Traction Battery Temperatures

Discussion in 'Prime Technical Discussion' started by Oniki, Jun 2, 2018.

  1. Oniki

    Oniki Active Member

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    Thanks to John1701 I learned about the android app 'hybrid assistant' which monitors battery temperature (and a whole lot more.)

    Today was my first day watching the data. We started our 250 mile trip in the morning at ~ 20C (68F) ambient and similar battery temperature. Over the course of the first 35 - 40 miles driving was EV only and by the time the battery was depleted it's temperature was 32 C (90F).

    Ambient temperatures climbed into the low 90s F (32 C) through the drive and A/C was set to 72 - 74 F Auto, then 4-5 out of 6 ? fan setting.

    At end drive battery temp was 35 C (95 F). If the battery fan came on I could discern it and I don't know yet if it is possible to monitor in the App.

    I'll continue to post in this thread and perhaps after a while I'll have some accumulated data to share. For now the experience matches what I saw in John's video: battery temperature in EV or HV modes are surprisingly (to me) similar. I'd like to know if that is controlled or the nature of each mode beast. My hope that cabin cooling would translate into a cooler pack is thus far not true.
     
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  2. Flaming

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    10 months of ownership and i still can't tell yet if my traction battery fans are working ... i mean i know they work but i can't hear them. i started to use hybrid assistant recently and the highest temp ive seen so far is 37 C . I think that in hybrid assistant the Gen 4 Fan monitor can't be implemented yet ... the fans work and all but the app can't tell the speed .. cabin temp is set between 20 and 22 C
     
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  3. Oniki

    Oniki Active Member

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    Thanks for the info, Flaming.

    Do you know if 'hybrid assistant' will report A/C or heating power draw ?
     
  4. john1701a

    john1701a Prius Guru

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    Yes. You can clearly see that in the start of both of these videos...



     
  5. john1701a

    john1701a Prius Guru

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    btw, the Torque app provided temperature data for the previous generation PHV. Here's a video of that, where I intentionally pushed the pack by not using the A/C to cool it... figuring the real-world data may come in handy sometime in the future:

     
  6. Oniki

    Oniki Active Member

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    ^^ I give up. Which monitor is it ?
     
  7. john1701a

    john1701a Prius Guru

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    Lastly, here's an example of the opposite extreme with PHV:

     
  8. john1701a

    john1701a Prius Guru

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    Overall kW is on the far right. When no electricity is being used for propulsion (vehicle on, but no movement), you can see the draw rate for accessories.



    Instead, look at it from perspective of not getting hot. You don't observe extremes, right?
     
  9. Oniki

    Oniki Active Member

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    The App has an informative user manual
    • Notification is given when the HV battery fan is active
    • I think that happens when the battery reaches 37 C
    I presume this is a trade-off between the energy cost of cooling and battery longevity. Tough choice for Toyota to make, although personally I would prefer that the battery spend more of its time at closer to 80F than 100 F while driving.

    This also suggests (although it remains to be shown) that the Prime is not taking advantage of cooler ambient temperatures when available to cool the battery. That is definitely not my preference. I'll have to see if turning off recirc mode while increasing ventilation into the cabin shunts more cabin air to the battery.

    It will also be interesting to have some information about battery temps related to charging. It would be very nice if the system cooled the battery down at the end of a charge.
     
    #9 Oniki, Jun 3, 2018
    Last edited: Jun 3, 2018
  10. Flaming

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    well , in hybrid assitant app we dont have the fan speed in RPM yet ( For Gen4 ) but i noticed that at 37C the little battery icon turn from green to yellow .. so maybe this is the indicator when the traction battery fans become active. I believe the fan can be forced ON at all time with the App but this is for Gen3 .. can't be done yet for Gen4.

    I suggest to download and install Hydrid Reporter app .. it's a free add-on for hybrid assitant .. at the end of a run , Hydrid Reporter will generate a nice and very detailed report with hybrid assitant data. Somewhere in the report i saw a line called '' Average services consumption '' so this is probably what you are looking for .. It's the average consumption used by everything but the electric motors .
     
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  11. Oniki

    Oniki Active Member

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    Yep
     
  12. Andres V

    Andres V Junior Member

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    I've being reading about weather temperatures and battery performance on many threads in order to understand if temperature could be the culprit for the death of my battery on a 2010 Prius with 93000 mi as of today.
    I bought my car used, I ignore the conditions in which it was kept, but I'm starting to think that ambient temperatures have something to do with this death just because I read of so many cases of Gen2 and 3 running for more than 200000 mi on the original battery.

