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Does my 12v Battery need to be replaced

Discussion in 'Gen 2 Prius Technical Discussion' started by geoffgan, Mar 28, 2020.

  1. geoffgan

    geoffgan New Member

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    Hi Guys, new to the thread! when I press power first time it reads 12.2 V and when I completely start the engine it reads 11.9 V. Most of the warning signs are on my dashboard by the way. Do I need to replace my aux battery? Thank you in advance and I hope y'all stay safe!
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Replacing the 12v may be a bit premature at this stage, how many hours per week do you currently use the vehicle?

    12v batteries don't last forever, when was the last time the 12v battery was replaced?

    Do you have a 12v AGM battery compatible trickle charger?

    If you have "Most of the warning signs", then you potentially have problems way beyond just the 12v battery.

    Have you had a chance to read the Prius owners manual, it can help define the 'warning signs' and offer further direction.

    You really need to read the OBD2 codes (DTCs) with a toyota hybrid compatible scanning device, once known post them here for help.
     
  3. sam spade 2

    sam spade 2 Senior Member

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    If this is really true as you stated it.......then your charging system has failed and needs to be fixed.

    When in "ready" mode.....car actually fully "running"....... trying to measure the battery voltage should give you the charging voltage instead.
    That needs to be about 13.2 minimum. Up to around 14.5 if the battery charge is low.