Originally Posted by mustang
I was always told that also, (low current will shorten compressor life)
I have a 13.5 k unit on my 31 footer and it does great. If I could have gotten a bigger 1 for the same price I would have done it without hesitation. So will a 3500 generator run A/C? I was told go 5000. Now the question Arises.
Low voltage lowers a compressors life, not current.
When the voltage becomes low, the current increases, which in turn causes the compressor to over heat.
The over heating causes the short life.
Low voltage can be caused by a poor source of power, an inadequate wire size extension cord, poor connections, and a generator that cannot supply enough current.
Any generator, should never have a demand that exceeds about 75 to 80 percent of it's maximum output.
To be safe, along with using minimal other electrical loads, a generator that has a maximum rating of at least 4000 watts, should be selected to run the Airstream properly.
4000 watts x 80 percent = 3200 watts. With an AC running at 1800 watts, X 150 percent = 2700 watts. That leaves 500 watts to tinker with.
Any charging system, even at standby, will use perhaps 100 watts. Add a few light bulbs, and there you have it.
Also remember that all RV AC's running current, is also a function of the ambient temperature. The higher the temperature, the higher the current, which can exceed it's normal amperage.
Accordingly, when running an RV AC in moderate outside temperatures, is one thing. Operating them in a desert when the outside temperature peaks, is an entirely different matter. The running current will be greater than it's normal running current.
Running generators at maximum power, shortens their life.
Running an RV airconditioner on low voltage, shortens it's life.
As with most equipment, such as a generator, operating them at or near maximum output, will shorten it's life, as well as the AC.
You don't run your tow vehicle at maximum engine output, since you know besides speeding, it will shorten it's life.
A gasolene or LPG generator, will do the same, at or near it's maximum output.
That's why many owners start at 5000 watts, to begin with.