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Generator Usage

Discussion in 'Technical Discussion' started by Condor Man, Apr 27, 2016.

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  1. Condor Man

    Condor Man New Member

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    Hi Guys,

    I have 2013 Sunseeker Manhattan 63 with a 17.5k generator on board.

    I have been told by the Chap that manages the boat that the generator uses 18L per hour.
    Even when at half load.

    Could this be possible?

    It sounds high to me.
  2. Sea Gull

    Sea Gull Member

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    Maybe he missed a decimal place. 1.8 sounds closer.
  3. Capt Ralph

    Capt Ralph Senior Member

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    Yep, 1/2 half gallon per hour / half load / around 1.8 L.
    Sea Gull had it.
  4. Condor Man

    Condor Man New Member

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    I was serious at 18l.

    How can I prove he is wrong.
  5. olderboater

    olderboater Senior Member

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    Buy a 63 and run it a while. Or just buy an Onan 17.5. Those who answered you were serious and far more on target. Why do you have to prove anything to anyone?

    Here's a general generator fuel usage chart. I've found all modern generators do better than the chart.

    http://www.dieselserviceandsupply.com/Diesel_Fuel_Consumption.aspx

    Here's a Cummins chart, but it doesn't include small units.

    http://www.powersystems.cummins.com/_literature_98391/Generator_Rental_Specs_and_Sizing_Charts

    They show the 35kw at 3/4 load uses 2.2 gph.

    We have a 21.5 kw on our Sunseeker (actually have two but only run one at a time) and use less than 1 gph on average.
  6. Condor Man

    Condor Man New Member

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    Thank you.

    It was just a discussion I had and he said that the generator on average uses 18L per hour.

    It sounded really crazy to me and I just wanted to hear some different views on this matter.

    Thanks Again
  7. Lepke

    Lepke Member

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    Does the 18L/hour x engine hours match fuel usage? If so, you may have another problem.
  8. Capt J

    Capt J Senior Member

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  9. Condor Man

    Condor Man New Member

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    He is saying 18L + Engines.

    I am never present when they fill the boat up and I feel as though they are seriously overcharging and not actually putting the fuel in.
  10. Condor Man

    Condor Man New Member

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    He emailed me with the following;


    Please ask your mate for the generator they use because I would like to buy one from them.

    I have never had a generator on any boat that uses that little. Never ever with any load. Min is with an 8 kva genset uses 4 litres half load 6.8 l per hour full load
  11. Condor Man

    Condor Man New Member

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  12. Capt J

    Capt J Senior Member

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    Just about any 17.5kw 50 hz uses the same amount of fuel from what I've seen as yours does. In a 63' Sunseeker, you're probably running 3/4 load at all times during the day if you have all of the a/c's running and probably 1/2 load at night.
  13. Sea Gull

    Sea Gull Member

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    The question is if he is stealing fuel, doesn't understand math, or there is a problem onboard that he also doesn't understand?

    How is he figuring out the fuel use of the generator? I do it when I top off both tanks and measure the difference, since the genset runs off only one of my two tanks. But this only gives a rough estimate, given that there can be slight differences in fuel use of the two main engines and differences in what "full" is.

    Many gensets can draw from either tank and return fuel to either tank. Check that you are returning fuel to the same tank as you are drawing from. This could cause the inequity that would cause him to think the genset is using more fuel. Also, try switching the fuel feed/return to another tank. The would indicate extra fuel being drawn by one of the mains.
  14. g36

    g36 Member

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    To shut him up install a fuel flow meter
  15. olderboater

    olderboater Senior Member

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    To shut him up, don't let him touch your boat again.
  16. Capt J

    Capt J Senior Member

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    This.

    The Sunseeker 63' only has 1 fuel tank. I'm guessing the engines are burning more fuel, that's easy to do at cruise.....an extra 30-50 rpms is at least 18 liters an hour more.
  17. Pascal

    Pascal Senior Member

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    We have a pair of 18kw Northern light on the boat I run and we burn on average 1 to 1.5 GPH.... 4 to 6 liters an hour.

    There is no way you could burn 18 LPH in a generator that size without a big black cloud and a fuel slick on the water, either woudl either land you in jail or result in some tree hugger riot. :)

    The "chap" managing the boat obviosily believes that boat means bend over and take it.
  18. olderboater

    olderboater Senior Member

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    He either doesn't know what he's doing and talking about or he's intentionally fabricating a story, thinking your stupid. So incompetent or dishonest. Doesn't really matter which, I'd be going elsewhere.
  19. Condor Man

    Condor Man New Member

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    Thanks Guys,

    I knew that he was taking the piss!