My generator, propane, and propane accessories

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36,639
Location
ME
So, I like to "prep" as much as the next guy and got thinking about hurricanes and whatnot. I have a few BBQ propane tanks and figure they might still be refilled if gasoline is unavailable. At present BJ's wholesale is $9.99 for 20 lbs which I understand to be 4.3 gallons. IDK how many BTU's but may compare favorably pricewise to unleaded too. Ordered this carburetor from this seller for $45 and it showed up three weeks later. I had intended to use it on a 1500/2250 watt tiny little 4 cycle with approx 2.8 hp motor but the carb stud spacing was too narrow, depsite nearly matching the obfuscated description. However, this carb has 42mm between the stud center lines and fits my larger generator: 6.5 hp, 2500/3250 watts. All right then! Man if it isn't a perfect match! The gas only carb even has a little cast spot where the propane hose goes. The little large doohickey hanging off the bottom senses intake vacuum and only allows propane to flow when there's vacuum, for safety. A spring loaded button presumably overrides the diaphragm for easier starting. Not included were any sort of instructions whatsoever or a hose/ regulator to go to my 20 lb bbq bottle. I snagged a hose/regulator (.5 lb?) from a bbq at the dump in preparation. I tug and tug and tug and tug and tug about seven times and it finally low idles on half choke. I would have expected propane to vaporize easier! It also backfires/ afterfires a bit on throttle-up. hide So I hooked up the gasoline and she started right up like I'd normally expect. Let it warm up for a minute with a hair dryer for load then I "weaned" it off gasoline and back onto propane. Now it carries the load and restarts normally. The propane regulator doohickey does fit nicely in the frame of my genny: If I had to do it again (from scratch) I'd get a generator with factory propane option. Don't think they're $45 more than the gas versions. And you'd get instructions, warranty, UL ratings, etc. laugh Also it appears amazon has the same thing for a little cheaper.
 
Messages
4,921
Location
Ca.
Originally Posted By: Al
A gallon of propane only has 80% of the btu's of a gallon of gasoline. Honestly doesn't make sense unless you have natural gas.
True the BTU content is 20% lower than gas and natural gas 20% less than propane, natural gas is fine for floods, but earthquakes like in cali- trigger a shutoff valve so sth whole city doesn't go up - and you got squat. add to that the 3600 rpm fixed speed gensets swill fuel like drunken sailors. Propane does solve the 'fuel going bad" problem. UD
 
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10,060
Location
Central Washington
Originally Posted By: UncleDave
Originally Posted By: Al
A gallon of propane only has 80% of the btu's of a gallon of gasoline. Honestly doesn't make sense unless you have natural gas.
True the BTU content is 20% lower than gas and natural gas 20% less than propane, natural gas is fine for floods, but earthquakes like in cali- trigger a shutoff valve so sth whole city doesn't go up - and you got squat. add to that the 3600 rpm fixed speed gensets swill fuel like drunken sailors. Propane does solve the 'fuel going bad" problem. UD
As long as you can vaporize enough propane to keep the engine fed. If the winter temps get low this could be a problem. Would suck to have to change tanks after consuming only 1/3 or 1/2 tank because the tank freezes.
 

eljefino

Thread starter
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36,639
Location
ME
True but I have enough tanks I could rotate the half dead ones somewhere warmer. But that would be a hassle.
 
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2,935
Location
Canada
Originally Posted By: eljefino
True but I have enough tanks I could rotate the half dead ones somewhere warmer. But that would be a hassle.
Many years ago I woke up to a -40 or more temperatures. It was pitch black darkness at approx. 0630 in the morning and my p.o.s. Ford pickup wouldn't start due to the cold. For that reason, I carried a tiger torch, a couple sections of 4" dia. stove pipe, a 90 degree elbow and a 20 lb. propane tank in the box. I hooked everything up, opened the valve and tried to light the torch. When it finally ignited, a 15' stream of blue flame shot out the end of the torch like a well defined flame thrower. The gas wouldn't vapourize due to the cold temps. Now this might sound crazy, but I aimed the flame at the tank to heat it up. Didn't take too long for the gas to warm sufficiently to give me a proper flame in the torch. Once I had the stove pipe good and hot, any liquid fuel coming out of the tank would vapourize in the pipe. The truck finally fired after 20 minutes of heating.
 
