air conditioner and generator while traveling

Bobbo wrote:

JaxDad wrote:
The dash A/C on a Ford E series chassis is FAR more powerful than the rooftop unit is

This is absolute hogwash. There is no way a Ford E series chassis air conditioner has the cooling capability of a 13,500 btu roof air conditioner. That is absurd on the face of it.

No, you’re right it DOESN’T have the cooling capacity of a 13,500 BTU air conditioner. It has slightly more cooling capacity than FOUR of them would.

According to the service manual, the system takes 68 ounces of refrigerant, that’s 4.25 pounds.

Speaking of manuals, I was helping my buddies kid redo his A/C system recently in his Honda Accord. According to the Honda manual the system has a 16,000 BTU capacity.

Bobbo wrote:
This is absolute hogwash. There is no way a Ford E series chassis air conditioner has the cooling capability of a 13,500 btu roof air conditioner. That is absurd on the face of it.

Below are just four (4) links talking about the BTU cooling capacity of vehicle cab air conditioning systems ... and a search yields many more articles that reinforce what these links are saying.

The information in the links confirms what I have experienced ... our motorhome's (and our sedan's and our pickup truck's) cab air conditioning systems have terrific BTU capacities (well beyond 13.5K BTUs at typical traveling engine RPMs). Our motorhome's E450 cab air conditioning system is easily capable of cooling our entire Class C when traveling at highway speeds in scorching temperatures - especially using it's MAX AC setting such that the interior air is only recirculated - instead of the cab air conditioning system having to constantly cool new hot air coming in from the outside.

https://www.google.com/search?lr=&hl=en&as_qdr=all&q=cooling+capacity+of+car+ac&sa=X&ved=0ahUKEwi6p_Hs7IDcAhViylQKHQCZBHIQ1QIItQEoAg&biw=1536&bih=737

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3023729/Average_auto_A/C_BTU_rating?

https://autoacforum.com/messageview.cfm?catid=2&threadid=20990

https://www.quora.com/What-is-the-typical-nominal-cooling-capacity-kw-or-BTU-h-of-a-car-air-conditioning-device

JaxDad wrote:
The dash A/C on a Ford E series chassis is FAR more powerful than the rooftop unit is

This is absolute hogwash. There is no way a Ford E series chassis air conditioner has the cooling capability of a 13,500 btu roof air conditioner. That is absurd on the face of it.

A friend of mine sold their motorhome because she said it was too hot inside while they were traveling. I said why didn't you run your generator and air, LOL. I think a lot of people are afraid to put hours on their generator, don't know why. We run both 75% of the time on the road.

At home we run our generator once a month for 20 minutes on a full load, same with our Honda 2000.

JaxDad wrote:
It’s easy to overcome this though, set the dash A/C to point straight down the back, NOT on Max A/C, and open the rearmost roof vent (bathroom in my case) wide open, ......

A couple of notes about that:

I would caution against opening a roof vent all the way unless you have a hood over it. The flapping in the wind might tear it up.
If you are going more than a few miles, you don't NEED it open all the way.

You might find that it works even better on MAX or RECIRC, where about 20% of the air still comes in from outside. That is with the vent open 1/4 to 1/2.

Good principle. If you haven't done this before, experiment a little.

The dash air/con will certainly be more efficient but likely won't cool the main cabin.

As long as the dash unit is keeping you comfortable while driving, that's the way to go.

MrWizard wrote:
the dash A/C can't do enough to cool the whole RV,
hang a curtain and you can keep the cab cool, but the house might be HOT when you stop.

Having a LOT of experience at this I respectfully disagree.

The dash A/C on a Ford E series chassis is FAR more powerful than the rooftop unit is, it’s serious shortcoming though is its fan. It’s easy to overcome this though, set the dash A/C to point straight down the back, NOT on Max A/C, and open the rearmost roof vent (bathroom in my case) wide open, the vacuum created will pull the hot air off the ceiling and pull cool air back there to replace it.

I did this just yesterday while using my C as a base camp while SeaDoo’ing with some friends. The dash A/C alone was able to keep the entire coach around 77 F while it was 95 F, 110 F with the humidex, outside.

I didn’t start the genset till I got to the lake and parked, then shut it off for the trip home.

We routinely used house air along with dash air in our Class A gasser, and now do the same with our Class A pusher. Don't notice a lot of difference in fuel useage.

GM

the dash A/C can't do enough to cool the whole RV,
hang a curtain and you can keep the cab cool, but the house might be HOT when you stop

the roof top A/C can cool the house section and ease the cooling load of the dash
A/C taking some of that load off the engine, and reducing engine heat

the dash A/C does increase engine load and engine heat

running the genny and roof top A/C is a common thing and IMO a good idea

My Sprinter based Winnebago View has a privacy curtain that hangs across the back of the cab, even with the back of the bunk bed. I am usually by myself, and when running the dash A/C I keep the curtain down and it holds the cold air in the cab.

I do however, frequently find myself driving with the window open and the A/C off, to help keep the engine cooler. With the A/C on the engine is heating up much quicker and the viscous clutch fan is having to cycle much more frequently. Being a diesel, it has not only the A/C condenser in front of the radiator, but also has an intercooler, lot of heat going on up there.

I made a trip out to the Black Hills in August last year, and found myself only running the A/C once or twice the entire trip.

Charles