Community Forums

philippo · 01-31-2023, 03:19 PM

We're planning to leave our Northern Lite Camper parked for 15 days with the Dometic refrigerator running on propane.

My thinking is that if I fill both 20 lb propane tanks; that amount of fuel will more than suffice to keep things cold for that particular period.

Am I correct?

Thanks,
Philip

MrMark52 · 01-31-2023, 03:31 PM

Where will the trailer be located; what are the outdoor temperatures and sun exposures expected to be during that period of time?

Any comparison of propane use to similar periods of use (when you may have been there to watch?

powercat_ras · 01-31-2023, 04:07 PM

If a single door refrigerator, you should be good with 40 lbs propane, depending on outdoor temps you will use between 5 and 20 lbs. If a double door, between 10 and 40 lbs.

You also need to consider your 12 volt power holding for 15 days. The fridge control board has to have DC power for the fridge to operate on propane. The control board will shut down somewhere in the 10.5 to 11.0 volt range.

Since you can't turn off the master DC switch and run the fridge, the refrigerator control board, the thermostat, the backup battery connection on your TT entertainment radio, and the propane leak detector will all draw a small amount of DC power, and your battery will slowly go down. Typically about 15-25 amp hours per day. So even if you have 2 house batteries you may not make it 15 days.

Be sure you have inverter switched off if you have one, it will increase DC drain another 25 amp-hours per day even with nothing being powered by the inverter.

If you have 100 watts or more of solar you should be OK.

Old-Biscuit · 01-31-2023, 04:14 PM

12V DC will be bigger concern than if you have enough propane

How do you plan on maintaining/charging battery?

153stars · 01-31-2023, 09:57 PM

You didn't list fridge model. Bigger the fridge the higher btu burner. But 40 lbs is more than enough. I see posted on google 1-1.5 lbs per day.
I loved my old Dometic pop up and TT fridges. No DC board just thermocouple the solenoid like a old water heater. The original Norcold in TT caused fire even after the recall front control panel was replaced. I bought it from a guard at work after the fire. I cleaned and remodeled it. Replace the fridge with an older model from Dometic this time.

TB673 · 01-31-2023, 10:07 PM

Quote:

Originally Posted by powercat_ras

If a single door refrigerator, you should be good with 40 lbs propane, depending on outdoor temps you will use between 5 and 20 lbs. If a double door, between 10 and 40 lbs.

You also need to consider your 12 volt power holding for 15 days. The fridge control board has to have DC power for the fridge to operate on propane. The control board will shut down somewhere in the 10.5 to 11.0 volt range.

Since you can't turn off the master DC switch and run the fridge, the refrigerator control board, the thermostat, the backup battery connection on your TT entertainment radio, and the propane leak detector will all draw a small amount of DC power, and your battery will slowly go down. Typically about 15-25 amp hours per day. So even if you have 2 house batteries you may not make it 15 days.

Be sure you have inverter switched off if you have one, it will increase DC drain another 25 amp-hours per day even with nothing being powered by the inverter.

If you have 100 watts or more of solar you should be OK.

Go to your 12 VDC Fuse Panel and remove the fuses of all the other loads except the refrigerator.

Tim

K7JV · 02-01-2023, 07:12 AM

How your refrigerator is powered depends on your coach. What kind of rig do you have? On our previous coach, an '06 Dynasty, the refrigerator was on a 12V bus that was NOT switched by the battery disconnect switch. So it always had power to the terminals on the control module. Turning it off when we left the coach parked each time was part of our checklist. On our current coach, a '21 Esteem, the battery switch DOES have to be on for the refrigerator to operate.

You could test it by turning off your battery disconnect and seeing if you can still turn the refrigerator on with the button on the front of it. If you can, you're golden. If not, battery life will be even way more of a factor.

As for the propane, your refrigerator burn doesn't hold a candle (if you'll excuse the inaneness of that statement) to what your furnace would burn, and you should be able to keep the coach warm with the furnace for several days in the coldest of weather. Again, like Old-Biscuit said, your battery will be your limiting factor.

philippo · 02-01-2023, 07:26 AM

Thanks for the input!
To answer a few of your questions:

1) Single door Dometic fridge
2) 650 watts of solar panels
3) 2 100AH Lithium Ion batteries
4) Inverter stays off when we're not using
it (usually for morning coffee...&#128526

Rig will be parked outside at the Phoenix AZ airport, daily temps look to be about high 40's at night wirh highs in the mid 60's during the day. (Luckily it looks like the highs won't be too brutal for the next two weeks in the southwest)
Major sunshine appears to be the current trend.

K7JV · 02-01-2023, 07:31 AM

With the solar you have and the propane you will have, if you leave your inverter off I can't imagine that you wouldn't be golden! At least I would make that assumption and run with it if your rig were mine.

MrMark52 · 02-01-2023, 07:52 AM

Quote:

Originally Posted by K7JV

With the solar you have and the propane you will have, if you leave your inverter off I can't imagine that you wouldn't be golden! At least I would make that assumption and run with it if your rig were mine.

I tend to agree with the above, as well as Old_Bisquit and others.

I guess I would only question - what are your alternatives?

And - you might make sure before you get to the airport and shut the coach down - that you don’t lose 12 vdc to the refrigerator.

powercat_ras · 02-01-2023, 01:18 PM

Another thought - with propane costs being what they are, would it be worth $ 40 of propane to keep the fridge/freezer running or is it a good time to clean out the fridge / freezer and start over with a grocery run when you get back?

philippo · 02-02-2023, 04:24 PM

Answers REALLY appreciated!

After reading...and hemming and hawking...we've decided to go with plan B: to eat everything in the fridge and turn it off. Right now (to do MY part) I'm working my way through the

Ben &Jerry's chocolate ice cream 😂😂Hard job but somebody's gotta do it! 👍👍👍🍧🍧
Thx again

Old-Biscuit · 02-02-2023, 07:55 PM

Some dry Ice , cooler and I'll pay the freight on Steaks

wopachop · 02-02-2023, 09:28 PM

I have the same struggles. Empty the fridge completely or leave it on propane. It wont use much propane in 60F daytime temps and never opening the door. A 20lb tank would be plenty for 15 days.

If i had your setup i would run the fridge off the inverter. Little late to test it.

For me i often run out of time to eat my food and defrost the fridge. End up going the propane route.