Those of you w/ generators...
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Depends on the fuel and the type of generator you are talking about.
I have a rather large gasoline generator that I have converted to use both propane and CNG form the public utility here in town...
Gasoline runs about a gallon an hour,
Propane will run slightly more...
I don't have any way to track 'Gallon' volume of that.
If you get a larger, stationary generator for outside the home, hook it to city CNG or Propane supply.
Liquid fuel spoils, evaporates, draws moisture, ect.,
Even if you use 'Fuel Stabilizers' in it.
If you want a smaller, portable generator, go with gasoline or propane.
It's VERY easy to convert a gasoline generator over to use propane as a fuel, and then you have a 'Dual Fuel' unit that will burn either.
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Have a look around salvage yards, or online salvage yards that handle boats and RV's.
With the hurricanes and floods, there are TONS of low hour generators on the market from larger boats and RV's right now!
Great deals on gasoline, diesel fuel and LP generators!
Go with a larger generator, like an Onan brand rather than one of the smaller ones that uses a 'Lawn Mower' engine.
The larger generators use a low RPM engine that makes so much less noise, and the engines live MUCH longer...
The generators on the other end are usually U.S. made and are MUCH better than the 'China' versions that are usually found behind the 'Lawn Mower' engines.
Buy as much generator as you can afford!
It's VERY hard to buy 'Too Much' generator,
But it's VERY EASY to buy 'Too Little' generator!
Watch for 'Peak' or 'Surge' ratings!
A bunch of the smaller 'Import' generators are rated in their absloute MAXIMUM output, which they won't live very long at that output...
For instance, a 'Peak' rated generator at 4,000 Watts,
but it was only designed to produce 2,300 to 2,500 Watts for any sustained period of time
(Voltage X Amperage = Watts,
OR,
4,000 Watts ÷ 110 volts = 36 Amps)
SO! I though I was buying a 36 Amp generator, which will power most of a household, fridge, freezer, lights, fan, ect.,
But what I got was a 20 Amp generator, which would be hard pressed to keep up with fridge, freezer, lights, fan...
The larger U.S. made generators are usually have 'Working' amperage ratings, so if they say '7,500 Watts', they mean 7,500 watts all day long, every day if that is what you need...
Not just surging to 7,500 watts for a short period of time...
AND,
They lend themselves well to 220 volt hookups, like your fuse box or breaker panel is wired to accept... So they pretty much plug right in to your existing panel with the proper switching...
Ours uses 2 gal. per hour. It has a 22,500 peak 15,000 watt sustained or 65 amps. It will run the whole house, well, 5 ton ac/heat pump, 2 fridges, water heater, etc. With the new blended gas I have seen the lights dim when the ac kicks on. I have it wired to a 200 amp. transfer switch for the linemans' sake.
Gasoline provides the highest BTU rating with Propane about 10% less and CNG 10% lower than that.
My Winco PSS12H produces 12kw continuous on propane but is rated 10kw on CNG
While I didn't really see the need for something that big to power my sump pump/fridge/freezer etc it was only $500 more than the 8KW unit.
If you have CNG to the house thats the easy way to power the gen set. I didn't and have a 250gall underground propane tank. Full for a propane tank is 80% of the size. The gen uses 1.4galls at 50% output. With 200usable galls I'm good for a week but refilling before that would be prudent.
http://www.wincogen.com/index.php?option=com_frontpage&Itemid=1
Sizing of the propane tank also requires consideration of outside temperatures as the lower the temp the poorer the vaporization of the fuel.
My Winco PSS12H produces 12kw continuous on propane but is rated 10kw on CNG
While I didn't really see the need for something that big to power my sump pump/fridge/freezer etc it was only $500 more than the 8KW unit.
If you have CNG to the house thats the easy way to power the gen set. I didn't and have a 250gall underground propane tank. Full for a propane tank is 80% of the size. The gen uses 1.4galls at 50% output. With 200usable galls I'm good for a week but refilling before that would be prudent.
http://www.wincogen.com/index.php?option=com_frontpage&Itemid=1
Sizing of the propane tank also requires consideration of outside temperatures as the lower the temp the poorer the vaporization of the fuel.
I have two generators, a 5500Watt unit and a 1000 watt unit. I've never really kept track of gas usage, but a good part of the time, I do not need the capacity of the 5500Watt generator. The 1000 watt generator is used during those times and saves a lot of fuel. For long term use, you will want a diesel powered generator or a propane generator backed up with a large propane tank (500 to 1000 gallons). Most gas generators run at 3600 RPM and do not last anywhere near as long as a diesel generator turning at 1800 RPM.
