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WhisperPower vs Onan

Discussion in 'Generators' started by etang789, May 7, 2020.

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  1. etang789

    etang789 Member

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    I am thinking to get a WhisperPower Variable Speed generator to replace the old Onan. The old Onan was great for many years and trouble free, but it was very noisy and basically shakes up the whole boat.

    I need a new 12kW while Im doing repowering the Bertram , based on the specification seems the latest WhisperPower is very quiet and smaller in size for the same kW output. But I dont see much examples using WhisperPower.
  2. Capt J

    Capt J Senior Member

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    Stick with Onan......Reliable and you can get parts for them...….and the new ones are quiet.
  3. Pascal

    Pascal Senior Member

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    Not familiar with whispepower but my experience with a pair of 2009 27.5 Ohnos isn’t that good. Even with the cooling system in top shape the exhaust is loud especially after Onan replaced the raw water pumps with an supposedly improved design which actually has a smaller outlet. Duh... many issues with sensors too and dreading loosing the main board while in the Bahamas... apparently you can’t just have spare because it has to be programmed after install

    my preference is northern lights. Stay away from small brands. I have an excellent Norpro 18 on my own boat and parts are hard to find
  4. Capt Ralph

    Capt Ralph Senior Member

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    Fischer Panda, WhisperPower and others run there smaller engines at higher rpm to make their power.
    Combined with lighter aluminum components, does make for a smaller and lighter gen-set assembly.
    Capacitor banks and inverter modules does further complicate the over all package.
    IMO, there is NO long term investment in this style of equipment.

    Simple, longer lasting and way more reliable gen-sets are available. AND, probably less expensive.
    Northern lights and their new Gem box (two layers of motor mounts), would be my suggestion.
    A distant second would be OhNo.
  5. etang789

    etang789 Member

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    Looking at Northen Lights price seems pretty good compared to Onan, is this the one you recommend?

    Northen Lights M843NW3 12 kW
    356 kg
    1000 x 573 x 692 mm

    Onan Marine QD 13.5
    404 kg
    1139 x 602 x 698 mm

    Whisperpower M-GV 15 MARINE
    210 kg
    822 x 563 x 660 mm
  6. Capt Ralph

    Capt Ralph Senior Member

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    Northen Lights M843NW3 12 kW Yes to this NL.
    I have installed a couple of them last year. Solid work horse.
    Not as smooth as a larger 4 cly engines but not noticeable in the new GEM box.
    20190104_115426a.jpg
  7. etang789

    etang789 Member

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    What’s the new GEM box? Is it the normal Sound Enclosure? Or there’s a different one?
  8. Capt Ralph

    Capt Ralph Senior Member

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    It's a newer box option for the NLs.
    4 soft iso mounts under the whole box. Alloy skins with 1/4 turn release latches. On the inside, the gen set sits on it's own mounts.
    Much quieter over the standard box option.

    There is one draw back to this box from the standard box. The end panel on the water pump end does not use the 1/4 turn release latches.
    Thumb screws on the inside are used to release this end panel to service the raw water pump. It's not fun if the engine is hot.
  9. PacBlue

    PacBlue Senior Member

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    The way to quiet and limit the vibrations of your genset is to double resilient mount them.

    That means the generator engine and alternator is mounted to the base frame with resilient rubber mounts. Then the entire unit is mounted to your boats foundation in whatever space it is located with another set of resilient rubber mounts between the base frame and the foundation it rests upon. There is some further work to pay attention to the center of gravity as that is where the mass of the unit works through (physics) so the smarter applications usual have at least 6 mounts, one at each corner and 2 aligned with the center of gravity. It will then be ultra smooth and barely noticeable during operation.

