Residential fridge electrical usage

[sseaner]

I believe (just my opinion) residential fridges are the way to go. You can add solar, batteries and always run the gen if you are boon-docking. More room, faster cooling, ice maker, and no level problems.

[sconnors11]

I'm surprised no one has brought it up, but these RV specific propane fridges run just fine on electric. One can manage between gas or electric modes of operation with the simple flick of the switch.

[The Renegade]

Originally Posted by sconnors11

I'm surprised no one has brought it up, but these RV specific propane fridges run just fine on electric. One can manage between gas or electric modes of operation with the simple flick of the switch.

Ding Ding Ding.... Great point.

[technomadness]

Please research the differences between absorption fridges and compressors. The RV fridges run on absorption and are less efficient than compressor based fridges. Their only advantages are running on propane and being quieter than compressors. On the other hand they cause RV fires, require two huge holes in the side of the RV to let water in, and draw a lot of power from your battery if you aren’t running them in propane, and they take a lot longer to cool down.

The pilot of a fridge blowing out while going down the road resulting in a propane fire is apparently one of the leading causes of RV fires.

[sconnors11]

Originally Posted by technomadness

Please research the differences between absorption fridges and compressors. The RV fridges run on absorption and are less efficient than compressor based fridges. Their only advantages are running on propane and being quieter than compressors. On the other hand they cause RV fires, require two huge holes in the side of the RV to let water in, and draw a lot of power from your battery if you aren’t running them in propane, and they take a lot longer to cool down.

The pilot of a fridge blowing out while going down the road resulting in a propane fire is apparently one of the leading causes of RV fires.

I don’t remember any fires in the decade or so that I ran a propane fridge. Also, I remember being surprised that the load on the batteries was so small. I guess we’ll have to agree to disagree on this one.

Personally, I wish my rig had a propane fridge as it would allow the solar to put more energy into the batteries and the doors have a built in latch mechanism.

Don’t get me wrong, I’m not about to retrofit, but if I were ordering new it would be up for debate with the wife.

[caseymyers]

I had two Norcold's go out on my last M.H., the expensive 4 door model with the ice maker, expensive to replace two fridges. And in 2016 I saw two fires in the Yuma area both Norcolds and the motorhomes were both totaled. There is a fix, it a 'high-temp' module or something like that. I had it added to my fridge, it shuts everything down if the unit gets too hot. I don't think it is limited to Norcold. It's been a couple of years since we sold that M.H., and maybe Norcold has resolved the issue? I have a pickup camper now with a Dometic and have had no problems.

[technomadness]

Fires are the number two cause of insurance claims, and there was a large lawsuit (or lawsuits) related to propane refrigerators due to the fact they eventually corrode and become dangerous. I’m sure the makers have improved the part that corrodes and added the safety mechanisms Casey mentioned, so they are probably safer now than they have been historically.

However, they are still less effective & less efficient.

[FFred]

"Additionally the up to 200 watts of heat produced in the kitchen area would have to be taken care of. 800 btu's per hour. Good in cold weather, not so good in West Texas in the summer."

Propane fridges have been going into RV for 60-70 years , so the vent requirements are part of the installation kit and are done at the factory.

30 years ago a very out of level fridge could overheat , but on more recent units if you can lay down in bed and not roll out , the fridge is just fine.

A propane fridge on propane cools down rapidly , when used with the electric element , it is about 20% slower , BUT as most units have overnight plugged in before trip , SO WHAT?

The most efficient fridges are the DC units that have a variable speed compressor.

These will eat 50-70Amps (12v) each day , which is exercise for a 200AH (at deep cycle 20 hour rate) dedicated battery set.

Being realistic about energy production and storage propane is the ONLY way to boondock, and have a cold reefer with out spending 1/2 ones time attempting to recharge the reefer batt set.

The old tales from decades ago were partially accurate , but today the propane reefer will be bought NEW and not suffer the hassles from units sold during the Korean war.

Electric compressor Efficiency is very poor if a gen set has to be operated 5-10 hours a day for 10- 30 days , and the cost of fuel , maint and eventual replacement is considered.

[sseaner]

The Option for the RV fridge was another $900.00 plus the tax on top of that. For that money I can run my diesel generator for over 500 hours!! Easy decision.

[tomkatb]

Everyone needs to think his situation thru carefully.

In the case of a $60,000 fifth wheel.

To boondocks with a residential fridge is tough. Most of Yellostone camping has no electricity.

You need a generator in the fifth wheel. $6000 or so. Plus $600 in better batteries. The generator is a problem. In a fifth wheel they burn propane. Lots of it. Likely would need a refill weekly or more. 12.5% more cost plus propane. More costs for solar. 400 watts of solar. Dragging a #150 generator out of the pickup bed is a drag for my old bones. Plus a tank of gas.

A cheap residental fridge is $1000 plus an inverter, $300.. A 12 cu. ft. Gas electric is $2400.

Modern residental fridges are built to lower standards today. Seldom do they last 10 years in a house. Removing and replacing one in a fifth wheeler can be pricy. Likely they would not pass thru the door. Fridges can be 30-36" wide and can be 35" deep. They are placed in the vehicle before the walls go up.

