Coach Engine and Gen.

[travelgirl]

Howdy again too all,

On our way home when we first bought our coach we ran the gen while driving down the road. The Onan gen is a diesel and our engine is a diesel as well. When my husband stoped for fuel to fill up for the second time we averaged out at 8.8 MPG and that was with running the gen. after speaking with some other motorhome owner we were told that the diesel gen is tied into our 184 gallon fuel tank there are two lines we were told one to the coach motor and opne to the Onan gen. if we are running down the road and we do not run the gen and/or tow does that inprove our MPG on the coach engine. Weather we run the gen or not does that change my MPG on our coach. Now I know if my husband starts to tow that yes will change the MPG but what about the gen and the engine running or runnign the gen the coach engine and towing I have my theory but want to hear what others have to say.

Thanks again

Happy Holidays to all

[JMonroe]

The engine will burn the same amount, but with the gen set taking fuel out of the same tank, it will take more to fill up.

If you're getting 10 mpg running at 60 mph, as example, and running the gen set at the same time, using 1 gal per hour, in that hour the engine will use 6 gallons, the gen set one, for a total of 7. If you don't account for the fuel the gen set has used and try to calculate fuel mileage simply by the amount it took to fill the tank, compared with the miles on the odometer, you'll get something like 8.6 mpg rather than the true rate of 10 mpg.

Make any sense?

[RJay]

Depending on the size of the generator and the load it carries when running the generator can use between 0.5 to 1.0 gallons of diesel per hour. You can adjust your mileage by how much time you drove between fuel up and multiply that by say 0.5 and subtract those gallons from the total amont at fueling, then divide that total into the mileage traveled.

[Dadeaux]

Originally Posted by travelgirl

Howdy again too all,

On our way home when we first bought our coach we ran the gen while driving down the road. The Onan gen is a diesel and our engine is a diesel as well. When my husband stoped for fuel to fill up for the second time we averaged out at 8.8 MPG and that was with running the gen. after speaking with some other motorhome owner we were told that the diesel gen is tied into our 184 gallon fuel tank there are two lines we were told one to the coach motor and opne to the Onan gen. if we are running down the road and we do not run the gen and/or tow does that inprove our MPG on the coach engine. Weather we run the gen or not does that change my MPG on our coach. Now I know if my husband starts to tow that yes will change the MPG but what about the gen and the engine running or runnign the gen the coach engine and towing I have my theory but want to hear what others have to say.

Thanks again

Happy Holidays to all

One thing you should be aware of is that the onboard vehicle computer does not include the generator usage in its caculations. To get the actual consumption using generator and vehicle engine it must be figured the old fashion way with pencil and paper or hand caculator.

[Vegasdan]

Originally Posted by Dadeaux

One thing you should be aware of is that the onboard vehicle computer does not include the generator usage in its caculations. To get the actual consumption using generator and vehicle engine it must be figured the old fashion way with pencil and paper or hand caculator.

Yep.