[Archived]

Per,

I cannot tell you how to run your A/C units from inverters, but at our last seminar the folks from Inverter Services supported what I have been suggesting for years. If you have to run the house A/C units while driving, save the inverters by using the generator when you want to run them. In fact, turn on all the systems and enjoy all the features of the coach while running down the road.

A lot of older coaches are running with some very strong inverters that are ideal for runing A/C units because they can carry a large load, but those inverters are no longer available and there is nothing out there to replace them. The specs of replacements may read as though there are alternatives, but in fact they said there are not any that can handle the loads imposed by the A/C units. They were very strong in insisting that running the generator was the best option. That applies to all coaches, regardless of the converter.

[AL]

Per,

You have to have the dash A/C buttons in the on position. Mine will only run the default Salon and Bedroom off the inverters unless I use another button on the driver dash side marked A/C Select. That A/C Select is designed to allow different choices in the default in case I want the Galley A/C instead. I’ve not used that button, so maybe Bernie will jump in here.

[Karl]

The A/C Select button will run the Salon and Galley airs off the inverters. You need to tell us more of what it’s doing, can you run the front or rear unit alone?

Later

bv

[Tim]

I can only run the salon & bedroom off the inverters, which I’ve down several times going down the road. No issues getting them to work.

[Archived]

As Bernie & Tom stated,

I can run the salon & bedroom ACs going down the road.

I I tried the AC select to specially use the Aux air and it didn’t work so Bernie’s correct that it will only engage the galley.

Tom,

If You’re dry camping for a few hours and the coach is off and you are just running on inverters, how do you turn the Dash AC on? Mine only turns on when the ignition switch & key are turned on.

[Bernie]

Jon, I hear you. We are used to running the generator for AC in our old coach, so that’s our plan if we don’t run OTR AC. Plan on alternating the two system, so both get exercise. Nevertheless, I would like to have the capability of running off the inverter.

Tom, I’ve tried both the dash switches and the driver’s switches with and without the AC select button on. No dice. When I turn on the salon AC button (no shore or generator), the lighted display (showing temp) on the SMX control goes out, and no AC.

It’s not one of the things I worry too much about, since, like Jon says, the generator needs exercise.

Nice to have the mileage display as well as the other info on the multi display! Just got home from Ruidoso. Reset the mileage indicator at the campground, and by the time we got to Roswell, we had 11 MPG average indicated. So I guess when we sell the coach, we can advertise “up to 11 MPG!” like some car dealers do. By the time we got home some 600 miles from Ruidoso in heavy wind, the average waas down to 7.3, not too bad!

[Jim]

Per

Have you tried to turn on the A/C at the SMX control after it goes dark when the dash button is pushed?

How old are your house batteries?

Later

bv

[Per]

My message center also says 7.2

It is lying. Over the last 9200 miles it is 6.4 based on fuel taken on divided into miles traveled. For the last 3000 miles it is 6.5, but the display says 7.2. The increase over the last 3000 miles I think is due to travel over flatter terrain than normal, and the fact half of it I was not towing.

If the message center is what you guys are using to plan fuel stops, be careful.

[Wilbur]

Per,

Chris says the following,

On the three Marathon coaches we have owned, XLV #740, H3-45 #586, and now XL 40″#593, all three with cruise airs we do as follows

1.) Press galley and bedroom button on dash or side dash, wherever they are

2.) Go to Galley and bedroom SMX pads and set to A/C.

Most Marathons are set up this way, unless a customer chooses differently You can then Press your A/C Select, then press salon SMX for A/C and the bedroom one goes off and salon comes on. If one of your SMX pads are going dark after you press dash buttons for that location, programming isn’t set up for inverter powering of that cruise air.

While powered on batteries, set all your SMX pad to A/C after pushing dash buttons for Salon A/C, Galley A/C, Bedroom A/C, and if you have a fourth which could be called “cockpit”. Check to see which SMX pads have gone dark. Those that are lit with front dash buttons on, are the cruise airs that operate from inverter power

Then go up front to dash buttons and press your A/C Select, go look to see which previously lit SMX pad is dark, and a new location is lit

[Archived]

Bernie,

Our house batteries are 3 months old.

Jim, I’ll try next time I fire up the coach. Like I mentioned, it’s not a do or die, but would be nice if I could at least get it working. Right now it’s time to mow the lawn and clean the pool. A man’s work is never done!

[Fred F.]

FYI – The later 4th A/C is labeled Aux A/C, is not on the inverter circuit and does not have a heat pump.

[Joe]

Jim,

I tried it out as you suggested, and indeed the galley and bedroom AC came on. However, the galley AC shut off after about 30 seconds–the inverter shut down. I had one inverter replaced (rebuilt Trace), but inverters are still giving me problems.

The only AC I would be interested in running at low AC loads, would be the cockpit AC, and like Tom said, you can’t run it on the inverters anyway. So I guess running ACs on inverters is pretty much a worthless feature for us. We’ll stay with running the generator when we want to use the CruiseAirs.

I believe you all had a person from the Inverter Service Center at the last seminar at Jeff’s. Would like to explore possibility of replacing one or both inverters with pure sine inverters–I really don’t care about losing the AC on inverters feature. Could I get the name of the representative that came to Jeff’s?

[Dick]

Per,

Switch to the Salon A/C from the Galley and see if that works for you.

[Corey]

Per,

The folks from Inverter Services should be contacted directly. I think they have a very strong affinity for the inverters you currently have in the context of their ability to work for your application. The inverter is very robust which makes it ideal for those times an owner may opt to run an A/C from an inverter. They made it clear there is currently no inverter available as good for your application because while the ratings of replacements appear equal they are not. Running an A/C on inverter is a substantial strain.

That perhaps is why they made it a point to recommend if an A/C is to be run it should be on generator or shore power.

However as you are aware some appliances now will not operate properly unless the inverter(s) are pure sine wave so if you opt to go that way they can likely make recommendations for replacements that are best suited for how you are going to use the coach and ease of making the switch.

[Raymond]

Thanks, Jon, I appreciate your input. With the issues we have with the inverter(s), I’m wondering if a pure sine inverter would be better, especially since we put a new refrigerator in the coach. I’ll chat with them shortly, and also see what Marathon says. Running the ACs on inverter is not a big deal like I mentioned, especially since the cockpit AC won’t work on the inverter, and that’s the one that does the best job of cooling the driver.