Fuel Mileage and Generator Use

[Coma]

I'm getting set for my first long trip to Colorado in the MH.

Does the Genny use more or less fuel than running the dash air?

I'm also wandering if running the Genny would make a difference, you'd notice, in the mountains in keeping the engine cooler?

Any other thoughts would be welcome.

[garymkrieg]

I see no difference in my fuel mileage when I use the dash air, so I think the generator would use more fuel. As far as keeping the engine cooler, I have no idea.

Gary
2011 Tiffin Allegro Bus 43 QGP

[RJay]

Usually the issue comes down to the fact that the dash air can't keep the interior cool enough during hot weather so the generator is run for the house A/C's. However the dash A/C uses less fuel because the it's system is smaller than the house A/C's and requires less energy.

[JFC]

Our 2002 Ambassador had a cummins 330 and our Scepter has a 400. We run the generator whenever temps outside make the coach uncomfortable. Haven't noticed any major change in mileage or preformance.

[kketterling]

Seems to me I read somewhere on here that the generator uses about a 1/3 to 1/2 a gallon per hour depending on load.

[roscoesdad]

Traveling this time of the year usually requires both dash and overhead a/c use to stay comfortable.

[Coma]

Thank you for the replies!

The reason I asked is when pulling a trailer in the mountains I could keep the Pickup engine from overheating by turning off the AC. Lots of differences in the engine/cooling system in the MH and just curious if the same strategy would work.

[rpasetto]

Turning off the AC should keep the engine running a bit cooler, especially when making uphill runs in this hot weather. I don't know what temp is normal for the engine you have in your Dynasty (the ISC 350?). My ISL runs at about 186F; I'll turn off the AC if it ever gets to over 196F.

I recall a few years back when a Cummins rep was speaking at a Monaco seminar. A coach owner raised the question of engine temp and Cummins said not to worry unless temp is above 210F.

[njs42]

It is not uncommon to see signs on long steep grades suggesting turning your AC off. It is obvious why---with dash AC on more cars overheat in such situations.

As to the fuel use---if your MH and your generator are in normal operating condition and if you are burning a half a gallon per hour on the generator as one suggest and you are traveling at 65 mph then you use an extra one half gallon for that 65 miles.

If you do not have your dash air on then you are saving some fuel----it seems to me the difference may be slight------certainly slight enough to warrant being more comfortable with your roof air running on the generator.

I read a lot of threads where people run both dash and roof air----so pick your personal comfort zone and pay the freight.

[kketterling]

Turning off your AC may not always cause your engine to run cooler. With newer coaches and cars the radiator fan is programmed to stay on all the time when the AC is on and when its off it cycles based on temp. I've noticed in my coach it runs about 8 degrees cooler when the AC is on. Now if you are pulling a long grade then i'd turn the AC off.

[justinnine]

I have a 1996 Allegro Bus and the A/C manual says the genny only uses .04 gallons an hour and I have a 7000 Watt Onan.

[rpasetto]

Quote:

Originally Posted by justinnine I have a 1996 Allegro Bus and the A/C manual says the genny only uses .04 gallons an hour and I have a 7000 Watt Onan.

I'd say that's a typo. It's probably 0.4 as opposed to .04. You could check with Onan.