Residential fridge electrical usage

[AnnArborBob]

I'm considering a DX3 as an upgrade to our current heavily modified Airstream travel trailer. We do extensive boondocking and are often off the grid for several months at a time. We have a 8.1 cf, 12 volt Danfoss compressor marine fridge in our current Airstream which typically uses about 90 - 100 AH @ 12 v. in a 24 hour duty cycle. We have 740 watts of solar and 600 AH of LFP's in our Airstream and with this setup have no problem running the fridge and supplying all the other electrical needs in our Airstream even in the dead of winter.

After living with an electrical fridge in our RV for several years, I really prefer them over the propane RV models. Accordingly, if we do get the DX3 I'm attracted to the residential fridge vs. the propane model or another marine fridge. I would plan to max out the solar on the DX3's roof and also use the LFP's in place of the AGM's so I suspect I would have the capacity to handle the residential fridge with minimal use of the generator but I still want to "run the numbers."

Does anyone one know the electrical usage of the residential fridge currently being installed in the Dynamax motor homes? I'm not looking for the "annual energy use" statement on the little yellow tab inside the fridge but rather the actual amps (or watts) consumed when the fridge's compressor is actually running?

Thanks, Bob

[caseymyers]

The Force HD For Boon docking? (Multi-page thread 1 2 3)
Mountieman

[ependydad]

Originally Posted by caseymyers

The Force HD For Boon docking? (Multi-page thread 1 2 3)
Mountieman

Here's a link to it:
The Force HD For Boon docking? - Page 3 - Forest River Forums

AnnArborBob, you sound like a Fulltime Family that I've met. You wouldn't happen to have a Hummer H2 or H3 that you also modified (swapped out for a diesel engine), would you?

[caseymyers]

P3 P4400 Kill A Watt Electricity Usage Monitor

You can buy at Amazon for $17. Simple plug in device will monitor just how many Amps your refrigerator used in 24 hours.

[AnnArborBob]

Originally Posted by ependydad

Here's a link to it:
The Force HD For Boon docking? - Page 3 - Forest River Forums

AnnArborBob, you sound like a Fulltime Family that I've met. You wouldn't happen to have a Hummer H2 or H3 that you also modified (swapped out for a diesel engine), would you?

Nope, not me! We pull our Airstream with a 2018 F-150 King Ranch.

The Force HD For Boondocking thread does not provide the specific information on the electrical usage I am seeking.

Thanks,
Bob

[AnnArborBob]

Originally Posted by caseymyers

P3 P4400 Kill A Watt Electricity Usage Monitor

You can buy at Amazon for $17. Simple plug in device will monitor just how many Amps your refrigerator used in 24 hours.

This would work if I already owned the DX3 and had access to the fridge. I'm a prospective buyer here.

Thanks,
Bob

[Magnatudes]

Originally Posted by AnnArborBob

This would work if I already owned the DX3 and had access to the fridge. I'm a prospective buyer here.

Thanks,
Bob

I bet in the end you'll find that sticking with a 12 volt Danfoss compressor-based fridge will be most efficient. No inverter energy losses. I would even venture to say that having two Nova Cool or Dometic frigs installed side by side with opposite door swings would be more energy efficient operating off of batteries than a residential frig of the same capacity running thru an inverter. More flexibility as well, setting different temps for each freezer & each frig. Or just run half of them for short trips. The frigs will cost more but that is the price you pay for boondoggle battery efficiency. Solar helps. I ran a 4 cuft Danfoss freezer just on solar power for weeks. Froze meat rock solid. Compressor hardly ever ran at night.

Nova Cool RFU8220 / RFU9000 / RFU7300
Dometic Americana DMC

[ependydad]

Originally Posted by AnnArborBob

Nope, not me! We pull our Airstream with a 2018 F-150 King Ranch.

The Force HD For Boondocking thread does not provide the specific information on the electrical usage I am seeking.

Thanks,
Bob

(thumbsup) Your Airstream is similarly modified as another I know. Sounds like a fun rig!

Wish I could help on the residential fridge- I’m “stuck” with gas/electric fridges for now.

[garbonz]

Obviously nobody actually read the thread, the OP know what he is doing an ask a simple question. What model of residential fridge does the rig he is asking about have? Anyone?

[RV Randy]

Went and saw mine today, its a Whirlpool 16.1 cu ft. unit. For what its worth, the rig was plugged into shore power and the only items turned on were the fridge and a few of the interior ceiling lights. The power management unit on the wall shows input AC voltage, battery voltage and amperage being used. It showed 1.2 amps. Its digital but I don't know how accurate is, but obviously the current draw is small. I'm sure it spikes up a bit if the compressor kicks on but these units are pretty efficient.

