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Traction battery fan

Discussion in 'Gen 3 Prius Technical Discussion' started by bear4, Apr 12, 2012.

  1. bear4

    bear4 Junior Member

    Joined:
    Dec 25, 2011
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    Location:
    FL
    Vehicle:
    2011 Prius
    Model:
    Two
    How often should the traction battery cooling fan come on? It started to be warmer here in FL, and I hear this fan more often now. I bought my 2011 in December and up until now almost never heard this fan working. Now it comes on at least couple of times a day, mostly under heavy acceleration in Power mode. How often do you hear yours?

    Thank you!
     
  2. mad-dog-one

    mad-dog-one Prius Enthusiast

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    Location:
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    Vehicle:
    2017 Prius Prime
    Model:
    ----USA----
    I have been monitoring the battery fan with a Scangauge and found that is runs more often than I previously thought. It has 6 speeds, depending the cooling required, and is barely noticeable until speeds 4-6.
     
  3. jdcollins5

    jdcollins5 Senior Member

    Joined:
    Aug 30, 2009
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    Location:
    Wilmington, NC
    Vehicle:
    2010 Prius
    Model:
    III
    I have been monitoring my battery fan ever since the temps starting getting in the 70's here in NC. After sitting in an asphalt parking lot all day the batteries warm up to about 95F. When I get close to home and hit start/stop traffic the battery temp pumps up to the 100-110F range and the battery fan increases in steps from Mode 1 to 3, starting at about 95F.

    I cannot hear the fan at these speeds as mad-dog-one points out even if I turn the radio off. After going to dinner one night the speed had increased to Mode 4 and I still could not hear it. I had my wife check it and she had to put her ear up to the rear vent before she could hear it and she can hear a pin drop.

    So, if you can hear the fan it is probably at Mode 5 to 6 and your batteries are really hot for some reason. Heavy acceleration in Power Mode will probably cause that in the FL temps :)
     
  4. Bob K.

    Bob K. New Member

    Joined:
    Oct 13, 2009
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    Location:
    Baltimore, MD
    Vehicle:
    2010 Prius
    Model:
    III
    The battery fan draws air from inside the cabin (filtered, and cooled by A/C).
    It is totally normal to hear it more often as the temp outside goes higher. This is to keep it cool, greatly increasing battery life.
     
  5. Vege-Taco

    Vege-Taco Junior Member

    Joined:
    Apr 3, 2012
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    Location:
    Arizona
    Vehicle:
    2012 Prius
    Model:
    Three
    Where are the intake and exhaust vents? Just want to be sure I don't inadvertently block them.

    Shawn
     
  6. Felt

    Felt Senior Member

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    Other Hybrid
    I heard the fan for the very first time several days ago (2010, IV, 55k miles). It was unusually warm, and ran for quite a while. I think the inlet is the small plastic port on the passenger side, at seat level. I have no idea where the exhaust is.
     
  7. jdcollins5

    jdcollins5 Senior Member

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    Location:
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    Vehicle:
    2010 Prius
    Model:
    III
    The intake is next to the right rear passenger seat in the lower corner next to the door. It does not move when the seat is lowered. Be sure not to let your passenger block this vent.

    The exhaust exits the HV battery case and then is vented outside of the vehicle.