LP Generator

[melensdad]

Originally Posted by 4sarge

Thanks for the info. It looks like this generator will only run for 10 hours on 16 gallon of gas and at todays prices that would be about 64 dollars. Does that sound right. The LP Gas models claim to use 1.61 gal per hour which isn't much better cost wise

Originally Posted by RogerB

. . .
I think I got it from Melens post that the LP and NG models don't produce as much output as those of gas. I'm thinking when I put out the bucks for all this, I'll get two of the 16Gal fuel staorage tanks. . .

Correct.

If you consider gasoline gives a relative 100% output running any given engine, then the same engine running on propane will only generate about 91% output and the same engine running on natural gas will only generate at roughly 82-83% output.

What that means is that you will get less electricity per running hour on natural gas than you will when powering it with propane and you will get less electricity output running on propane than you will when running on gasoline.

So from the 'efficiency' standpoint, not only do you have to factor in "running time" but you have to factor in "power output."

For example, if a 5 gallon tank of gasoline will run a small generator for 5 hours and provide 10,000 watts per hour you will get 50,000 watts for $20.00. ($4 per gallon x 5 gallons of gas)

If you run the very same generator on LP gas you will generate about 9100 watts per hour so over the same 5 hour period you generate 45,500 watts and use 8.05 gallons of LP at ??? cost. (1.61 gal LP per hour x 5 hours = 8.05 gal LP)


FIRST, you should figure out how many watts you need to generate.

SECOND, you should consider IF you can store enough fuel to run the generator for at least 24 hours.

I personally think the COST TO RUN the generator should be given VERY LITTLE consideration. Again, these generators do not run very often. So the real cost of running a generator is not much per year. On the other hand if you are thinking of using a generator to power your house so you can get off the power grid, then I think you are looking at powering your house the wrong way.

Of much more concern to me is the storage of gasoline. I know some people who have small underground tanks, for those people a gasoline generator is no big problem because they have a safe place to store the fuel. But do you really want to keep 25+/- gallons of gasoline in storage at all times? I personally do not. Also you may want to see if your insurance company voids your homeowners insurance if you store excess gasoline.

When it comes to powering the generator, to me I look at the RELIABILITY OF FUEL SUPPLY as the number 1 consideration.

In my 47 years of life I've not lost my natural gas feed. I've lost power many times. I've lost city water many times. I've run out of gas for my lawn mowers and diesel for my tractors. I've run out of propane for my grill, but I've never run out of or lost access to natural gas. So my #1 choice is natural gas. I use propane and gasoline as my "plan b" options should I ever lose natural gas.

[in812]

my .02$ i have a 5500 portable generator i've used for several years for when the power goes out it will run 2 1/2 ton a/c unit light in the house and garage fine but i have a gas stove and hot water heater
just have to make sure the others dont use curling irons or hair dryers but to stay cool have lights tv etc. the 5500 has worked fine
I have a onan i was going to install and hard wire in but it just sits there as a back up
IMO if you need over 5500-6500 for back up you need to start turning some of the stuff you dont need OFF !
Oh and the 5500 also runs the fridge and deep freeze

[melensdad]

Originally Posted by in812

IMO if you need over 5500-6500 for back up you need to start turning some of the stuff you dont need OFF !

Well I guess I could technically disagree with you, but in principle I do agree.

There are some electric loads that will really pull a lot of power. Starting up and running a 1.5hp deep well water pump draws a good bit of power. I believe the deep freeze and refrigerator also draw quite a bit at start up but far less when running. Furnace motors I believe also work the same way with a heavy draw at start up and a lower draw while running.

When I sized my generator I sized it to handle the 'surge' at start up if several large things hit at once. That said, I do not power my entire house in a major power outage, but my house requires more than 5500 watts. If I didn't have a well pump to worry about I could probably get by with 5500 to 6000 watts.