bus ac units

[thesaltydog24]

Hopefully someone can answer this for me. I was wondering if the AC units that come in some skoolies can be operated when the bus engine isn't running. I'm not sure how these ac units work but I wouldn't think they need the bus to be running if power is provided to them by either shore or genny. second question if this is possible, are the ac units that come in some buss's worth it? do they put out enough cold air to justify keeping them, or should I scrap that idea and go with a roof top AC.

Thanks
Chris

[kamoo]

On the schol busses they have automotive AC compressors that are run off of the engine so you would need to have the engine running. Personally, I have thought that it would be nice to have the coach AC for going down the road and the rooftop for when you are parked. Then you wouldnt need to run the genny while traveling.

[Seeria]

You can check into alternatives like marine or rv AC units but if you're not willing to expend that huge amount of money, I suggest looking up (google) using small home units. Usually run around $100.

[thesaltydog24]

I don't mind spending $ on an RV AC unit. I see used ones on craigslist usually between free and $100. just saw one on there last night for $50. its just why spend $ if I can just use the bus AC but it doesn't look like I could unless I do some drastic changes to the system. I can use the Bus AC while going down the road then switch over to RV one once parked. I kinda like that Idea.

Another question. I hear all this talk mostly from RV owners that they have to have the RV level for the fridge to work. Is this a must or does this really not matter as long as its close to level. What do you do if your going down the road? not run your fridge?
Chris

[jam0o0]

you could get a small gas engine and mount the bus a/c compressor to that. then you don't have to run the bus engine to run that a/c. and you don't have to deal with the huge losses from converting the energy 5 times like when you run a home unit from a generator.

as for the fridge thing. level is a relative term. if you can stand or sleep comfortably then you shouldn't worry about the fridge.the propane ones seem to be the most finicky.

[greatidea]

How about this air conditioning alternative? It will use much, much less energy but not be as effective. I have seen (on the Internet) units where the container holding the water is covered and it is kept partially filled with ice:

http://www.youtube.com/watch?v=zR9CA8lJGvs

[cschlessman]

Chris
Arer you talking about the ac that comes out of the dash or a remote mounted unit in the rear of the bus? While highly rare the remote mount units are usually ran from the batteries with a key on circuit some are made by Carrier and can be adapted to work off gen or shore power. To go any further let me know which type you are refering to.
Chuck

[Seroflorus]

Originally Posted by cschlessman

Chris
Arer you talking about the ac that comes out of the dash or a remote mounted unit in the rear of the bus? While highly rare the remote mount units are usually ran from the batteries with a key on circuit some are made by Carrier and can be adapted to work off gen or shore power. To go any further let me know which type you are refering to.
Chuck

i realize this is an ooollld thread but I'd love to know more about re-wiring a remote mount A/C...TC2000 with one huge part under the carriage and two gigantic cold blowers inside...looking to justify them b/c of their size.

thanks.

[cowlitzcoach]

Every coach A/C unit I have ever seen had an engine driven compressor to make the A/C system work.

IMHO, if you have one in your bus it would be best to scrap it all out rather than try to make it work. The cost of maintaining coach A/C is cost prohibitive due in large part to the size of the system.

Most automotive A/C systems use less than 3 lbs. of Freon. Most coach systems use more than 10 lbs.--it take a lot to fill up the lines from the compressor to the evaporators to the condenser and back again. Some coach systems use in excess of 30 lbs. of Freon.

Because the lines are so long and there are so many joints in the system it is virtually impossible to seal the system up 100% over any period of time. Every time you go down the road you shake, rattle, and roll the system. All that shaking, rattling, and rolling contribute to joints loosening up and leaking.

The best solution would be to get some roof top A/C units and install an auxiliary alternator to power up a house battery bank/invertor to run the A/C while going down the road.

Whatever you do, make sure you size the unit appropriately. A too large unit running on low will cool things much better than a "just right sized" unit that has to run on high when things get hot outside.


I just spent a long weekend in our 1981 Avion 34V travel trailer. With outside ambient temps of over 105* our 13,500 BTU roof top struggled to maintain inside temps that were 20* cooler than outside. It takes a lot of BTU cooling to cool something that is more than 30' long inside.

[mjh2901]

One thing to think about is you setup. If place a long thick drape like curtains accross the middle of your bus when driving you can change the space that needs cooling when on the road, or off. Cut the bus down to 15 feet of space that needs cooling vs 40 feet and you ac will go further.