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Old 04-15-2018, 02:47 AM   #21
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Originally Posted by Chance View Post
Assuming data is correct (and granted it has to be confirmed), 3.2 Amps for an entire day is 77 Amp-hours. A couple of typical golf cart batteries are rated 225 Amp-hours, so for those who will boondock and charge from solar, or run generator at least once a day, it will be very possible to obtain a 24-hour energy cycle.

Another way to look at it is that these refrigerators require one extra battery beyond what other 12V electrical loads require.

Spending over $1,000 to convert an existing fridge is something I wouldnít do, but if given an option to buy a new Axis with 12V compressor in lieu of an absorption one meant to run on propane most of the time, Iíd go all electric. Itís just a personal preference based on fact that it would power off alternator while driving, or shore power at campsites. Stopping overnight on road trips would be even easier since MH would only be stopped for 12 hours or less. Mostly, Iíd see it as an investment towards making the motorhome simpler, and thus better for me.
Golf batteries can have 225 AH but they ARE 6V so 2 would be required to stack for 12V. The 50% discharge rule has to be taken into account as well if you want any life out of the batteries so again we are down to 225/2 AH realistically. We could put in a 85 KWh Tesla battery for an additional $30,000-$50,000 and why stop there...Propane is a very practical high energy source for it's weight and that is why it is used for heating, cooking AND refrigeration that are all high energy demand appliances. I think residential or highly efficient compressor refrigeration is only for the very high end motorhomes whose owners are not likely to mind the shortcomings I am talking about. With 6-8 house batteries it could be acceptable.
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Old 04-15-2018, 06:00 AM   #22
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Golf batteries can have 225 AH but they ARE 6V so 2 would be required to stack for 12V. The 50% discharge rule has to be taken into account as well if you want any life out of the batteries so again we are down to 225/2 AH realistically. We could put in a 85 KWh Tesla battery for an additional $30,000-$50,000 and why stop there...Propane is a very practical high energy source for it's weight and that is why it is used for heating, cooking AND refrigeration that are all high energy demand appliances. I think residential or highly efficient compressor refrigeration is only for the very high end motorhomes whose owners are not likely to mind the shortcomings I am talking about. With 6-8 house batteries it could be acceptable.
Seriously?

You are comparing the INCREMENTAL energy requirement that calculates to that of one standard RV house battery (cost as little as $100) to that of Tesla’s 85 kWh lithium battery bank?

There are a lot of advantages to compressor refrigerators compared to absorption — which partly depends on application. It’s not all just about being able to run longer on a tank of propane.

For you propane appears to be the best option. Others who have different requirements may feel differently. I do.
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Old 04-15-2018, 06:09 AM   #23
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Tesla Battery

I was, of course, being facetious.
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Old 04-15-2018, 10:05 PM   #24
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PEOPLE PLEASE!!!!
I posted this info for those who are thinking about replacing an absorption fridge that is failing with a residential one,, This is just another option that would allow one to retain their current fridge instead of having to do woodwork and having "fitment" issues....NOT about which (Propane/Electric) has an advantage or is better!
My post was NOT about how much power or how big of a battery bank needed or any of the other "jumping the rails" observations..
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Old 04-15-2018, 10:16 PM   #25
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I LIKE MY PROPANE POWERED FRIDGE! i like that it does not require large amount of electric, the batteries need to runs resi fridge is to much. and it keeps every thing cold
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Old 04-15-2018, 10:43 PM   #26
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PEOPLE PLEASE!!!!
I posted this info for those who are thinking about replacing an absorption fridge that is failing with a residential one,, This is just another option that would allow one to retain their current fridge instead of having to do woodwork and having "fitment" issues....NOT about which (Propane/Electric) has an advantage or is better!
My post was NOT about how much power or how big of a battery bank needed or any of the other "jumping the rails" observations..

Actually, you brought it up in your second post. And rightfully so because thatís a key part of what youíre indirectly recommending.
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Old 04-15-2018, 11:09 PM   #27
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I LIKE MY PROPANE POWERED FRIDGE! i like that it does not require large amount of electric, the batteries need to runs resi fridge is to much. and it keeps every thing cold
That's cool to!
Nobody is going to be holding a gun to anyone's head, and forcing them to convert...

But it's kind of nice to know that there ARE options...
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Old 04-16-2018, 01:02 AM   #28
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or try this...
https://www.costco.com/Unique-9.0-Cu...100362122.html
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Old 04-16-2018, 01:13 AM   #29
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9 cu ft runs on 2.5A/12V

This may be just what the compressor fan wants. They use a LOT of insulation to maximize overall efficiency.
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Old 04-16-2018, 02:36 AM   #30
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Just based on what my experience has been, seems to me the problems with absorption refrigerators are more limited to the bigger ones. In my former DP, the absorption refrigerator was a very large 4 door, had lots of trouble cooling when first turned on, and problems maintaining temps in very warm weather. On the Gemini, its a much smaller absorption refrigerator, which cools very quickly in comparison, refrigerator section stays at a pretty consistent 38 degrees, freezer at about -3 degrees. I have yet to run it on propane for any period of time, its wired to the inverter, so while driving its still running on 120 volts, alternator replacing what energy is used. If I am parked for any period of time with no shore power, I will switch it to LP, but for us that does not happen often. The need to be level does not seem to be a problem while driving, and since the Gemini has an auto-leveling system, its not a problem when parked either. We could probably get by with either the absorption, or a residential refrigerator, but frankly the currently installed absorption refrigerator is working just fine for us.
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Old 04-16-2018, 05:49 AM   #31
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Peltier cell refrigeration

