Onan Quiet Diesel 7500 consumption

Thanks for the great responses folks.

We have the 2005 Excursion with the Onan 7500 - basically the same as your rig. I'd say we're using about a half gal per hour when both ACs to are on - that's when the generator is running full tilt. Other times may be a little less. It's hard to measure as you always have drive to and from where you're using it.

Bill

The way to gen set prime mover economy is two-fold both offset by trade-offs and compromises.

3,600 RPM is awful. Two pole generators suck for economy. 1,800 RPM is more common. Fuel economy improves 5-8%. A six pole 12-turn gen set is the best. 1,200 RPM but horribly big and heavy. 12-turn is ideal for long run times.

Coolant versus air makes a huge difference in economy. This is why VW was forced to change. Efficiency was so poor emissions could not be controlled. Today's water cooled cars could haul a beetle on their roof, pass another going uphill and get better fuel economy doing it all the while.

A water-cooled direct injection Honda 2000 would use about 65% of the fuel of a standard Honda.

Thanks all. Appreciate the response's!

I only use about 1/2 gallon an hour while running both roof airs and my refer while traveling with the same genset you have.

The numbers I've seen on here is more like 1/2 gallon/hr for one AC and 3/4 for two ACs... not enough to worry about.

As a rule of thumb, I use the one quart an hour estimate. That's what I was told the 10K diesel generator in my coach uses by a Onan technician at a rally. I can't believe it is that little, but possibly so. I'd even be happy with a one gallon an hour usage level.

I've used the generator on trips to run the house air conditioner and while dry camping out in the desert in Arizona. I never noticed any change in my fuel consumption overall and with a 150 gallon tank, I couldn't tell any change in the fuel level gauge after boondocking for several days and running the generator for several hours twice a day.