    This a critique on the way that these battery are badly cooled in my opinion.
    I live in an area with an average temperature of 86 °F all year long, that might not be so much, in fact I was reading other threads of much worst conditions but you have to keep in mind that under the sun the closed car can reach much higher temperatures because of a sort of greenhouse effect so adding this up to the heat generated by the own battery I don't think much higher ambient temperatures are needed to damage a battery. I still haven't found concrete data on temperature working rage on the traction battery, everybody just mentions what temperatures peaks they reached.
    In my case, I don't have a garage, neither at home nor work and not many trees around either, at least big enough to have enough available shade around the city, so my car is in the sun pretty much all year long. If this battery is such a critical part of the hybrid system, why isn't it cooled properly like the ICE has it's own radiator, I don't see Toyota recommending spraying water on it, blowing or making very short trips to avoid incurring in excessive temperatures, so why the traction battery doesn't get it's own cooling solution instead of depending on the user's AC... In my opinion that's a "halfassed" job.
    Don't get me wrong, I am not saying I can do a better job in engineering hybrids but just look at the battery own fan, it's embarrassing for such a massive piece of hardware, it doesn't take a genius to understand that it is insufficient.
     
    #12 Andres V, Oct 15, 2018
    Last edited: Oct 15, 2018
  13. Flaming

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    I agree .. but i dont see how Toyota can customize the fan per region ... up here a ''hot'' summer day is 35c Top .. for sure, cars in the southern U.S.A / Mexico must have tougher life .. but what is worst ? 40c and up or bitter cold -25c ? our winter range is like an average -10 and -25 with short dip in the -30+ in January/February. Primes sold in Canada and Alaska include a battery heater .. in 15 months of ownership i never saw my battery going below 10c and never higher than 38c .. do i live in the sweet spot ? i do not know .. but im confident with Toyota engineering .. i see plenty of Gen2 on the roads.
     
  14. Andres V

    Andres V Junior Member

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    My point is, that I think I'm learning a hard truth that it may not be openly spoken for obvious sales reasons, but maybe, maybe...anyone that lives in a constant very hot area, should avoid hybrids altogether or has to be at least warned that its battery expectancy will be much much lower than living in temperate or cold area. Just that..........and the cooling on Prius batteries sucks.
     
  15. davecook89t

    davecook89t Active Member

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    It is well known that cold temperatures are best for battery longevity but not efficiency. I believe the Gen 1, 2 and 3 cars with the NiMH batteries were expected to have an battery operating temperature of 30 to 35 degrees C. In the videos @john1701a posted above, you will see that he got much better MPG when the car was driven on a hot day without having the AC turned on, than on a cold day with no heat. I would expect that the cars with Lithium-Ion batteries have been designed similarly. I believe the battery fan does a good job of keeping the battery temperature in an optimum operating range no matter what the outside temperatures, as long as it is not clogged.

    Edit: corrected reference to Lithium battery
     
    #15 davecook89t, Oct 15, 2018
    Last edited: Oct 15, 2018
  16. Old Bear

    Old Bear Senior Member

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    If you have a spare hour, you might want to watch this video where John Kelly of the automotive technology program at Weber State University in Utah does a complete re-assembly and detailed explanation of the Prius Prime battery.



    He also has produced this somewhat shorter video showing how the Prius Prime battery assembly fits into the vehicle:



    At about 14 minutes into the video, he shows the ducting and the two blower motors which provide the battery cooling function.
     
    #16 Old Bear, Oct 15, 2018
    Last edited: Oct 15, 2018
  17. Flaming

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    Awww.. WeberAuto call me a geek if you want .. i watched all his vids with chips & pop-corn
     
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  18. Andres V

    Andres V Junior Member

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    You guys are the best. Best forum community I've been in years! I'm here trying to be all toxic and shit and you keep coming up with convincing arguments and videos to teach me otherwise.... I was joking, not being toxic, just very frustrated, I have a beautiful car sitting in my walkway, the very best I have ever owned and I can't use it and very probably going to sell it after I get a hold on a battery just because I'm afraid it might die on me again because of the weather I live in. I wouldn't be able to afford another battery. I can't afford one now.

    Posted via the PriusChat mobile app.
     
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