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L2C

Placentia ca

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Posted: 04/23/12 07:48am Link  |  Print  |  Notify Moderator

Planning a long trip this summer. Is it ok to run the roof Ac while driving for long periods? Traveling to east coast with a family of 6.

Finally Fulltiming

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Posted: 04/23/12 07:51am Link  |  Print  |  Notify Moderator

No problem with the A/C - problem is it runs on electricity. You'll need to run your generator to power it.

Depending on the size of your rig, the dash a/c should suffice.

joelc

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Posted: 04/23/12 07:53am Link  |  Print  |  Notify Moderator

When I had a motor home, I did run the A/C many times while traveling, as well as the heater in the respective seasons. Remember for A/C you need 120V (generator)

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Posted: 04/23/12 07:56am Link  |  Print  |  Notify Moderator

We run ours in the summer all the time while driving. Requires Gen of course. Was told a while ago that the gen running the central AC is more fuel efficient than the dash air due to the proximity of the vents cooling the coach as well power drain on the motor. I've never really noticed much of a decrease in MPG running the gen but I don't pay a lot of attention to my MPG. Ignorance is bliss.


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carp65

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Posted: 04/23/12 07:58am Link  |  Print  |  Notify Moderator

Dash air on our GeorgieBoy will not cool when temperatures are extreme.
Solution is to run generator and turn on roof a/c. Cools nicely and
excercises generator, too.

Dale.Traveling

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Posted: 04/23/12 09:09am Link  |  Print  |  Notify Moderator

Did it last summer. Roof AC + Generator creates much more cooling effect per gallon of fuel then the dash + engine AC. Also shifts the fridge off propane save it bit more. If you are ever driving into the summer sun all the glass of the windshield creates a lot of heat for the driver. A couple of times I did run both, dash and roof.


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jvander

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Posted: 04/23/12 09:39am Link  |  Print  |  Notify Moderator

carp65 wrote:

Dash air on our GeorgieBoy will not cool when temperatures are extreme.
Solution is to run generator and turn on roof a/c. Cools nicely and
excercises generator, too.

x2

I've heard it a lot that the gen/roof ac provides more efficient cooling than the dash ac, but that makes no sense. The main engine is already running and pushing air through the evaporator coil, so the energy losses are already 'paid for'. Adding the ac load to the main engine costs 5-10 hp, plus minor loads to the alternator and cooling system.
Running the generator adds new energy losses in converting petroleum to electricity, plus the roof ac has additional energy losses in converting electricity to mechanical energy. Plus the roof ac is not as powerful as the dash ac.


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Effy

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Posted: 04/24/12 06:01am Link  |  Print  |  Notify Moderator

jvander wrote:

carp65 wrote:

Dash air on our GeorgieBoy will not cool when temperatures are extreme.
Solution is to run generator and turn on roof a/c. Cools nicely and
excercises generator, too.

x2

I've heard it a lot that the gen/roof ac provides more efficient cooling than the dash ac, but that makes no sense. The main engine is already running and pushing air through the evaporator coil, so the energy losses are already 'paid for'. Adding the ac load to the main engine costs 5-10 hp, plus minor loads to the alternator and cooling system.
Running the generator adds new energy losses in converting petroleum to electricity, plus the roof ac has additional energy losses in converting electricity to mechanical energy. Plus the roof ac is not as powerful as the dash ac.


Man you must have one heck of a dash air system to cool the whole coach. Mine barely cools the cockpit. I can tell you with most gas engines when you turn on the AC compressor there is a definite draw on your motor. Your motor was designed to move your vehicle. The gen was designed to provide electric efficiently. And the rooftop AC unit is far more efficient at cooling a larger space than your constrained dash air. I would agree with most here that I don't see a big difference in MPG using gen or not. What I can see is a huge difference in comfort. Even in a worst case, I'd rather me and my family be comfortable than miser about a half an mpg. That's just my opinion. Last thing I want to do on a trip is fuss over numbers on an already inefficient vehicle. I want to be comfortable and have fun. I run the gen and rooftop. That's why they are there.

jpajax

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Posted: 04/24/12 06:24am Link  |  Print  |  Notify Moderator

It was told to me by my dealer, and was stated by the manufacture of my gen. that it consumes about 1/2 gal of fuel at 1/2 capacity in a hour. You do the math, it seams that for comfort has a small price to pay. Plus the whole coach is comfortable when you arrive at your camp ground.

Mr.Mark

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Posted: 04/24/12 06:36am Link  |  Print  |  Notify Moderator

On hot days driving through the southwest, you will definitely need the roof air system. On extremely hot days and the added heat from the engine (diesel pusher), the back of the coach can get pretty warm.

Arriving to your destination with an interior that is already cool is nice. A couple of years ago driving from Southern California through the Arizona desert, the temp outside reached 114 degrees. Running the genny with all three roof airs going, we arrived in comfort.

L2C, don't hesitate to use your genny to run your air. That's what it's there for, especially, when you are traveling with motorhome full of people!

MM.


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