[caseymyers]

Some of the units have this fridge:

http://www.frigidaire.com/Kitchen-Ap...or/FFHT1621QS/

[VinceU]

Mine was a 21cu/ft two door fridge with drawer freezer and water-ice in door. It drew 7 amps AC or 70 amps through inverter/batteries. That compares closely to the 16,1 cu/ft unit drawing 6 amps AC

[Bluepill]

When thinking about a residential, I did a test of my 25 Cu Ft. Home reefer with a Kill-a-Watt tester. Came up with 2KWH a day at 120 volts. Adding in losses for the inverter, that is about 200 amp-hours a day from the 12 volt batteries. With a maximum battery discharge down to 50%, 400 amp hours of battery capacity would be needed for every 24 hours of usage.

This would require 5 to 6 hours of generator time daily to recharge just the bank that supplies the refer (based on the C/10 formula). Whatever other battery and converter usage there is would be in addition to the above.

[Bluepill]

Some more thoughts here:

What Type Of Refrigerator Should You Use In Your RV?

[technomadness]

The above Frigidaire uses about 79AH a day, based on its annual rate, not accounting for inverter losses (which are variable.) A 200AH 24v LFP system should last about a week before needing to recharge.

[FFred]

The above Frigidaire uses about 79AH a day, based on its annual rate, not accounting for inverter losses (which are variable.)The above Frigidaire uses about 79AH a day, based on its annual rate, not accounting for inverter losses (which are variable.)

The yellow tag ratings do not include the resistance heaters to dry out the thin insulation , or the heater strips to keep the seals working.

When you obtain the exact model number search for the mfg wiring diagram and see how powerful the heaters are .

For real boondocking propane is the only realistic answer , otherwise you may need to purchase expensive batts and never park in the shade to keep the solar setup working.

The reefer is the biggest power draw in most coaches and battery power is seldom yp to the task.

Perhaps a Sun Frost could be kept up, but battery fridges are always a huge problem.

Refrigerators & Freezers - SunFrost.com

Refrigerators & Freezers - SunFrost.com


Sun Frost RF19, R19, and F19 shown with 13" Cabinet These refrigerators and freezers are our largest models, and all have two equal sized compartments. The Sun Frost RF19: one compartment is a refrigerator and the other a freezer. The RF19 can be ordered with the freezer on the top or on the bottom. The freezer is ...‎Sun Frost RF12 · ‎Sun Frost RF16 · ‎Energy Efficient Refrigerators

[tomkatb]

I just did the math to,decide on our recent fifth wheel purchase.

For us, the more ocassionally user, it came down to solar collectors and batteries.

In your case I would guess that with the typical three door residential fridge you might make 3 days sort of worse case without topping up somehow. I looked up,usage of several refrigerators.

For us more average users the cost of maxing the collectors and expensive batteries was prohibitive.

The typical 4 wet cell batteries, worst case is they might not make 24 hours. 200 amps. Using a gas fridge those four batteries would last us 4 days maybe.

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.

In your case having that much solar and a generator it looks good. But, in my case, too,expensive.

It is really the age old battery problem. There is no good way to store electricity. The new batteries are 100% better but only 25% as good as they need to be. Solar is still in its infancy.

[Magnatudes]

Originally Posted by VinceU

Mine was a 21cu/ft two door fridge with drawer freezer and water-ice in door. It drew 7 amps AC or 70 amps through inverter/batteries. That compares closely to the 16,1 cu/ft unit drawing 6 amps AC

Wow, 70 amps @12VDC 21cu/ft, so estimate 60 amps for a 16 cu/ft

Compare to a 12volt Danfoss compressor (no propane, auto switching 12VDC/120VAC w/low voltage protection:

Nova Kool RFU9000 9.1cu/ft - 5.2 amps @12VDC
Adding 2" rigid foam insulation to the outside will reduce energy consumption by 1/2. 1100 watt hours per day at 70* as delivered, 550 watt hours per day if insulation is added on-site.

Dometic Americana DMC 8cu/ft - 9.6 amps @12VDC
Variable speed compressor

Doing simple math, let's take the worst case, two Dometic 8cu/ft = 16cu/ft
9.6amps x 2 = 19.2amps @12VDC if both are running full speed simultaneously

At Full Tilt Boogie:
Dometic Danfoss 16cu/ft = 19.2amps @12VDC
Nova Kool Danfoss 18.2cu/ft = 10.4 amps @12VDC
Residential 16cu/ft via Inverter = 60 amps @12VDC

Retail prices:
Nova Kool = $1700 each
Dometic = $1100 each

[tomkatb]

In trying to buy a fifth wheel, most of the sales guys suggested the residential refrigerator. Assuming I suppose that no one would overnight without 110. They said is is about all they sell.

I was the odd one wanting a 12 cu ft gas/electric, a gas cooktop and range.

[Bluepill]

The dealers probably love the 120 volt AC residential refers. No complaints about poor performance due to being run out-of-level like the LPG units. More reliable and cheaper. No learning curve for owners who are already familiar with the residential design.

No doubt that I would choose residential if all I ever did was stay at campgrounds in a Class A.