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Battery fan or road/wind noise?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by rtotheichard, Mar 31, 2015.

  1. rtotheichard

    rtotheichard Junior Member

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    Hey all.

    I've owned a 2012 Prius Two for less than a month now, and today while driving home I noticed what sounds like road/wind noise coming from the rear passenger side area.

    Googling about this revealed information about the battery fan. However, I'm unsure if what I'm hearing is the battery fan or road/wind noise that I just haven't heard before.

    Here's information regarding the conditions I was driving in:

    - 84 degrees outside temperature
    - car had been sitting in an open-air parking lot for about 2 hours
    - no tint, no windows cracked for hot air release
    - upon returning to the car I turned on the AC to 68, set at midrange speed
    - was driving on the interstate doing some stop-and-go, but mostly 50-plus MPH
    - windows rolled up completely, no doors ajar
    - it sounded like air rushing by
    - could not hear anything coming from the left rear side, but my left ear is partially blocked by the headrest, so...
    - sound would decrease in volume if car slowed down
    - sound would increase in volume as car got faster, but would eventually level out it seemed
    - sound would completely go away at speeds below 20ish mph
    - sound would not change based on level of AC, whether on, low, high or off
    - checked battery vent for obstructions/debris, saw nothing, and was cool to the touch
    - car has about 28k miles on it, replaced rear tires yesterday but all bolts, caps, etc. are securely in place

    Any thoughts would be appreciated! Thanks a bunch.
     
  2. bisco

    bisco cookie crumbler

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    think it's the battery cooling fan. btw, that's not a bad thing, that's why it's there. you could get a scan gauge to confirm. or just have someone sit in the back and listen at the intake vent. 84 in okie? wow!:p
     
  3. CR94

    CR94 Senior Member

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    If the fan is running at above its lowest speed, wouldn't you hear it whenever you stop the car, assuming the engine has automatically stopped as usual? Then there would be no wind, engine, or tire noise to confuse you.

    I've never heard mine, but haven't been through a summer with it yet.
     
  4. bisco

    bisco cookie crumbler

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    i've never heard mine in 3 different pri, but i'm pretty deaf.
     
  5. Former Member 68813

    Former Member 68813 Senior Member

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    yup, HV battery fan alright.
     
  6. rtotheichard

    rtotheichard Junior Member

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    Excellent. Thanks for the information, everyone!