Convert gas powered genny to propane?

[Badfish740]

I think this question was beaten to death after Hurricane Sandy, but I have a few specific questions that weren't really addressed in the other iterations of this thread. Right now I have a 4500W Craftsman generator that I run on gas. I had the presence of mind to stock up prior to Sandy and never had to wait in the gas lines, etc...that ensued. Over the weekend I just installed propane at my house to power the new gas stove. Since the stove is the only thing we're running we opted to go with two 100lb tanks and an automatic changeover regulator:

(broken link removed)

In my situation would it be worth it to convert it (or some other generator, maybe a 5000-6000W) to run off of one of the tanks? Would this even be possible? I haven't been able to find specs on propane consumption and how it relates to horsepower and load. I am planning on semi-permanently installing my generator in the sense that I've already put wheels and handles on it so that I can easily move it into place when needed. I'm planning on building a three sided enclosure for it near but separate from the house to keep the rain off and deaden the sound. Finally, I want to have an inlet plug right there, and if propane is the way to go, a hookup for that as well so it would be as simple as wheeling it into place, connecting the feed to the house and the hose to the tank and starting it. It would make it a lot easier for the wife to operate too-she doesn't like dealing with the heavy gas cans, spills, etc...

 

[Jags]

I think you will drop about 10% of HP so keep that in mind as far as your load is concerned. A full 100# tank (23.8 gal) will run a 5000W genny at 50% load (2500W) for about 40 hours. Those are ball park numbers.

Take a look:
http://uscarb.websitetoolbox.com/post/How-much-propane-will-I-use-compared-to-gasoline-5337749

 

[Badfish740]

Very helpful-thanks! During long outages I tend to run mine four hours on/four hours off in order to keep my own sanity and that of my neighbors while still keeping the food cold, the basement dry, and the house warm, so I could stretch 40 hours out a while. Still not the amount of time I'd be hoping for. We were out for five full days last time

 

[Jags]

Maybe consider a small propane tank, like a 175 gal or even a 250. It doesn't go bad. Buying by the pound is much more expensive than by the gal. Consider purchasing your own tank so that you are not married to a single supplier as well as avoiding tank rental. I wish I would have done that 20 years ago. Tank rental alone would have paid for it, then I would have the flexibility to buy from any supplier.

 

[Badfish740]

Maybe consider a small propane tank, like a 175 gal or even a 250. It doesn't go bad. Buying by the pound is much more expensive than by the gal. Consider purchasing your own tank so that you are not married to a single supplier as well as avoiding tank rental. I wish I would have done that 20 years ago. Tank rental alone would have paid for it, then I would have the flexibility to buy from any supplier.

I'm new to the propane world as I just bought my tanks last week and got everything installed this weekend. I bought two 100lb'ers since I read that they should give me about a year's worth of stove/oven usage each and they're relatively easy to move when full with a handtruck. I didn't realize there was a difference between buying by the gallon or the pound? I had one tank filled over the weekend and the guy wrote on the receipt "23.8 gallons @ 3.19/gallon." I got it filled at an equipment rental place. A larger tank would be great, but I'm assuming at that point the suppliers would be coming to you unless you had a liftgate truck?

 

[Jags]

Yes - it would be delivered via truck and hose. I paid $1.60 per gallon earlier this year (beginning of winter). It is possible that they are charging gallon price and not #. Around here you only get gallon price on tanks measured in gallons, not pounds. It might be worth calling a couple of suppliers to ask what their gallon price is.

 

[Badfish740]

Yes - it would be delivered via truck and hose. I paid $1.60 per gallon earlier this year (beginning of winter).

Wow-did I get robbed at $3.19 or is there just that much variation in propane between here (NJ) and Illinois? Or is it some combination of how much I bought vs. how much you bought, when you bought it, etc...?

 

[Jags]

Wow-did I get robbed at $3.19 or is there just that much variation in propane between here (NJ) and Illinois? Or is it some combination of how much I bought vs. how much you bought, when you bought it, etc...?

I do know that there is regional variation - and it is possible that you got nailed with a small purchase. It could be one or the other or even a combo of the two.

Make a few phone calls - that should clear up the pricing issue.

 

[Highbeam]

It is possible that they are charging gallon price and not #. Around here you only get gallon price on tanks measured in gallons, not pounds. It might be worth calling a couple of suppliers to ask what their gallon price is.

When you buy an LPG tank it is often sold as an X lb tank but it is a tank and will also be labeled with a gallonage. This has nothing to do with propane price. When you are filled from a metered propane pump it will be in gallons since pumps measure liquid volumes and you are buying a liquid. If somebody is trying to boof you by selling you lbs of a liquid then you should be worried.

 

[Jags]

When you buy an LPG tank it is often sold as an X lb tank but it is a tank and will also be labeled with a gallonage. This has nothing to do with propane price. When you are filled from a metered propane pump it will be in gallons since pumps measure liquid volumes and you are buying a liquid. If somebody is trying to boof you by selling you lbs of a liquid then you should be worried.

