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Charging 12 volt battery

Discussion in 'Generation 1 Prius Discussion' started by Dirt Digger, May 10, 2015.

  1. Dirt Digger

    Dirt Digger Junior Member

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    Is it ok to charge the 12 volt battery with a 15 volt battery? My car sat for four months and needed to be charged which i did with a portable 3 in 1 (charger, compressor, work light) charger. It charged and ran normally for five days. After that, when i turned the car off the dashboard light stayed on and flickered crazily. Thanks for any insights.
     
  2. Mirza Murtaza

    Mirza Murtaza Junior Member

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    Some questions to know:
    How old is your car's battery ? If its life exhausted then must be replaced.
    Is the Battery Charging System in your car working properly ? If system is not working as per its rated out put, then repair or replacement is required.
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The maximum voltage that should be used to charge a 12V AGM battery is 14.4V. Once the battery has been charged, if it fails to hold the charge over a reasonable period of time, then it needs to be replaced.

    The 14.4V charging voltage should be stopped when the charging current no longer drops as time passes. If desired, a trickle charge to maintain the battery charge can be applied at ~13.2V.

    Measure the voltage across the 12V battery when the Prius is IG-OFF. A new, fully-charged 12V AGM battery will measure ~13.0V. If the voltage measurement is ~12.0V, the battery is near-discharged. An intermediate measurement value will show you the approximate % charge - for example, 12.5V would be ~50% charged.

    Then, measure the voltage across the 12V battery when the Prius is READY. The voltage should measure ~13.8V which would indicate the DC/DC converter is working OK. If much lower, the 100A DC/DC fusible link has blown or the converter has failed which means the inverter needs to be replaced.
     
    #3 Patrick Wong, May 10, 2015
    Last edited: May 10, 2015
  4. Easy Rider 2

    Easy Rider 2 Senior Member

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    Didn't you already ask this question in another thread ??
    Where do you get a 15 volt battery and why is that part of the question ?