Removing the slide to replace one would be expensive.

Residential fridges are 800 btu heaters in the vehicle. They vent heat under the unit not out the outside vent.

It takes a lot of thought. If I bought a motor home with a diesel or gas generator, the residental fridge sounds pretty good. Add fancy batteries and solar, great system.

With a trailer or fifth wheel, not so much. I am buying one of those table top ice makers for $100 to go with my gas fridge. One needs fresh ice with the evening libations.

[sseaner]

Yes, I am strictly talking about a residential fridge in a diesel Dynamax.

[Magnatudes]

Originally Posted by FFred

The most efficient fridges are the DC units that have a variable speed compressor.

These will eat 50-70Amps (12v) each day , which is exercise for a 200AH (at deep cycle 20 hour rate) dedicated battery set.

True = The most efficient fridges are the DC units that have a variable speed Danfoss compressor.

False = These will eat 50-70Amps (12v) each day , which is exercise for a 200AH (at deep cycle 20 hour rate) dedicated battery set.

Once the fridge/freezer is cold/frozen, the cycling of the compressor is minimal to maintain desired temp.

Based on my earlier posting, in a worse case scenario, a residential fridge will kill batteries at least 3 times faster. And that analysis compared two Danfoss fridges vs. one residential to better compare cu/ft capacity. However, if only one Danfoss fridge is used, worst case would be that a residential fridge would kill batteries 6 times faster than a Danfoss. My experience with variable Danfoss compressors is that they are much more efficient than what I describe here, especially if they are installed to replace an absorption type where there is already venting to the outside.

Another approach, one that I have done for years, is setting up a hybrid scenario. Use an absorption frig inside the MH & a Danfoss portable in a storage bay. I used to use Engel fridge/freezers that can be used as one or the other depending on thermostat setting. Today I use a Whynter FM-62DZ Dual Zone Portable Refrigerator/Freezer that has two separate compartments & temp settings. Either compartment can be a freezer or a frig and has plenty of room for many cold and frozen ice cream & meat.

By the way, the Danfoss compressor is extremely quiet when running.

[Magnatudes]

Whynter Portable 62Qt Dual Zone Fridge Consumption Chart.

Back in 1999 I started using Waeco Portables. I still have a Waeco in my boat that's been running since 2005. Dometic bought Waeco a few years ago for their technology & worldwide support. This is Dometic's latest Dual Zone Danfoss variable compressor-based portable.
Dometic Model CFX95DZW

Dometic CFX 95DZW Dual Zone Portable Fridge Freezer Video Overview

Dometic/Waeco down under

[technomadness]

Originally Posted by tomkatb

. The new batteries are 100% better but only 25% as good as they need to be. Solar is still in its infancy.

Lithium is more like 10X better, and always cheaper than AGM in the long run. They cost more up front but last ten times longer and provide twice the power per AH as they can be fully discharged.

Solar is down to $1 a watt which seems super cheap. 500 Watts is a lot.

[technomadness]

Originally Posted by FFred

"Additionally the up to 200 watts of heat produced in the kitchen area would have to be taken care of. 800 btu's per hour. Good in cold weather, not so good in West Texas in the summer."

Propane fridges have been going into RV for 60-70 years , so the vent requirements are part of the installation kit and are done at the factory.

30 years ago a very out of level fridge could overheat , but on more recent units if you can lay down in bed and not roll out , the fridge is just fine.

A propane fridge on propane cools down rapidly , when used with the electric element , it is about 20% slower , BUT as most units have overnight plugged in before trip , SO WHAT?

The most efficient fridges are the DC units that have a variable speed compressor.

These will eat 50-70Amps (12v) each day , which is exercise for a 200AH (at deep cycle 20 hour rate) dedicated battery set.

Being realistic about energy production and storage propane is the ONLY way to boondock, and have a cold reefer with out spending 1/2 ones time attempting to recharge the reefer batt set.

The old tales from decades ago were partially accurate , but today the propane reefer will be bought NEW and not suffer the hassles from units sold during the Korean war.

Electric compressor Efficiency is very poor if a gen set has to be operated 5-10 hours a day for 10- 30 days , and the cost of fuel , maint and eventual replacement is considered.

Nope.

[technomadness]

By the way, I think the most efficient compressor fridges are not residential but swing arm type. These are sold in the US under the brand Engel.

[Magnatudes]

Originally Posted by technomadness

By the way, I think the most efficient compressor fridges are not residential but swing arm type. These are sold in the US under the brand Engel.

Yep. I used to have an Engel MT80. Never had an issue. Had it on a rollout slide in a belly storage bin on a class A. Used it strictly as a fridge to maintain ice cold

At the same time I also had a 4 cu/ft upright freezer replacing of a dumbshit wash machine inside the coach for frozen meats, for freezing fresh filets & making ice.

All this basically ran on four 18v 85watt solar panels with a Solar Boost 2000e controller out in the middle of nowhere.