I know for a fact (around here) that there is a distinct price difference in filling a 100# propane tank vs a little 175 gallon tank. At my cabin I run two 100 pounders, my neighbor runs a 175 from the same company. I try to coordinate our fill ups for the same day. They are wildly different if figured "per gallon". It could be regional??

Edit: for a 100# fill it costs a flat $90. At 23.8 gallons that comes to $3.78 per gallon. My neighbor filled at $1.65 per gallon at the same time.

 

[Highbeam]

I know for a fact (around here) that there is a distinct price difference in filling a 100# propane tank vs a little 175 gallon tank. At my cabin I run two 100 pounders, my neighbor runs a 175 from the same company. I try to coordinate our fill ups for the same day. They are wildly different if figured "per gallon". It could be regional??

Edit: for a 100# fill it costs a flat $90. At 23.8 gallons that comes to $3.78 per gallon. My neighbor filled at $1.65 per gallon at the same time.

Ah, I see your problem. You are allowing your vendor to charge you a set price for a "fillup" of the 100# tank instead of paying by the pound or gallon as your neighbor does with the 175 gallon tank. The funny part is that I bet your vendor often just tops off a 100# tank and still gets the full 90$. It's not that you're paying by the pound but that your guy has set prices for each size of small tank. He's a crook and is choosing to price it this way to make up for the extra effort required to fill little tanks.

You say your neighbor has a little 175 gallon tank but your 24 gallon tank is the little one. Is there any reason you don't just load the tank into your pickup and take it to town for a refill from a metered source? Is that even an option in your region?

It is perhaps regional but all of the LPG vendors where you take them your tank (gas stations, minimarts, rvparks) charge by the gallon in my region. I filled two empty 5 gallon BBQ tanks last month for 20$ after taxes, that was paying just over 2$ per gallon and 80-90% fill where the OPD shuts off.

The setup in your region really seems to encourage buying a bulk LPG tank that is large enough that your particular vendor is willing to only charge you for the propane that you are buying instead of some flat fill charge.

 

[Jags]

Is there any reason you don't just load the tank into your pickup and take it to town for a refill from a metered source? Is that even an option in your region?

The setup in your region really seems to encourage buying a bulk LPG tank that is large enough that your particular vendor is willing to only charge you for the propane that you are buying instead of some flat fill charge.

1 hour trip to the nearest refill source. I have thought about going to a bulk tank, but the tank rental makes it a wash. I only use one 100 pounder in about 2 - 2.5 years. So the thought of less than $45 per year for the limited heat I require (only when I am there) really makes it a moot point for my specific application. I only go there a handful of times during winter and I share the heat load with electric baseboards or I will get too much condensation.

 

[Badfish740]

If somebody is trying to boof you by selling you lbs of a liquid then you should be worried.

When I was a kid I remember going with my dad to the hardware store to get the grill tank filled and the guy would put the tank on a scale, and fill it based on weight. Not sure what it cost back then.

 

[heat seeker]

Around here they fill the 20 pounders for grills on a scale. But, you get no credit for anything in the tank - you pay for the full 20 pounds, whether you need it or not. And I caught one dealer short-weighting, so avoid that place.

 

[Badfish740]

So I figured out that the company I linked to makes a kit for my generator and since I already have a high pressure regulator I only need the simple low pressure kit. I think it runs about $130. I did a little digging on McMaster-Carr's website and found quick disconnect style fittings (like the ones you see on compressed air systems) for use with propane:

http://www.mcmaster.com/#lp-gas-hose-fittings

They work with this heavy duty outdoor rated propane hose:

http://www.mcmaster.com/#lp-gas-hose

I'm thinking of doing the following:

Remove the plug from the tee in the outdoor piping of my propane system (under my deck) and install a lockable (with a small padlock) ball valve, then attach a quick disconnect propane socket to the ball valve. The sockets, like compressed air sockets, have an internal valve that closes when decoupled, so the system would be redundant. When not in use, the ball valve would be locked closed, and the socket valve would also be closed as it would be decoupled from the hose. The generator end of the hose would have another set of quick disconnect couplings so that it could be easily connected to the generator as well.

Basically the idea here is to be able to wheel the generator into place, connect the propane hose, open the ball valve, connect the inlet plug to my breaker panel, start it up, and be in business in a matter of minutes. I realize that there may be code issues with the propane connection, but I'm not worried about it. Unless someone can point out something I've overlooked and that there is some kind of major safety issue I'm not taking into account, it seems plenty safe to me. Also, I will be installing a main breaker lockout panel so there is no change of backfeeding to the grid.

Of course, after all of this is finished, I'm sure the power will stay on reliably for many years after having two 5+ day outages in the last two years

 

[Jags]

It sounds like a good idea - except - why would you QD the genny side? It has to be there to run...it is another point of potential failure....QD's get dirty. Go direct connect to the genny (In my opinion). I like the rest of the solution.

 

[Badfish740]

It sounds like a good idea - except - why would you QD the genny side? It has to be there to run...it is another point of potential failure....QD's get dirty. Go direct connect to the genny (In my opinion). I like the rest of the solution.

Good point-I could just coil the hose up around the carry handle when it's not in use. It will also save me some $$$ since the connectors aren't cheap.