Mini Split AC Installation

[david.dgeorge07]

Originally Posted by TJones

Thanks for the info everyone. I think that a mini split with an inverter compressor set up for 12v or 24v would be more efficient than using an inverter to run a conventional 110v ac unit. From what I was reading the 110v ac unit first coverts from ac to dc and then switches the dc to create the frequency to drive the motor. If using a battery bank using dc would eliminate the inefficencies of inverting and then rectifying the currant.

Ted

I wonder what the voltage drop would be with that many amps in 12 volts? Cabling could be a consideration. A 12k btu mini split will draw between 100 and 150 amps at 12 V.

[TJones]

Originally Posted by david.dgeorge07

I wonder what the voltage drop would be with that many amps in 12 volts? Cabling could be a consideration. A 12k btu mini split will draw between 100 and 150 amps at 12 V.

Thats where a 24v would be more practical.

Ted

[Juicifer]

How does everybody feel about mounting the condenser on the outside rear of the bus? It just feels so easy compared to mounting underneath and routing linesets through the interior or all over the place underneath the bus.

Check out what The Adventure or Bust did:

For my rear unit, I'm really about to pull the trigger and do this as well. The only drawback is I'll have to mount some new running lights. I also left my solar racks long like they did which would do a bit to protect the unit from tree limbs. My rear deck might even be able to go over the unit a bit and protect it a little bit from the sun. Sorry to hijack your thread Rick.

[Ninjakitty]

I think that as long as you have help to get it you there, it's a good location. I have seen a number of busses that have the condenser on a roof deck or roof mounted.

[cadillackid]

I domnt like a minisplit condensor on the roof.. these units arent made to have 70 MPH wind-driven rain blasted at them constantly.. they just arent sealed upo that well inside.. the high voltage electrical connectrions are made inside the outdoor cabinet but arent in a water-proof boix inside that cabinet.. they dont need to be for a normal residential installation.. the circuit boards are enclosed in a box but not sealed..



under a bus they are somewhat shielded at the top where the most vulnerability is..

on the back of a bux they are also shielded more than on top..



I havent heard of issues when runningthem while drivng other than if a wierd wind current hits one it will momentarily stop the outdoor fan and cause the unit to error out and restart... but thats rare... they arent however designed to cool you when driving on the road.. the BTU isnt high enough to make you nice N cool against hot summer sun and the big windshield.. if a front engine bus you have engine heat to contend with too.. you'll sweat in the seat in hot weather.. the original A/C if your bus has it is the best way to stay cool while driving... dont rip it out..
-Christopher

[T-Bolt]

I had just decided to remove my factory AC then Christopher pipes in. Mine does not work and I'm afraid to find out what the cost would be to fix it.

[Juicifer]

Okay so nobody asked for it here, but I see people ask all of the time: "How did you mount your outdoor unit?" And since I've been trying to answer that for myself for too long, I'm dumping all of the mini split mounting photos I've collected for you all to ponder like it or not.

[cadillackid]

Originally Posted by T-Bolt

I had just decided to remove my factory AC then Christopher pipes in. Mine does not work and I'm afraid to find out what the cost would be to fix it.

not having any idea of what your factory system is.. but I can guess that being a 2003 bus, its likely a dual compressor. (could bne a single coach compressor or pony engine).. R-134a system like is in a car..



if I knew more about your system i could advise you easier on what may be wrong..



many of these busses have 2 full systems in them.. removing one of them (the rear) to save space is often advantageous.. whiole keeping the front one for nioce A/C when driving.. in an insulated bus. one system will keep the driver and front area Nice N cool on the road..



-Christopher

[T-Bolt]

Mine is a Carrier dual system. Removing one system is an option that I hadn't thought of.

[pengyou]

Are there any of the splits systems that have dual inside parts? It would sure be easier to make a comfortable environment if you have the dual innards, rather than having to blow cool air from the front of a 40' bus all the way to the back.

[ermracing]

I know there are larger household units that have multiple head units per single outside compressors. Not sure if any of the 110v systems do.

[david.dgeorge07]

Originally Posted by pengyou

Are there any of the splits systems that have dual inside parts? It would sure be easier to make a comfortable environment if you have the dual innards, rather than having to blow cool air from the front of a 40' bus all the way to the back.

They exist for sure, but there are advantages to having two. For one, if one has trouble, you have another working unit. Also you can better limit your power use in a situation with little power available. And as weird as it sounds you can run them in opposite modes or with one in dehumidifier mode if you have two units. Not possible with a dual headed one.

I think the kicker is needing 220v though. I think, but am not sure, that they all require it.

[cadillackid]

all of the units over 12-15k BTU are 220 volt.. there are many 12k btu units that are 110 volt.. i have 3 in my house.. 2 are 12k and one is 18k. and the 18 requires 220..



i havent yet seen a dual zone unit (1 outdoor with 2 indoor) that will run on 110 volt..

the compressor unit on my 18k unit is much larger than thaty of the 12k.. esp in height. an uinder-bus mounting of an 18k or larger unit seems like you would be hanging down quite far compared to the 12k btu that most here are using.

-Chris

[ComfortEagle]

Originally Posted by ComfortEagle

I am starting a (another...) new thread to document the the install of our mini split...

"Document the install" indeed... You all are like a dog with a bone...

[Alan N]

Does anyone, (hey Christopher!) know if it would be possible to operate the outside unit mounted horizontally? Perhaps the compressor would need to be re oriented?
Laying the outside unit on its side would greatly increase the potential mounting options.

[david.dgeorge07]

Originally Posted by Alan N

Does anyone, (hey Christopher!) know if it would be possible to operate the outside unit mounted horizontally? Perhaps the compressor would need to be re oriented?

Laying the outside unit on its side would greatly increase the potential mounting options.

Not even supposed to be laid on their side temporarily. Maybe if you rework like you say...

[rydawg3000]

Originally Posted by david.dgeorge07

Attachment 27587

Attachment 27588

Stupid amount of work, nice once done.

David, nice work!!!
This looks spot on to what I was trying to envision in my head. Could I trouble you for some more contact info so I could discuss your undermounting a little more in-depth?
Thank you so much at the very least for the pictures. They are very helpful.

-Ryan
@phoebusthebus