[Gem930]

Well, after dumping countless dollar$ in my coach (639) ... brake pads /rotors/ calipers/ bearings / suspension / complete Hydro hot rebuild / new blinds / 3200 watts of solar / 1200 amp hours of lithium batteries / 5000-watt 48v Victron inverter / new Gerard awning /etc..... I have decided to continue to spend my kid's inheritance by replacing one or both of my SCS AC units with mini split(s).  I have installed a few and I feel comfortable going down this road.  With the solar/ battery system I have, I'd like to be able to run at least one unit off it, which limits me to 120v 12000 btu units.  Initially I was hoping to gain back some storage space, but it appears the condensing units are just large enough that will not be possible.  I have moved my TV to a televator (sp?) in a fireplace cabinet across from the couch in the salon, so that is where I envisioned installing the inside evaporator unit.

  BUT....... then I came across the invertor style "U" shaped AC units.  Initially I dismissed them but the more I think about it, I am wondering if I might be doable.  The entire unit would fit in the area where the TV was.  I would obviously need to install a compartment to speperat the two halves and some ducting to get the air into and back out of the condenser, which would necessitate some custom ducting and grills on the sides and maybe the front of the coach.  Also need and option to deal with the condensate, but these do not seem any harder than installing both the evap and cond and fishing the line-set from one to the other.  The obvious benefit would be reclaiming the storage.  One issue may be that it will likely be louder than a true mini split (though, according to YouTube videos, still much quieter than a standard RV roof unit.  I am thinking a thick foam wall where the window normally would be with a tinted black plexi sheet to separate the hot side from the cold side and help keep the noise down.   Thoughts???? Check out U shaped ac units on amazon and Youtube.

[Gnawrocki1]

Since you have already gone with 48v, have you thought about replacing one of your roof vents with a 48vdc roof ac unit.

That way you run the ac through your batteries without using up your inverter capacity or generating all that inverter heat.

It could be an additional ac to your existing SCS capacity since you seem to imply that your existing ac units are still functional.

[Gem930]

I have considered it but not sure I will have the space as my Solar takes up most of my rooftop. Additionally, I really do not have any feedback on how well they work or how noisy they are. Do you have any information on the efficiency or noise of these units?

[Jack Houpe]

Gregg being comfortable to me is #1, its work but well worth it. You have a 4 slide coach so if it were me I would put everything you can in the original bays where the current units are. Slides really are inefficient for heat and cooling. In our 99 newell there is zero insulation in the floor of the front slide and very little in the walls on any of them.

[Gem930]

Jack, I’m with you on being comfortable!!!! My coach is actually only a three slide, but you are correct. Not very well insulated. My ACs are both working fine although one compressor seems to be pulling more amperage than the other three. My main reason for doing this was to try and get some more storage space, so doing ACs on the roof would certainly accomplish that. I have 300 amp hours at 48 V and 3200 watts of solar so idea of running the ac without being plugged in or running the generator (even if only for a few hours) is nice. I did do some research and there are some 48 V 13,000 BTU units that look pretty interesting (Countrymod) and I got up on top and I probably could work them around my Solar. Unfortunately, one of them would be in the rear bath which, while not ideal, would probably work OK as long as the door was open, they are inverter units and quiet, which was my other requirement. I think I can fit three units on the couch - one above the rear bath one in the middle at the kitchen area and one directly over the driver and passenger seat I would have to come up with some creative ducting for that one to go down and come out where the TV used to be mounted. Just wondering if three 13,000 BTU units would be enough to cool the coach.??? When Newell started putting roof ACs on their coaches are there three and if so, what size are they?

[Jack Houpe]

Gregg I purchased a 24k btu 24vdc split unit and it was 3 phase DC compressor and it was worthless. Not saying the one your speaking of is so do your research and look at reviews. The footprint on the roof of our 1999 was 24 inches between the stringers on the roof so keep that in mind. I think they rated most all of the standard compressor units between 12-15k btu but in my opinion they overrated them. (Coleman and Dometic)

[Gnawrocki1]

The roof units that I looked into a while back would replace one of the existing vents on my coach. It will not interfere with my solar panels.
I am thinking that I would 3d print a manifold to the internal unit so that I can duct it out in the hallway above the refrigerator vent holes. This would augment my fully functional SCS units to add cooling being that I am located in Phoenix, and you can never have enough cooling...