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9,832
Location
Ontario, Canada
Originally Posted By: eljefino
True but I have enough tanks I could rotate the half dead ones somewhere warmer. But that would be a hassle.
Maybe just put the propane tank in front of the gen exhaust or cooling fan if its out of the wind? A 5hp engine load would draw about 50k btu so way below freezing I guess it could "freeze" the tank. Fortunately you've got about 20k btu in heat waste from the generator so you could figure something out.
 
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26,102
Location
Upstate NY
Propane is the way to go for a generator. Cannot say about the conversion kits. I would forget about the 20 lb tanks. Use at least a 100 lb tank. Better yet, one that has several hundred gallons. The vaporization rate is in charts. You should see on the conversion kit the requirements for propane for a given size engine. It will be in gallons per hour or BTU per hour. Charts tell you how many gallons you can pull from a given tank size (per hour) at a given temp.
 
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367
Location
FL USA
Originally Posted By: Donald
Propane is the way to go for a generator. Cannot say about the conversion kits. I would forget about the 20 lb tanks. Use at least a 100 lb tank. Better yet, one that has several hundred gallons. The vaporization rate is in charts. You should see on the conversion kit the requirements for propane for a given size engine. It will be in gallons per hour or BTU per hour. Charts tell you how many gallons you can pull from a given tank size (per hour) at a given temp.
If you are going to get permits and place these tanks 50 feet from the house you are going to make a large investment but once in you do not have to worry about fuel.
 
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6,259
Location
Illinois
You should check around with the local propane companies for a deal. I was looking for a bigger tank a few years ago and found one local delivery company that would provide and install the 500 gallon tank for free as long as I signed a contract to only allow them to fill. Most places wanted me to buy the tank and then they charge for installation too as well as requiring them to fill. I only use one tank a year but still get a break on the fill if I get in on their late summer fill program. And they only hold 80-85% of their rated capacity.
 
Messages
26,102
Location
Upstate NY
Originally Posted By: Blueskies123
Originally Posted By: Donald
Propane is the way to go for a generator. Cannot say about the conversion kits. I would forget about the 20 lb tanks. Use at least a 100 lb tank. Better yet, one that has several hundred gallons. The vaporization rate is in charts. You should see on the conversion kit the requirements for propane for a given size engine. It will be in gallons per hour or BTU per hour. Charts tell you how many gallons you can pull from a given tank size (per hour) at a given temp.
If you are going to get permits and place these tanks 50 feet from the house you are going to make a large investment but once in you do not have to worry about fuel.
While laws vary, in most cases a 100 gal (420 lb) tank can be mounted next to the house, people often get two or three. Only restriction is it cannot be under a window. The larger 500 gallon (and above) tanks need to be mounted away from the house but I think its more like 25' than 50' or buried. But in the dead of winter in ME, 20 lb tanks will simply not work, 100 lb tanks would be marginal. Smallest tank would be a 100 gal tank.
 
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26,102
Location
Upstate NY
Originally Posted By: SHOZ
You should check around with the local propane companies for a deal. I was looking for a bigger tank a few years ago and found one local delivery company that would provide and install the 500 gallon tank for free as long as I signed a contract to only allow them to fill. Most places wanted me to buy the tank and then they charge for installation too as well as requiring them to fill. I only use one tank a year but still get a break on the fill if I get in on their late summer fill program. And they only hold 80-85% of their rated capacity.
Be aware of this. Companies that own the tank charge a much higher cost per gallon than when you own your own. They can charge what they want and you have no recourse. If you do not use at least one tankful per year they will charge you a rental fee. if its for a genertor many will not supply a tank unless you buy it. So, buy the tank. New or used. I brought home a used empty 420 lb tank in pickup and had propane company pull theirs and connect to mine. New home in DE has a 500 gal in the ground owned by propane company. I negotiated to buy the tank for $750.
 
Messages
4,921
Location
Ca.
Originally Posted By: eljefino
True but I have enough tanks I could rotate the half dead ones somewhere warmer. But that would be a hassle.
IF you have spare amps you can wrap a tire warmer or an electric blanket around the tank to warm it up. Ive used the fan and exhaust heat from a honda 2K to warm stuff up on occasion. UD
 
