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Johno02's avatar
Johno02
Explorer
Oct 11, 2017

Big suprise, but it worked! Wouldn't recommend.

Brought rig home from minor repairs shop yesterday, and parked in drive as usual. Everything normal. Decided to check genny, as it hasn't been run in a while. Generac 5500 K system. Fired it up, started OK, and when power switched to it, BOTH 13.5 AC units came on at the same time! Genny bletched a bit of black smoke, picked up the load, and just kept chugging! After a minute to figure what happened, I went back and whut down one unit, then the other. Genny said thanks, and just kept chugging. Shut it down, and all is well! So, for those of you that have and will ask, it will work. I wouldn't do it again, and woudn't recomment it to others. I did forget to check my voltage meter with both running, after thinking about, I would really like to see what it was doing. Not going to try again to see.

8 Replies

  • joebedford's avatar
    joebedford
    Nomad III
    Oct 14, 2017
    Are you SURE both ACs came on at the same time, or just their fans?

    On mine, the fans come on immediately and the compressors come on later at staggered times.
  • wilanddij's avatar
    wilanddij
    Explorer
    Oct 14, 2017
    I admit I haven't really paid much attention to this, but it seems to me that my EMS puts the second AC into "Shed" until the power draw settles down. Doesn't make any difference whether on shore or genny; it works the same.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Oct 12, 2017
    NOT
    A good idea to proof generator ability by voltage. Forcing The Field is # 1 cause for Generac voltage regulator failure.

    Use a frequency meter on non inverter generators. A 1-2 Hz slump while starting loads is OK. Exceed the 55 Hz "cornering frequency" and you beg disaster. I am fooling around with ELEVEN failed generac voltage regulators to see if they are repairable. The potting removal is proving to be a challenge.
  • RJsfishin's avatar
    RJsfishin
    Explorer
    Oct 12, 2017
    You wouldn't do what again, run both A/Cs off that genset, or have both switches on while firing up the gen set.
    No problem running both A/Cs off that 5500,...that's why its a 5500.

    Having both A/Cs on before firing the genset, maybe not the best idea, but it ain't gonna ruin it.
  • Johno02's avatar
    Johno02
    Explorer
    Oct 11, 2017
    I usually try to exercise the genney on a regular basis. That is why I decided to start it ths time. It just suprised me that the ACs were on.
  • time2roll's avatar
    time2roll
    Nomad
    Oct 11, 2017
    As long as the generator had not run in a while I would have recommended a solid 20 minute run under load just for good exercise.
    Do check the oil level.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 11, 2017
    Done it many times. No problems. It works.... Only both 13.5's have been upgraded to 1500's.. one still draws 13.5 amps (though starting seems a bit more .... hard) the other is 13.9 running.. last time I did it was Monday

    Today I need heaters

    Man oh man is the weather fun.
  • Dutch_12078's avatar
    Dutch_12078
    Explorer III
    Oct 11, 2017
    We routinely run both of our 13.5 AC's on our Onan 5500 generator. I can't say for sure that both compressors have kicked in at the same moment while on the genny, but they definitely both run at the same time with no problem.

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