Which AC is which?

[mikeinca]

I have a 40 AMP circuit in my garage that I'd like to use to run the AC on our 2018 30' RB Twin Classic when it's in "port". I realize that I shouldn't run both AC units at the same time on 40 AMPS but I'd like to run the larger 15,000 BTU unit. On my trailer, which AC is 15K BTU and which is 13.5K? It seems like it would be useful to know in any event.

Maybe the answer is out there already but I've done a search and haven't been able to find a definitive one. I'd rather not climb on the roof to find out if I don't have to.

[rmkrum]

Most air conditioners have a nameplate accessible behind the vent grill that would give the data you need.

[uncle_bob]

Hi

You can safely run either AC unit on a 30A hookup at a campsite. Their current draw and performance are so close as to pretty much not matter. In fact, if you *happen* to ... errrr...run a controlled experiment , it turns out you can run *both* AC's on a 30A hookup. Don't ask how I found this out .....

I believe the "typical" configuration is to put the larger unit over the living area and the smaller over the sleeping section. It's AS, so trust very little, and verify everything .

Bob

[mikeinca]

Originally Posted by rmkrum

Most air conditioners have a nameplate accessible behind the vent grill that would give the data you need.

Originally Posted by uncle_bob

I believe the "typical" configuration is to put the larger unit over the living area and the smaller over the sleeping section. It's AS, so trust very little, and verify everything .

Bob

Bingo! You were both correct. I found the tags with a flashlight and removed the grills so I could read them. The larger 15K BTU unit is indeed over the living area at the front with a 13.5K unit at the rear....on my AS Classic at least!

Thanks!

[brick1]

On my Serenity 28, the front (living) area is the larger 15K unit, and is # 2 on the thermostat. The rear (bedroom) is the 13.5K unit, and is # 1 on the thermostat.
You will not run two A/C’s on a 30 amp plug for long...

[uncle_bob]

Originally Posted by brick1

.....
You will not run two A/C’s on a 30 amp plug for long...

Hi

You can do it for longer than you might think ..... (hours).

Bob

[Silvertwinkie]

You can run both with a 30a, but be advised that there **is** the **possibility** that long term damage (read years) could prematurely reduce the life of the compressors if they cycle at the same time. I mean if you are running both A/C units in your garage, you are prob either in the trailer with other things turned on, or you have more on than just the A/C unit(s) on in general (fridge may come to mind, TV or stereo too). There is a reason they put 50a on the rig and if it were my rig, I would run one or the other if I was connected to a 30a. 40a, I've never seen, only 30 and 50, so could your 40 be a 30? If so, that's my advice. If your 40 is a 50, then you can run it all day long so long as the power supplier and circuit are providing ample power (no brownouts or surges).


If your garage already has a 30, 50 is not a major jump in cable gauge size and breaker. There are calculators on-line that can easily tell you if the cable in your garage setup is aqueduct for the length of the cable run (30 or 50a). This is a major variable that can't easily be given a thumbs up or down on on a forum without knowing the cabling infrastructure. I went through this excercise about 7 years ago when putting in an EV charger for my car. Power decreases with distance, requiring larger cable.


This is a fair one I've used in the past:


https://www.electricaltechnology.org...alculator.html

[Mollysdad]

Originally Posted by mikeinca

On my trailer, which AC is 15K BTU and which is 13.5K? It seems like it would be useful to know in any event.

Living area is 15 and bedroom is 13.5

[guskmg]

If you want to run both A/Cs at the same time on a regular basis you need MicroAir's SoftStarts on them. You would be amazed at how this computerized start/run system really improves the situation. Low amperage starts, no more jolting to a stop and smooth quiet running. Plus much longer motor life. I'm on my 15th season with no trouble yet.
guskmg

[uncle_bob]

Originally Posted by Silvertwinkie

You can run both with a 30a, but be advised that there **is** the **possibility** that long term damage (read years) could prematurely reduce the life of the compressors if they cycle at the same time. I mean if you are running both A/C units in your garage, you are prob either in the trailer with other things turned on, or you have more on than just the A/C unit(s) on in general (fridge may come to mind, TV or stereo too). There is a reason they put 50a on the rig and if it were my rig, I would run one or the other if I was connected to a 30a. 40a, I've never seen, only 30 and 50, so could your 40 be a 30? If so, that's my advice. If your 40 is a 50, then you can run it all day long so long as the power supplier and circuit are providing ample power (no brownouts or surges).


If your garage already has a 30, 50 is not a major jump in cable gauge size and breaker. There are calculators on-line that can easily tell you if the cable in your garage setup is aqueduct for the length of the cable run (30 or 50a). This is a major variable that can't easily be given a thumbs up or down on on a forum without knowing the cabling infrastructure. I went through this excercise about 7 years ago when putting in an EV charger for my car. Power decreases with distance, requiring larger cable.


This is a fair one I've used in the past:


https://www.electricaltechnology.org...alculator.html

Hi

I'm by no means suggesting that running them both on 30A is a good idea. It's not a good idea. The point is that you *can* do it if the one who plugs in the trailer does not keep track of what the one who turns on the A/C's is doing ....

Bob