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Third day with new car, dead 12V battery, second day in a row :(

Discussion in 'Gen 5 Prius Main Forum' started by mountaineer, Jul 30, 2023.

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  1. mountaineer

    mountaineer Active Member

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    Finally after 18 months' wait from my order, picked up my 2023 Prius XSE premium on Thursday. And today, for the second day in a row, the car wouldn't start, with the display flickering and random error messages popping up like not being able to operate the parking brake.

    Both days, I was charging at night to use off-peak hydro. The first time, I had left the headlights in the "daytime running" position, and the charging cable was plugged in, but with no juice flowing (it was remotely turned off by a separately-operated Sinopé circuit controller). Last night, the headlights were in the "auto" position, the charging cable was also plugged and active all night.

    Both mornings – could not start the car.

    Has anyone else encountered this? Never once had a dead battery in my base trim 2019 Prius Prime. It's only been three days, but I haven't been able to charge it overnight without draining the 12V battery. Sad start.
     
    #1 mountaineer, Jul 30, 2023
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  2. Louis19

    Louis19 Active Member

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    Very sad start , bummer , and I know reading your post that you are not a novice, since you had a 2019 Prius prime . So operator error is not your case .....trip to the dealer is needed
    seems to be quite a few problems reported here with the Gen 5....hope Toyota quickly reacts to those problems.
     
    #2 Louis19, Jul 30, 2023
  3. BiomedO1

    BiomedO1 Senior Member

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    Sorry to hear about your issues.
    Did you put the 12VDC battery on a charger after the first incident? It sounds like the second incident is related to the first incident. I'd take it back to the dealer, to get it sorted. If you don't have time, at least make sure your 12VDC battery is charged up; to see if the problem persist.

    Hope this helps.....
     
    #3 BiomedO1, Jul 30, 2023
  4. bisco

    bisco cookie crumbler

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    Loose connection at the battery?
     
    #4 bisco, Jul 30, 2023
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  5. mountaineer

    mountaineer Active Member

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    Thanks for the messages. I actually drove for a couple hours after the first dead battery, so it should have been fully charged.

    Did have a thought today: could be the new car had a bad reaction to my ScanGauge II, which was plugged into the ODB port. Never had a problem in the previous car. I might ask with the maker if they've heard of any issues.
     
    #5 mountaineer, Jul 30, 2023
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  6. Louis19

    Louis19 Active Member

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    Hey maybe you have nailed it ! Please update your findings
    BTW i'm curious to know your impressions about your new car
     
    #6 Louis19, Jul 31, 2023
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    If it was near fully drained driving for a couple of hours will help, but I doubt it'd fully recharge it. Too, it's capacity may be permanently diminished, just slightly, or more.

    Do you have a volt meter?
     
    #7 Mendel Leisk, Jul 31, 2023
  8. GeoJ

    GeoJ Member

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    A bad battery might be the best resolution. Extremely frustrating obviously, hope you get good support from Toyota. Good luck.
     
    #8 GeoJ, Jul 31, 2023
  9. Preebee

    Preebee Senior Member

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    User error?
     
    #9 Preebee, Jul 31, 2023
  10. BiomedO1

    BiomedO1 Senior Member

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    Yes; I believe one of the OBDII pins is connected directly to the battery (always Hot). So if your scan gauge never goes to sleep - it's the equivalent of leaving a lamp on, in the car. That's an idea; check to see if someone has the trunk lamp manually flipped on.

    PS even though you drove the car for a few hours; the cars charging ECU prioritizes traction battery charging over starter battery. A while ago someone posted a power chart; when the 12VDC battery got to 12 V; the charge current was dramatically reduced. I'm guessing it was redirected to the traction battery.
     
    #10 BiomedO1, Jul 31, 2023
  11. Gwyd

    Gwyd Member

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    #11 Gwyd, Aug 1, 2023
  12. mountaineer

    mountaineer Active Member

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    I previously had the ScanGauge II connected to a 2006 Yaris, then a 2019 Prius Prime, and never had a battery drained. It always put itself to sleep. Maybe it doesn't with the new model for some reason... may need a firmware update.

    Meanwhile when the car is on it does report the voltage of the 12V battery being 14.1V – would that be different when the car is off, @Mendel Leisk ?

