Community Forums

roknjohn · 09-04-2013, 01:42 PM

On my first trip this past weekend, there were times when only one of my rooftop A/Cs would run at a time. One unit would "SHED" power, i.e. the red light would stay on, on the ECC panel. I could run either one, but not both at the same time. We were running the generator (Onan 6500 LP) which should have a 54amp output, which is even more than the 30amp shore power service.

Granted it was a hot day and we had lots of traffic in and out, but shouldn't 54 amps be sufficient to run both? The night before and the night after, both A/Cs would run OK. At home in the driveway, both units work OK.

We had a few other things plugged in, but tried systematically to disconnect things to see if the issue would go away. Here's a list of what was on:
Inside: 1 LED TV, DISH Receiver, frig; Patio: LED TV, small lamp (40w), 2 strings of miniature Christmas lights (40w each), small fan. At one point, I switched the refrig to gas.

My question is what should I be expecting? Should the genny be able to run both A/Cs on a hot day along with a normal load? What is the best way to check to make sure the output of the generator is optimal? How can I (easily) check the actual load of each A/C? Thoughts?

vsheetz · 09-04-2013, 03:29 PM

On my coach with 30a service and EMS the rear A/C is connected to the 5500w genny and no shedding occurs when on genny. Both A/C run simultaneously. When on shore power shedding only occurs when an additional substantial load it introduces - microwave, hair dryer, etc. TV's and such do not initiate shedding.

Your coach may be set up differently, so YMMV. Suggest you get a wiring diagram so you can see what is wired where.

Clayobx · 09-04-2013, 03:44 PM

I am it familiar with your generator so I can only speak of past experiences. My 03 Excusion had a Onan 7.5 KW gen set. It ran both AC's with no problems along with most house items, had to watch hair dryers for DW and microwave. On thirty amps we had to run one unit on auto and the other on low cool. So at 54 amps you should be ok. Most likely need to test amperage draw at your units plus output of your Generator. Present coach with 7.5 runs all three plus house no problem. Best of luck!