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Yellow Top low voltage after only 2 years

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by landolfi, Jan 25, 2023.

  1. landolfi

    landolfi Junior Member

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    I installed a yellow top in my 2011 Prius Gen 3 around 2 years ago, the label on the battery says 11/20. Today when I went to start the Prius in reasonable (32 F) winter temperature it quickly became clear it wouldn't start as the various display elements went dim and then off. Finally I see only a check engine light. Measuring voltage on the 12V battery It reads only 6V.

    Is this a premature faiure of the 12V battery or something else? From what I read the Prius 3 doesn't have an alternator. There has been no warning before this except it seemed the ICE would hesitate a little when the car was cold.
     
    #1 landolfi, Jan 25, 2023
  2. ASRDogman

    ASRDogman Senior Member

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    The 12v battery just boots up the computers, if all is okay, the hybrid system starts.
    The inverter/converter supplies 14.+ volts to the battery and runs the computers.

    I've read on Prius Chat about those batteries only lasting a few years. I forget what the warranty
    is on them. I'm sure you can look online. Hopefully you still have your receipt for it.

    "Maybe" if you put a 4 amp charger on it for several hours it will put some life back in it.
    But for how long????

    Toyota OEM battery seems to be the best one.

     
    #2 ASRDogman, Jan 25, 2023
    Foxglove likes this.
  3. xliderider

    xliderider Senior Member

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    If you do mostly short trips, or drive infrequently, then it is not outside the realm of possibility for the battery to only last 2 years.

    It's always a good idea to put the battery on a charger/maintainer on a regular basis, especially if you do short trips or use your car infrequently.

    Posted via the PriusChat mobile app.
     
    #3 xliderider, Jan 25, 2023
  4. landolfi

    landolfi Junior Member

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    It is with considerable embarassment that I admit I blamed the battery when there was a more reasonable explanation: Human error. My wife said she noticed that my grandson had the dome light on Monday night in the back seat so he could read his book, and she recalled that she meant to turn it off but did not.

    This reminds me of the time I posted on here about 15 years ago when I had accidentally hit the km/h button on my Prius 2 and asked why the speedometer was acting strangely. Duh!

    Well, at least it all makes sense now and once I get my battery pack recharged it will likely be fine (and inexpensive to fix!).

    Thanks for the replies.
     
    #4 landolfi, Jan 25, 2023
    bisco, StarCaller, xliderider and 1 other person like this.
  5. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    6 volts may be too much for it to recover. Give charging a try, but think replacement too; see how it goes.
     
    #5 Mendel Leisk, Jan 25, 2023
  6. landolfi

    landolfi Junior Member

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    This happened in my Prius 2 a long time ago, but that time the dome light was on for 24 hours. This time it was 48. It's a miracle the display even came on.
     
    #6 landolfi, Jan 25, 2023
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  7. CR94

    CR94 Senior Member

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    Leaving any door, including the hatch, less than fully latched will have substantially the same effect, even if all switchable lights are off.
     
    #7 CR94, Jan 25, 2023
  8. ASRDogman

    ASRDogman Senior Member

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    You should get a jumper pack and leave it in the car. Once you drain a battery,
    it's life is shortend. Then at least you won't be stranded.

     
    #8 ASRDogman, Jan 26, 2023
  9. landolfi

    landolfi Junior Member

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    Just jumped it using the jumper pack and now the battery reads 13.01.

    And as if to dispel any doubt as to cause, the dome light was on when it started.

    I just have to remember to turn the jumper pack off after I use it. Last time I apparently didn't, because when I went to jump it yesterday, not only was the jumper pack dead (it was still on from the last jump) but the AC adapter was missing. Fortunately I found the adapter and all's well that ends well.
     
    #9 landolfi, Jan 26, 2023
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  10. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Check the voltage again first thing in the morning, for the next few days.
     
    #10 Mendel Leisk, Jan 26, 2023
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  11. MikeDee

    MikeDee Senior Member

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    I wouldn't replace the battery based on this one off event. I depleted my battery twice by leaving the door ajar/dome light on and it still lasted at least 5 years (maybe 7, can't remember). I had the dealer test it and they said it was still good but weak so I replaced it. It needs a load test to test a battery's health.
     
    #11 MikeDee, Jan 26, 2023
  12. sam spade 2

    sam spade 2 Senior Member

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    That is NOT the actual battery voltage but the charging voltage.
    And it is a bit low.......but it's trying to charge up a very dead battery.

    People have found that you can NOT trust the onboard system to fully charge a really dead battery
    and it needs to be done with an external charger.
    The battery will suffer if allowed to sit only partially charged for a long time.

    Also, the Yellow Tops don't have a very good reputation.
    I suggest a new battery is in order.
     
    #12 sam spade 2, Jan 26, 2023
  13. ASRDogman

    ASRDogman Senior Member

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    You might want a better jump pack, that shuts off after it jumps the car.
    OR maybe put a note on it to turn it off...
    It is BEST to get a 4 amp charger and charge the battery for 8-12 hours.
    Then it should be fully charged. The inverter charges very slowly, really only
    tops off the battery. Since it doesn't start the car or run the electronics after the
    hybrid is started, there isn't a lot of drain on the battery.

     
    #13 ASRDogman, Jan 26, 2023
  14. bisco

    bisco cookie crumbler

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    from what i have read, the yellow top will stand up to deep draining better than the oem
     
    #14 bisco, Jan 26, 2023
  15. Grit

    Grit Senior Member

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    Time to trade in the wife
     
    #15 Grit, Jan 29, 2023
  16. Todd Bonzalez

    Todd Bonzalez Active Member

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    Yellow top batteries have a three-year warranty. If you have proof of purchase, bring it back where you bought it for a replacement
     
    #16 Todd Bonzalez, Jan 29, 2023
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