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Running DrPrius for longer battery life

Discussion in 'Gen 3 Prius Technical Discussion' started by Noahdoge, Jul 11, 2022.

  1. Noahdoge

    Noahdoge Active Member

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    With the heat index reaching over 115 here in south Mississippi I’ve been running DrPrius for the entire duration of every drive. I haven’t found another way to have the HV fan running consistently in traffic. Does anyone else do this to keep their HV battery cooler while driving in traffic? To me this makes a big difference in battery temp and health.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    I'm just going with the car's programming. The battery fan may be running more than you think. Do you have anything monitoring the fan speed and battery temp?

    I found with ScanGauge II, with an X-Gauge programmed in to monitor fan speed and another for battery temp: car fully warmed up, doing about 80 kmh on a coastal highway on a cool summer evening, something like 20c outside temp, the hybrid battery was around 35C, and the fan speed was 2 (out of maybe 5 speeds?).

    Then, in stop-and-go traffic, using AC, hot day, IIRC I'd see battery temps around 40C and and fan speed 4. Something like that. Nicely synced with Celsius temps?

    FWIW, I've never "heard" the fan.
     
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  3. ASRDogman

    ASRDogman Senior Member

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    If you are using the a/c, then you have cool air blowing over the battery.
    You don't need to have the fan running full on the whole time.
     
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  4. Kyosha

    Kyosha New Member

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    If you are using an Android phone there is an app called Hybrid Assistant, and from my understanding it allows for manual control of the fan. I have not used it personally, but it could possibly be something to look into.

    I'm new to the Prius, but from my understanding as long as you have A/C blowing, you should be able to keep cool air flowing over the battery as long as air path is unobstructed, and the fan is clean.
     
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  5. bisco

    bisco cookie crumbler

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    yes, others do this. at 115f i think it's a good idea, can't hurt.

    it would be interesting to see battery temps with normal operation vs high speed all the time.
     
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  6. rjparker

    rjparker Tu Humilde Sirviente

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    As long as you run your ac in very hot weather you don't need to run the battery fan faster. Here is 102f ambient with over an hour of driving and the battery intake is 88f. You will notice the motor generators run much hotter as does the engine but they are all designed for those temperatures. But the battery "could" get much hotter without ac.

    7DC665EC-0EF8-4133-9122-3783662275CB.jpeg
     
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  7. Noahdoge

    Noahdoge Active Member

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    So by running the AC the hv battery is cooled even without the hv fan running at all? Like when I’m in park but letting the ac run, is that cooling the battery as well?
     
  8. rjparker

    rjparker Tu Humilde Sirviente

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    Anytime you are in Ready the hv fan will also run if the hv battery needs it. The ac will cool it better than using 95-100f ambient.

    When you have a ten year old hybrid battery, replacement or major maintenance is in your future. There is no magic preventative strategy other than avoiding months long periods of non use. I would concentrate on the engine health more. A blown head gasket or engine is more expensive than replacing the battery cells.
     
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  9. Noahdoge

    Noahdoge Active Member

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    I definitely agree about the engine part. I did the full PriusChat special on my 2012 when it had 140k miles. I hit 158k miles on it today and it’s still running like a dream getting about 47 calculated mpg. No detectable signs of oil consumption other than the OCC getting half full every 5k miles.
     
  10. Eddie25

    Eddie25 Active Member

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    I'd be interested in that as well. Not sure it's possible to have a good control in a natural setting though. I like to ride with windows down in the summer and my battery gets pretty darn hot (120-140F is not uncommon). The fan, which I'll often run full speed, seems to have a very minimal effect if any. I've cleaned out the fan but never cleaned the battery area or anything (if there's anything to clean there, I've heard the air flow path can get dusty).
     
  11. CR94

    CR94 Senior Member

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    Despite the energy it consumes directly, running the air conditioner enough to keep the interior under 80°F or so is likely to cost less in the long term than trying to cool the battery with hot, dusty outside air.

    The highest battery temperatures I've seen were around 48°C (118°F), always during traffic jams on Interstates.
     
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  12. bisco

    bisco cookie crumbler

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    i've read others who say a/c doesn't make much difference either.

    i think the whole design is geared to get as many batteries beyond warranty, with the least amount of cost
     
  13. rjparker

    rjparker Tu Humilde Sirviente

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    AC does make a difference. Not using it at 120f is very bad for the hv battery.
     
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  14. bisco

    bisco cookie crumbler

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    i could accept that with evidence
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    I've had our car heat-soaked in direct sun after an extended drive, parked for about 30 minutes. Ambient temp around 90F. Started up, and drove without AC for about 10 minutes, monitoring battery temp sensor #2. Battery temp sat stable, somewhere around 40C. Then turned AC on, set it cold. After about another 10 minutes battery temp had dropped, about 1C...
     
  16. bisco

    bisco cookie crumbler

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    there's your evidence :p
     
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  17. Eddie25

    Eddie25 Active Member

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    I do use AC when it's really hot and it makes a difference but 120F is still not uncommon. I have a black interior, always parked in the sun and take constant short trips where I often attempt to hyper-mile, it's also a 2011. I'll take the trade off (enjoying driving more).
     
  18. bisco

    bisco cookie crumbler

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    window tint and shades?
     
  19. Paul E. Highway

    Paul E. Highway Active Member

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    I use Dr. Prius to run my battery intake fan at full blast and have the AC on 98% of the time. Battery temp is usually around 102-107F.

    Dr. Prius only works for this if it’s the active app on the screen, app goes inactive if you get a phone call or play a podcast. Serious flaw IMO. So when I drive Uber I bring an iPad with me to just run Dr. Prius and that has been working well.
     
  20. Noahdoge

    Noahdoge Active Member

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    If it could run in the background that would be awesome. I’m just so glad it’s free and for IOS.