My first time using Dr. Prius - are these numbers good?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by amaranth, Feb 17, 2026 at 5:49 PM.

  1. amaranth

    amaranth New Member

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    (I originally posted this on the Prius V forum, but then realized that for engine/battery stuff in a Prius V I should post on this forum instead)

    I'm trying to learn more about the hybrid battery system and eventually become a Prius wizard.

    Currently driving a 2014 Prius V with close to 80k miles on it. Car currently runs fine, and an OBDII scanner shows zero error codes, but I think the hybrid battery has gotten significantly worse since buying it at 70k miles last year. "EV mode" seems to last for less distance every time I try it, and EV mode will end (engine restarts) at much lower speeds than it used to. Also my gas mileage is slowly getting worse - average dropped from about 40 to about 37. All this makes me suspect that the hybrid battery is dying.

    I downloaded Dr. Prius and ran a battery monitor log (spreadsheet attached) while idling the car. I kept an eye on the "VOLT DIFF" statistic while doing it - VOLT DIFF is not reported on the spreadsheet but it hovered around 0.04-0.08V while the car was idling. Is that bad? I've heard it should always be zero on a healthy battery.

    Is there anything else I should be looking for in these test logs? Do I need to buy the full version of Dr. Prius and do a full battery test to learn if my battery is going bad?
     

    Attached Files:

    #1 amaranth, Feb 17, 2026 at 5:49 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    Archives would be you're best buds. Hashed out millions of times and then left for !!! It'll pass .
     
    #2 Tombukt2, Feb 18, 2026 at 6:46 AM
  3. indel

    indel Member

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    How did you get that spreadsheet out of the app? IOS or Android? Can you post some screenshots? To this day, I have never seen any way of exporting data out of Dr. Prius.
     
    #3 indel, Feb 18, 2026 at 9:03 AM
  4. amaranth

    amaranth New Member

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    On the "Battery Monitor" page, the red circle, item #10:

    [​IMG]
     
    #4 amaranth, Feb 18, 2026 at 8:06 PM
  5. amaranth

    amaranth New Member

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    The main thing I'm asking about, which I can't find a good answer for by searching the forums, is what to make of a VOLT DIFF of 0.04-0.08V, on a battery that's not currently showing error codes

    It does sounds like I should buy the pro version of Dr. Prius and do the battery lifetime test though
     
    #5 amaranth, Feb 18, 2026 at 8:33 PM
  6. indel

    indel Member

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    Thanks for posting that
    It seems that functionality is only available on Android. What a shaft!

    IMG_8454.PNG
     
    #6 indel, Feb 18, 2026 at 10:11 PM
  7. Tombukt2

    Tombukt2 Senior Member

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    No it sounds like you should drive the ever living Hale out of the car and watch your energy monitor . Are you rapidly changing from magenta blue to green rapidly like 90 second intervals ? force charge in driveway .? Is something wrong ? Do you want to replace modify buy something?
     
    #7 Tombukt2, Feb 18, 2026 at 10:11 PM
  8. indel

    indel Member

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    @amaranth

    If you don't have any DTCs set, your best bet is to test each module under load and then look at how much voltage it drops. Then do charge/discharge cycles on each module to see if they retain at least 5000 MAh. If not, replace the faulty modules.

    There are numerous videos on yt about this process. Here is one:

     
    #8 indel, Feb 18, 2026 at 10:13 PM
  9. Tombukt2

    Tombukt2 Senior Member

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    The 12 volt battery looks like it's not doing too well back there it's only 13.5 standing ready ? About a volt low technicaly.
     
    #9 Tombukt2, Feb 18, 2026 at 10:14 PM
  10. Tombukt2

    Tombukt2 Senior Member

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    Yeah you start doing that when you start getting lights and codes and stuff is happening . Not like an Oil change. Doing this before you even get started you should order bus bars and nuts have about 4 modules on hand ready . That way when you break down you can reassemble immediately
     
    #10 Tombukt2, Feb 18, 2026 at 10:16 PM
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