I has been done. Another Airstream owner outlined how to do it on airforums.com. I would get you the link but something seems to be wrong with that site right now.

Since BOTH of mine were 20 years old at the time of purchase and ratty looking a "Polar cub" was installed in the bedroom, Bath & restroom area which flat freezes me out.

Up front a "Coleman power saver" (13,500) was installed and both work together....
Power saver draws a dab less than 10 amps.
Polar cub draws a dab less than 7 amps.

Jim

You can make what we call a jump cord. In this instance it would consist of a 50 amp mail plug and wire, this goes into a 4 by 4 electrical box with cover. In there you are going to split the 220 volt 50 amp circuit in two. Coming out of that box will be one cord going to a 30 amp rv receptical that can be mounted in another 4 by 4 box, the other line from the 50 amp cord will go to a 20 amp receptical contained in another 4 by 4 box.

So here is how the wiring would work. You take one hot wire from the 50 amp plug and connect that to the 30 amp rv receptical, the other hot leg goes to the 20 amp receptical, the neutral wire from the 50 amp cord is connected to both recepitcals, the ground wire from the 50 amp plug will also go to both recepticals.

Now you plug your rig into the 30 amp recepitcal and then run a drop cord from the second AC unit to the 20 amp receptcal. Thus allowing you to run both AC units at one time. Thing is, you have to be in a sight with 50 amp service.. Otherwise you can plug into the 30 amp receptical at the campground and plug your second AC unit into the 20 amp receptical on the post, but the 30 amp and 20 recepticals must be on serperate lines in the camps electric box.

Remember, the jump cord does not have it's own fuse's or circuit breakers, you can add them it you like.  Otherwise the only circuit protection you have is the breaker in the box.  I would add in the circuit breakers myself.

There is also a device available that installs in the rig that runs each unit in cycles, the front runs for a bit and then the rear runs for a bit and it switch's back and forth.

Hope this helps.

Thanks for the detailed info!

I have akeen interest in the device you mentioned that cycles between the two A/C units.  Do you have any idea what it is colled, or where I can find more information about it?

The switching device used to be sold by camping world, I don't find it online and don't have a current cataloge, did not find it in my other RV cataloges either. Might not be available anylonger although I don't know why not. For the life of me I can not remembe the name of that thing!

Thanks for looking, my friend!

where would you make the connection for your second a/c?. Will it be also easier to make a new 50 amp power cord that can be parallel with the gen.since the gen is 50 amps all you need to do is make some kind of a switch.this case you dont have to change any of your breakers.Any electrical engineer out there that can check this out if its safe?

You can use a switch and relay, run the AC to the relay (Would have to be a double throw double pole relay) one set of wires to the fuse panel the other set to a cord that would plug into the jump cord. The easiest thing to do is just unhook the second AC from the fuse panel and connect those wires to a cord and then plug it into the jump cord.

When you start trying to hook all of this in with the generator is when it gets a little hairey, as you can develope grounding and neutral wire problems. That is an area I choose to stay out of. Much better to run the system independently.

You are delving into an area here where electrical engineers and the manufacturers are going to walk away from, they do not wish to take any liability for "home brew" equipment. We use a jump cord at work all the time as a way of getting the power we need for our equipment at various job sites, no one manufactuers one, you have to build it yourself and have the knowledge needed to safely operate it. Safety is also why we have ours circuit breaker protected.

I have a geneator on my 2004 Airstream and it will run both a/c units, however it does build up time on the generator. I went one summer not knowing there are 2 cbs on the generator and must be on to make both units run. Some Airstream were equipped with a 50 amp option. I checked with the factory in Jackson Center and it can be added for about $1700. This an also be done by other RV service people at less costs.

I think i ran across the switching device you referred to. Power Solutions www.psrv.net has one.  It looks like it would do the job.

The power solutions unit will work, but if I'm reading it right, the 20 amp receptical would have to be on a different circuit then the 30 amp circuit. Many older campgrounds 30 and 20 amp circuits are on the same line. This is another possibility for running two AC units though.

I can no longer find the device that cycled both AC units. Can't beleive there isn't enough demand even yet today to still manufacture them but evidently not.

Tip.