Messages
2,935
Location
Canada
Originally Posted By: Donald
Originally Posted By: SHOZ
You should check around with the local propane companies for a deal. I was looking for a bigger tank a few years ago and found one local delivery company that would provide and install the 500 gallon tank for free as long as I signed a contract to only allow them to fill. Most places wanted me to buy the tank and then they charge for installation too as well as requiring them to fill. I only use one tank a year but still get a break on the fill if I get in on their late summer fill program. And they only hold 80-85% of their rated capacity.
Be aware of this. Companies that own the tank charge a much higher cost per gallon than when you own your own. They can charge what they want and you have no recourse. If you do not use at least one tankful per year they will charge you a rental fee. if its for a genertor many will not supply a tank unless you buy it. So, buy the tank. New or used. I brought home a used empty 420 lb tank in pickup and had propane company pull theirs and connect to mine. New home in DE has a 500 gal in the ground owned by propane company. I negotiated to buy the tank for $750.
Not sure what propane tank rental/fill policy is that you're talking about but it's not like that up here in Canada. We have a 400 liter tank for our camp that we rent for $75.00/yr. The camp is 60 miles from the city and we get it filled by the provider twice a year or as required with no charge for delivery. Cost of propane is no different than bringing a tank into town to have filled. If, for whatever reason we exhaust the propane supply in the first tank, the provider will supply a second tank with no rental fee. We only pay for the propane. Many people use this service in remote areas. I know that I prefer this service vs. having to haul 100 lb. tanks to and from town plus having to replace the valves every ten years. Did that for 25 years and now it's far more physically taxing wrestling 180 lb. tanks than when I was 30. It's a good deal all the way around.
 
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6,259
Location
Illinois
Around me propane is a big business and there is plenty of competition. I haven't paid over $1.45 a gallon since I got it. This year was $0.95 a gallon.
 
Messages
10,060
Location
Central Washington
I did a little looking and the minimum I think I would go with for my 5K would be two 100lb tanks with a parallel hose kit. Assuming 10k btu/hp and 100% load that would be 10HP or 100k btu/hr According to http://www.nbmc.com/heaters/lpchart.html At 20F I can draw down to about 20lbs remaining in each tank before it no longer vaporize enough to feed the gen. That would be a bit over 33 hours at 100% load. At 0F I'd lose another 10lbs dropping me to under 30 hours, again at full load. It doesn't get the much colder here, and even then only rarely. Is a nice worst case number though. Honestly, I would be happy with that kind of run time. In reality it probably wont be running full load ALL the time so it would take longer to draw down to that level and I could draw the tanks down deeper as well though that would derate the gen and might cause a problem if say a refrigerator kicked on. Of course, the cockford-ollie would be 3 tanks. Even at 0F they could be drawn down to pretty much flat empty; somewhere under 10lbs left in each tank, giving me over 60 hours of running time at full load. I hadn't looked too deeply at propane before; but this is actually a really nice way to keep fuel on hand for the gen. And 100lb cylinders are reasonable enough.
 

Al

Messages
19,277
Location
Elizabethtown, Pa
Originally Posted By: Colt45ws
I did a little looking and the minimum I think I would go with for my 5K would be two 100lb tanks with a parallel hose kit. Assuming 10k btu/hp and 100% load
Closer to 17,000 Btu/hour ...generators are 15% efficient at best.
 
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10,060
Location
Central Washington
Originally Posted By: Al
Originally Posted By: Colt45ws
I did a little looking and the minimum I think I would go with for my 5K would be two 100lb tanks with a parallel hose kit. Assuming 10k btu/hp and 100% load
Closer to 17,000 Btu/hour ...generators are 15% efficient at best.
Hmm. Looking at the specs for my generator it goes through about 3/4 a gallon of gas per hour at rated load, which is only 4500w. I looked up btu content of gasoline and its 120k/gallon, so its using 90k btu/hour @ 4500w. So estimating an extra HP or another 10k btu for the last 500 watts which seems to track with otheer information I have found.
 
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Al

Messages
19,277
Location
Elizabethtown, Pa
Originally Posted By: Colt45ws
Hmm. Looking at the specs for my generator it goes through about 3/4 a gallon of gas per hour at rated load, which is only 4500w.
You are getting 17% efficiency (unless my math is wrong) that's pretty good.
 

JTK

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13,634
Location
Buffalo, NY
Originally Posted By: Al
Originally Posted By: Colt45ws
Hmm. Looking at the specs for my generator it goes through about 3/4 a gallon of gas per hour at rated load, which is only 4500w.
You are getting 17% efficiency (unless my math is wrong) that's pretty good.
That is good if it's indeed a 4500 watt continuous draw for that hour. eljefino, thanks for posting your experiment here! Looks like a great option if you've got propane handy.
 
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