Battery Capacity Drops to 1-2 bars and sets P0A80

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Prius_let_me_go, Sep 30, 2023.

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  1. Prius_let_me_go

    Prius_let_me_go Junior Member

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    So I just finished putting my hybrid battery back together after replacing one bad module that was at 6V when all the others were at 7.85V - 8.10V(which I thought would fix the issue) and to my surprise the issue still occurs, maybe a little bit less quickly though.

    The issue: When I start the car from sitting overnight the HV battery capacity indicator on the info screen will read out either green, somewhere in the blue, or 1-2 bars red, and if it is green or blue the issue can occur almost immediately. If I floor it the battery capacity level will drain very quickly and then I will get a P080A and red triangle of death and very poor power starting from a stop. I am guessing this is caused because there is a big drain on the battery and it can't keep up with the demand and so the voltage drops and sets the code - or- maybe the corroded battery voltage measurement leads in the pack are giving bad readings due to high resistance.

    I will still drive it and get halfway decent mileage and the battery capacity will come back up as I drive, but I am wondering if it is truly a bad pack or bad harness. Side note: I refurbished my battery pack and a junkyard battery pack and took the best modules of the bunch to build my current pack. It lasted about one year and quite a few miles before this issue popped up.
     
    #1 Prius_let_me_go, Sep 30, 2023
  2. Tombukt2

    Tombukt2 Senior Member

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    So when you rip this battery out and you're looking at things and you have done all this work. How do those connections look where the bus bars run everything together are they new cleaned sandblasted what That's the main connection point that needs to be well. So in a year's time or however long that lasted you said the initial repair when you took the battery back out all the nuts and bus bars looked good everything was fine? Was there corrosion on the orange plug or the orange receptacle on the battery ECU?
     
    #2 Tombukt2, Oct 1, 2023
  3. Tombukt2

    Tombukt2 Senior Member

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    Basically this behavior which has happened in several that I owned is your battery falling on its face for whatever reason. I usually replace the battery with something that someone has built or a brand new one If a built one is done well it can go 5 years some of the guys I know what I've seen them do has worked out pretty well generally for most people they'll be out of the car I mean let's be real.
     
    #3 Tombukt2, Oct 1, 2023
  4. Prius_let_me_go

    Prius_let_me_go Junior Member

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    Dang, so no chance its the pack voltage measurement wires?

    Also where do you get your replacements from?
     
    #4 Prius_let_me_go, Oct 1, 2023
  5. Prius_let_me_go

    Prius_let_me_go Junior Member

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    Oh I missed your first reply, I replaced all the bus bars and nuts so they're brand new and clean and they still look pretty good, the voltage measurement leads are corroded where the wire comes into the crimp point and the negative battery terminal lead was pretty corroded with a build up of battery acid and I brushed off a lot of that corrosion with a wire brush.
     
    #5 Prius_let_me_go, Oct 1, 2023
  6. SFO

    SFO Senior Member

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    That code doesn't apply to a prius, check the code again. It might be p0a80, and please post any other codes that you have in this thread.

    Consider using techstream (dealer diagnostic software), or a compatible device from this thread : Gen2 OBD2 app review | PriusChat

    You might try reconditioning the existing pack with a gridcharger, which could bring back some capacity and balance the modules.

    FYI : you're moderated until you've posted 5 times.
     
    #7 SFO, Oct 1, 2023
  7. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Sounds like it is time for a repeat. That seems to be about how it goes.
     
    #8 Leadfoot J. McCoalroller, Oct 1, 2023
  8. mr_guy_mann

    mr_guy_mann Senior Member

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    If the car does set a P0A80, then the HV battery ecu sees too much voltage difference between battery blocks for too long.

    A handy way to monitor block voltages is the Dr Prius app. Monitor voltages while driving - including heavy accel and braking. Usually the voltage difference between blocks shouldn't exceed 0.3V for more than a few seconds.

    Posted via the PriusChat mobile app.
     
    #9 mr_guy_mann, Oct 1, 2023
  9. ChapmanF

    ChapmanF Senior Member

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    If the code is a P0A80, the thread title should be changed. (A mod can do it, if the OP doesn't have the button anymore.)
     
    #9 ChapmanF, Oct 1, 2023
  10. Prius_let_me_go

    Prius_let_me_go Junior Member

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    Yeah that was a typo, my bad
     
    #9 Prius_let_me_go, Oct 2, 2023
    Last edited: Oct 2, 2023
  11. Prius_let_me_go

    Prius_let_me_go Junior Member

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    I will have to give that a try it looks a bit more user friendly than the techstream SW

    I am surprised it only lasted a year, but maybe I shouldn't be, the pack's average age is pretty old. Some of the date codes on the modules were pretty old like 05 and 06.
     
    #9 Prius_let_me_go, Oct 2, 2023
    Last edited by a moderator: Oct 9, 2023
  12. Tideland Prius

    Tideland Prius Moderator of the North
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    Title fixed
     
    #10 Tideland Prius, Oct 9, 2023
  13. txexplorer

    txexplorer Junior Member

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    I'm going through something similar, looks to be a bad Module or Modules in Block 3 for me. I got another P3013 code which is block 3
     
    #11 txexplorer, Oct 11, 2023
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