Run 2 ACs with 5.5K Generator

[Lfresin1]

In a 2020 FR3 30DS can you run both AC units (18K + 15K) at the same time with the 5.5K Onan generator that it comes with?

[CHICKDOE]

i am not sure about 18K & 15K. we run our 13K & 15k plus residential refrigerator from an onan 5500 LP generator.

[bikendan]

Never heard of an 18k RV a/c.

[Lfresin1]

See this set of specs; second page: https://www.forestriverinc.com/broch...r3brochure.pdf

Dual Air Command Ducted Roof A/C’s (Front 18K
equivalent with Heat Pump/Rear 16K equivalent)

[ependydad]

I can tell you that it is possible to run a 13.5k and 15k A/C at the same time.

A 5.5k generator gives you about 46 usable amps. My generator has 2 x 30 amp breakers feeding L1 and L2.

Assuming the A/C circuit breakers are 20amp and 20amp, you’ll be fine.

You’ll just need to be mindful of what else you’re running.

[Lfresin1]

That's what I thought. My main interest, while driving, is to run both ACs when it's 100 plus degrees out and the dash AC isn't keeping up and one AC isn't enough.

Thanks.

[CHICKDOE]

i'm thinking they will turn out to be a 13K and 15K a/c. they are described as '15k equivalent' and '18K equivalent' in the specs. seems like the marketing people found a new way to make things sound better than they are. just my uninformed opinion.

but yes, the onan 550 should run both of them.

[rlh1957]

Marketing gimmick "equivalent"... like saying it has a 15K that cools like it was an 18K.

It really doesn't matter how many BTU's cooling they claim, it's the running and starting amps that matter. An air conditioner 15 - 20 years ago may have pulled 35 amps startup and ran at 27 amps... Today they are more like running at 12 amps and starting maybe 18 or 20.
So depending on your AC specs one could start and then the other start and both run on 5.5K easily. But starting both at the same time maybe, maybe not, depending on other things on. You'll discover as you go along what will and will not run at the same time.
Something that can increase amp draw is a less than secure connection or junction. Over time the heat will melt and short out

[Lfresin1]

Forest River's answer...

Forest River recommends running the front A/C and only the fan on the rear A/C to circulate the air. Also make sure that the water heater is not ON electric while traveling.

[TominVegas]

I have two 15k Ducted Dometic Atwood Aircommand a/c's on my 34H5.

The brochure says:

The Dometic Atwood AirCommand 15,000 BTU (18,000 BTU Equivalent) rooftop heat pump is designed to withstand even the harshest elements while still delivering cool air to your mobile living space.

For what it's worth I have an Onan 5500 and I've run them both when boondocking in Utah and driving in the desert southwest and haven't had a problem so far. Stated draw from the brochure is 13.5 amps at full operation so even with a 5 to 6 amp additional at start up like ependydad mentions (And I'm no expert so I'm guessing here) I've never blown a fuse. That would be with the Reefer on auto and it can pull 5 amps if it's working hard. Now I'm guessing that like rlh1957 mentioned if everything hit at the same time you could blow a fuse so your mileage may vary. This is just my experience so far.

Just as a point of reference since your in Henderson I ran the generator for two hours this weekend to exercise it with both a/c's on and it did fine. I believe the outside temp was close to 102 around oneish when I turned it off. Probably a little more sitting on the concrete pad in my backyard.

[Lfresin1]

Thanks. I think FR is just doing a CYA for worst case scenarios.

[McCormickJim]

In my GT 31L5 I run both ACs when it's HOT, plus the dash air.

I also set my ACs to dump air vs. push air through the ductwork. Some air still goes through the ductowork for circulation.

[Lfresin1]

Me too. I never close my main AC vent.