Roof a/c options

[DuaneMC7]

Hi all,
I am just starting my roof raise on my MC7 and I need to choose my a/c options in order to set my final height. Do I have any options for a basement a/c unit? This would be my preference if it could be run off the SW4024  and that hefty engine generator while going down the road. If roof a/c's are the way I go who makes the lowest profile that can be ducted?

Thanks for any help with this, Duane

Hope to meet some of you in Oregon in a few weeks. 

[David Anderson]

I've got 3 ducted low profile Colemans. 10.5" tall.  Most folks poo poo them because of the lack of a 3 speed fan.  That hasn't been a problem for me.  4 years old now and working fine.  I think that there are others out there with a low profile besides Coleman.  At the time I bought this was the lowest I could get.

I run the front AC off the Trace SW2512  inverter, however, I generally find I need to run more than one, so the genny is required anyway.

David

[JackConrad]

Carrier and Dometic both make low profile units also, not sure which is the lowest profile.  Our Coleman basement AC requires 2 20 amp circuits. If I remember correctly, the primary compressor (includes blower motor) uses 17 amps and the secondary compressor uses 14 amps. The circuit board that controls the system will not allow them to start at the same time.  I do not know of anyone that has ran one of these off an inverter. Our feeling is that if your bus alternator is running at max capacity to provide the power for the AC, that is abouit 20 HP that is not available to the wheels to climb that long grade, and with our 8-V71 in our MC-8, we need all the horsepower we can get to the wheels.  So we just run the generator. Our generator only uses about .4-.6 gallon per hour and we have all the 8V71 HP available to the wheels.  Just "our way" YMMV  Jack

[TomC]

Actually a 270amp alternator at 28 volts is creating a max of 7560 watts which at 80% efficency works out to be about a 12.6 horsepower draw.  Personally, if you are to run the front A/C with an inverter from the engine alternator fine, but as Duane mentioned, just run the generator if you run more. I have three Coleman 13,500btu with the normal ceiling hang down diffuser.  They work well, haven't had any problems with them in the 12 years I've had them.  They are a little too loud for me for night time use.  Am thinking on replacing the middle one with a Duotherm Brisk Air since that would be the same height as the Colemans (about 13") and then would modify a Coleman shroud so to fit the Duotherm and then it would match the other two.
For low profile, the Duotherm penquin is about 8" high, but the Carrier has the lowest profile (7.5") available.  Roof tops-while not the prettiest thing on the top of the roof, but most everyone has them-is the easiest, cheapest A/C available.  Then you keep the area in the cargo compartment open that would be taken up with a basement A/C.  Good Luck, TomC