JimBollman
Lost State of Franklin
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Before I switched to an all electric B, I had four 20lb tanks that I used one at a time in my camper. I kept a chart of the 4 tanks and how much they weighted when full and after each outing and notes on the trip. So I knew were I was for the next trip. Repeat trips that I did every year I knew about how much LP I would probably used. Some trips I used partial tanks others I started full. I tried to get close to empty before refilling and more than one tank before I made a trip for refilling at a location that filled by meter. I stoped using one supplier when my records showed they consistently under filled for what they charged. I like several above only used the prefilled tanks to get better expiration dates. Using the above record keeping, I only ran out on the road once.
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MrWizard
Traveling
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Tanks marked in gallons of water capacity, meaning total enclosed volume,
Not the propane full volume, full volume is 80% of water capacity,, that's the law,
Butane is also an LP Gas , in warmer climates the propane you buy will contain some butane, its lighter in weight per gallon than propane and doesn't vaporize at the same temperature as ,propane, so what your bottle weights when full is dependent on location and climate , the lp you are getting can vary
I can explain it to you.
But I Can Not understand it for you !
....
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ktmrfs
Portland, Oregon
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MrWizard wrote:Tanks marked in gallons of water capacity, meaning total enclosed volume,
Not the propane full volume, full volume is 80% of water capacity,, that's the law,
Butane is also an LP Gas , in warmer climates the propane you buy will contain some butane, its lighter in weight per gallon than propane and doesn't vaporize at the same temperature as ,propane, so what your bottle weights when full is dependent on location and climate , the lp you are getting can vary
and a propane/butane mix has a higher boiling point than propane, So.... if you get LPG (note most places say LPG NOT propane, therefore they can sell a propane/butane mix) in a cylinder fill with a high % of butane and then hit a cold spell,...... you may find the boiling point is to high to get much vapor and don't get much flow.
Pure butane boils at 30F.... get near that temp and you've got a problem. Pure propane boils at -40F.
Similar to the problem of using to small a bottle of propane for the expected flow rate. e.g. disposable bottle on small patio heater. Propane boils fast, cools way down, vapor pressure drops like a rock.
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time2roll
Southern California
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Joined: 03/21/2005
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matthfam wrote:After reading on this site about what a propane tank should weigh when empty/full, I decided I should weigh mine. I had used one tank only with the other one shut off ... The "full" tank weighed in at 44 lbs. the used one at 35.5 lbs. While it makes sense that I used about 8-9 lbs from the tank I was using, it makes no sense that they weighed 44 lbs when full. I was ripped off.
There could be a small difference to the 55 lbs supposed weight when full, but 11 lbs? They advertise as the cheapest propane in town. Not cheap at all! Take a scale with you when refilling! How is the price set?
If 7 gallons goes in and you pay for 7 gallons that seems fair.
Or if you pay for 30 pounds of propane and get 30 # of propane that seems fair also.
If all cylinders are filled for a flat fee.... bring in a 100# rated cylinder for the best value.
So before you decide if you are ripped off how exactly is the price set?
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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matthfam wrote:After reading on this site about what a propane tank should weigh when empty/full, I decided I should weigh mine. I had used one tank only with the other one shut off ... The "full" tank weighed in at 44 lbs. the used one at 35.5 lbs. While it makes sense that I used about 8-9 lbs from the tank I was using, it makes no sense that they weighed 44 lbs when full. I was ripped off.
There could be a small difference to the 55 lbs supposed weight when full, but 11 lbs? They advertise as the cheapest propane in town. Not cheap at all! Take a scale with you when refilling!
That's actually not far off, I am assuming a 30lb bottle which weighs in the range of 25 to 28lbs empty and up to 55lbs 100% full. since you can only fill them to 80% by law that is about 23.4lbs of propane add this to your 25lbs tank is 48lbs. now have you had your home scale certified, if not the numbers are not accurate so that could account for the other 3 lb. I know the propane scales here must be certified every so often, the same as gas pumps and everything else.
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StirCrazy
Kamloops, BC, Canada
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theoldwizard1 wrote:opnspaces wrote:They can only fill to 80 percent.
ABSOLTE BULLSH!T !!
It is call a "20 lb tank" because it is design tested and certified to hold 20 lbs of propane ! Some refill stations just crack the overfill screw and fill until liquid vents. This is usually very close to 20 lbs.
actually by cracking the bleed screw it vents at 80%. I used to have my propane certification for work so we could fill the bottles for the forklifts and other things. the bleed screw is to be used in the absence of a scale to ensure filling to no more than 80%.
here is a Q and A from Texas propane if you don't believe me.
"How does a bleeder valve work on a propane tank?
The bleeder valve is built so that during the filling process, when the propane is going into the tank reaches 80 percent, liquid will come out of the opened valve. This allows the delivery driver to know that the tank has reached its maximum filling capacity."
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joebedford
Home for the summer.
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Joined: 09/03/2003
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I usually get 20lbs in a 20lb cylinder (by weight). Not 20lbs less 20%.
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time2roll
Southern California
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Yes 80% full is the 100% rated capacity. There is no 80% of 80% then fill to 80% of that.
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ktmrfs
Portland, Oregon
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Joined: 06/22/2005
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For the OP original concern, if he paid by gallons and got the gallons charged all is ok. if he paid by weight (never seen that but possible) and got the weight he paid for all is ok.
If he paid by gallons and then weighs the cylinder, depending on the mix of propane and butane, trying to figure out if it was correct is not real possible unless he knows the exact propane/butane mix, cylinder weight beforefill etc.
In virtually all places I've filled tanks, your buying LPG, if you read the fine print. That covers a variety of liquid petroleum gas mixes, usually mostly propane, but can also contain some % butane and other gases. The weight will vary depending on the mix. (as well as energy content, and suitability for low temp use)
"Liquefied petroleum gas (LPG or LP gas) is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, propylene, butylene, isobutane, and n-butane.
In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane"
Most, if not all states have very tight regulations and annual or more often checks on gas/diesel/propane pumps. If they are off, store is in BIG trouble.
Personally, while on a very few occasions they did the fill stopping at a certain weight, I was still charged by gallons on the pump.
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markchengr
Seattle
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It seems that we are discussing both volume (5 GAL of space in a standard DOT tank) and weight (approx. 20 LBS LPG in a standard DOT tank). You should get about 20 lbs in a tank which makes the tank 80% full or about 4 gallons. The mix of propane/butane can vary which slightly affects the weight of a given volume of the liquified gas.
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