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12v battery / charging questions

Discussion in 'Gen 2 Prius Main Forum' started by misterdean, Jan 12, 2024.

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  1. bisco

    bisco cookie crumbler

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    i don't think we can know anything for sure. but just like there's a surface voltage, there's a drawdown voltage that boinces back when the draw is reduced.
    better testing is over a period of time with everything connected and no unusual draws likeopening a door.
     
    #41 bisco, Jan 20, 2024
  2. misterdean

    misterdean Member

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    12.54
    12.49
    12.47
    12.39

    car off, trunk opened once daily to test, car hasn't been started in 5 days.

    i wasn't seeing drops like this when testing outside the car. i'm starting to wonder if the car is killing these batteries.

    the only problem i am aware of is the combination meter. does that have any effect on the battery?

    want to make sure i'm understanding correctly, is load testing the voltage and conductance testing the CCA?
     
    #42 misterdean, Jan 22, 2024
    Last edited: Jan 22, 2024
  3. misterdean

    misterdean Member

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    i was thinking about how the battery was at 12.72 in the house and dropped to 12.44 by hooking it up to the car. i decided to unhook the battery and test. it instantly went from 12.39 to 12.43. i held the meter on the battery and i watched it climb to 12.44 12.45 12.46 within a minute.
     
    #43 misterdean, Jan 22, 2024
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    You can just leave the hood ajar, check at the jump point. Avoids any "wake up".

    Any modern car is constantly using the battery, to maintain memories, blip the security icon on the dash (does gen 2 have that?), perhaps to maintain "vigilance" in case anyone comes up to the car with the fob. Anyway, the baseline usage is typically at least 20 milliampers.

    If the car is regularly sitting for multiple days, even a week, and punctuated by only short drives, you will run the dimnutive battery down in short order. That's our usage, and I've got ours hooked to a CTEK 4.3 smart charger, pretty munch constantly. Installed in September 2015, still testing like new, with a conductance tester. Voltage readings (FWIW) around 12.7~12.9.

    Yes. I'm using a Solar BA5 (same tester used in the video I linked). It shows volts and (as tested) CCA , and gives a verdict, either Good, Good but charge, or Fail. Current iteration is Solar BA9 I believe, around $50~80 USD on Amazon.com IIRC.
     
    #44 Mendel Leisk, Jan 22, 2024
  5. misterdean

    misterdean Member

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    it does have the security light icon. i understand not driving daily will wear down a battery. you must also understand a brand new battery should not be like this. i looked up when i bought my last battery, 2018. it lasted 5 years with my driving frequency. this battery lasted 2 months. my driving frequency is not the problem.
     
    #45 misterdean, Jan 22, 2024
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    A conductance test will help resolve if you’ve got a dud. A lot of automotive retailers, especially those selling batteries, will test for free. Whoever sold you the battery is somewhat obligated to provide free test too, dealership?

    the test takes a couple of minutes.
     
    #46 Mendel Leisk, Jan 22, 2024
  7. bisco

    bisco cookie crumbler

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    didn't you already eliminate the phantom drain in post#1?
     
    #47 bisco, Jan 22, 2024
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    The phantom never sleeps...

    Normal "phantom draw" is not much, but long periods not using the car (say a week or more), and only short drives, it'll run it down.
     
    #48 Mendel Leisk, Jan 22, 2024
  9. bisco

    bisco cookie crumbler

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    not as fast as posted though. so if the phantom (quiescent?) draw is within specs, a bad battery?
     
    #49 bisco, Jan 22, 2024
  10. misterdean

    misterdean Member

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    in my previous post, with the previous battery, you guys walked me through the parasitic draw test. i shared the results, and was told it looked good. not sure what else i can say about phantoms. my experience with cars is limited and i just do what you guys suggest.

    drove the car today for about hour and half. before i hooked it back up, i tested again to see if the battery went up more, which it did, 12.52. when i got done driving i tested again, 12.95. i know surface charge, but wanted to share as much info as i can.

    i did a load test, the needle was where the green and yellow meet, at the top by the 1000 line.

    they did not have the ability to test the CCA so i guess i will have to try another place.
     
    #50 misterdean, Jan 22, 2024
    Last edited: Jan 22, 2024
  11. misterdean

    misterdean Member

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    seems unlikely, but i guess it is within the realm of possibility. will definitely get another one. i don't know what else to try, and it looks like you guys don't know what to say either. i actually like this car, and don't want to get rid of it. but between my combo meter, dead batteries, and lack of trust with mechanics, i might get rid of it at 125K.
     
    #51 misterdean, Jan 22, 2024
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  12. bisco

    bisco cookie crumbler

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    Might be the best course of action.
    If it’s not the battery or car, I am at a loss
     
    #52 bisco, Jan 22, 2024
  13. misterdean

    misterdean Member

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    it has to be one or the other. i'll try another battery. if that one drops off a cliff too, isn't it logical to say it's the car?
     
    #53 misterdean, Jan 22, 2024
    Last edited: Jan 22, 2024
  14. bisco

    bisco cookie crumbler

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    i think it is, but like yourself, i'm no expert. i'm going by what i have read here over the years, and 12 years of leaving my car for up to 2 months at a time without starting it.
     
    #54 bisco, Jan 22, 2024
  15. misterdean

    misterdean Member

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    i hear you. just checking to see if my thought process is flawed or reasonable. guess i'll cross my fingers and hope i got a dud or somebody comes through with another suggestion or test for me.
     
    #55 misterdean, Jan 22, 2024
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    That sounds like an old-school load tester, not an electronic conductance tester.
     
    #56 Mendel Leisk, Jan 22, 2024
  17. misterdean

    misterdean Member

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    it was. they didn't have a conductance tester.
     
    #57 misterdean, Jan 22, 2024
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