Just a note that there is also refrigeration that uses Peltier cells that are semiconductor, solid state devices that while they are not effcient, they can be of great convenience for cooling down a few cans or bottles of refreshment. A unit that will hold 6 12 oz cans will run around 4 A at 12V input. These units can be plugged into the cigarette lighter outlet in the dash but are also slow to cool like the absorption style refrigerator. They take a lot of power for what they do but can be purchased for around $50 - $80. Larger cooler size units are available as well.

The Peltier cell is a very interesting device and can be used for cooling or for heating. Many individual semiconductor junctions are tied between two flat ceramic/aluminum sheets. When current is passed through the junctions one side of the structure gets hot and the other side turns cold. If the polarity of the DC wiring is reversed, the opposite sides heat/cool. A single polarity switch is normally provided to cool or heat the beverage(s). A fan is normally used on each side of the structure to extract heat from the hot side (and keep the Peltier cell cool) and spread the cooling on the other.
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Old 04-16-2018, 01:25 PM   #32
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Just based on what my experience has been, seems to me the problems with absorption refrigerators are more limited to the bigger ones. In my former DP, the absorption refrigerator was a very large 4 door, had lots of trouble cooling when first turned on, and problems maintaining temps in very warm weather. On the Gemini, its a much smaller absorption refrigerator, which cools very quickly in comparison, refrigerator section stays at a pretty consistent 38 degrees, freezer at about -3 degrees. I have yet to run it on propane for any period of time, its wired to the inverter, so while driving its still running on 120 volts, alternator replacing what energy is used. If I am parked for any period of time with no shore power, I will switch it to LP, but for us that does not happen often. The need to be level does not seem to be a problem while driving, and since the Gemini has an auto-leveling system, its not a problem when parked either. We could probably get by with either the absorption, or a residential refrigerator, but frankly the currently installed absorption refrigerator is working just fine for us.

Not to drag this out since OP already thinks weíve drifted off topic, but I think itís very important to note the differences between absorption and compressor refrigerators to help educate newbies who may not know.

Specifications shown below show that a similar size Norcold absorption unit running off 120 Volt AC power uses 3 Amps, or roughly 360 watts.

By comparison, the similar size Norcold compressor fridge list power at 3.2 Amps at 12 Volts, or about 40 watts. In this case the absorption refrigerator requires 9 times more power.

If powering from shore power, the extra 3 Amps at 120 Volts may not matter. Powering off alternator may make more of a difference because the 360 watts would need roughly 30 Amps, which is significant. However, if powering from batteries, it wouldnít take long at 30+ Amps (12 VDC) to kill them.


Some of us understand all these options fairly well, but a lot of RVers donít know, and honestly donít care, how all these options relate and interact. For that reason manufacturers should try to make RVs simpler when possible, and in my opinion a refrigerator that can work efficiently directly from battery bank is a good step in that direction.

I personally like the simplicity of an On-Off switch which everyone can understand. No need to worry about turning off while fueling, or whether pilot light goes off while traveling, or extra vents to the outside which creates added holes in RV, outside temperature limits, etc. Many of them also provide more storage volume in same space because the cooling equipment packaging is more efficient.

Just saying there is a lot to like about compressor refrigerators, and not all of it is achieved with a retrofit kit like mentioned in OP. If you want one it should be done from the start. I expect this trend like used in Winnebago View to continue. In the long run it should cost less too.
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Old 04-16-2018, 08:12 PM   #33
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Also not to drag it out, but an absorption refrigerator can be switched to LP when parked, reducing electrical consumption to near zero, and LP usage isn't much in that mode. Having said that, there are pro's and con's to both, though I see compressor refrigerators becoming more and more common as they cost less, and installation is less complex. I frankly could live with either.
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Old 04-16-2018, 09:20 PM   #34
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Thetford, which makes Norcold RV refrigerators, just announced acquisition of Nova Kool, which seems to have a lot more capabilities in DC and AC compressor refrigerators for RVs, marine, etc.


Thetford Announces Acquisition of Nova Kool Mfg. | RV Business


There is little doubt that there is a trend towards compressor refrigerators, or away from propane. Thatís not to say propane will disappear, because some RVers will be better served by propane.
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Old 04-17-2018, 04:58 AM   #35
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Pic of Dutch Aire fridge compressor cooling unit...
Looks simple enough for a retro fit replacement of the absorption units....
http://jc-refrigeration.com/wp-conte...g-from-top.png
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Old 09-28-2019, 12:51 AM   #36
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Acknowledging up front that this is an old thread:

Do any of our forum members have actual experience with the Dometic or Norcold RV fridge residential conversion, such as the JC Refrigeration Dometic 2652 conversion cooling unit? I see they now have a DC 12V compressor model with a 5.5A draw.

If you have experience with this conversion, what are your impressions?
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