First and foremost, lets stay cool - Air Condition

[ZacharyDash]

Hello Skoolie Family,

I recently bought a Chevy P-30 Shuttle Bus and am in the process of removing the seats. I simply want to get one thing accomplished this month so I can live in it, so any help would be appreciated!

The one thing I need to get this project started... is Air Conditioning. In Texas, we have 11 months of summer and one month of a lousy winter. I have searched and searched Skoolie.Net for tips and tutorials for getting electricity, but none of it is sinking into my brain. I will continue to do the proper research, but if you could point me in the right direction for setting up and Air Condition unit to run without the bus running, I would appreciate it. I plan on having the ac running 16 hours at a time.

Currently, my bus has front and back AC pre-installed.

From the little I have gathered, I will need three things. AC/DC Power, and an Inverted. Is this correct or am I completely off? I do not mind paying an initial investment to power this bus with the proper electricity, I just need a little help getting started =]

 

[Ponyracer-SKO]

Will be doing the same, from my research your either going to need shore power or a generator. No way a batt bank/solar can keep up with the draw from ac units.

 

[lornaschinske]

Shore power is needed. The only other thing that will keep up is a generator. Minimum size to run an A/C unit (single roof top RV type) is 3K. Bigger generator is better as you probably will evenutally have other things that require shore type power and sizing your generator for half loads will be kinder to your generator and it's fuel consumption.

 

[lornaschinske]

You might want to look into the units you already have. If they operate like the one we had on the old Eagle did, you may be able to use them. The big OTR air condioner (A/C) on our Eagle ran on AC voltage not DC voltage. There was a INVERTER (DC into AC) box dedicated to just the A/C unit. If you are running a generator that puts out AC voltage (normal) then you will just have to figure out the wiring to hook up the A/C to the AC voltage. I suggest an idiot proof plug system (plug into the vehicle AC - inverter OR plug into shore/generator AC). Two air units may require that you wire up your bus for 50 amp shore power.

 

[r_w]

Those look like engine-run AC. The compressor is on the engine just like a car (but about 10 times bigger) if so.

There are ways to make them work from a small pony engine, but the cheap answer is to just add a small AC for being parked.

It is possible to run AC from solar and battery, but is expensive. You can run an efficient AC from a small generator or shore power.

For a bus that size, you should be able to get away with a 8-12k BTU unit if you are in the shade or in the evening, that can run on a 15 amp (normal outlet) or the tiny generators. You may need more if parked in the sun during the day.

My plan (to do it cheap but not need RV plugs)--I will have a minispit AC unit (more efficient than window AC's) that I can run from inverter or genny that is the "all the time" unit plus a small window-shaker as an auxiliary when it is really hot. The plan is to have enough solar to run the minisplit all the time and maybe even both during the peak of the day.

 

[ol trunt]

r-w, I've tried to make that solar/inverter/ac thing make sense but have had no luck. What have you got calc'd out? Thanks

 

[r_w]

Best calcs I have found are here: http://www.hotspotenergy.com/DC-air-con ... ystems.php

The problem with their system is it is 48v (makes sense for a house). I want to stay 12v so I can charge from the engine easy and make all the other stuff simple. But the calculations are very helpful and I can account for the extra inverter losses easy enough.

I will probably go with a 120v mini spit like this: http://www.highseer.com/19-seer-inverte ... 12am9.html
That one is the biggest that will run from 120 that I can find. It will run from a Honda EU2000 or a good inverter. Initially I will build the house battery banks up and charge from the engine. That will get me a few hours of AC after the engine is off so I can sleep.

No matter how I slice it, AC is expensive (maybe more than the bus). I am looking at 5-10K to get the bus off-grid AC. But at 10K you are off-grid for everything.

 

[bapos]

I have kicked around the mini split idea and really want to have someone try it. I am really curious as how better or worse they are from a regular rv ac unit.

 

[ol trunt]

Hey bapos, It seems the mini splits work just fine overall and they do allow for max space utilization. They are frequently used on the "big boys" coaches . I have read over and over on the coach forums that there is a problem with the copper coolant lines cracking from vibration--both of the bus body and the pulsing of the high pressure coolant. Maybe the lines could be substituted with rubber automotive lines to overcome this problem. That'd cost some bucks though. Jack

 

[bapos]

Yeah I could see that. I think if you had the liquid line encased in armor flex (the rubber type) and then encase the suction and liquid line in another wrap of it maybe it wouldn't vibrate so bad. i would think the line set would not be very long though?

I am a HVAC tech and have more experience with split systems in residential so I am really wanting to put one in the house but would also like one for my bus. I am not sure how the 120v units work but I know the 230v models don't mess around. If I have a bitchin genny to put out 230v I would consider it but Id really like to see someone pull the trigger on it.

I saw a small casita travel trailer had one in it but it was only used when parked and ran off a honda generator.

I think the car ac line would be good but not sure how you would check your super heat and sub cool since you would have to copper to get a temp for measuring levels in it?

 

[r_w]

You should be able to read the temps on the fittings, no?

I think you could use automotive lines and/or steel lines, or better grade copper. The right answer probably depends on the distance between the units.

Biggest problem I see is where to mount the "outdoor" unit. They seem to need premium space. My initial guess is right behind the driver above the wheel well boxed in for a bulkhead mounted indoor unit. Rear wheel well for a rear unit, part of a mechanical room. They are too big to hang on the rear bumper and still use the rear door or mount below deck.

I wish they made inverter style window units.

 

[bapos]

I have help relocate one in a wine cellar for work. They are not super common but are getting that way.

I would think on the fitting but I am not 100% sure. I know the clamps I use are pretty wide for copper.

I would say it would need the same amount of room as a generator…. rv type. I know its always best to have the line set as short as possible on any type of mechanical system.

THe one I saw on that casita was mounted on the triangle of the trailer so they are not huge I would be more concerned about making sure it had plenty of air flow to get rid of that heat. If you get the heat pump version it would need to be open to the air more so than straight ac. I was thinking on a belly storage box but that would only have the condenser open to one side.

 

[bapos]

 

[r_w]

The total cubic feet needed is about the same as a generator, it is just that the size is too tall to fit completely below deck of a skoolie. It would fit fine on many RV's and coaches. The vibration and shock is something that needs more thought.