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How does HV Battery cooling airflow work...

Discussion in 'Gen 2 Prius Main Forum' started by JPR, Aug 9, 2020.

  1. JPR

    JPR New Member

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    ...if I can't blow air through any of the battery modules? Is there a valve or something that opens in operation?


    Here's more details on what preceded this question:

    I am a new owner of a 2006 Prius with 177k miles.
    Had the red triangle and HV battery codes when I bought it.
    I used an OBD monitor and reset the codes (so I could use cruise control), ran OK on the 130 miles home, got 52mpg.

    I did have to reset the codes every 15 minutes or so, when doing 65-70. When I slowed to 60mph, I could go over 30 min. (The code was always a low voltage code, sometimes also a battery temp, IIRC)

    (Incidentally, when I first took it for a test drive, I thought the stereo system had a bad speaker, because it sounded like loud static coming from the right rear. Turns out, it was the HV battery blower; it did this frequently, but not all the time, on the way home)

    When I got it home, I installed Dr. Prius and discovered one bad module; so I took the battery out and swapped the module. I checked the blower filter, it looked brand new, not a speck of dirt or even dust.

    I bought a kit of new battery contact nuts and plated bus bars. I've reassembled the battery, torqued all the nuts, and am about to re-install it in the car.

    Is there something I can do to test for cooling airflow before during or after I get the battery back in the car?

    Thanks!
     
    #1 JPR, Aug 9, 2020
  2. SFO

    SFO Senior Member

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    Have you cleaned the HV battery fan?

    In the future, record the OBD2 codes (DTCs) so that you can share or reference them as needed.
     
    #2 SFO, Aug 9, 2020
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  3. ChapmanF

    ChapmanF Senior Member

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    The cooling air blows between the modules. Nothing blows through any module. The modules have dimply sides to create a bit of space between them in the stack, and that's where the air flows.
     
    #3 ChapmanF, Aug 9, 2020
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  4. JPR

    JPR New Member

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    Ah, ok... I was wondering about this, but the airflow picture in the manual looked to me like it was going through the black plastic tubes... it looks to me now that that is for off-gassing if that should ever happen (in which case, I think there is a pressure valve in each module)

    As for cleaning the filter, I checked it and it is spotless... I'm guessing it was changed just before I bought the car.

    Once I get the battery back in the car, I sure hope the airflow quiets down because it was extremely obnoxious, and that was from the front... I'd hate to be sitting right next to it. I should probably check the motor bearings, since everyone else says it's barely noticeable.

    Thanks!!
     
    #4 JPR, Aug 9, 2020
  5. ChapmanF

    ChapmanF Senior Member

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    Exactly. (y)

    Also, it sometimes seems that the pressure valves get a little stuck, and if a module does seriously overpressure, its top will protect the safety valve by blowing off first. At least they tried.
     
    #5 ChapmanF, Aug 10, 2020
  6. valde3

    valde3 Senior Member

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    What filter are you talking about? There's no filter from the factory.
     
    #6 valde3, Aug 10, 2020
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  7. AzusaPrius

    AzusaPrius Senior Member

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    Here it is. Screenshot_2020-08-11-10-28-22.jpeg
     
    #7 AzusaPrius, Aug 11, 2020
  8. valde3

    valde3 Senior Member

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    So that's a aftermarket air filter? Part number doesn't look like Toyota part number. And you know that JPR has it installed?
     
    #8 valde3, Aug 11, 2020
  9. AzusaPrius

    AzusaPrius Senior Member

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    That is OEM but the point is there is a filter.
     
    #9 AzusaPrius, Aug 11, 2020
  10. fotomoto

    fotomoto Senior Member

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    Not for a gen 2 it isn't (this thread).
     
    #10 fotomoto, Aug 11, 2020
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  11. valde3

    valde3 Senior Member

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    No. There's no filter from factory.
     
    #11 valde3, Aug 11, 2020
  12. edthefox5

    edthefox5 Senior Member

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    Nope no filter.

    I have velcro'ed some filter material to the face of the inlet that i custom cut as I have a sheddy doggie.

    if your in there working on the hybrid battery you must clean that hybrid fan itself. Take the fan out and when you remove its power plug look carefully at the plug as most G2's have a bad water leak in the top hatch/roof seam and sometimes it will drip down perfectly into that connector and corrode the pins. This is very very common.

    In fact get a flashlight and look down in the well your 12 volt battery is sitting in as its probably sitting in water. That hatch leak is super common including mine. I would be surprised if your well is dry.

    Pop the black plastic running strips on the side of the roof off. They pop right off. You will see cracks running from the hatch valey corner up into that seam.
     
    #12 edthefox5, Aug 11, 2020
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