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How to make the HV battery fan to run all the time?

Discussion in 'Prime Main Forum (2017-2022)' started by ESh, May 23, 2023.

  1. ESh

    ESh New Member

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    Is there any possible way to make the fan run all the time, automatically, without using Dr. Prius or similar app?
    The idea is to net let the battery run hot.


    Thanks.
     
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  2. Plugin_RK

    Plugin_RK Member

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    This is an interesting idea. Toyota's goal is probably to reduce energy consumption and only use the fan when it is most effective.

    I used to have a Hewlett Packard business laptop with a fan that was off most of the time. The fan didn't run mostly and allowed the temperature to build up until it was hot esp. for the CPU, then the fan turned on - unfortunately the fan was unpleasantly loud. So, HP made a firmware modification allowing the user to choose to run the fan at low speed permanently as an option, which many users enabled. This was great as it reduced fan noise dramatically, indicating presumably that the laptop was seldom operating at higher temperatures (... but at the expense of increased energy use).

    So, your suggestion might similarly result in lower average HV battery temperature. Presumably, this would incur slightly higher energy usage but this may be of no concern e.g. if your daily commute doesn't deplete the battery. For example, my daily commute to work leaves between about 10% and 20% battery level depending on season, etc.
     
    #2 Plugin_RK, May 27, 2023
    Last edited: May 27, 2023
  3. bisco

    bisco cookie crumbler

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    i know you can run the fan with a scan gauge, but idk if you can run it manually
     
  4. Plugin_RK

    Plugin_RK Member

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    Could it be as simple as connecting the fan via a manual switch to a suitable power source in the car i.e. bypass the automatic control?
     
  5. bisco

    bisco cookie crumbler

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    idk, the fan speed is controlled by the attached logic board, so you would have to now something about the electronics.
     
  6. Plugin_RK

    Plugin_RK Member

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    It would depend on the type of fan. Many older fans just required power to their terminals and they'd run, which would bypass any electronics completely.

    That's not always the case though. There might also be a sensor detecting whether the fan runs or not to protect against loss of cooling leading to battery overheating. Someone will know, unfortunately I don't.
     
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  7. kenmce

    kenmce High Voltage Member

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    A possible work around would be to mount a small fan over the air inlet and have it run whenever the car was on. The existing fan could still come on if needed.
     
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Part of making a fan that only runs as much as needed is so that the item to be cooled gets exactly enough cooling.

    Another part of it is making sure the fan lasts as long as the rest of the car.

    If you do rig your fan to run full-time, make a reminder to check on it periodically, because it might not last as long as it was originally designed to.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    A little cooling is good, so more is better? Maybe yes; maybe no?

    The fan is also multi-speed, about five speeds IIRC: so full speed all the time?

    I’d think Toyota’s engineers thought a lot about this, dialled in fan activation and speed carefully.
     
  10. rjparker

    rjparker Tu Humilde Sirviente

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    Sometimes the battery needs to be warmed up so forcing full speed fan will slow that process. Remember the battery is not a human who performs better at 72f.
     
  11. bisco

    bisco cookie crumbler

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    can a battery receive too much cooling, outside of cold weather?
     
  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    It can receive too much dust. More air means more dust.
     
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  13. bisco

    bisco cookie crumbler

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    interesting, i never thought of that
     
  14. prius16

    prius16 Active Member

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  15. rjparker

    rjparker Tu Humilde Sirviente

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    EV range is different than an air cooled hybrid battery's best operating temp. EVs use battery power to heat the cabin and to heat or cool the battery. Running a hybrid battery's fan faster than necessary (which varies) just reduces efficiency and increases fan wear and blower accumulations. If a hv battery is overheating its usually a clogged blower or a really bad battery.
     
  16. prius16

    prius16 Active Member

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    Sorry, there isn't anything magic or special about the hybrid or EV batteries that Toyota uses.
    Yes, every vehicle manufacture has there own very specific requirements.
    However, the general uses/limitations exist.
    Battery temperature is battery temperature.
    I'm not going to argue, or debate, something extremely basic, and super well known.
    Google.....
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    I had a Scangauge monitoring the middle temp sensor on hybrid battery (on our ‘10). I recall one cool evening, driving a quiet coastal highway, on a cool evening, around 80 kms (50 miles) an hour. The sensor temp stabilized around 35C, while ambient was maybe 18C. That seemed a baseline case, what the engineers were aiming for?
     
  18. bisco

    bisco cookie crumbler

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