Looking to upgrade our existing skoolie. One of the many items we want is ac we can use while going down the road. If we get an activity bus with ac, can you adapt it to run off the engine, and also run off a generator/shore power when parked?

I doubt it would be possible to have both. For me my bus came with two a/c units in it. I found out they were two separate systems with each having its own compressor lines and condensers. One that could run off of shore power would have a 120v or 240v powered compressor. I know of no way to run both. We opted to remove our bus powered system. Its was heavy and very inefficient and had leaks. Each one held close to $200 of Freon. I picked up a generator, which we wanted anyway and a portable heat pump system. We will run the generator as we ride if we need the ac.

__________________
Not all those who wander are lost.

It is possible, but not cheap. Cheapest way is going with generator.

If money wasn't a problem, an example setup would be to power the a/c off of a true sine type inverter. While on the road, have a high powered alternator charging the house batteries the inverter runs off of. You would be looking at >$10,000

Yeah, I'm struggling with the same thing. In my research, there are a couple options for coach air that can run while parked:
1. Those with pony motors (usually small kubota or yanmar diesels) running the compressors. Can add an alternator to charge house batteries and run the bus off inverter 24/7. They can run the AC all the time as long as you don't have a NO GENERATOR rule in camp. No way to run these from shore power. They probably weigh 1,000 lbs all-in. The engines are built to last, but the freon lines are prone to leaking and a nightmare to fix.

2. Those that are all electric and normally run from 500 amp engine alternators. Too new and expensive to be an option on any skoolie I can afford, so I haven't looked further than that.

Best option I have found for lots of BTU/dollar in a "professional" looking install is a 240v generator and a multi-room mini split heat pump. They can also run from a 50 amp RV hookup (but not a 30). Big problem is mounting the outdoor unit somewhere. I would probably mount it inside in the back of a closet or cabinet and vent. Similar to this guy: http://overthetopcargotrailer.blogspot. ... egree.html

If you need to limit yourself to 120v only (like I do) then you spend more money on separate mini splits (and find space to hide multiple compressor units) or go to windowshakers and figure out hard start capacitors to get them to run on extension cords and small inverters or generators.

After the research, I see why buses with air always bring so much more. There isn't a cheap solution to cover everything.

You might look into some of the APU units that the large trucks use they are stingy on fuel and
produce both heat and cool with rather low noise levels. You just need about a 30" length of open
frame rail to mount it. Trucks are using them more and more since some states don't allow
idling the truck for extended periods.

Dometic has a good overview of truck option on their website, including planning for 100% battery options. But their BIG AC is only 10,000 BTU. The info is good, however.

RED DOT makes products for adding a compressor and system to any vehicle. but not engine/electric driven. you can add coach air for running down the road but the best bet would be a 120v A/C system, Mini Split run off a generator. Your proubly not looking to drive your bus 365/days a year so just pickup a 120v A/C system weather mini split (most efficient they make 27seer units that draw as little as 350 watts for 10,000btu. ) or roof airs but are very inefficient ,or the window type. portable A/C is expensive and suck electric.stay away from portable units.

__________________
"Thunder Bird"