Two is One and One is None

[ray h]

Cruise Craigslist.

There are 30 and 100 pounders available too. More storage for the same size footprint.

Good point, but it's easier to exchange 20s. Preparing is all about options.

[streaker69]

Good point, but it's easier to exchange 20s. Preparing is all about options.

I've read way back when I did my LP conversion that 20lb tanks are not recommended for generators because they have a tendency to draw so much fuel from the tank so quickly that the tanks can freeze, lose pressure and starve the generator for fuel. You may want to contact the manufacturer of your conversion to see if that's a problem or not.

[ray h]

I've read way back when I did my LP conversion that 20lb tanks are not recommended for generators because they have a tendency to draw so much fuel from the tank so quickly that the tanks can freeze, lose pressure and starve the generator for fuel. You may want to contact the manufacturer of your conversion to see if that's a problem or not.

I didn't buy a "conversion", it's a factory dual fuel gen. Don't know if that makes a difference or not. The manufacturer (Champion) states it has 34 hr run time (25% load) from a 20lbs bottle, I think that's probably a slower draw than a gas grill, and I'm sure it's slower than the heater I used to have. Maybe I could see this with a larger generator that's drawing a lot of fuel. My smaller gen, not so much.
Now that I think about it, our forklifts at work burn 3lbs an hour and they don't freeze up. Granted, that's from a 30, but it's 4 - 5 times the flow.

[Walleye Hunter]

Exchanging 20s is a scam, they usually only give you 15 but they do have a notice on the cage as to what you get. Propane is a liquid at around 100PSI. The tanks have liquid at the bottom and gas at the top. As you use the gas, pressure drops and the liquid vaporizes. As gasses expand, they cool and as they are compressed, they get hot. As they get low on gas, there is not enough liquid to dissipate the cold and the liquid does drop in temp, which results in lower pressure. That will happen regardless of size of tank when they get low. They actually have a pressure difference between winter and summer but I don't know how much, I just know that I can see it in how my grill burns.

[ray h]

Exchanging 20s is a scam, they usually only give you 15 but they do have a notice on the cage as to what you get. Propane is a liquid at around 100PSI. The tanks have liquid at the bottom and gas at the top. As you use the gas, pressure drops and the liquid vaporizes. As gasses expand, they cool and as they are compressed, they get hot. As they get low on gas, there is not enough liquid to dissipate the cold and the liquid does drop in temp, which results in lower pressure. That will happen regardless of size of tank when they get low. They actually have a pressure difference between winter and summer but I don't know how much, I just know that I can see it in how my grill burns.

I know it's a scam, but it's an option that I can take or leave if I have 20s.

[markshere2]

I've read way back when I did my LP conversion that 20lb tanks are not recommended for generators because they have a tendency to draw so much fuel from the tank so quickly that the tanks can freeze, lose pressure and starve the generator for fuel. You may want to contact the manufacturer of your conversion to see if that's a problem or not.

With the correct length hose, you position the tank next to the Genny's exhaust. That kept mine from freezing last winter.

[free]

I've read way back when I did my LP conversion that 20lb tanks are not recommended for generators because they have a tendency to draw so much fuel from the tank so quickly that the tanks can freeze, lose pressure and starve the generator for fuel. You may want to contact the manufacturer of your conversion to see if that's a problem or not.

I wonder if you can addrsss that by not opening the valve all the way, to restrict the flow.

[762xIan]

I wonder if you can addrsss that by not opening the valve all the way, to restrict the flow.

No not really. The bad thing with propane for large volume use like a generator is this is going to happen. Propane is a great refrigerant for this reason. Pressure drops, the liquid boils off more vapor and the temperature of the bottle/liquid propane inside continues to drop.

Best use of propane for a house generator is an in ground larger tank. Ground temperature and the larger supply will keep this from happening.

The only way to try to offset would be to get the fittings and hoses to hook up 2 or more bottles together and have all of them running the generator.

[ray h]

Not sure what you guys are talking about, your basic barbeque grill runs through a 20 lbs propane bottle in less than 20 hours. The manufacturer of my generator says it uses 20 lbs in 34 hrs. Granted, my generator is a smaller size, but I'm not sure how you all can say generators are higher flow than a grill or even a heater.

EDIT:
Ok, I found a chart that basically says generally if you are pulling less than 1600w you don't have to worry about your 20lbs bottle freezing or not vaporizing fast enough. My little generator is rated for 1650 continuous on propane.

[Frizratz]

Weird.
I put a LP gas genny in for a customer at a remote location for a water company some years ago.
I don't remember the Tw but it was not a very big engine.
It was all brand new & I tried to use a BBQ grill type gas bottle to run it.
No Go.
The thing would not run
When I called the manufacturer they told me the tank has a " stopper" in it so if the BBQ grill hose springs a leak and a large volume of gas begins to flow, the stopper will close.
They said the generator was drawing so much gas that the stopper would not allow that amount of flow and did it's job.
In the end we had to swap the tank out with one you would use for a fork truck.