HV Battery Fan Air Filter Mod

Discussion in 'Prius c Accessories and Modifications' started by Freeekonaleesh2, Mar 6, 2015.

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  1. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    Well I did attempt.
    I got a 36x18 air filter(9merv), cut 5" wide and 36" long strip.
    That turned out to be to long and restrictive once squeezed in the hole.
    I cut about 2/3 off(about 12" long now) and now the filter breaths(well i can breath trough it like it was with the original filter, but with more peeks and valleys for more surface area). Does not seem restrictive to me.

    Here are some pics:
    [​IMG] [​IMG] [​IMG] [​IMG]
     
    #1 Freeekonaleesh2, Mar 6, 2015
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  2. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    That's a lot of filter... Hopefully it isn't too restrictive... Hope it works out for the best!
     
    #2 Eclipse1701d, Mar 6, 2015
  3. kingnba6

    kingnba6 Active Member

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    That looks like it will restrict a lot of the flow, but hopefully it doesnt.
     
    #3 kingnba6, Mar 6, 2015
  4. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    The more surface area the less restrictive a filter is. As long as the peeks and Valleys of the filter are not touching you are getting more flow.

    I do wish I could run a test of the HV battery fan on a certain speed and use a CFM-Monitoring Device to see the difference. If I knew how to make the fan run I would buy a CFM-Monitor.

    Since ive had it, ive never felt the fan running with my hand while driving. (Even before the filter mod.)

    I do new home inspections and it is DUSTY at all the new neighborhoods. To me, this will hopfully keep it clean as I like to have my windows down on good weather days.
     
    #4 Freeekonaleesh2, Mar 6, 2015
  5. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    Don't you think that maybe you should put less in there? I understand the reason for upgrading it, but the last thing you want is your HV Battery to overheat.... I understand that you have not witnessed it or heard it running, but that doesn't negate the fact that when the HV pack reaches a certain temperature, you WANT as much airflow as possible to cool it down in a timely manner. Extending the time it takes, or impeding the ability for it to maintain the right temperature may have costly consequences, in the future.
     
    #5 Eclipse1701d, Mar 6, 2015
  6. drysider

    drysider Active Member

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    You can force the fan on using an ODB device, such as ScanGauge. However, taking 180 sq. inches of filter surface and squeezing it down to 12-15 sq. inches has to have a negative effect on its' filtering ability. Were you having problems with the factory filter?
     
    #6 drysider, Mar 6, 2015
  7. bisco

    bisco cookie crumbler

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    the mother of invention.
     
    #7 bisco, Mar 6, 2015
  8. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    There is not a filter of any type on the HV Battery Fan Blower(other than a mesh screen{like a window screen} that lets dust through).
     
    #8 Freeekonaleesh2, Mar 7, 2015
  9. bisco

    bisco cookie crumbler

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    but that's all you really need. clogged fans have always consisted of large debris like dog hair.
     
    #9 bisco, Mar 7, 2015
  10. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    OK, I did some testing.
    I got an old PC 12v fan and hooked it up to a Volt Meter.
    Using Torque, I set the HV Battery Fan to 6(Max)

    With the outer covering off:
    With the air flowing through the pc fan, no filter, directly on the HV Battery Fan, I got a reading of 4.43 Volts being made from my PC 12v fan.
    Adding the Air Filter I got 0.300 Volts (300mv) being made from my PC 12v fan.(also tried increasing and decreasing the surface area of the filter with same results) 93.2% Reduction

    With the outer Covering on:
    No Filter - 3.5 Volts being made from my PC 12v fan.
    With Filter - Could not get the PC fan to turn. Unknown% Reduction

    Conclusion:
    Not going to keep the air filter on.
    If Toyota decided not to have an air filter on the HV Battery Fan then maybe there should not be one.
    Even though I will be in a dusty environment most of the time being in New Home Construction.
    I guess just keep the windows rolled up, use the A/C system and its filter to filter the air.


    Just wondering, were does the HV Battery fan Exhaust to?
    Any comments? Please let me know. :)
     
    #10 Freeekonaleesh2, Mar 8, 2015
    Last edited: Mar 9, 2015
  11. chriswong

    chriswong New Member

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    I would be concerned about the restrictive issue too.
     
