Wednesday, October 15, 2008

Can a 30-amp electrical system run two air conditioners?

Dear Mark,
We are considering buying a Winnebago Sightseer 35J with two roof air conditioners. But the coach only has 30-amp service with an Onan 5.5 KW generator. Can these two air conditioners run at the same time with only 30 amps?

Mark Says: Most RV manufacturers use some type of energy management system so both roof air conditioners can operate at the same time on a 30-amp system. Our 2006 Bounder 35E is a good example. It will power up one A/C and then the other. Once they are both running it can sense if there's a requirement for more power placed on the system, like somebody making a pot of coffee, and it will shut one A/C down or both depending on the power requirement. When there is no longer a requirement the A/C units automatically start back up.

Many manufacturers use smaller BTU air conditioners. It was no good to have two 15,000 BTU units if you can only run one, so now they might use a 13,500 and an 11,000 BTU unit which a 30-amp system can run at the same time.

Basically what I am saying is most of today's manufacturers offer some type of power management system to operate both A/C units with a 30-amp system. On the other hand most manufacturers have a built-in system to prevent you from using both A/C units and attempt to use the microwave or other power consuming appliance.

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Posted by Staff Report at 2:30 PM

5 comments:

  1. I have a 1999 Winnebago Adventurer with 30 amps and 2 a/c's. I run both a/c's and still have amps left over. With both it only uses about 22 amps and that includes having some small appliances like lights/radio on at the same time. If the RV park is full and everyone is using a/c on a hot day, sometimes the park's breaker will trip. In which case I use one a/c. But the rig can handle both easily.
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  2. I have an Itasca Sunova 35J myself and can attest to the fact that yes both will run. Winnebago includes the power management system that is described in the forum that will make sure you dont overtax the power. It works extreamly well. If you should say turn on the microwave, it will drop the 2nd AC off unitl its done. Enjoy your unit, as we love ours!
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  3. So how do you know IF your 30 amp rig has that energy management system that will allow you to run BOTH air conditioners at the same time? Mine has the switches up to run one with electricity and down to run both WITH the generator running. Nothing about how to run BOTH while being plugged in.....
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  4. I installed a 2nd A/C unit in our 32' TT, to cover the bedroom (king in the rear) last year. The camper does NOT have any special power management, and I didn't relish putting anything special in to replace what was there.

    My solution was to simply run the power line from the new unit separately from the main. I have an extra cord that I can run when I need the 2nd unit.

    This is based on 2 premises
    1- I don't need the 2nd unit all the time. The primary is ducted, and covers the entire camper under 'moderate' heat conditions.

    2- The campground has a power box that provides both a 30amp connection and a 20amp outlet. The camper's 30amp goes to the normal outlet, and the 2nd A/C goes to the 20amp standard 110v outlet.

    I've found that 90% of the campgrounds do have both 30 and 20 (usually 2 20amp outlets) with separate breakers for each.

    It's less than the elegant solution found in units designed for 2 A/Cs, but it solved my problem with minimal work.
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  5. Question why would they put in a 5.5kw generator and only have 30 amp service 5.5kw is for 50 amp service
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