Post recall charging curve

Discussion in 'Hyundai Kona Electric' started by CharlyM, Dec 9, 2020.

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  1. CharlyM

    CharlyM Member

    I know a bunch of folks were (legitimately) worried about this, here is a data point from today. This is in California winter, outside temperature around ~21C, so you see it going up from 55kw to 75kw when the battery reaches 25C.

    upload_2020-12-9_17-7-53.png



    Screen Shot 2020-12-09 at 5.08.30 PM.png
     
    lars2885, FloridaSun, Joev and 2 others like this.
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  3. I have another curve in my video discussing warm vs. cold weather range on a very consistent 260 mile commute including a fast charge.

     
    KiwiME and electriceddy like this.
  4. Basically the same curve, thanks to both for the well illustrated examples.
    Look forward to 21C (it will be a while yet) to enjoy those rates once again.;)
    What I am getting now is equivalent to the 80% to 90% SOC level, tried again this morning.
     
    Esprit1st likes this.
  5. GeorgeS

    GeorgeS Active Member

    Good research. It is nice to see the correlation in real world data.
    There is an interesting increase in charging speed at 62% SOC. Did something happen at this time?
     
  6. CharlyM

    CharlyM Member

    If you wait the battery will warm up and the charge level will be higher :). On Canada models I think the battery warmer will turn on as well.
     
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  8. Not even close to the temperature required to activate the "winter mode" pack heaters around here. I usually stop at the (right now free) 50 kW local charger just for a top up (40 minutes) and usually in the cool morning as it gets very busy (understandably) later in the day when the temperature is warmer - generally a 2 car wait. So no big deal- until they start applying a fee, supposed to happen in April 2021 and not charged by the kWh (by the minute):(, so that habit is very temporary. Eventually I will have to make sure I am at a low SOC (below 30%) with a warmed up (driven) pack or it will not be very cost effective.
     
    Last edited: Dec 10, 2020
  9. No, that is normal behavior and happens with all cars. The higher the SOC of the battery is, the higher the voltage. The amps stay the same but pack voltage increases which results in higher power. Voltage times Amp equals Power. And that's what's on the y-axis of the diagram.
     
  10. 62% SoC? I’m not seeing any notable changes on either graph. What am I missing?
     
  11. I assume the door at more like 59%.
     
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  13. Just for the record here's a graph of trickle charging at around 1.7 kW from 75 to 94% showing the infamous pause at 82%. It's exactly 10 minutes during which it seems to still be charging at a lower rate. The pause has not measurably affected the overall gain of 2%SoC/hour.
    Slow charge profile post-BMS 196.PNG
     
    Last edited: Dec 20, 2020
    Esprit1st and electriceddy like this.
  14. This explains a question I had raised in another thread on this forum. Thanks for posting. But if I may ask a newbie question: How does one know what the battery temperature is? Is there special instrumentation and software required?
     
    electriceddy likes this.
  15. There are several apps available for use with an OBD II dongle which will show you the battery temp, voltage and numerous other details. I use "car scanner" which is a free app for ios and android. For android you can also use "torque pro" and "soul spy" among others. There are a number of threads on how to set up and use these apps.
     
  16. For those who don't run any apps, the pack will pretty much be at ambient temp - unless really cold when the battery heater will cut in:
    https://www.insideevsforum.com/community/index.php?threads/kona-ev-winter-mode-defined-and-condensed.7977/
    The battery pack will warm up slightly with a long drive or while charging as well. This applies for cold conditions and warm as well (above 70 F);)
     
    mho likes this.
  17. CharlyM

    CharlyM Member

    Technically the battery pack will warm up quite a bit from fast charging, I've seen it go from 10C to 30C :).
     
  18. Well, it's simply about 2% of the prevailing power in both directions lost to heat, so however that applies to the circumstances you find yourself in.
     
  19. Here you can see on the graph, a charging process, from SOC ~20% to 80%, at 1°C, using a 50kW DC charger (Kona Highway 64kWh 2020 model).
    Batt temp was at 6°C and the batt. heater kicked in until 16°C (SOC 36%, in ~25 minutes): Screenshot_20210108-205255_Blynk.jpg
    Power drops to 34kW at 72%, where batt temp is almost 30°C (in ~55 minutes): Screenshot_20210108-205323_Blynk.jpg
    At 80% the temp. rised a little bit to 30.5°C: Screenshot_20210108-205603_Blynk.jpg
    And here you can observe the total energy loss (~9%), during this charge period: TotalEnergy.jpg Screenshot_20210108-205607_Blynk1.jpg
     
    electriceddy likes this.
  20. I realize not "post recall " but had to post this, a video showing a 21 Kona EV DC charging peaking at 94 kW...anyone else w/a 21 model experience this ~ 20% increase in charging speed?:confused:
    https://www.reddit.com/r/KonaEV/comments/kueqej/94kw_charging_speeds_someone_asked_for_a_video/
    If Hyundai tweaked the speed, one would think their media would be all over it. Maybe the charger interpreted the car to be a different make? I have not tried to start fast charge in sports mode,(not that that should have anything to do with it), but I will definitely give it a shot once it warms up a bit (even though the video shows -1C ambient) .
    In following the comments, this was using a Petro Canada charger.
     
    Last edited: Jan 10, 2021
  21. Even at the part of the charge curve where the charging voltage can be 4.2 V per cell, the CCS current limitation of 200 A works out to 4.2V x 98 (3 parallel cells) x 200A = 83.3kW. Something seems amiss.
     
    Kirk likes this.
  22. CharlyM

    CharlyM Member

    You add the battery heater and cabin heat and you get to 83kw…
     

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