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Old 03-28-2014, 10:07 AM   #1
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20 lb "exchange" propane tanks

The 20# LP exchange tanks, (sold at various locations), are not full!
They contain less than 20# of propane....the net weigh, (usually 15#), is printed on the label.
However, if/when you have a 20# LP tank filled/re-filled you will leave with 20# of propane.

BTW, all propane tanks have their empty weight, (aka: "tare weight", T.W.), stamped on the collar of the tank.


20 lb LP tanks have a "tare weight" of +/- 17 pounds when completely empty, therefore a "full" 20 lb propane tank weighs about 37 pounds.... (the weight of the empty tank + 20 lb of propane).

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Old 03-28-2014, 10:24 AM   #2
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They have less on purpose. It is call the 80% rule, see below:

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. So why aren’t propane tanks ever filled up all the way? That has to do with the 80% fill rule.
The 80% fill rule is a preventative safety measure against the fluctuations that happen inside a tank. Propane, like water, will expand when heat is added to it. Propane, however, will increase in volume nearly 17 times greater than water over the same teperature increase. To allow for this expansion, propane containers are filled to only 80% of their capacity.
That means a tank that is 80% full on a mild March day, might register as 85-percent (or higher) at the mid-July cook out. It’s the same amount of propane, but it’s taking up more space. So the extra space in the tank is a cushion against the pressure that builds up in a tank when it’s hot.
Want to know the fill capacity of your propane tank? Multiply the tank’s total capacity by 0.8. Here’s a handy cheat sheet showing you total number of gallons remaining based on your tank size and current gauge level.

If you look at the vent - it is opened when you get it filled - will shoot out liquid when the tank is 80% full. Anyone that fills a propane tank completely full is asking for problems if the temp goes up.
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Old 03-28-2014, 10:28 AM   #3
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Quote:
Originally Posted by mel stuplich View Post
The 20# LP exchange tanks, (sold at various locations), are not full!
They contain less than 20# of propane....the net weigh, (usually 15#), is printed on the label.
However, if/when you have a 20# LP tank filled/re-filled you will leave with 20# of propane.

BTW, all propane tanks have their empty weight, (aka: "tare weight", T.W.), stamped on the collar of the tank.


20 lb LP tanks have a "tare weight" of +/- 17 pounds when completely empty, therefore a "full" 20 lb propane tank weighs about 37 pounds.... (the weight of the empty tank + 20 lb of propane).

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To complete the scenario you need the cost of the pre filled tanks. Cost for propane varies so much from vendor to vendor, city to city and state to state it may be difficult to make a case that this is significant.I'm certainly not saying this is good but it just part of the story.

I have long suspected that these tanks are "short" but it turns out to be so much more convenient because I am going to the location anyway. With the price of gasoline if i seek out the best propane price and go there it cost more in gas than I save.

I haven't stopped to check the representation made at the trade in site at my local Lowes regarding what to expect in each tank. Propane is 4.2 pounds per US gallon so @ 3.95 per gallon that would be 18.80 for 20 pounds. What do they cost?
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Old 03-28-2014, 10:42 AM   #4
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I am not so sure they do not take the fill capacity into account in the weight. Recently I used a 40 pound auxiliary tank (new) and it held 9.4 gallons. Roughly 39.48 pounds of propane, close enough given the variable of when they shut the spill etc;.
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Old 03-28-2014, 10:46 AM   #5
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Originally Posted by njs42 View Post
With the price of gasoline if i seek out the best propane price and go there it cost more in gas than I save.

I haven't stopped to check the representation made at the trade in site at my local Lowes regarding what to expect in each tank. Propane is 4.2 pounds per US gallon so @ 3.95 per gallon that would be 18.80 for 20 pounds. What do they cost?
I must agree
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Old 03-28-2014, 10:58 AM   #6
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I just went thru a little investigation on this. I normally get Blue Rhino exchange tanks at Wal-Mart. Years ago I filled tanks at a hardware store and these seemed light to me. I weighed the last 2 I bought and they netted out at 15#, and I was paying $18.42 WTH!!
I Goggled Blue Rhino and found this is their policy, bunch of rhetoric on their part why, but basically 15# is all you are going to get. In addition to this they are also replacing the fill valves so they are the only ones that can refill them. I started taking my empties to a refill service and now get actual 20#'s for another $2.00. I have three tanks and none are the new valve (it has a diamond shape depression in the side of the valve) no way will I do the Blue Rhino exchange again.
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Old 03-28-2014, 11:17 AM   #7
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Originally Posted by Brockx View Post
I just went thru a little investigation on this. I normally get Blue Rhino exchange tanks at Wal-Mart. Years ago I filled tanks at a hardware store and these seemed light to me. I weighed the last 2 I bought and they netted out at 15#, and I was paying $18.42 WTH!!
I Goggled Blue Rhino and found this is their policy, bunch of rhetoric on their part why, but basically 15# is all you are going to get. In addition to this they are also replacing the fill valves so they are the only ones that can refill them. I started taking my empties to a refill service and now get actual 20#'s for another $2.00. I have three tanks and none are the new valve (it has a diamond shape depression in the side of the valve) no way will I do the Blue Rhino exchange again.

