Community Forums

Mr_D · 12-11-2017, 09:11 AM

Quote:

Originally Posted by Coarsegold

I would not run unless really needed as no reason to run the hours up on a good generator.

And what keeps it running "good" is being used.

Cooperhawk · 12-11-2017, 09:35 AM

A good way to convert hours to a more understandable form is to take 45 mph times the hours on the genset. 45 mph is usually what a driver will average overall.

Exp. 100 hrs X 45 mph = 4,500 miles

1000 hrs X 45 mph - 45,000 miles.

As you can see that's not a lot of wear. It's worse it they're not run.

RVPioneer · 12-11-2017, 09:43 AM

Reese,

Your coach is equipped with an Onan 7.5K diesel. Per the owners manual it consumes approximately, .1 gal/hr at idle, .5 gal/hr at half load and 1 gal/hr at full load. Disregard numbers from owners with different generators. It will have an impact on mileage as you will be consuming more fuel than running the engine alone. Perhaps MPG will decrease by .1-.2 mpg if you run the generator the entire time while driving. Hardly noticeable and variations in terrain, wind and speed can have a more significant impact. Additionally, once the fuel tank drops below about 1/3-1/4 tank, fuel to the generator will be cut off.

I have found in our 2005 that the dash AC works quite well even when outside temps are in the 90's. The rear of the coach will not be as cool so if the DW wishes to have a nap it may be wise to run the generator and roof AC. Additionally, if you rarely run the generator while parked it would be good to run it occasionally while driving. I've seen these generators with 10,000 hours on them so don't be afraid to use it.

thomasfalco · 12-11-2017, 02:06 PM

Quote:

Originally Posted by RVPioneer

Reese,

Your coach is equipped with an Onan 7.5K diesel. Per the owners manual it consumes approximately, .1 gal/hr at idle, .5 gal/hr at half load and 1 gal/hr at full load. Disregard numbers from owners with different generators. It will have an impact on mileage as you will be consuming more fuel than running the engine alone. Perhaps MPG will decrease by .1-.2 mpg if you run the generator the entire time while driving. Hardly noticeable and variations in terrain, wind and speed can have a more significant impact. Additionally, once the fuel tank drops below about 1/3-1/4 tank, fuel to the generator will be cut off.

I have found in our 2005 that the dash AC works quite well even when outside temps are in the 90's. The rear of the coach will not be as cool so if the DW wishes to have a nap it may be wise to run the generator and roof AC. Additionally, if you rarely run the generator while parked it would be good to run it occasionally while driving. I've seen these generators with 10,000 hours on them so don't be afraid to use it.

Well said.

ThePowells · 12-11-2017, 05:56 PM

So far 130 hours since new delivery on March 5. It will be more by morning since our S&B power is out. Another good reason for us not to winterize.

texkayaker · 12-11-2017, 06:03 PM

Quote:

Originally Posted by triplewide

Better to run the generator frequently under load than seldom. We run ours whenever we want the AC, microwave, keurig. We run ours every 30 days or so for 30 minutes under load when storing coach.

Our 4K Onan uses about .5 gallons per hour @ 50% load. If we run both AC's we are at about 75% load.

If you get 8 miles per gallon with the generator off and travel 50 miles in one hour, then travel 50 miles in one hour with the generator on, you will get 7.4 miles per gallon.

Another way to look at it is if I drive 300 miles in an 6 hour day with the generator running I will use about 3 gallons of gas extra. Currently at $2.35 per gallon the daily cost is about $7. If you averaged this daily for a month it would cost you $200+.

We think it is worth it for the only thing to be hot is the food and the coffee, (and maybe the generator).

PS: For us about 100 hours per year would be average.

Running two A/C units Onan 4KW Onan and only at 75% load on the Onan. You have an exceptional Onan

triplewide · 12-12-2017, 02:04 AM

Quote:

Originally Posted by texkayaker

Running two A/C units Onan 4KW Onan and only at 75% load on the Onan. You have an exceptional Onan

One 15K BTU, and one 11k BTU Power Saver. It's not the generator producing more than average, it is the AC's using less than average.

triplewide · 12-12-2017, 02:45 AM

Quote:

Originally Posted by RVPioneer

Reese,

Your coach is equipped with an Onan 7.5K diesel. Per the owners manual it consumes approximately, .1 gal/hr at idle, .5 gal/hr at half load and 1 gal/hr at full load. Disregard numbers from owners with different generators. It will have an impact on mileage as you will be consuming more fuel than running the engine alone. Perhaps MPG will decrease by .1-.2 mpg if you run the generator the entire time while driving. Hardly noticeable and variations in terrain, wind and speed can have a more significant impact. Additionally, once the fuel tank drops below about 1/3-1/4 tank, fuel to the generator will be cut off.

I have found in our 2005 that the dash AC works quite well even when outside temps are in the 90's. The rear of the coach will not be as cool so if the DW wishes to have a nap it may be wise to run the generator and roof AC. Additionally, if you rarely run the generator while parked it would be good to run it occasionally while driving. I've seen these generators with 10,000 hours on them so don't be afraid to use it.

One of the questions in the OP's original post was:

"Just curious to know how much does running the generator while driving effects fuel mileage"

Fuel mileage will be affected if the generator uses the same fuel as the coach. Fuel mileage is affected by amount of fuel consumed, not fuel type, generator size, or brand. Generator efficiency would be a factor if it consumes less fuel per watt generated.

On a 50 mile trip that takes one hour to complete and your generator uses .5 gallons per hour:

If your rig gets 15 mpg with out generator it will get 13 mpg with it.
If your rig gets 5 mpg with out generator it will get 4.76 mpg with it.
If your rig gets 3 mpg with out generator it will get 2.9 mpg with it.

If your generator is only affecting mileage by .1 mpg I would assume it is only consuming about .1 gallons per hour. I am guessing you get better than 3 mpg without the AC(s) running.

Dtwallace · 12-12-2017, 02:48 AM

Our generator runs from the time we disconnect from shore power until we reconnect to shore at whatever destination we arrive.
I’m never concerned about hours on generator and keep it service on time if not ahead when ever we are planning a long trip.

DTW

badturks5 · 12-12-2017, 05:13 AM

Over all I lose anywhere between 1 to 3 mpg running the gen while driving. 1998 American Tradition 40 foot diesel. Cummins 8.3 all mechanical no electronics.

guardrail53 · 12-12-2017, 07:18 AM

I only lose about 1 mpg when running the generator, and i keep a close eye on the fuel mileage! Rail!

Ray,IN · 12-12-2017, 10:31 PM

Generator use does NOT affect engine fuel mileage, it gets the same mileage whether the generator runs or not. The generator does affect total fuel used when both are running.

triplewide · 12-13-2017, 01:53 AM

Quote:

Originally Posted by Ray,IN

Generator use does NOT affect engine fuel mileage, it gets the same mileage whether the generator runs or not. The generator does affect total fuel used when both are running.

Sorry, I misunderstood the OP's question. Thought he was questioning the effect on his coach fuel mileage.

Do you happen to know what the rated fuel mileage is for your Cummins 350?

OLYLEN · 12-13-2017, 08:20 AM

Interesting about fuel mileage on an 8 letre diesel. I have heard that the Gen servicing an AC uses .5 gallon or there snouts per hour. Also that a diesel chassis motor developed 15HP to use the AC. Now I know on my previous coach it averaged 50-80 hp going down the road no real hills, so I would think there would be a toss up for fuel. I run mine gas or diesel when needed, comfort on the road.

LEN