AC soft start

Discussion in 'Electrical Stuff' started by dmorris800, Apr 22, 2023.

  1. dmorris800

    dmorris800 Member

    111
    Mar 8, 2012
    League City, Tx
    350 Sundancer Coupe 2020

    Prior
    310 Sundancer 2015
    Dual Horizon 8.2 V Drive
    Hi
    Has anyone placed a soft start on their AC units? Trying to protect the generator from the hard start / inductive load of starting them.

    thanks
     
  2. SKybolt

    SKybolt Well-Known Member SILVER Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    Reel Nauti
    460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
    Depending on the size of your generator and the number of AC units you have, the soft start is a good idea, but even more beneficial could be a staggered start.
     
    dtfeld likes this.
  3. dmorris800

    dmorris800 Member

    111
    Mar 8, 2012
    League City, Tx
    350 Sundancer Coupe 2020

    Prior
    310 Sundancer 2015
    Dual Horizon 8.2 V Drive
    Hi, 7 KW generator with 2 16k btu AC. I do stagger start or more common just run one of the units. Just curious if anyone else on the board has done this and if they have seen a benefit?
    Thanks
     
  4. northern

    northern Well-Known Member

    Jan 17, 2007
    Anacortes Washington
    380 Aft Cabin 1989 Charts Timezero radar Furuno
    Twin 454 strait shaft
    We have an 8KW generator and a watermaker. If anything is on when the watermaker starts they go off momentarily. I start it with all things off the system is fine after that.
     
  5. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    And the staggered start is free.
    Its easy to program in a start delay (if you can remember the 3 finger salute to get into the menu mode). I have mine set at like 5, 10, and 15 seconds. You really shouldn't need soft starts unless you are cruising to areas with bad or linmited AC shore power, or are trying to run on an inverter.
     
  6. dmorris800

    dmorris800 Member

    111
    Mar 8, 2012
    League City, Tx
    350 Sundancer Coupe 2020

    Prior
    310 Sundancer 2015
    Dual Horizon 8.2 V Drive
    As always thanks for the advice, never knew the AC had that setting, was just doing it manually (ie give a minute between throwing the breakers)
     
  7. Bill Curtis

    Bill Curtis Well-Known Member

    722
    Mar 24, 2022
    Eastern NC
    '95 220 Overnighter
    454 Mag. Bravo3 w/ 2.0:1 gears and 27 pitch props
    454 Mag Bravo3. 2.0:1 ratio gears w/ 27 pitch props
    Don't know if a soft start would work against any head pressure, unless the system has an unloader built into the HP gas circuit
     
  8. John E3

    John E3 Member

    105
    Nov 21, 2022
    Rock Hall, MD
    1999 370 Aft Cabin
    Horizon 454
    In another thread I have regarding replacing a genset with a smaller 1800 rpm unit, soft start was suggested, and a search lead me here.
    What exactly is "staggered start"? The obvious, to me, answer is to turn on things one by one, but there must be more to it, as you have no control over when AC units cycle, and an overlap could easily overload and stall the genset. I have a 16k unit that would be an ideal candidate for a soft start. The other 2 units are only 7k. The in rush current for the 16k unit could reach 50% of the genset capacity, 7kw.
     

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