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Hybrid battery cooling mod

Discussion in 'Gen 3 Prius Accessories and Modifications' started by AzusaPrius, Jun 19, 2020.

  1. AzusaPrius

    AzusaPrius Senior Member

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    Here is my take on giving the hybrid battery a little extra cooling.

    Using 3 25mm fans installed inside the air duct where the heat leaves the hybrid battery.

    This also fixes the issue where the plastic duct gets warped and doesnt allow the normal amount of air to pass through.

    The Dr. Prius image is without it connected on a 95F day to show what the temps are of the hybrid battery.

    I will test further and upload more pictures.
    20200619_123252.jpeg Screenshot_2020-06-19-14-27-25.jpeg

    Posted via the PriusChat mobile app.
     
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  2. PriusCamper

    PriusCamper Senior Member

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    cool idea... any calculations on cfm with and without this mod?
     
  3. AzusaPrius

    AzusaPrius Senior Member

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  4. bisco

    bisco cookie crumbler

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    wow, well done!(y)
     
  5. Grit

    Grit Senior Member

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    Ran AC on half blast for 30 minutes w/HV fan speed at 6, HV bat temp went down only 1 degree yesterday. With those fans with ambient air, may not be any effective than my method above even after 8 hours.
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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  7. AzusaPrius

    AzusaPrius Senior Member

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    No worries this is way better than trying to cool down the hybrid battery with the A/C is runs on its own.

    Posted via the PriusChat mobile app.
     
  8. AzusaPrius

    AzusaPrius Senior Member

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    95F again and driving around with the fan mod on and not doing anything else with the Dr. Prius app besides looking at the idle temps. Screenshot_2020-06-22-11-57-27.jpeg

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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    How are the fans wired, to the same 12 volt source that activates the stock fan? That fan has something like 6 speeds: any idea how that happens? Would your extra fans also change speed?

    What I worry about is pulling into a hot garage on a hot day, after a longish drive. I suspect the battery in that scenario does a punishing heat soak. It'd be nice if there was some way to get the fan(s) to run on, for say an extra 5 minutes.
     
  10. AzusaPrius

    AzusaPrius Senior Member

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    I have them powered by a usb cable running to the front of the car, where I have a Halo portable charger that charges while driving and powers the fans, then when the engine is turned off I have the option to turn on the portable charger as the car sits.

    Posted via the PriusChat mobile app.
     
  11. PriusCamper

    PriusCamper Senior Member

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    Based on those temp readings your fan idea may cost you lots of $$$... I've shown your pics to some folks who are studying similar mods and my one friend said those tiny fans are not only restricting the air flow / CFM of the Prius' existing fan, but those fans are to pump a tiny amount of air onto radiative cooling structures inside small electronics, not to move large amounts of air over a long distance.

    Before you over-heat and kill your hybrid pack you need to remove those fans and try a different mod. I'm suggest buying the tiniest 12v refrigeration/air conditioning system and use it's components to cool the air at the air intake for battery cooling instead.
     
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  12. TMR-JWAP

    TMR-JWAP Senior Member

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    See post #6................aaarrrrggggg
     
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  13. AzusaPrius

    AzusaPrius Senior Member

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    Mmm I think not but will certainly let the forum know when shit goes bad. For now this little $25 mod will stay in place. Also when the main hybrid fan is not on the hot air between every module just sits there, where my mod will continue to pull the hot air out. This will not constrict the air flow because when the main fan kicks on it will just push the air through and around the fans.

    Posted via the PriusChat mobile app.
     
  14. TMR-JWAP

    TMR-JWAP Senior Member

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    Also when the main hybrid fan is not on the hot air between every module just sits there....defeating the laws of physics
     
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  15. AzusaPrius

    AzusaPrius Senior Member

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    Oh excuse me for leaving out that heat rises and then it will just sit there and the metal shroud will act as a heatsink. Oh hey now I got these fans to help out with the heat that just sits there.

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  16. TMR-JWAP

    TMR-JWAP Senior Member

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    the metal shroud will act as a heatsink.

    I suppose it would, however, I was just thinking more along the lines of natural circulation.
     
  17. AzusaPrius

    AzusaPrius Senior Member

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    I understand but if the main hybrid fan is not on then there is no circulation.

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  18. PriusCamper

    PriusCamper Senior Member

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    You have no idea what the CFM of the tiny wimpy fans you're using are... Nor do you know the CFM requirements of the system and how these tiny fan may well be limiting efficiency rather than increasing efficiency. But I get it... You got a whole Summer ahead of you of your pack running too hot to realize that you're using the wrong kind of fans to improve cooling. And I don't have enough details to discuss this rationally so I'm out....
     
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  19. AzusaPrius

    AzusaPrius Senior Member

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    8000 rpm and 1.53 cfm each.

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  20. davecook89t

    davecook89t Senior Member

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    Your first screen shot without the mod shows temperatures that are slightly higher than those with the mod, but we don't have an exact elapsed time for your drive in each case. It would have been good if you had taken a screen shot before a 30 minute drive and then after, both with and without the mod. (I don't think outside air temperature would make much difference, if you have your A/C set to the same temperature in each case). Now that the fans are in place, you can't really do a test that would show how the temperature would change without them. Is it a lot of trouble to take them out just for the test? There are a lot of naysayers, and I might be in that camp, but you could prove us all wrong.
     
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