HV battery health check

Discussion in 'PriiDash (TM)' started by 2009Prius, Sep 9, 2013.

  1. 2009Prius

    2009Prius A Wimpy DIYer

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    The drive data logged by PriiDash includes the HV battery current, and the voltages and resistances of individual modules. We can use the data to check the health of the HV battery pack. Here is an example from the data shared by Glenn Blanc. First we look at the current to see if the battery is exercised enough to give meaningful result. We want some large charging and discharging currents that's close to 100A, not all tiny small currents. Here we do see a good current range:
    [​IMG]
    Now we can look at the distribution of the voltages and resistances of individual modules to see if any module deviates from the population. The voltages:
    [​IMG]
    [​IMG]

    The resistances:
    [​IMG]
    [​IMG]

    They all look good, no significant outlier module that I can see. Good result!
     
  2. 2009Prius

    2009Prius A Wimpy DIYer

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    Here are some old data from my car:
    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  3. 2009Prius

    2009Prius A Wimpy DIYer

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    More old data shared by usbseawolf2000:

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    The data is more sparse and may contain unwanted delay/mix-ups (logged by Torque, not PriiDash). Still the HV battery looked OK.
     
  4. mfa-prius

    mfa-prius Old member

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    How did you generate those plots? Anything exotic or just Excel?
     
  5. 2009Prius

    2009Prius A Wimpy DIYer

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    I used Mathematica. I think Matlab or even Excel should be able to do the same.
     
  6. 2009Prius

    2009Prius A Wimpy DIYer

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    2014-09 data:

    [​IMG]

    compare with three years ago:

    [​IMG]
     
  7. marlinsmobile

    marlinsmobile Active Member

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    @2009Prius, thanks so much for the interesting visualizations throughout this sub-forum (and for all of the work on PriiDash)! I'm not using PriiDash yet (mainly because I'm hesitant to carry another device around), but I'm intrigued and love seeing how others are using their OBD2 log data!

    I thought this was a really interesting way to visualize these data related to the HV battery, so I thought I'd try recreating the visualizations using Tableau and data that I collected using the EngineLink app (iOS). I know that there may be some differences in sampling frequency, precision, etc., between EngineLink and PriiDash.


    2013 Prius two
    Data collected May 2016 (~3 years old, ~35,000 miles)
    Data collected using an OBD2 wireless dongle + EngineLink app for iOS on an iPhone 5


    I've logged over 230 trips since I got my new-to-me 2013 Prius in Feb 2016. My normal commute is mostly highway, so I don't see a lot of extremely high/low current draws. The data below are for five trips in May 2016 that had observed draws of +/- 100 A, although there still very few observations in that range. Most of my results are consistent with the earlier analyses in this thread, although I know that my results may be suspect due to not observing enough stress on the battery.

    upload_2016-5-22_22-30-40.png


    If I correctly understand the charts, they are comparing each individual block's reading at timestamp t to the average of the 14 blocks at timestamp t. Using that method...


    Scatterplots:
    In general, no blocks appear far from the average. Consistent with the results from previous analyses above, the "outside" blocks (e.g. 1,14) tend to run higher, and the "inside" blocks (e.g. 7) tend to run lower.

    upload_2016-5-22_22-31-33.png

    Histograms:
    I was surprised to see that the mode for block voltage was pretty far from zero for a few blocks (e.g. 1, 14). However, each bar represents only 10 mV, so it's really not that far off!

    upload_2016-5-22_22-32-13.png

    On the block resistances, I was again surprised to see the lack of symmetry around zero, particularly in blocks 1 and 14. These results are again pretty consistent with those above. The measured precision is to the nearest milliohm, so some of the spikiness is probably due to rounding.

    upload_2016-5-22_22-32-47.png

    Here's the link to this dashboard on Tableau Public:
    | Tableau Public

    More Prius visualizations on Tableau Public:
    | Tableau Public
     
    #7 marlinsmobile, May 22, 2016
    Last edited: May 22, 2016
    2009Prius likes this.
  8. 2009Prius

    2009Prius A Wimpy DIYer

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    Wow this is the first set of data from gen 3 that is analyzed and presented the same way here! Thank you so much!
     
  9. marlinsmobile

    marlinsmobile Active Member

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    My pleasure - thanks for the idea. We'll see how it looks in a couple of years...

    Also, I recently discovered your treasure trove of visualization links here - awesome!
     
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