I have two 13.5k ac units on the SunCruiser we just purchased .. Seems I read in the information some where that the two units required the 50 amp service , for both to run at the same time on shore power as they're each pulling 14-19 amps ..

Appears that they were factory installs , so why would they install the 30 amp service box ??

Is it a matter of just changing the service box to a fifty , or is there more between the box and the master panel that would need changing ..

Hi JackHammr,

Two 13500 units may possibly run on a 30 amp service, if they are the new technology air conditioners.

Changing to a 50 service may require a great deal of rewiring an RV. It may be possible--but pricey.

My advice is to try running both on the existing 30 amp service.

With 30-amp service you won't be able to run both ACs at the same time, but it is nice to have a choice of whether to have it in the front or the rear of the RV at any given time.

A friend of mine converted his 30-amp motor home to 50 amps. It was not simple. Take a look here: Bob's Web Site

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Dave Rudisill

The rest of you can tell me I'm wrong, but I believe I have heard of a type of AC system specifically for use with 30amp service that automatically alternates between running one unit and then the other unit. In other words it runs the front for a while and then turns it off and runs the back for a while and keeps going back and forth so they are not on at the same time. If your coach is a newer unit, it might have this kind of system.

Hi Denali,

With the new soft start technology it is possible to run two 13500 btu AC units on 30 amps. Mine draws only 1120 watts (just under 10 amps @115 volts). I don't have a reliable way to measure the start up surge. unfortunately.

Thanks for the correction, Don.

Our ACs each draw about 13.5 amps. Right now, with every light in the place turned off, we are drawing 5.0 amps from the various wall warts and other parasitic loads. Even if I could kill all those, a campground 30 amp breaker is unlikely to sustain a 27 amp continuous load.

--
Dave Rudisill
2004 Beaver Monterey

I have a friend with a Fleetwood Bounder, and his works like that.

--
Dave Rudisill

Hi Denali,

Wow--5 amps for essentially lost energy. I'm floored. I think my system draws about 100 watts (1 amp) when "nothing is turned on". but I have no wall warts to suck up power.

I agree, in your case the start up draw would most likely flip the breaker if one AC unit was already running. Is that 13.5 amps a guess or a measurement?

QUOTE(Denali @ Aug 3 2009, 09:20 AM)

...various wall warts ...

Love this term!
Was amazed at all the stuff in this rig with either a little red, green, or digital clock light, brightly shinning 24/7. Now some of them, like the carbon monoxide and propane detectors, are a given.

However the sets of walkie-talkies, hand-held vacuum, Directv descrambler box, microwave, refrigerator, even the electric blanket controls had lights going. OK the electric blanket is a no-brainer to unplug...sigh. I was oblivious to all this in our stick house!

The 13.5 amps is a measurement. Our rig has a system that displays the volts, amps, and frequency on each of the two 120 VAC legs. When we turn on either AC the draw on that leg increases by 13.5 amps after it is past the startup phase.

I agree, five amps is a lot of "lost power", but when you add up the parasitic draws from the various gee-gaws on board, it isn't surprising: two laptops, rechargeable battery charger, one or two cell phones charging, PDA charging, printer, microwave, three TVs, portable vac, VCR, DVD player/home entertainment center, Dish Network DVR, video signal distribution box, inverter/charger for both house and chassis batteries, coffee maker, fan for entertainment center, etc. That doesn't count lights or the stuff running off the chassis batteries.

Remember, we aren't "camping". This is our home.

--
Dave Rudisill
2004 Beaver Monterey