Question about LP Generator

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alann

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Joined
Jul 16, 2007
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18
Just wondering how long I can expect it to run on the 23# LP tank?  Also is it a good idea to run the generator and roof ac while driving if the cab a/c does not cool the coach?
 
alann said:
Just wondering how long I can expect it to run on the 23# LP tank?  Also is it a good idea to run the generator and roof ac while driving if the cab a/c does not cool the coach?

Having never had a propane genset I can't say from experience.  However, the fuel consumtion will be something more than a similar size gas genset.  Our Onan Diesel burns less than .4 gals per hour when we use it.
 
However, the fuel consumtion will be something less than a similar size gas genset.

Are you sure of that Ron?  That would be surprising because propane has substantially less energy per gallon than gasoline (84,000 btus vs 114,000).  And everybody I've ever known who had a propane generator said it literally gulps fuel.
 
RV Roamer said:
Are you sure of that Ron?  That would be surprising because propane has substantially less energy per gallon than gasoline (84,000 btus vs 114,000).  And everybody I've ever known who had a propane generator said it literally gulps fuel.

You are correct and I was meaning to say less efficient.  Darn just can't seem to multi task very good anymore.  Yes all the comments I have heard from folks that have propane Gensets report they are pretty inefficient.  Thanks for catching that.
 
Once had  a friend with a LP Genset and he called it a succarator the way it went thru fuel.
 
how long I can expect it to run on the 23# LP tank?

Is that 23 lbs or 23 gallons?  The # usually means pounds but standard propane tanks don't come in a 23 lb size (20#, 30#, etc).  A 20# LP tank contains only 4.8 gallons and that would run a typical 5 KW generator no more than 8 hours at 50% load.  But if it is a 23 gallon tank (fairly typical for a large motorhome) then you've got fuel for many hours, probably 40 or so.

These estimates are based on 0.5 gallons/hour at 50% load which is fairly typical for large diesel gensets and somewhat smaller gas gensets.

Yamaha has some estimating tables for their propane generators but the assumptions have a somewhat higher energy content for propane (92000 btu/gal) than I see elsewhere (84000 btu/gal). Using the Yamaha figures, a 5000 watt generator at 50% load would consume about .55 gal/hour of propane. At the lower (84,000) btu/gal figure it would be about 0.6 gal/hour.  [Propane energy content varies with the blend, which is adjusted regionally and seasonally as well as varying from refiner to refiner - there is no standard blend for LPG]

Yamaha propane consumption charts
 
Thank you so much for the replies.  Guess I will have to be careful with generator times. :)
 
Bernie is close on the Onan suck-a-bility

One thing  you can do if you are going to be there a while is order up a bigger bottel from the local Propane supplier,  The park can provide the supplier's name.  The bottle is professionally delivered.  Usually a 100 lber  Or even larger if you must.
 
The typical automotive air conditioner is actually capable of about 21000 BTUH.  To maximize the cab air, use the "recirc" or "Max" air path setting so you are not cooling outside air, and do not moderate the temperature with the heater.  Move the dash air outlets so they don't blow on the crew.  I have a Class B, and the roof air is only about 7000 BTUH...  the dash air cools the van much faster than the roof air.
Art
 
Wife just asked "Instead of asking why don't you just look it up?"  Again, she is right.  ::)  It is only a 2500 and Onan says at half load it should use about .3gl per hour.  We shall see.  Our maiden voyage (only one night due to work schedule :( ) will be the 26th/27th.
 
Hello,

I have over 5 years experience with selling and fixing generators, and can answer your question.

An LPG Generator is a Gas/Petrol generator that has been converted to accept LP Gas. If it has been converted after manufacture it is hard to calculate without actually running it, but it does work out much cheaper and more efficient, but as it is build to use gas, in the long term it can wear the engine differently from gas.

So make sure you regularly service the unit, clean the spark plug and change the oil.

I have made a website about generators called www.whatgenerator.com this might also help you decide.

Thanks

Styles Beagley
www.whatgenerator.com
www.generatorguru.com
 
Based on the Onan generator specs for the 2800 (gas) and identical 2500 (propane) and the current prices at the Mill Hall PA Flying J,  the cost per KW per hr. for propane is higher.

Gas $2.799/gal,        0.3 gal/hr half load,    1.4 kW            $0.5998/kw/hr
Propane $2.049/gal,  0.4 gal/hr half load,    1.25 kW            $0.6557/kw/hr

Art

 
alann said:
Wife just asked "Instead of asking why don't you just look it up?"  Again, she is right.  ::)  It is only a 2500 and Onan says at half load it should use about .3gl per hour.  We shall see.  Our maiden voyage (only one night due to work schedule :( ) will be the 26th/27th.

How did that  maiden voyage go alann?
 
King said:
Based on the Onan generator specs for the 2800 (gas) and identical 2500 (propane) and the current prices at the Mill Hall PA Flying J,  the cost per KW per hr. for propane is higher.

Gas $2.799/gal,         0.3 gal/hr half load,    1.4 kW             $0.5998/kw/hr
Propane $2.049/gal,  0.4 gal/hr half load,    1.25 kW            $0.6557/kw/hr

Art

As expected.
 
It was great.  No problems except van need alignment and 2 light fixtures.  Will be done on Sept 6th.  Plan on LOTS more trips. 
 

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