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Time to Diagnose the Battery

Discussion in 'Prime Technical Discussion' started by mr88cet, May 15, 2020.

  1. mr88cet

    mr88cet Senior Member

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    Short version: Wuzzit called? “Hybrid Assistant”? And since I don’t currently have any Android devices, what Android would you recommend just to cheaply run that app only?

    Longer version:

    I’m starting to conclude that I need start making a case to Toyota for replacing our Prius Prime’s big traction battery. That, or at least get them to reset something or other in the charging-management SW, since I really doubt the battery cells themselves have been significantly compromised.

    I expect they’ll just tell me to go to a certain place, but at a little over 50K miles, it’s still on warranty, and only 3 years into its lifespan, it’s already considerably below the promised 25 miles EV range, and waaaaay less than it started out.

    It’s sitting at a little over 21 miles now, promised to be 25 miles, and started out delivering ~34 miles of range.

    So, to do that, I need to gather some really-detailed information about what exactly has changed, and the state of the battery.

    So wuzzit called? “Hybrid assistant”? Well, what would tell me as much as I could to make a well-informed warranty claim that to the O’Toyta folks?

    I have a Carista OBD2 dongle sitting in its original packaging that I haven’t had a chance to play with yet.

    If there’s an app that lets me reset the charging SW parameters myself, that would be good. Again, I really doubt the battery cells themselves are bad since it dropped from 34 down to 25 for a year, then went up to 28-29 for a year, and now dropped to about 21ish shortly after I stopped driving it much due to shelter-in-place orders.

    Also living in Austin, it’s really unlike cold weather is affecting the battery. Hot weather, maybe, but not likely cold. In any case, it seems to be reacting to charging and driving conditions much more likely than the condition of the battery cells themselves.

    Thanks, guys!
     
    #1 mr88cet, May 15, 2020
    Last edited: May 15, 2020
  2. Salamander_King

    Salamander_King Senior Member

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    For Hybrid Assistant app, you can use any cheap Android phone that is running Android OS 4 or higher. Any working Android phone you can find now would be running version of Android OS higher than 8. You can use Carista dongle, but it may be slow. The app developer recommends using OBDLINK LX.

    But I really don't know what you are trying to record using it. For one thing, even if your traction battery is really degraded, it is not warranted by Toyota. Even the initial 25 miles is not a promised mile. The term "Your mileage may vary" apply here.
     
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  3. john1701a

    john1701a Prius Guru

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    Short version: Film a drive when you first get your car, under carefully observed conditions. Each year under those same conditions (route, speed, traffic, temperature, wind, etc), repeat the drive.

    I did that and noticed no difference at all after 2 years, see below. I achieved a little over 30 miles each time. Keep in mind, there is no promise of any particular range. It is only an estimate. Exactly like MPG, it is just a standardized measure for the sake of purchase comparison. When you read the fine print, you'll find variation is a normal outcome.

    June 2017...


    June 2019...
     
    #3 john1701a, May 15, 2020
    Last edited: May 15, 2020
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  4. mr88cet

    mr88cet Senior Member

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    Excellent info, SK. Thanks!

    So yeah, like I said, I expect Toyota will just hand me a map to Hades and tell me to go there, but do not know, maybe I’ll find something worthwhile pursuing.

    What am I trying to record? I’ll answer that question with a question: What can I record with these sorts of tools? For example, can they provide information about battery-cell condition, or about charging margins the SW is enforcing.
     
  5. Salamander_King

    Salamander_King Senior Member

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    No battery-cell condition AFAIK. I thought Dr. Prius has that diagnosis, but I have never used it myself, and I have read elsewhere that the app is not highly accurate. You might be able to diagnose the cell state using Techstream better, but again I don't have an experience with it. For charging margin SW, there is no known apps that can change the margin. In fact I have never heard or read anywhere that this margin changes ever. For me it has always ranged from ~83% to ~12% on HA corresponding to 100% to 0% SoC on the dash.
     
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  6. john1701a

    john1701a Prius Guru

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    Aftermarket apps, like "Hybrid Assistant" and "Dr. Prius" are routinely discussed on this forum. That's your answer.
     
  7. fotomoto

    fotomoto Senior Member

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    In my personal and anecdotal observations, LiOn's being used today have A) the largest degradation over the first couple of years and then the rate tapers and B) warmer climates have larger rates of degradation.

    GOOD LUCK!
     
    #7 fotomoto, May 15, 2020
    Last edited: May 15, 2020
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  8. Bob Comer

    Bob Comer Active Member

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    I'd just add that there are a lot of things that change gas mileage on our favorite car. Tire pressure makes more of a difference than I would have guessed. Windows down, AC/heater, road conditions, oil type, speed, they all make a difference. I have over 40,000 miles on my prime and the average miles shown by the display is about 3 mpg lower than about a year after I got the car, but I know my tires are slightly lower than normal right now. (27 miles of charge at start of commute) Also remember that that display is just a guestimate, that's how far it thinks you can drive and it really really isn't a very good guess.
     
