like to point out one minor flaw in the results. They ran the test simultaneously, but they pulled out the sample and measured it and talked about it before moving on to the next fridge. From the video time clock, the SnoMaster got over 3 minutes more time before taking a reading. In my testing of the Apenora, that 3 extra minutes lowered the fridge temperature by 2 °C. It still would have won... so no harm... no foul.

Below, are the results from the test video and also includes the Aspenora. I was able to simulate the test quite accurately, except... I used 250 ml of room temperature water. You decide if that's significant.

​

Fridge​	30 min Water T​	30 min Fridge T​	60 min Water T​	60 min Fridge T​
Waeco	21	2	12	-9
Engel	20	-4	13	-7.8
SnoMaster	17	-10	6	-19
Aspenora	15.6	-4	4.7	-17

In this test, I think the Aspenora held its own quite well especially since it is 54 quarts. Objectively...

1. The Aspenora reports a warmer temperature. This may be because the thermostat sensor is closer to the top where it is likely warmer. It does have the ability to calibrate the temperature in the settings.
2. The Aspenora is clearly chilling the water better than the other fridges, but that can be questioned based on it being just water and not soda. Also, the measuring device they used is more questionable. It is calibrated for cooking meat. Whereas the one I used claims to be +/- 0.5°C. As he points out in the video, since he uses the same one on all fridges, its all relative anyway. He is correct, but since I'm not using his same relative, the numbers may be better or worse.

This test is of less value to me. I'm more concerned about long-term (days / weeks) power usage. Getting things cold is less important than keeping things from spoiling in week three in the tropics. But others may find it important in their evaluation.

 

[schmism]

Is it normal for your fridge temp to be well below freezing? I would call this a freezer (object designed to keep items below the freezing point of water) not a refrigerator (object designed to keep items cold but not frozen).

 

[Inq720]

Is it normal for your fridge temp to be well below freezing? I would call this a freezer (object designed to keep items below the freezing point of water) not a refrigerator (object designed to keep items cold but not frozen).

All these "car" chest freezers are meant to be very flexible - For the Aspenora, you set the thermostat to whatever you want in the main, big compartment. When set to -4F (-20C) its as good a freezer as my home model. At that temperature, the small section above the compressor runs right above freezing 33-35F and acts like a fridge. If you want the main compartment to be a fridge, you can set the thermostat to say... 37F (what my home fridge temperature is). The section above the compressor at that point hovers around 50F. Not much good for anything. Close to wine cellar temperature, but a wine bottle won't fit.

I'm not sure which mode I'd use. This is for a sailboat. I think if I provision a lot of vegetables, I set it at fridge temperatures. As I run out, I'd set it to freezer temps for freezing caught fish and/or frozen boat drinks.

 

[DeVerm]

Who is "we"? I searched on this forum and found a reference to this test. For instance the "Episode 3 Fridge Cycling" sounds similar to my steady-state, but there are very few conditions listed, so I'm not sure. If I try to interpret that table, -20.4C is the same at my -4 °F test. In it they state an average utilization of 6.7 A/H. And the other units tested even higher (8.1 to 11.7 A/H). The Aspenora above only draws 36 watts (3A at 12VDC) when the compressor is running and averaged 1.7 A/H during my 24 hour test. That big of a discrepancy says we're comparing apples and oranges.

Do you have a link to your actual tests? I'd like to see the conditions and re-create them with the Aspenora so we can do a valid comparison.

Thanks.

”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.

 

[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.

Beautiful boat... Mine would tip over if I put a 95 liter on her.