Changing the oil often keeps the gas powered ones alive longer.
JK
Changing the oil often keeps the gas powered ones alive longer.
JK
Generator fuel use.
We live in a RV full time. Most power is solar, however during long overcast periods we use a small inverter type (Kipor 2kw) generator. Fuel consumption depends on load. On average, I charge the batteries at about 50 amps DC, tapering as they charge. Takes about 3-4 hours depending on depth of discharge. Total battery capacity is 640ah. I discharge no more than 50% so maximum depth of discharge is about 320ah, but I seldom get that low.
The generator had a .9 gal fuel tank. It takes about 3/4 of the tank so that is about .7 gal. During reallllly overcast periods where there is very little solar charging we can easily run two days of very heavy electrical use (satellite tv, satellite Internet, ham radio, computer, pumps etc.). I require a CPAP machine to assist with breathing at night and that is a significant power load.
Of course the actual charge times vary with the battery depletion. This provides 100% of our electrical consumption.
nomad
We live in a RV full time. Most power is solar, however during long overcast periods we use a small inverter type (Kipor 2kw) generator. Fuel consumption depends on load. On average, I charge the batteries at about 50 amps DC, tapering as they charge. Takes about 3-4 hours depending on depth of discharge. Total battery capacity is 640ah. I discharge no more than 50% so maximum depth of discharge is about 320ah, but I seldom get that low.
The generator had a .9 gal fuel tank. It takes about 3/4 of the tank so that is about .7 gal. During reallllly overcast periods where there is very little solar charging we can easily run two days of very heavy electrical use (satellite tv, satellite Internet, ham radio, computer, pumps etc.). I require a CPAP machine to assist with breathing at night and that is a significant power load.
Of course the actual charge times vary with the battery depletion. This provides 100% of our electrical consumption.
nomad
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92 Posts
Loving this thread! We are considering buying a generator very soon.
Our 1100 sq ft house is total electric. We already have other measures in place to stand in for heat and lights. I would love to have a gas or diesel generator to keep the fridge , freezer and computers going. How do I estimate amps so I know I have enough? After reading all the posts, I'd hate to put out the money and find we shorted ourselves on power.
Our 1100 sq ft house is total electric. We already have other measures in place to stand in for heat and lights. I would love to have a gas or diesel generator to keep the fridge , freezer and computers going. How do I estimate amps so I know I have enough? After reading all the posts, I'd hate to put out the money and find we shorted ourselves on power.
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289 Posts
Almost all electrical devices have power usage details on the info plate.
Volts x Amps = Watts
Add up the wattage of all major appliances, add in a "fudge factor" and you should be OK. I'd err on the side of a larger "fudge factor" if there's any question. Appliances with motors have a large startup current and that should be considered as well.
With your air conditioner running, you can measure the current draw on your electrical panel. For an 1100sf house, I'd be guessing an 8kw generator would be plenty, but don't take that as gospel.
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696 Posts
I can run everything and then some on 7,500 Watt unit.
Can't have it all on at once, but you can even run the cloths dryer or central A/C unit off it.
We DO have a pretty energy efficient home... Compact fluorescent bulbs, low draw appliances for the most part, stuff like that.
And the Furnace & Water heater are gas...
Can't have it all on at once, but you can even run the cloths dryer or central A/C unit off it.
We DO have a pretty energy efficient home... Compact fluorescent bulbs, low draw appliances for the most part, stuff like that.
And the Furnace & Water heater are gas...
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38 Posts
Fuel is not the only limitation.
Beyond 100 hours or so you will need to change oil, filters, and possibly need spare parts.
14 days x 24 hours x 1.5 gallons per hour = just over 500 gallons of fuel, three oil changes, a new air filter, plus anything that might break.
The fuel and parts quickly become unmanageable unless you have batteries or a setup where you only have to run the genset an hour or two a day.
Beyond 100 hours or so you will need to change oil, filters, and possibly need spare parts.
14 days x 24 hours x 1.5 gallons per hour = just over 500 gallons of fuel, three oil changes, a new air filter, plus anything that might break.
The fuel and parts quickly become unmanageable unless you have batteries or a setup where you only have to run the genset an hour or two a day.
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