I dont know the noise of the units, but imagine it to be fairly unobtrusive.

[Richard]

This is my OPINION. It is not the only option. When I owned 512, with two SCS basement airs, I studied every mini install into a Newell I could find. I went into many of the coaches. Some of them worked well, some of them not so much. I did NOT do an install, so my comments can and should be interpreted as an “internet” expert.

My comments ONLY apply to coaches with SCS units. They do not apply to coaches with roof airs or Dometic split units. My recommended solution is NOT the most energy efficient, since I was not interested in off gridding for very long.

The best and easiest solution that I derived was to use 1 4k condenser unit mounted on the driver side bay coupled with a residential high CGM high static evap unit in the center. Fabricate custom duct work to utilize the existing air intake, and discharge into the existing ductwork for the rear and elephant trunks for the front. Utilize a manually adjustable damper to balance the front and rear air flow since only one air handler is in use. I would also recommend one additional elephant trunk into the front cabin tieing into the front dash air con.

You will find a 4k unit will NOT fit into the existing bay because of height. You will have to fabricate and weld in a 3 inch drop down to allow it to fit. After you remove the SCS you will understand it is not a hard thing to do. No danger of dragging since you are right behind the front tire. There are some that say you do not need 4k with mini efficiency. They do not live with my wife. I agree less capacity will work IF using interior cassettes.

Draw air in from the side and discharge under the coach.

You already have 220 voltage in the supply to the SCS.

The downside of this approach is single point failure. This is a way to use two condensers and two evaps in the same way. PM me if want more details.

Yes there are infinite options. The most energy efficient are the wall mounted cassettes. If your interior cabinetry and your interior decorator can live with that in the coach they cool for the least energy expenditure. My coach would not allow that. If you use wall mounted cassettes you may easily get by with less tonnage. Besides space and aesthetics, some areas may not be cooled as well as others.

Another option is to stash ducted units behind TVs, over cabinets, or in closets. Lots more work in making it fit and running line sets than the basement replacement

Obviously you can cut holes in the ceiling and mount any number of AC or DC units. Pulling wire into the ceiling will be a challenge.

I could go on about everything I considered in my above recommendation, but I will just mention a couple of fundamentals that must be considered with any retrofit.
Physics ——-cool air sinks warm air rises——put your AC discharge on floor level and live to reconsider it’s location
Aesthetics—-although we don’t often think about selling our baby, how will the change I made look
More physics. Coolest air you can get into the condenser unit makes it work better, hence my point don’t pull air off the hot pavement and generator cooling exhaust to route to the condenser.
More physics—the more air you move inside the more comfortable it will be. It doesn’t matter if the air is 33 degrees, if it is not moving the coach will not be comfortable

[Jack Houpe]

I was at my son's Newell yesterday and he keeps it set at 65 degrees, it was uncomfortably cold in there but he likes it that way. The outside temperature was in the mid-80s and humid. We did the conversion a few years back and it has been working flawlessly ever since. I have nothing against ducted units but they must be high-static (high-CFM airflow) as Richard stated. It is not an easy or quick job but it is worth the effort.

There has never been a single person in our Prevost or Newell who has not been impressed with the performance or the quiet nature of the system.

[Gem930]

My scs units are still working and most of the time they are sufficient. I should probably just leave things as they are run them until they blow themselves up!!!BUT …. That is not in my nature…. Based on my desire to utilize my large solar/ 48v battery system to help off set the $$$ when moochdocking at my kids house in California ($0.55 a kilowatt) and my even bigger desire to gain storage space I am seriously leaning toward 3 48v roof units. I’ve spent a lot of time on the roof with the tape measure and I think I can make this work. It appears that the countrymod 48 V unit has lots of good reviews. does anybody have any experience with this unit?