    #11 chriswong, Mar 9, 2015
  12. ericbecky

    ericbecky Hybrid Battery Hero

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    Since there isn't a filter, I would at least suggest you check the fan periodically.
    I posted some pics this week on my company facebook page showing some horrendous Prius fans I've seen this week.
    They were both on cars whose hybrid batteries failed.
    http://bit.ly/1MnVrXE
    http://bit.ly/1AbvqD6
     

    Attached Files:

    #12 ericbecky, Mar 9, 2015
  13. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    Did another test with different filters.
    This time I used Foam Filters with better and more promising results. They came from PC add-on air filters for your PC fans.
    Also, a picture to contrast the size of the holes(Coarseness) between the filters and the OEM Mesh Screen.

    [​IMG]
    [​IMG]

    Still using my PC fan as the % reduction.

    With the outer covering off:3-9-15
    With the air flowing through the pc fan, no filter, directly on the HV Battery Fan, I got a reading of 4.20 Volts being made from my PC 12v fan.
    With the Less Coarse filter the Voltage dropped to 3.60 Volts. 14.2% Reduction.
    With the More Coarse filter the Voltage dropped to 3.46 Volts. 17.6% Reduction
    With both, Less Coarse in front then More Coarse in back, Voltage Drop to 3.20 Volts. 23.8% Reduction
    End, rechecked without filters and got 4.20 Volts.

    I think I will use the More Coarse Foam Filter to help keep the dust out and clean it every 5,000 miles(but will check every 1,000 for the first 2k to see how it is doing).

    These results are more promising than the Fiber Filter I first Tested.

    Comments & Questions are welcome. :)
     
    #13 Freeekonaleesh2, Mar 9, 2015
    minkus and Yakoma like this.
  14. bisco

    bisco cookie crumbler

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    someone else used this type of foam with good results. i think the fan exits into the 12 volt battery area out from there?
     
    #14 bisco, Mar 9, 2015
  15. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    Bravo! Much better.
     
    #15 Eclipse1701d, Mar 10, 2015
  16. Yakoma

    Yakoma Active Member

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    Great work, Freeek! Nice to have some science to compliment all the anecdotal info.

    This may lead to a reliable mod that may prevent the disasters that Eric illustrated above. Holy Back Hair, Batman!

    Where did you source your filter material?
     
    #16 Yakoma, Mar 10, 2015
  17. Freeekonaleesh2

    Freeekonaleesh2 Junior Member

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    I got these filters from Microcenter, (A local computer mega store). Im sure you can get them from any online store like NewEgg.com

    Coarse Filter:
    Kingwin 120mm Fan Filter: microcenter.com/product/410252/120mm_Fan_Filter
    Less Coarse Filter:
    Evercool 120mm Plastic Finger Guard with Filter(FGP-120): ::EVERCOOL Thermal Co., Ltd. ::

    I wish I knew were to just get the foam from, but you can't beet 4.99 each for a reusable filter pre cut basically. Also, just wash it out and reuse for the life of the vehicle.(Meaning I could just put it over the fan and put the plastic on to hold it in place, or just trim it a little to fit inside the plastic hole.)

    From looking at this site below, it seems I have a 30 holes per inch and maybe a 100 holes per inch foam filters.
    Plastic Fan Filter Assemblies

    Here is the More Coarse Foam Filter Installed. It kindove stuck to the foam cushion around the fan. Then I put the plastic on that goes under the seat, and it holds it in place.
    [​IMG]

    Regards. :)
     
    #17 Freeekonaleesh2, Mar 10, 2015
    Last edited: Mar 10, 2015
  18. c4

    c4 Active Member

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    Anyone have a diagram of the battery ducting system that they can post?

    I'm thinking about a mod to the battery cooling that places a suction fan at the output of the battery.. This is the way the Gen1 battery cooling system worked and I believe it would be much more efficient (pulling air through the battery vs. trying to push it).
     
    #18 c4, Mar 11, 2015
  19. Sean Nelson

    Sean Nelson Active Member

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    If you install a filter that traps finer particles then you should be careful to check it regularly, since it's more likely to get clogged up. Most cooling problems are the result of filters getting clogged rather than them letting fine particles through.
     
    #19 Sean Nelson, Mar 12, 2015
  20. CR94

    CR94 Senior Member

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    Right. Even something as coarse as a single layer of typical cheap fiberglass furnace filter material should work well to keep big stuff our, and not clog too readily.
     
    #20 CR94, Mar 12, 2015
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