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Just how dead is a battery?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Javier Oropeza, Oct 30, 2019.

  1. Javier Oropeza

    Javier Oropeza New Member

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    I have a 2010 Prius with a P0A80. The #7 bank is showing damage. Here’s my question. What determines a bad cell? Just how dead does a battery have to be to consider changing the battery? Bad cell? Cells?
     
  2. bisco

    bisco cookie crumbler

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    you have to measure everything under load. an app like dr prius will tell you the cells that are out of parameter
     
  3. Grit

    Grit Senior Member

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    I guess it’s when the car doesn’t start up anymore.
     
  4. sam spade 2

    sam spade 2 Senior Member

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    It has to be bad enough so that the system is able to detect that it is getting weak.
    You can find a LOT of information about the batteries on here with a search for "battery".
     
  5. tankyuong

    tankyuong Senior Member

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    Just 1volt off
     
  6. Javier Oropeza

    Javier Oropeza New Member

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    I think it’s 1/2 volt
     
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    @tankyuong said......Just 1volt off

    and then @Javier Oropeza said......I think it’s 1/2 volt

    Now, I ask.....where do you get those values from? Is it just something that sounds good or do you have a Toyota Proprietary Information source?
     
  8. sam spade 2

    sam spade 2 Senior Member

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    You both are wrong......or both right.
    It depends on the load being supplied at the time of the measurement.
     
  9. Javier Oropeza

    Javier Oropeza New Member

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    The tech that worked on my car at the Toyota dealership
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    The Tech was making it up. He doesn't know either. Toyota Proprietary Information.....The tech you talked to probably can barely even recognize what a hybrid battery looks like, much less how one works.

    It's a variable trigger point and the time I've spent observing Tech Stream and experimenting make it obvious it's some type of algorithm that depends on battery SOC and load condition, along with who knows what other parameters (oh yeah, Toyota knows, TPI)

    I can guarantee you there's more than 1/2 volt difference between highest and lowest block voltages when at full acceleration, even with a relatively new battery. I can even guarantee there's more than 1 volt, and even 1.5 volts in many cases. If the trigger was 1/2 volt, there would be a 100% fault rate within the first week of ownership.
     
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  11. iskoos

    iskoos Active Member

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    I tend to agree with TMR-JWAP. It is not that simple to name a voltage difference that will identify the damaged block. It depends on many things like State of Charge of the block, load value, its age, temp and possible many other.
     
  12. Javier Oropeza

    Javier Oropeza New Member

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    Welp my battery was dead. Toyota replaced it last week after a long battle. Toyota way over sells the gas mileage on the Prius and fixes design flaws with software patches. This is my second and last Toyota. Over it!!
     
  13. Grit

    Grit Senior Member

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    Did you buy the car new? And what was the overall MPG on the previous hv battery?
     
  14. Javier Oropeza

    Javier Oropeza New Member

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    We bought the car new in dec 2010. My wife complained that her mpg was crap for a while. I did all the things you would normally do with a car. Emissions filters tires etc. cleans the hybrid cooling fan but kept getting the P0A80. Not sure if exact mpg but it was no where near what we got with the car when it was new. Battery is a design flaw
     
  15. George W

    George W Senior Member

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    This is why Dr. Prius has a battery test that includes quick acceleration followed by quick deceleration, to measure under real loads.
     
  16. George W

    George W Senior Member

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    If you were getting the P0A80 while the car was still new (under warranty), what did the dealer do for you?
     
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