Running ac off of generator while driving.

[jfskeet]

Has anyone noticed much of a difference with running house air over chassis air while driving. Is the power gain noticeable with house air generator combo? . Around the campfire last weekend was a few different opinions. with fuel use and power gain/ loss.


We all had A gassers.
What did you see in the difference?

Jeff

[tropical36]

Fuel is the least of our concerns with the overall cost of ownership, so not only do we run the roof ac's but the dash ac, as well, with one probably using as much fuel, as the other.
Thing is about the dash units, if you don't use it, you'll lose it and probably will anyway, with the most of them. In fact, can't believe that ours still works, after all these years, but then again, we've only owned it for two of those years.
The roof air, is always on and when in the driveway, as well, even though turned up a good bit and especially in summer.

[Two_Jayhawks]

Running genny with 1 or maybe 2 (rarely) costs me about a gallon of fuel per hour. Running dash air has little to no effect on mpg. I seem to hover around 7 regardless.

[Gjac]

jfskeet wrote:
Has anyone noticed much of a difference with running house air over chassis air while driving. Is the power gain noticeable with house air generator combo? . Around the campfire last weekend was a few different opinions. with fuel use and power gain/ loss.


We all had A gassers.
What did you see in the difference?

Jeff

The difference that I see is about .5mpg. With no AC I average 8.7 mpg(over 90k miles) with chassis AC mpg drops to 8.2, with 2 roof top AC's running from 5.5 kw genset mpg drops to 7.7. Having said all that on very hot days (90 degrees plus)the roof top AC's do not cool the front area very well without the chassis AC running also. Most of the time(70-85 degrees) I just run with the chassis AC. I made a curtain that goes in back of the seats that really keeps the front cool but have only had to use it a few times in 15 years. I look for ways to use the genset so I don't have to exercise it at home each month so running it while driving for an hr under AC load is good.

[malexander]

If I'm driving the MH, the genny is running, for the a/c's and the fridge. My dash air doesn't work. The blower does, but it doesn't blow cold air.

[rgatijnet1]

FordDiesel250 wrote:
When I run my genny while driveing the A/C units will run for awhile and then the genny will shut down and I cannot restart it for a couple of hours. Is this normal or is it telling me something is wrong? To me it acts like it has some kind of timer but that does not make sense to me. Any Ideas?

Sounds like a vapor lock. Perhaps you have a fuel line for the generator that is running too close to an exhaust pipe.

[MrWizard]

my first guess would be fuel issue, generator pump having trouble getting fuel .... try replacing your Gas Cap on your tank filler

second guess is a generator heat issue

[FordDiesel250]

When I run my genny while driveing the A/C units will run for awhile and then the genny will shut down and I cannot restart it for a couple of hours. Is this normal or is it telling me something is wrong? To me it acts like it has some kind of timer but that does not make sense to me. Any Ideas?

[wa8yxm]

Biggest difference I notice is House air works.. Chassis is not working when I checked.. again.

[J-Rooster]

I run the heat pump to cool the inside of the coach from Barstow to Lake Havasu City with no engine power loss.

[rbonecrusher]

I like to think about is the cost worth it to run the generator to cool my coach while traveling. If the generator uses 1 gallon per hour it will cost about $3:00 pr. hr. to drive in comfort. It will cost more for miles driven that day. If your coach gets 8 miles per gallon and you drive 3oo miles that day in 5 hours you would use 37.5 gallons of fuel for the coach and 5 gallons for the air for a ttl of42.5 gallons at a cost of $127.50. $15.00 of that was for the air. The cost per mile for air was a whole 5 cents pr mile. Your coach engine cost 37.5 cents per mile. Cost per mile was affected that day by 5 cents per mile for using the air.
Ray

[azdryheat]

I was shuttling Class A's in Phoenix on Monday and the dash air did nothing to combat the heat. Turning on the gen and roof air took care of the heat. Wednesday I took a Winnibago Vista across the desert and having the gen and roof air on was a must. The other nice thing is when climbing mountains the dash air can be turned off to keep the engine temp down while still having the roof air going. This was very nice while climbing the mountains outside of San Diego.

[4x4van]

Assuming 6.5 mpg and 65 mph, that's a total of 10 gallons of fuel burned per hour. The generator, running the roof A/C, burns about 0.5 gal per hour. Drops my overall mpg from 6.5 to 6.2

Your numbers may vary a bit, but the difference in fuel burned is negligible for the comfort provided.

MrWizard wrote:

as far as gas milage for the drive engine
it has NO effect
but since it does use fuel for the genny
your next fill up means more fuel from the pump to the tank
but this is NOT engine fuel mileage, this is additional overhead fuel use by the genny for 'personal comfort'

we get people on here, saying i used my genny for the roof top A/C and mileage went down,
NO your engine mileage did not change

You are of course correct, my "engine" mileage doesn't change. But my "motorhome" mileage does. 😉 The easiest way to quantify the fuel consumption and comfort while driving WITH the generator/AC vs WITHOUT the generator/AC is to compare apples to apples; i.e. mpg to mpg.

[Goldencrazy]

And it is comfortable when you arrive at the days destination. Otherwise you need an hour or two to catchup.

[wildtoad]

Those that worry about mileage should not be driving an RV. It’s great to know your average MPG to help budget for a trip but that’s about it. We use the dash air mostly until it gets uncomfortable. Then crank up genny and run roof air. The other day it seemed that once the roof air kicked in the dash air got colder. Must have been sucking in the cold air from the roof unit.