Inverter generators and decibels

Discussion in 'Bad Dog Cafe' started by LGOberean, Nov 10, 2019.

  1. LGOberean

    LGOberean Doctor of Teleocity

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    I'm guessing that same basic science applying to guitar amps and decibels applies also to inverter generators and decibels, so I'm looking for help from my TDPRI brethren.

    My wife and I have owned an RV travel trailer since June. Thus far we've camped in state parks both in Texas and other states in the Union (Louisiana, Mississippi, Tennessee & Arkansas) that have water and electrical power outlets. We're wanting to add a generator to our rig for boondocking/drydocking purposes.

    One 2000 watt inverter generator unit we are looking at is purported to be quieter (53dBs from approximately 25 feet away), and is relatively lightweight (48.5 lbs.). Problem is, one such unit is not sufficient for running our trailer's AC. Two such units connected in parallel can provide 30 amps of power sufficient for the task. But double the generators, double the noise? That's the question.

    From discussions I've read regarding amp wattage output and decibel levels, I believe that double the wattage is not equal to double the volume as measured in dBs. So I'm wondering if the difference between running two of these units simultaneously will be in real world numbers like 3dBs or so louder than one unit by itself. IOW, the level of noise increase will be barely perceptible.

    Am I right? Or at least in the ballpark of "right"?
     
  2. schmee

    schmee Poster Extraordinaire

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    I've been told that it is double in discussions about small amps. The discussion was like "If I have two tweed deluxes, will that be twice the volume of one?". My logic said "No". Each amp is what it is. But the consensus from the guys who are astute said "Yes". Still doesn't logic out to me.
     
  3. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    The engines will not be in sync, and the noise it generates will vary according to the load. It will waver. It may or may not be 3~6dB louder[1] with both running than just one. Imagine two cars idling and the difference in volume compared to just one.

    If you can, take 2x2kW electric heaters to the dealer showroom and ask them to power two up and run your heaters to get a clearer idea of the noise before parting with money.

    [1] Based on warming a fleet of motorcycles up and daily checking them each morning. Load the engine, the noise gets a lot louder. What is the dB rating based on?, unloaded/50%/75% load?
     
  4. Art VanDelay

    Art VanDelay Tele-Afflicted

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    Decibels are calculated logarithmically and not linearly which is why 100dB is not twice as loud as 50dB. Therefore, 2 sources of sound of roughly equal dB's won't just be twice as loud. Louder? Yes.

    Remember that distance plays a huge role in perceived volume which is why I bought a 50 foot 10AWG cord to plug into my generators output. Just like a speaker cabinet's SPL rating.
     
  5. Splodgeness

    Splodgeness TDPRI Member

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  6. LGOberean

    LGOberean Doctor of Teleocity

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    I get that the noise will vary according to load. The generator we're looking at boasted 53dBs from 23 feet, but also had lines in the description about "50% load" and "economy mode," so I figured the loudness would vary depending on the load.
     
  7. geoff_in_nc

    geoff_in_nc Friend of Leo's

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    Question because I have no knowledge of these things. Wouldn't you have to sync phase of the two generators to parallel them? Can that be done?
     
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  8. Obsessed

    Obsessed Telefied Ad Free Member

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    I suspect that you are looking at the Honda 2000. A great little generator, but as you know, not enough for RV AC. My neighbor has a Honda 3000 EU which has the "economy" switch similar to the 2000. A fantastic generator and almost as quiet. Just because of maintenance issues of two 2000s, I think the slightly louder 3000 might be a better choice regardless. It is heavier, but there are after market trailer/wheels kits that would allow rolling them around the corner to move the sound away as desired. Plus it has a key start with a backup pull start.
     
  9. LGOberean

    LGOberean Doctor of Teleocity

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    Well, good question. We are just learning about these things ourselves. Like I said, we bought our trailer 5 months ago, and thus far we've camped in state parks offering both electric and water, so we haven't had a need for a generator. Never owned one before, so we're looking into it. My wife is asking question on her Facebook group, I sought help here.

    Someone on that Facebook group commented along the lines of syncing phase...

     
  10. LGOberean

    LGOberean Doctor of Teleocity

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    Actually, that's not the brand of the one we're eyeballing. And since we'd be loading/unloading a generator into and out of our SUV, a unit that weighs 131 lbs. is pretty much out of the question.
     
  11. Rick330man

    Rick330man Tele-Afflicted

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    Honda sells the adapter that allows you to run 2 together and thus double your available amperage.
     
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  12. 1300 E Valencia

    1300 E Valencia Friend of Leo's

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    "53 dB" is two people having a normal conversation. Background noise. If you stand in the middle of any *empty* room with a decibel meter you will get 55 dB.

    If they're in an adjoining room with the door closed, you won't hear them. 56 dB will be louder but just barely noticeable. Each additional three decibel increase is about the smallest increment the human ear can detect.
     
  13. stxrus

    stxrus Friend of Leo's

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    Get a 4-5 kw genset to drive everything you need with headroom (to use an amp correlation) and be done with it
    We had an inverter generator that died and was not worth trying to repair. A $1300.00 machine would cost $900.00 minimum to fix
    Both of my nom-inverter units are running strong and over 13 years in service
     
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  14. Junkyard Dog

    Junkyard Dog Tele-Afflicted

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    Are we talking tube generator dBs or solid state generator dBs?
     
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  15. rickthescot

    rickthescot Tele-Holic

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    is your AC a 13.5 or 15K? I am in the RV industry and would be happy to answer questions. Also an avid RV user and I own 3 portable generators. Feel free to PM me.
     
  16. LGOberean

    LGOberean Doctor of Teleocity

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    You do the RV thing too? Where in Texas are you? Our time away are mostly 4-5 day jaunts, and since our starting point is so far south, we've only ventured out of Texas once in these first five months of RV camping. But Texas sure has some great state parks. Hope to cross paths with you one day. Same goes for Allen, a.k.a. @Big_Bend .
     
  17. BobbyZ

    BobbyZ Doctor of Teleocity

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    Who cares about air conditioning? It's 4 degrees outside the Avion right now. The AC unit is covered and stuffed full of fiberglass insulation.
    In about six months I'll change my mind on the issue.
     
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