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Glenn_And_Kitty's avatar
Glenn_And_Kitty
Explorer
Jun 22, 2020

ongoing generator issue

I had some problems with my generator but just had a new control panel and interface installed by a certified dealer. It is now running fine but it trips when my RV A/C compressor kicks on. Gen shop is closed for a few days so maybe I can get some advice here. Please allow me to explain:
I have a Yamaha EF6300ISDE gen. Specs say it is rated for 5500 watts and I think the 6300 watts is for surge or start up. Amp rating is 45.8/52.6 amps when running on 120 volts.
RV A/C is a 13,500 BTU that should be drawing about 14.5 amps on start up and about 2700 to 2900 watts on start up.
Here is the problem:
I turn off everything in RV. Start up gen and run full throttle (about 3450 RPM), I go in and turn on A/C. Fan comes on and gen barley does anything. The A/C compressor kicks on, there is a big surge on gen, and I note a large drop in voltage on a meter I have inside RV. Generator continues to run but power trips and no power is being generated. There is zero voltage on RV meter and no lights on Gen. It does not show overload on gen but no power is being generated and motor runs back at 3450 RPMs.
I turn off A/C control so there is once again nothing on in RV. I shut down gen for maybe 30 seconds, start it back up and power is restored and available. I repeat turning on A/C, fan comes on (no problem), then compressor comes on, gen surges, and then power trips/fails again.
I tried turning gen to Eco mode and same result. I also tried not turning on A/C and turning on microwave and some other electronics. gen surges a bit but power stays on. Gen power only fails when RV A/C compressor comes on.
Gen should have more than enough capacity to start/run A/C. I don't have any load testing meters but with gen just coming out of dealer repair shop it should be in top notch condition.
Could my single A/C unit, which is on a 2019 Coleman TT, be drawing more than what is considered normal? Even at that it seems that my gen is rated well above what is needed for a 13,500 BTU A/C and probably should be able to run a 15,000 BTU unit.
Anyone have any idea what is going on. I'm in Louisiana so altitude is not an issue. It was 90 degrees plus degrees today with high humidity. Could that be an issue?
Does anyone think I have an A/C issue for an RV dealer to look at or do I have a gen issue and I should take it back to gen repair shop?
Glenn
  • jjrbus's avatar
    jjrbus
    Explorer
    Jun 23, 2020
    In my bumbling electrical diagnostics, I would have done about what you are doing. At this point with the AC working well on shore power there is a remote possibility of a fluke in the wiring, BTDT but rare.

    It should be the generator, a micro air may mask the issue but it not the cure. There is no re4ason your generator should not start your AC, it waaaaay more generator than needed.


    A weak or defective breaker on the genny was mentioned, that would be my next guess. Or the generator has to go back to the shop. I would want to hook up the genny to a heavy load to test, preferably another 13.5 AC. A long shot would be a intermittent short or some other defect in the AC, that is absolute worse case scenario and a nightmare. Good luck
  • byronlj's avatar
    byronlj
    Explorer
    Jun 23, 2020
    The 30amp breaker on the generator could be weak causing it to trip before the compressor winds up. Try the 2 1500w heaters as stated and turn them on simultaneously with a switch, like a good power strip. See if that breaker pops on the generator.
  • Lynnmor's avatar
    Lynnmor
    Explorer
    Jun 22, 2020
    Gather up a couple of 1500 watt electric heaters and see if the generator will power them.
  • Glenn_And_Kitty's avatar
    Glenn_And_Kitty
    Explorer
    Jun 22, 2020
    Another update:
    I purchased a replacement capacitor and installed it. No help. Ran gen at full throttle, plug in RV, nothing else on in RV (hot water heater does run on electric or gas but it is off completely). Turn on A/C, fan comes on, no change in gen or very slight, compressor kicks on, gen revs up and loses all power, gen motor then slow down to normal full throttle mode but is not generating any power. I unplug RV from gen, shut gen down for about 30 seconds, start gen back up, and it is generating power again.
    I plugged my RV back into 30 amp shore power and A/C works fine. I left the new capacitor on A/C and will keep the old one as a spare. Obviously it is not the A/C capacitor and I'm back to square one.
    I guess my two options are one: wait for Micro Air Easy Start 364 to come in and try that or two: take gen back to repair shop and have it tested some more.
    Any other suggestions would be greatly appreciated
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Jun 22, 2020
    Glenn And Kitty wrote:
    RV A/C is a 13,500 BTU that should be drawing about 14.5 amps on start up and about 2700 to 2900 watts on start up.

    You A/C draws a LOT MORE than that on start up !

    Seattle Steve wrote:
    I would think that an Micro-air easy-start or softstart rv for the AC would solve the problem. I won’t go without it again.

    Concur !
  • bgum's avatar
    bgum
    Explorer
    Jun 22, 2020
    Is it possible that your water heater is on electricity? That with AC and converter charging would exceed abilities.
  • Glenn_And_Kitty's avatar
    Glenn_And_Kitty
    Explorer
    Jun 22, 2020
    Reply to questions:
    My rig is 30 AMP
    A/C unit is a Dometic Brisk II - 13,500 BTU
    I have had the shore power 30 amp beaker, at some campgrounds, trip on rare occasion when I first turned on A/C unit. I had to turn off all switches and A/C in my RV then go out and reset campground breaker. That would only happen once per place I stayed that it did that and I would not experience any more problems while staying at that particular spot. This has only happen maybe three times in the last eight to ten outings. I had not used my generator with this RV until recently.
    It does sound like it is a capacitor issue.
  • enblethen's avatar
    enblethen
    Nomad
    Jun 22, 2020
    Is your rig 30 or 50 amp?
    If it is 50 amp you should be using the four wire twist lock with adapter.
  • bgum's avatar
    bgum
    Explorer
    Jun 22, 2020
    With that size AC and gen you don't need a hard start kit. Did it work before the gen needed work?
  • jjrbus's avatar
    jjrbus
    Explorer
    Jun 22, 2020
    5500 watts should start a 13.5k AC with ease and 6300 surge is waaaaay overkill. The info I have from Duotherm specs a 3500 watt generator for a 13.5. I would suspect another problem.

    Any inexpensive watt meter will not do you any good as they are not fast enough to measure LRA, locked rotar amps. Which is starting amps when the compressor first kicks on, lasts only a micro second. Is there another RV around you could hook up to and try and start their AC or can use their gen to try and run your AC, that might isolate the issue or hook up to shore power to test AC.

    My best guess is the start capacitor on the AC is going bad, my way of dealing with it, not having the proper tools to test is to replace the start capacitor. Does not take an electrical degree and should be $20 or less, if it is not the issue, you have a spare capacitor. Google or you tube replace RV AC start capacitor.

    Disclaimer, I am not an electronics guy, just another RV'er trying to get by.

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