Rooftop AC while driving

[urbanbye]

I'd like to be able to run my rooftop AC while driving. This website is offering a secondary alternator to do this job. Does anyone out there have any experience with this? Can this actually work? When not in use, will it affect gas mileage?

"http://vehiclepower.com/sprinter%20van.htm?_kk=sprinter%20van&_kt=ac1029cd-d24f-404f-8da7-964d07cef6e1&gclid=CIqI1rXIiJYCFQrAGgoddXzxEg"

Specifically made for the 5 cylinder and V6.

Thanks

[BaywoodBill]

I know nothing but I nevertheless have some thoughts.


There would be a slight engine drag when you weren't using any power from the thing.

Will the output fluctuate too much to be a reliable power source for the A/C? That is, I know you would have an intermediary device convert the output voltage to the A/C requirements but when the rpm of the engine is too low for adequate output?

Wouldn't this require an additional pulley to be added to the engine?

Maybe if you hooked a generator onto your van you would have a better source of electricity?

[urbanbye]

Baywood:

Thanks for the response.

I already have a 2.5Kw Onan generator. I just don't like running it while driving. It's noisy and illegal in some states to operate propane when driving. Expensive too.

It looks like the kit uses the secondary pulley off the engine and a second alternator is installed. Yes, I have concerns about rpm vs. output. I suppose it could be tied into the auxillary battery for stabilizing the output.

I'm not sure that the HP needed when not in use would be very significant. At least not any more than the pulley for the regular AC compressor, that runs off the regular serpentine belt takes.

I've also heard that the bracket for this second belt can fail when used with a secondary compressor. Not what I am doing, but still a concern.

Arthur

[BaywoodBill]

I already have a 2.5Kw Onan generator. I just don't like running it while driving. It's noisy and illegal in some states to operate propane when driving. Expensive too.

It looks like the kit uses the secondary pulley off the engine and a second alternator is installed. Yes, I have concerns about rpm vs. output. I suppose it could be tied into the auxillary battery for stabilizing the output.

I'm not sure that the HP needed when not in use would be very significant. At least not any more than the pulley for the regular AC compressor, that runs off the regular serpentine belt takes.

I've also heard that the bracket for this second belt can fail when used with a secondary compressor. Not what I am doing, but still a concern.

Arthur

Well, I was figuring you were wanting to run the A/C for keeping cargo cold cause I couldn't think why you wanted to run it while driving. We've found that the regular dash A/C does the job. Even when we have passengers in the rear (they have to crack open the rear windows to get the flow through but when they do that then the A/C does the job).

As for running the gen while driving, I can't imagine that the cost of running the gen exceeds the cost of buying this other alternator and attachments plus the reduced economy while using it.

[urbanbye]

Bill:

Thanks for the input. My dashboard AC works fine. I'm freezing in front and the kids in the back are still hot. Maybe I just need to circulate the air better. I guess it's an idea worth pursuing.

Arthur

[sikwan]

Urbanbye...what kind of Sprinter are you running? RV or passenger?

[urbanbye]

Sikwan:

Im running a 2006 Chassis, 2.7 Liter, 22' LWB Great West RV, Elite Legend, with all the normal goodies. 2.5 Onan LP generator, 200 or 250 amp stock generator, 12V converter, auxillary battery (no inverter yet), black and grey tank, bathroom, stove, 3 way fridge, king bed, TV, stereo.

Had the grand kids in back sofa in Florida. They wanted to watch TV (In Motion satellite) and were scalding hot in back. I ran the LP generator the whole time to give them rooftop AC and TV. The front dash AC just could not cut it. It was way too noisy with the generator running. It sounded like I had a lawnmower in the back of my RV. Got funny looks from other drivers too.

I know I can get a converter and run a TV, but how can I get AC in the back while running down the road on a hot summer day?

Thanks for any advice you can offer.

Arthur

[sikwan]

You're right Arthur, I think what you have linked would probably be your best bet to run a roof top A/C. It's probably going to cost a huge sum of money though.

Maybe you can cool the living space prior to your departure, that way the front a/c doesn't have to struggle as much to keep the back cool. Not as convenient, but winter is almost here.

Or how about these 12V coolers...

http://www.swampy.net/12vcombo.html

Not as slick as the one your linked, but definitely cheaper.

[urbanbye]

Sikwan:

Thanks for the information. I was not aware of this product. Sounds interesting, especially since I could also use it at night with the generator off. I'll try one out

Arthur

[efxjim]

I have the 5kw generator and it will run the A/c (I converted a 10,000 btu split A/C unit). The only negative is running the vehicle A/C at max (load on alternator and compressor) plus the load of the generator running the 120v A/c unit the engine will drop to about 400rpm as you come to a light before regaining normal idle speed. This will cause the generator to momentarily shed its load. Then the 120v A/C unit has to wait 3-4 min before the compressor restarts. If your trips have long stretches without stop or you are stationary with high idle (.6gpm) it works well.

[urbanbye]

efxjim:

Thanks for the reply.

Are you running the rooftop air on a supplemental alternator or is the stock alternator replaced? Is your connection a straight up connection to the rooftop unit only or do you have a battery in the loop?

Arthur

[efxjim]

Stock 200A alternator for 12V system, 3AGM batts for 3KW inverter. Separate vehicle power 5KW 120v generator like in earlier post. I can run 120v A/C from either inverter (about 1 hour if van off) or Generator.

[efxjim]

"Rooftop unit" is actually mounted under van with other part of split unit mounted in overhead cabinet.

[windsprinter]

Sikwan:

Thanks for the information. I was not aware of this product. Sounds interesting, especially since I could also use it at night with the generator off. I'll try one out

Arthur

Let us know if you try one of these. They look perfect for running of the auxiliary battery during the day or at night; just what my wife wants if dogs are to be left in crates during dogshows etc (or me for camping, don't really want a rooftop unit if I can help it)