    And if you want to get fancier, mount your lift muffler base with a set of rubber resilient mounts to the boats foundation to round out the quiet system.
  10. Capt Ralph

    Capt Ralph Senior Member

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    I hung all the 2" exhaust with straps. I wanted to isolate the mufflers also but never got to experiment with that.
    In one Hatteras, the original OhNo MD4/20kw was removed and a NL20 and NL12 were installed in the same forward area. With both running, you can have a normal conservation with somebody while sitting between them (approx 3.5 feet apart).
    At the helm, you really have to listen hard to hear them running. So, far, no loads that large to require both running at the same time.
    Running either one by itself, the water splashing outside is the whisper maker.
    This fall if all else comes together; Gas Seps... Then not a sound, in or out of the boat.
  11. Fishtigua

    Fishtigua Senior Member

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    I fitted exhaust separators to two Onans. Seriously, all you could hear was a trickle of water from the aftdeck.
  12. Capt Ralph

    Capt Ralph Senior Member

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    The original Hatteras gen-set room decks were solid but had drooped down a little in this project. I epoxy sealed a new 3/4" ply pad to bolt down. Then the NL external mounts with the gen-set tray on top of those. I was worried the modified deck would act like a drum. 2 cartridges of 4200 were applied between the deck and new pad to fill the voids. A few days later I started tightening down the carriage bolts between the original deck and new pad.
    Ahh, Perfect.
    There is no drum effect under the gen-sets.
    20181230_141605a.jpg
    20190107_161624a.jpg

    20190107_155112a.jpg
  13. Capt Ralph

    Capt Ralph Senior Member

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    Yes; I'm sure your exhaust separators is what I meant by Gas Separators (Gas Seps).
    On a previous project where I did install a gas sep, while running, just a spit of water would come out of the above water outlet and make an annoying dribble sound.. I closed that top thru hull just a micro bit and the water stopped. No sound at all.
    You may want to try this.:)
    Last edited: May 17, 2020
  14. Pascal

    Pascal Senior Member

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    On most genset the exhaust separator works great to eliminate the water splashing out under pressure from the exhaust gases. Problem with our 27.5 OhNo is that there isn’t enough water to really muffle the exhaust note. They run cool, everything has been checked (impeller, heat exhchanger etc) but the new water pump just don’t seem to have enough flow. The old style was quieter
  15. Capt Ralph

    Capt Ralph Senior Member

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    Seems I'd be shopping for the old style pump.
    Bet ya it was a Sherwood cost reduction and probably past OhNo in the dark.
  16. Pascal

    Pascal Senior Member

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    Yeah probably. It was a different design where the the pump body would pull from the back end. Not a plate cover. But it had a slightly larger output hose
  17. Capt Ralph

    Capt Ralph Senior Member

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    I remember that pump. Same on the MD4/20kw. Pain to service. I think the impeller lasted longer also.
    More of a cam Collapsing the impeller blades with fatter fingers.

    I remember on my Isuzu based gen-set, I worked with my rep at Depco Pump and found a next sized up Jabsco pump that fixed our problems.
    Eating impellers and front bearing. Found a nice pump that used 2 bearings and a wider impeller.
    Sometimes, you do have to re-invent the wheel.

    BTY, I think I still have that MD4/20kw raw pump, maybe 2 with spares. You need it?
  18. Bigsalmonfish

    Bigsalmonfish New Member

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    NL all the way. Just installed a new one with the Gem enclosure. Have it on the isolation pads. Quiet and no vibration. 500 hours in 2 months.
  19. rtrafford

    rtrafford Senior Member

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    Very much the key to the decision making process. Lower RPM bolsters longevity and reliability. Northern Lights has really nailed the engineering. Your doubling of engine mounts is truly the right setup.
  20. DOCKMASTER

    DOCKMASTER Senior Member

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    I just installed two NL gens; a 9kw and 20kw, both with their Gem series enclosures and doubling the isolation mounts. This went in place of an Onan (20k) and a Kohler (8k). The NL units are fantastic so far. Much quieter and less vibration. And their customer service through procurement and installation has been great! I couldn't be happier!