Propane

[Larry Tiner]

We have one large propane tank full and one half full. I want to leave the RV sitting with the propane keeping refrigerator cooled. Any guesses on how long the propane would last?

[BarryD0706]

It will last longer than your battery, unless you're plugged in to "shore power", and if you are, why not just run the fridge off of that?

[dcheatwood]

Originally Posted by Larry Tiner

We have one large propane tank full and one half full. I want to leave the RV sitting with the propane keeping refrigerator cooled. Any guesses on how long the propane would last?

Weeks or even months on a full 30 pound tank. Frig uses very little gas, like a pilot light.

[Larry Tiner]

No electricity available, just propane. I think I can use the battery disconnect to conserve the battery.

[jtstromsburg]

Even on propane, the fridge uses 12v

[wmtire]

How long are you wanting to leave the RV fridge running for on propane/ 12 volt DC for the control panel?

Do you have a way to recharge the battery (solar, generator, etc.)?

Are you going to using anything else in the RV that will need battery power (lights, heater, propane leak detector, etc)?

If you can provide the brand/model of your fridge, it will help to see exactly what the minimal 12 volt draw for the control panel on propane will be for it.....then it might can be guesstimated how long it can run depending on your battery. Temperature is going to be a needed consideration too, to see how much cooling the fridge will need to do. A fridge in TX temperatures will have to work harder than one in Minnesota.

As far as your original question, the propane fueled flame needed for the fridge to cool is close to the size of a pilot light (as dcheatwood stated), if that helps you understand how long your cylinder may last.

[Larry Tiner]

Thanks to whoever for reposting this for me. Never knew propane had its own post.
After my original post, I realized that the frig HAD to have an electrical power source. That made my inquiry moot. Thank you all for your comments and guidance.

[Larry Tiner]

Jtstromsburg, thank you for that info.

[gasman6674]

FYI
Most units use 1550 btu per hour (dm2652) LP gas has 91,500 btu's per gallon, 21,548 per pound. A 30# cylinder when full will hold 6 gallons or 59.03 hours per gallon times 6 = 354.18 hours or 14 days. I dont think the battery will last that long without solar back up

regards

[garbonz]

Originally Posted by gasman6674

FYI
Most units use 1550 btu per hour (dm2652) LP gas has 91,500 btu's per gallon, 21,548 per pound. A 30# cylinder when full will hold 6 gallons or 59.03 hours per gallon times 6 = 354.18 hours or 14 days. I dont think the battery will last that long without solar back up

regards

Where does the ambient temperature come into the equation? Is that 1550 btu per hour when operating.

How does the propane system know when to shut off when the fridge reaches it's temperature.

I guess I need to understand how the propane works since the flame never stops, once it is lit. Hmmmmm.

[BigTJohn]

Either the pilot light on the fridge is minuscule and will light the "burner" when needed or the burner is lit each time the fridge t-stat requests cooling (probably the latter in newer units). I don't hear the burner unless I am outside near the vent and my fridge is in a slide so it also has aux 12vdc fan to assist in venting heat from fridge.

[gasman6674]

The fridge is controlled by a thermostat (12v) that cycles the gas on and off with a spark igniter to light it, otherwise you would have an ice block. Ambient temp will affect vaporasation rate of the tanks and how long the fridge stays on. All the info I posted is based on 60 deg f. For ex a 30# cylinder at 25% full @ 60 will vaporise a max of 32,000 btu per hour but at 30 degrees will only do 21,100 btu per hour

[gasman6674]

The "pilot" light is the main burner on most units. It does not that much to do the job just a while to get the box cold.

[BarryD0706]

Originally Posted by garbonz

...
I guess I need to understand how the propane works since the flame never stops, once it is lit. Hmmmmm.

The flame does stop. DSI re-ignites it as needed.

[dcheatwood]

And mine has no burner. The only flame is the little "pilot-light-like flame which cycles on and off.

[BarryD0706]

Originally Posted by dcheatwood

And mine has no burner. The only flame is the little "pilot-light-like flame which cycles on and off.

That is a burner. "Pilot light" refers to a flame used to ignite another burner, so it's not a pilot light (although you did say "like").

[dcheatwood]

Originally Posted by BarryD0706

That is a burner. "Pilot light" refers to a flame used to ignite another burner, so it's not a pilot light (although you did say "like").

Yep. "Like" as in "similar size." I knew that. The poster of the question needed to know that the little pilot light-looking flame is all there is.

[garbonz]

Thanks.. I have never heard it lighting after the first ignition... so I assumed it was always on, and used something else to modulate temperature.

Love this forum...

[RPAspey]

Originally Posted by gasman6674

FYI
Most units use 1550 btu per hour (dm2652) LP gas has 91,500 btu's per gallon, 21,548 per pound. A 30# cylinder when full will hold 6 gallons or 59.03 hours per gallon times 6 = 354.18 hours or 14 days. I dont think the battery will last that long without solar back up

regards

GREAT INFO!!

So at 24-7, it'll last about 14 days per tank. Since there are so many variables, predicting exact duration would be nearly impossible. Variables like ambient temps, fridge temperature setting or how much time the fridge door is opened change how much of the propane is used. My general experience is that a tank will last about a month in the cooler climates we generally camp.

[OldCoot]

Originally Posted by RPAspey

GREAT INFO!!

So at 24-7, it'll last about 14 days per tank. Since there are so many variables, predicting exact duration would be nearly impossible. Variables like ambient temps, fridge temperature setting or how much time the fridge door is opened change how much of the propane is used. My general experience is that a tank will last about a month in the cooler climates we generally camp.

Since we got our 5er in Feb 2012, the frig has been off propane 5 weeks and we've not used a 30# cyl of propane yet.