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HV fan preset overriding

Discussion in 'Gen 3 Prius Technical Discussion' started by abubin, Jun 13, 2024.

  1. abubin

    abubin Member

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    I read a few thread on the analytics and control of the HV fan. However, I just need something simple. Let the fan run at max (level 6) at 36c. I don't mind the fan sound as music can drown the sound a lot even at low volume.

    Or possibly to just lower the temp in the HV fan control in the ECU? I am currently using OBD2 with hybrid assistant that I override to run the fan at 36c (lowest possible settings in the app). However, this need connecting to my phone every time and the phone need to run the app all the time. If I can change the setting in ECU, then I don't need to constantly connect to the OBD2. It will just run when temp is 36c.

    Is it possible to even change settings in ECU?
     
  2. AzusaPrius

    AzusaPrius Senior Member

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    Besides Hybrid Assistant and the Dr. Prius app there is this device, though it is very pricey at $300 so not sure many people would buy this but I am thinking of it.

    From SystemHybrid.eu Screenshot_2024-06-13-21-26-02.jpeg
     
  3. abubin

    abubin Member

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    Thanks! Good to know someone already thought of the idea and comes up with the solution. Perfectly something that I am looking for. However, price is too high.
     
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  4. Tombukt2

    Tombukt2 Senior Member

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    I would think pretty much any competent soldering station operator would be able to whip up something similar to this pretty quickly if they wanted to have the desire was there. Me personally I run the air conditioner even if it's on low and it's a million degrees outside it's still keeps the cabin reasonable I'm not riding around in a business suit and all that if I was I'd tint the windows a little bit and that would solve that problem The cold air and the cabin is what gets sucked across the battery and generally keeps it fairly happy unless you're running in the mountains daily driving or something then this system's probably not ideal for those conditions That's pretty rare though but I guess if you live in the mountains it wouldn't be. And I guess if your air conditioner is broken well then that's another issue so the fan controller could be a thing I would think if you really wanted to do that you could just rig up the fan to a switch and just flip it and turn it on of course you have to remember to do that and just let it rip the whole time you're in the driver seat maybe wire it to a ignition controlled wire so when you turn the car on and boot it up the fan is on I mean it's not using that much juice and look at the fan it isn't really that large I was thinking of a larger or thicker squirrel cage fan assembly same diameter just taller since it's sitting sideways in my application there's room a little more CFM.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    There’s an assumption, that Toyota’s programming is not optimal?
     
  6. ChapmanF

    ChapmanF Senior Member

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    Or that they optimized it to a different objective function than you would choose.

    Still, even if you lay out your own choice of objective function, there may be an assumption that your control strategy would score better on it than Toyota's.
     
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  7. Eddie25

    Eddie25 Active Member

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    I used Hybrid Assistant fan control for a while after constantly seeing my battery at 130F and the fan on 2. I don't use an android phone anymore so I can't now. Usually it'll get up to 5 (out of 6) eventually, but boy does it take it's time.
     
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  8. AzusaPrius

    AzusaPrius Senior Member

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  9. Grit

    Grit Senior Member

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    Scan gauge.
     
  10. abubin

    abubin Member

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    Thanks!! This is exactly what I need and able to do. I will start looking into doing this project.
     
  11. AzusaPrius

    AzusaPrius Senior Member

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    Excellent let us know how it goes.

    I may go this route since the guy at systemhybrid.eu never responds.

    Maybe you can make more after you make yours and make some extra cash.