Propane: 1 vs 2 tanks

[parmm]

And locally where I go they charge by the gallon and 10th meter reading, And it always varies because I don't always empty my tanks. And when on the road the stations I've filled at usually use a meter, gallon and 10th.

[Bonnie RB]

Originally Posted by Glenn Baglo

It is called a 20 lb. tank because that is its capacity. You don't then reduce that to 80% because that rule is already accounted for.

That contradicts other propane industry statements.
from the AmeriGas link previously posted:
How many gallons of propane are in a 120-gallon tank? Some of you may recognize this as a trick question. The tank has a 96-gallon capacity.
and
Want to know the fill capacity of your propane tank? Multiply the tank’s total capacity by 0.8.
from the Learn Metrics link:
Key part: A 20 lb propane tank can hold at most 16 lb of propane.

Despite one using gallons, and the other using pounds, BOTH factor the filled capacity to 80% of the nominal.
I can't (won't) participate in this conversation/argument any further. Have fun.
Jon MB

[parmm]

Originally Posted by Bonnie RB

Despite one using gallons, and the other using pounds, BOTH factor the filled capacity to 80% of the nominal.
I can't (won't) participate in this conversation/argument any further. Have fun.
Jon MB

But not all 20 pound tanks are 20 pound tanks.
A typical barbecue tank is also referred to as a 20-pounder. This is because the tank can hold approximately 20 pounds of propane. This equates to 4.7 gallons of propane. Propane weighs 4.24 pounds per gallon so now you get the 20 pound reference.
So, does a full tank weigh 20 pounds? No, because the tank itself has weight to it, too. That is called the “tare weight” which is the weight of an empty tank. Tanks have “T.W.” (tare weight) stamped on the collar of the tank. On average, the tare weight of a propane tank is about 17.2 pounds. Some might be 18 and some might be 16.6 depending on who made them. All in all, a completely full BBQ tank weighs approximately 37 to 38 pounds.

And if you exchange your "tank" for a filled one, those exchange companies only fill the "tanks" with 15 pounds of propane, 1.2 gallons less than a place that fills your tank for you. And that place which fills your tank usually charges less per gallon. That 1.2 gallons less equals out to 4 to 5 hours less grilling time!!!

[Jon in AZ]

I don’t do exchanges because (1) they’re more expensive, gallon for gallon, (2) you can’t be certain of what you’re going to get tank-wise, and (3) my tank is rarely completely empty, which amounts to a donation..

I take my low-but-not-empty tank to one of several local places that charge by the gallon. Usually takes 3-4 gallons. Price fluctuates, but it’s typically less than half the cost of an exchange.

Then I go camping.

Y’all are thinking too hard!

Okay, I admit I do appreciate precision, and I am a little curious what actually constitutes a “full” tank and whether the exchanges intentionally short-fill the tanks (below the OPD-regulated 80%) as often reported. But either way, they’re still a lot more expensive than a refill. I would only do it as a last resort, and i won’t be quibbling about whether I’m getting 3.5 or 4 gallons.

I’m not the least bothered whether the usable capacity of the tank is less than the full rated capacity. My tow vehicle has a gas tank rated at 21.0 gallons. The most I have ever put into it (after driving on E with the warning light on) was about 18 gallons. Not quite the same thing, I know, but from a user standpoint it kinda is. I don’t want to run out of gas on the side of the road, and I really don’t want to run out of propane before my coffee is done.

[Glenn Baglo]

Originally Posted by Bonnie RB

I can't (won't) participate in this conversation/argument any further. Have fun.
Jon MB

Ask Google. "How many pounds of propane in a 20 lb tank"? The first result is shown here. Other answers are similar. If you won't participate, you won't learn.

[Jon Vermilye]

To continue the argument as to how much propane can be put in a 20 pound tank, I over winter in Quartzsite & get an empty 20 pound tank filled every 14 days or so. Filled by the gallon, and it was always within .1 gallon of 4.7 gallons to fill. That works out to 19.317 pounds if you use 4.11 pounds per gallon for the weight of propane. The weight varies with temperature; quote is at 77°F.

[Jturcot2]

2 - 2 - 2 - 2

[Glenn Baglo]

Amerigas site linked to by Bonnie RB says ( see image ) and 4.6 gallons X 4.24 lbs equals 19.504 lbs., which is almost 20 lbs and certainly not 16 lbs.

[Raz]

Originally Posted by Jon Vermilye

The weight varies with temperature; quote is at 77°F.

Hi John. Twenty five degrees last night and 1/2" of snow on the ground this morning. Just thought you might like you know .

I don't understand why the weight would vary with ambient temperature?

[John in Santa Cruz]

unlike liquid water which is essentially incompressible, liquid propane's density varies with temp.

[JamesML]

G'day: I can't miss all this fun. We carry two propane tanks of "20 lb" size. One is mounted on the tongue and feeds the 3 way frig. and the on-board stove. The second one is carried inside the Boler, secured over the axle on the closet side while travelling. As soon as we set up camp, the inside tank is removed and set up with the outside kitchen, never kept inside while occupied. Always have plenty of propane for any camping trip, and have never gone empty. BTW, tanks are from Costco, with float guages. Don't know their accuracy but certainly better than pressure.