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  9. mr88cet

    mr88cet Senior Member

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    Can any of these apps measure it estimate the charging margins, even if they can’t change them?

    The fact that the capacity went back up from ~25 miles to 28-29, for about a year, after dropping from 34ish, seems to suggest that the cells themselves are not what’s deteriorating.

    I see no evidence of seasonality in the range variations, since the range has been fairly consistent month to month over the course of each year, and since it just doesn’t get very cold here in Austin. Now it does get hot here, and that is likely to cause gradual, permanent range loss, but that’s not consistent with nearly-instant drops in range, occurring at most over the course of a small number of days. Battery-cell deterioration is also not consistent with the range increasing back from charging 4.5KWh back up to 5.8ish around a year ago.

    Yeah, the miles/KWh has stayed fairly consistent at around 4.6. What has changed is the number of KWh charged into the battery. It started at about 6.3KWh, then about 7-9 ish months after we bought it, it dropped to around 4.5-4.8KWh, around a year ago, it went back up to around 5.8KWh. I don’t have a reading on how much it’s charging now — now that it’s down to a 21.5ish mile EV range.
     
    #9 mr88cet, May 15, 2020
    Last edited by a moderator: May 15, 2020
  10. Bob Comer

    Bob Comer Active Member

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    I have no clue why that would happen. It's quite bizarre.
     
  11. Salamander_King

    Salamander_King Senior Member

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    HA shows the actual SoC of the traction battery, but estimating actual capacity in kWh value stored in the 100% SoC battery turned out to be somewhat convoluted. My feeling is that the actual capacity in kWh is so variable depending on the various extrinsic and intrinsic conditions, that no easy way to estimate this number from know other data.

    I have no idea why your kWh used from the wall is varying as much as you state. In my 2017 PRIME, over three years a full charge from the wall was consistently above 6 kWh. See the graph below. GoM, on the other hand, showed vastly different numbers on a full charge from low of 21miles to high of 45miles. Using GoM as a measurement of traction battery capacity variation is a bad idea, IMOH.

    Screenshot 2020-05-15 at 10.58.03 AM.png
     
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  12. bisco

    bisco cookie crumbler

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    have you ever tried driving it until the juice runs out to see how many actual miles you get?
     
  13. mr88cet

    mr88cet Senior Member

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    Yeah. Interestingly, the actual mileage works out to pretty close to the GoM mileage estimate. GoM is optimistic by ... around 5-10%ish, typically.
     
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  14. drash

    drash Senior Member

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    Well if you want to stick with your iOS device you can use the same app I use called OBD Fusion. Had to pay $20 for it but it does record things like individual cells voltages, internal resistance, very specific temperature logs, etc. I used the same Bluetooth OBD dongle I used with the PiP. It can get really deep very fast and even has diagnostic modes for those who know what they are doing. It saves to log files in CSV format and I've attached an example in Excel format. Yes you can get individual cell voltages and other items but I would get the overall battery voltage first before diving into the details.
     

    Attached Files:

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  15. bisco

    bisco cookie crumbler

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    is that tootin' around town or something more demanding?
     
  16. jerrymildred

    jerrymildred Senior Member

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    That looks like a great app! May I ask a couple questions?
    1. Pricing. It says $9.99, but then they charge $5 for oxygen sensor results. That's pretty clear. But what do you actually get with the "On-board monitoring Tests" for $6 and the "In-performance Tracking Counters" for $9? The description isn't clear what those are. DO you know?
    2. I assume that it already has Prius Prime PIDs. Do I assume correctly or did you have to install them separately?

    Thanks. I'll probably get this either way, but it would be nice to know which extra cost modules I'll want.
     
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  17. drash

    drash Senior Member

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    I never installed the O2, performance or monitoring tests. But I believe they will charge you another $5 for the Prime PIDs and another $5 for the Lexus PIDs which I used for my wife’s NXh. Overall I’m pretty pleased with the just the basics.


    iPad ? Pro
     
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  18. jerrymildred

    jerrymildred Senior Member

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    Got it. Played with it. LIKE IT! Thanks for the tip. When I got the PIDs, though, the Lexus & Prime ones were combined for $9.99. Nice little self selected and purchased present to start by birthday. LOL!
     
  19. mr88cet

    mr88cet Senior Member

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    Mostly driving around town.
     
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  20. bisco

    bisco cookie crumbler

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    yeah, you should be getting at least 25 doing that
     
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