    @Louis19 , I've been holding off talking about it just yet. The grumpy old man inside me wants to facetiously write a blog post about it titled "2023 Prius Prime: The Enshittification of Modernity Continues", but don't take it seriously. I'm just bitter about losing both the CD player, AND the audio input jack – ~150 years of tradition in audio connectivity.

    Oh, and the terrible iOS app, whose 2/5 star rating is well-deserved. And the fact that when my 12V battery died (but only the second time), I lost all my settings and my car was removed from all Toyota connectivity subscriptions and I had to re-add my car. And the wireless phone charger that mostly just makes my phone super hot, however I place it (more on that later). And the loss of the daily/monthly distance & consumption logs. (Am I right about that? Haven't read the manual yet.) And the side-to-side headroom – I didn't realize how much I move my head and upper body when I drive until I got this car!

    But there is so much I love. It's impossible to have everything you want. Every car is a collection of compromises. Bottom line is that I'm delighted.
     
    #12 mountaineer, Aug 1, 2023
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, that voltage is reliant on the car being on. Measuring with a voltmeter when the car’s off (preferably after sitting overnight to remove “surface charge”) it’ll be just battery voltage.

    to really see where you’re at, an electronic load tester (tests CCA) is more definitive. DIY testers of this ilk are available, SOLAR BA9 would be my current pick.
     
    #13 Mendel Leisk, Aug 1, 2023
  14. Louis19

    Louis19 Active Member

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    Really....are you saying that the sytem is constantly observing your driving position and reminds you to keep a good position :censored: if so , it is kind of intrusive......not shure i would like being annoyed while I drive :eek:
    On my prius prime 2022 I defeated the road center line correction , bothered me, feeling the steering wheel poking me constantly , because i prefer driving a little more to the right of the lane that the system wants . On degraded roads it will tend to keep me in potholes and road rut :(
     
    #14 Louis19, Aug 1, 2023
    Last edited: Aug 1, 2023
  15. mountaineer

    mountaineer Active Member

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    Actually it's not the attention-tracking that bothers me. What I meant to say is that I keep hitting the ceiling of the car with my head, not in a standard sitting position but when I lean forward or to the side, either to see around the pillar, or for whatever reason.

    I also like to stay more to the right of the lane; wish that could be adjusted.
     
    #15 mountaineer, Aug 3, 2023
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  16. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    @mountaineer
    Did you call Toyota Roadside Assistance that supposedly comes with the car?

    Did you get the car to the dealer for a battery diagnostic?

    It’s great that you love the car, but some of us are deeply stressed here, with empathy.
     
    #16 tovli, Aug 3, 2023
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  17. mountaineer

    mountaineer Active Member

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    Yeah, I called Roadside assistance and I was boosted both days.

    You definitely should not be stressed here, and perhaps my headline was a tad an inflammatory. I'm quite certain it's an incompatibility between a new car model and my ScanGauge II. There haven't been any more dead batteries the past three or four days.

    I'm going to take your suggestion of getting a battery diagnostic at the local dealer.
     
    #17 mountaineer, Aug 3, 2023
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  18. vvillovv

    vvillovv Senior Member

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    To get an idea of just how many people have posted here about the prius 12 volt just use the priuschat search box at the top right hand side of any priuschat page. Here is what I got with simple search options
    ( 12 volt battery - and clicking the box for - In Titles Only ) Looks like 6 pages of post links
    https://priuschat.com/search/477195115/?q=12+volt+battery&o=relevance&c[title_only]=1

    Several years ago past member Rob43 started a thread about the 12volt battery behavior in the Prime.
    It might be worth reading and maybe trying some of the tests that have already been run by other Prime owners / members.
    12v Battery Is Discharging, Re-Charge Now ! | PriusChat
     
    #18 vvillovv, Aug 3, 2023
  19. bisco

    bisco cookie crumbler

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    i wonder if toyota made any changes to gen 5. i know gen 4 was worse than pip.
     
    #19 bisco, Aug 4, 2023
  20. Mr.Vanvandenburg

    Mr.Vanvandenburg Senior Member

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    I think my new to me 2020 Prime has a “ lojack” system installed. When I called my sales person about the sticker on the door jamb, he said don’t worry you didn’t pay for it and it’s deactivated. But I suspect it is adding parasitic drain. They connect it through the obd port. Someday I will take the panel off around obd and see what they did. Spireon makes it and their label is on the door jamb on mine. Never heard of it before.
    LoJack : GPS Device
     
    #20 Mr.Vanvandenburg, Aug 4, 2023
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