Sorry guys and gals, can't resist having a little fun with this one. Physics 101. Technically while we may be towing our trailers, we are in fact pushing, not pulling with the tow vehicle. At the point of contact between the ball and socket, the ball is pushing on the socket. So are we really pushing or pulling??? Had a physics professor sort me out on a similar consideration more than 60 years ago--one of the few things I learned and still remember.

[Sunrisetrucker]

Originally Posted by JamesML

Sorry guys and gals, can't resist having a little fun with this one. Physics 101. Technically while we may be towing our trailers, we are in fact pushing, not pulling with the tow vehicle. At the point of contact between the ball and socket, the ball is pushing on the socket. So are we really pushing or pulling??? Had a physics professor sort me out on a similar consideration more than 60 years ago--one of the few things I learned and still remember.

Physics be damned, the unit behind(trailer) is being pulled by the unit in front (tow vehicle).

The exception to this is of course going down a very steep hill.

[Jon Vermilye]

My tale of two tanks (I know, cylinders, but I like the alliteration) is if you want to depend on the auto switchover, you better learn how to read the indicator that the feed has switched.

When my Escape 17 was new, I thought there would be a "stronger" indication that the regulator switched cylinders. At Desert View Campground in the Grand Canyon National Park at 34°F on May 18, 2011 I discovered that both cylinders were empty - mostly green with just a bit of red showing. 2" of snow & more falling, 46°F in the trailer and falling, and 40 miles to the nearest available propane (@ $4.75 a gallon in 2011 prices).

As to why I leave both cylinders open? If I'm off on a hike, etc I want the refrigerator to keep going while I'm gone. With practice, I've been able to come within a day or two of knowing when to start looking at the indicator.

[Jann Todd]

Originally Posted by Glenn Baglo

Plenty of stories about people getting shorted though; only getting 16 lbs, but paying for 20, all based on a misunderstanding of what a 20 lb. tank is supposed to hold.

There are gauges on propane filling stations and they should only charge for the gallons that register. The reason you can't put 20 gallons in a 20 gallon tank is to allow for expansion for heat and elevation changes. Some places charge for a full fill even if you only get 1/2 of a tank because of the hooking up time. I won't fill at these places even if my tank is completely empty.

[Glenn Baglo]

Originally Posted by Jann Todd

The reason you can't put 20 gallons in a 20 gallon tank is to allow for expansion for heat and elevation changes.

See post #68.

A 20 lb. tank holds 19.505 lbs. of propane. Expansion is already accounted for.
The industry would be in real trouble if they relied on what the public reads on the internet.

[Jann Todd]

Originally Posted by Glenn Baglo

See post #68.

A 20 lb. tank holds 19.505 lbs. of propane. Expansion is already accounted for.

If that is the case then why when a place put about that much into our tanks that they both blew the seals and leaked. We had to take them into a field and open the valves so they'd empty a bunch out. We took them to a propane dealer and they said the tanks had been overfilled and in the heat the expansion caused the problem. That is why they now put an overfill device on the hose that fills the tanks. At least in Colorado they do.

[Glenn Baglo]

Originally Posted by Jann Todd

If that is the case then why when a place put about that much into our tanks that they both blew the seals and leaked.

If you toss a propane cylinder into a fire it will explode, eventually.
Your tanks may have been overfilled and the relief valves opened, as they are supposed to. In any event, you are challenging numbers with an anecdote.

[JamesML]

To sunrisetrucker.

Yes the tow vehicle is pulling. However, at the point of contact, as I stated, the force on the trailer coupler socket is actually pushing--that is the only direct contact between the TV and the trailer. Think about it.

[floyd]

Originally Posted by Jann Todd

There are gauges on propane filling stations and they should only charge for the gallons that register. The reason you can't put 20 gallons in a 20 gallon tank is to allow for expansion for heat and elevation changes. Some places charge for a full fill even if you only get 1/2 of a tank because of the hooking up time. I won't fill at these places even if my tank is completely empty.

20 Gallon ?

[floyd]

Originally Posted by Jann Todd

If that is the case then why when a place put about that much into our tanks that they both blew the seals and leaked. We had to take them into a field and open the valves so they'd empty a bunch out. We took them to a propane dealer and they said the tanks had been overfilled and in the heat the expansion caused the problem. That is why they now put an overfill device on the hose that fills the tanks. At least in Colorado they do.

There is a vent on the newer tanks which can be activated, I have seen the supplier use the vent to allow "overfilling".
For me it just meant a better deal, However.... It is still a fact that the Cylinder holds 20# of propane when properly and safely full.
18# empty and 38# full has been the measured standard on my cylinders for the last 20 years.



The safe headspace can be defeated and diminished by using the vent while filling with liquid.
Unless the cylinder temperature is stable and you use propane immediately, it is considered an unsafe practice to do that. Vented propane could find an ignition source!