Quite a disparity and enough to raise the ire of any fair minded person. But it still depends on situations such as how far does a person have to go to get a fill, how much is gasoline in their area, how much fuel does their vehicle burn etc, kind of a headachy computation.

Certainly if Blue Rhino is representing each tank as having 20 pounds then that is despicable and against the law. But people pay for convenience all the time and in certain situations and locales this "service" may be worth it to some.

It is good to know however because I always like knowing I am getting the shaft rather than it being a secret.
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Old 03-28-2014, 11:30 AM   #8
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I have two 4.5 pound (1 gallon) tanks to fuel my Coleman stove and Weber Q. They each get filled about 2 times per year, and we are fulltime and grill a lot.

A fill here in AZ is $1.80. In PA it is $2.35. So, about 8 bucks a year. I get the empty tank filled "as we go" with no special trip. So, at $40 each, they have not owed me anything since the end of season 2.

Less space and weight, and cheap, and no guessing.

Just my 2c
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Old 03-28-2014, 11:39 AM   #9
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Quote:
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They have less on purpose. It is call the 80% rule.
Cobra1
Your explanation of the 80% rule is correct ..... (with one exception)!

The so called "20 lb/5 gal" LP tank/bottles hold 20lbs/4.7 gal of propane when filled to 80%.
see: Propane Cylinder and LPG Bottle Information

BTW, the point of my OP is this: although exchange tanks are covenant they are seldom a bargain....AND, (since exchange tanks only contain 75% of the fuel that a tank filled at a LP dealer or campground will contain), they only last 3/4 as long as a re-filled tank.

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Old 03-28-2014, 12:18 PM   #10
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Quote:
Originally Posted by mel stuplich View Post
The 20# LP exchange tanks, (sold at various locations), are not full!
They contain less than 20# of propane....the net weigh, (usually 15#), is printed on the label.
However, if/when you have a 20# LP tank filled/re-filled you will leave with 20# of propane.

BTW, all propane tanks have their empty weight, (aka: "tare weight", T.W.), stamped on the collar of the tank.


20 lb LP tanks have a "tare weight" of +/- 17 pounds when completely empty, therefore a "full" 20 lb propane tank weighs about 37 pounds.... (the weight of the empty tank + 20 lb of propane).

Mel
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This is true. Blue Rhino and AmeriGas exchange tanks are clearly labeled with the NET PROPANE WEIGHT. Currently it is 15 lb. A few years back it was 17 lb. Nothing illegal regarding the actual quantity ... they just "choose" to sell you 15 lb. of propane at each exchange.

However, the FTC has brought a complaint against both companies for collusion regarding the change.

FTC Charges Two Leading Suppliers of Propane Exchange Tanks with Restraining Competition | Federal Trade Commission


See here for maximum fill weight of a 20 lb. cylinder:
Consumer Information | Grill Gauge

It should be noted, from "Propane 101", that fill stations have different methods of charging the customer:

"Bottle filling policies vary by company. Some companies charge by the cylinder while others charge by the gallon. Charging by the cylinder is a common industry practice so know in advance that consumers may be charged the full amount even if the bottle isn't completely empty."
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Old 03-28-2014, 12:24 PM   #11
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I just went thru a little investigation on this. I normally get Blue Rhino exchange tanks at Wal-Mart. Years ago I filled tanks at a hardware store and these seemed light to me. I weighed the last 2 I bought and they netted out at 15#, and I was paying $18.42 WTH!!
I Goggled Blue Rhino and found this is their policy, bunch of rhetoric on their part why, but basically 15# is all you are going to get. In addition to this they are also replacing the fill valves so they are the only ones that can refill them. I started taking my empties to a refill service and now get actual 20#'s for another $2.00. I have three tanks and none are the new valve (it has a diamond shape depression in the side of the valve) no way will I do the Blue Rhino exchange again.
Do you have a source for this ??
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Old 03-28-2014, 12:39 PM   #12
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I just went to Publix to weigh a new, full LP bottle from Lowes. It weighed just under 28lbs. I know their scales aren't precise, but with a bottle tare weight of 16.6 lbs. and 15lbs. on the label, seems they are fudging(quite a bit) on their labeled bottle weight by almost 4 lbs. At 4.23 lbs per gallon, I'm shy just under a gallon in my new 'full' bottle.

Time to start having them filled again.
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Old 03-28-2014, 12:44 PM   #13
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This is all interesting as last week I had a 20 lb bottle filled. Took the Blue Rhino label off as I was unloading it and the man filling it told me that the quick exchange places do in fact only put 15 lbs in whereas he, a bulk propane dealer filled it to 80% which was 20 lbs. I actually thought he was fibbing but after reading this thread I guess he was right!
Luckily for me there is a bulk supplier 2 blocks from where I work so it is a snap to stop in and fill a bottle! I guess at the quick exchange places you are indeed paying for the convenience. Additionally, who ever reads to see how much we were buying at those places anyway? I know I never did and until a week ago didn't have a clue!
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Old 03-28-2014, 12:47 PM   #14
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Talking Easy comes with a price tag......

Maybe there is a "price to pay" for convenience?.....
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