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Why are 12 volt regrigerators so expensive?

Milford Cubicle II

NAXJA Forum User
Location
Out there.
Any 12 volt fridge I've seen (ARB, Engel, etc.) is craaaazy expensive and I'm wondering why. I realize that they tend to have more insulation, for fairly obvious reasons; to keep the power consumption low. Also they tend to be "rugged," whatever that means. But the refrigeration system is exactly the same as any other AC or household refrigerator. Hell, I can pick up a good mini fridge for well under a hundred bucks. So why is it that when it comes to portable 12 volt refrigerator, the price goes through the roof? You'd be hard pressed to find one for under $500, which IMO is ridiculous.

And no, I'm not including those thermoelectric BS jobs that you can get from Target for 30 bucks, I'm talking about actual refrigerators.

The compressor, which is the heart of a refrigerant system, is driven by an electric motor. Electric motors are by nature, DC devices, not AC. So it seems to me that it would cost more to make an AC compressor than a DC compressor. But in reality it seems to be the other way around. Good quality DC motors are a dime a dozen, and all a DC refrigeration system is, is a DC motor instead of an AC motor. Am I missing something? Whiskey Tango Foxtrot??? :soapbox:
 
It's probably because they are made for the expedition market and just like everything else built for that market, they want 10X the cost.

I heard a term kicked around over on Expedition Portal. Exposexual.

Basically the sexiness of the tools made for that nieche market drives the cost up.

That being said...I paid $700 for an ARB fridge and I haven't regretted it ever. Out of everything I carry it's probably the one item that brings a smile to my face every time we are on a trip. To reach in, grab a nice cold frosty beverage and never have to worry about soggy anything makes it all worth while to me.
 
I have thought about getting a CL mini fridge for cheap and just buying a converter for it to work.

This:
http://indianapolis.craigslist.org/app/2441636365.html
+
This:
http://www.sears.com/shc/s/p_10153_...o=1&blockType=G1&prdNo=1&i_cntr=1308153280553

Puts you at under 70 bucks easy. Add more insulation if you want better inefficiency. But really, I am not going to pay 10x as much for an ARB model.

That would work as long as you don't plan on shutting your rig off for any amount of time. One of the big advantages of a 12v fridge built for a vehicle is that they draw almost no current. I can leave my jeep off for three days and still start it. The fridges made for vehicles also have low voltage cutoff switches to prevent them from leaving you stranded in the middle of nowhere.
 
That would work as long as you don't plan on shutting your rig off for any amount of time. One of the big advantages of a 12v fridge built for a vehicle is that they draw almost no current. I can leave my jeep off for three days and still start it. The fridges made for vehicles also have low voltage cutoff switches to prevent them from leaving you stranded in the middle of nowhere.

Yes... Plus I think I read somewhere that it takes 3 watts input for every watt output on an inverter.
 
Yes... Plus I think I read somewhere that it takes 3 watts input for every watt output on an inverter.

Most inverters are about 80% efficient, good ones can reach 85-90% so it's more like a 5 watts in, 4 watts out ratio.

I have thought about getting a CL mini fridge for cheap and just buying a converter for it to work.

This:
http://indianapolis.craigslist.org/app/2441636365.html
+
This:
http://www.sears.com/shc/s/p_10153_...o=1&blockType=G1&prdNo=1&i_cntr=1308153280553

Puts you at under 70 bucks easy. Add more insulation if you want better inefficiency. But really, I am not going to pay 10x as much for an ARB model.

I've thought about doing that too. I'll admit that an actual ARB style "expo" fridge would be much better suited, for the reasons already mentioned by Moab. But for short camping trips instead of "expeditions,' I bet it would work just fine.

An idea to keep in mind is that if I'm not mistaken, the 12 volt compressors are usually variable speed. Which helps efficiency because instead of shutting off and having to restart (start up drawing a lot more amperage), they can just run at a lower speed (drawing very little power) to maintain a constant temperature instead of the constant fluctuation of traditional fridges.

But here's the kicker, I found compressor out of an ARB fridge and even the compressor itself is pricey, compared to other compressors:

https://www.hvacusa.com/store/danfo...gorized-c-1010747_1010804/101z0200-p-90143520

Which is this compressor:

http://www.danfoss.com/Products/Cat...a4b/302ae202-0654-49eb-8f85-c8614fbc7175.html
 
So I just found something very interesting on the Danfoss website in the link above.

I noticed under "motor type" it says DC/PM. If by PM they mean "permanent magnet" then that just means it's a regular brushed DC motor driving this compressor. Meaning that it's not a brushless "DC" motor that's really AC, meaning that these compressors are not just using brushless DC motors with inverters to run them.

All that means is that these freakin compressors should be even cheaper than regular AC compressors. Brushed DC motors have been around for like a hundred years and they're cheeeeap :banghead:
 
Most things like this the price is because of limited demand, which requires development and production and ROI to be spread across fewer units.
Again, it's the number of units sold. That's a fairly specialized piece of equipment, for a very low-volume market. There are probably about as many cars in the US as homes, but how many cars have refrigerators in them? Almost none.

Also:
Look at that pic at the Danfoss web site again. Do you see the compressor motor? No. You can't because it's a hermetically sealed compressor. The motor can not be serviced. Not only can the brushes never be changed, the dust off them can't contaminate the refrigerant the motor is running in. It's not just a standard brushed DC motor. It's a very specialized DC motor that is engineered to run in a R-134 vapor environment, without throwing off sparks, dust, or any other contamination.
 
Borrowed an old model ARB Freezer/Fridge this weekend...and no matter the cost I'm sold after not having to deal with ice and wet food. Very efficient, too, even though the newer models are even better.
 
Borrowed an old model ARB Freezer/Fridge this weekend...and no matter the cost I'm sold after not having to deal with ice and wet food. Very efficient, too, even though the newer models are even better.

Told you.

Once you go camping ice free, you will never do it any other way.

Woke up this morning and grabbed a water bottle out of my fridge. It had little ice flakes in it. I had put the water in the fridge last night and it was about 85* outside.
 
Told you.

Once you go camping ice free, you will never do it any other way.

Woke up this morning and grabbed a water bottle out of my fridge. It had little ice flakes in it. I had put the water in the fridge last night and it was about 85* outside.

Indeed. :D

Wheels get put on the trailer in the morning when I have guys around to help me flip it over. I'll post pics on FB. Can't wait!!
 
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