Chester ,
I ran mine for 12 hours on a full tank of fuel to the brim and then refilled to the brim and it took 6.7 gallons and I did this when the Genset had 1200 hours on it. Had 2 a/c running and the clothes dryer.
That was my test and my own certified results.
Chester it should be .9. If I am correct and Tom or others correct me, but a 20 KW Gen. puts out about 180 amps. So 50% would be 90 amps. and there is no way my MH would pull that much amps. Now if I had a 5trh wheel buddy next to me plugged into the buddy plug and we both had everything running we might. So when Tom said he thought a 20 KW gen. would use about .6 or so gals an hour it probably about correct. So the gen. is pulling about 10 or 15% total or about 18 or 25 amps on average in a 8 hour period. Because the A/C and other stuff doesn't run the total time. So I would say my gen. would use about .6 to .8 a gph in a 8 to 10 hour period. It is all according to the weather.
The manual is just giving us a base to go by. If it was loaded with 10 KW the total time it would use 1.2 gals. an hour. That is the way I see it.
Based on the above posts, my estimated average of .8 gph is about right. With A/Cs running and drawing a total of 40 amps, that represents about 22% of 180 amp capacity. If 25% is .9 gph, I am close enough. This is a good subject and I appreciate the posts.
Our 12.5 is similar to Michael. .5 gal/hr very light load, .75 gal./hr with 3 AC's, 2 TV's, water heater & microwave. (almost forgot heated tile in galley & lavy)
For years, I have used a figure of .0785 gallons per KW per hour and it has been very accurate. Four rooftops on balanced legs will draw around 20A per leg.
20A X 240V = 4.8KW. Throw in an occasional refrigerator load or water pump (Head Hunter) and likely round up to 5KW. That times the factor results in .390 gallons per hour.
That load requires a bit over 8HP from the engine. The Yanmar fuel consumption rate is .39lb/HP-hr. That works out to be .43 gallons so the .39 figure is close.
I'm too windy !!
gordon, you are amazing. thanks for real data on how to calculate it
tom
Gordon, I am amazed too. With that kind of figuring one would never need a Silver Leaf to know how much fuel the DD is using for each horse.
Based on the above, is .5 gph and reasonable number to use vs .8 that I have been using. An accurate figure helps in deciding to run the generator vs paying a RV park.
Chester, when there is a good reasonable park around stay at it. l figure 1 gal an hour in the summer just to make it easier. The other thrills of a park such as water and dump and safety make it worth while. Just my thoughts and not always correct.
This note is to all the posters that ignored my common sense approach in doing my own simple consumption test and instead depended on manuals and math to arrive at Genset fuel consumption. Gordon has the formula and so do the manuals, but no user can depend on these numbers, except for general discussion. Why ? Because everyone uses different power draws at different times and in different uses and loads and every Newell is different. So if you want to really know your consumption, do a simple test for a few hours and then apply math to arrive at your own true consumption, that day during that test as ALL of them will be a bit different and the way your Genset is running will also effect consumption. BTW, Everyone is right, just not practical in real use.
