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2006 Prius 12v battery not taking a charge

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by yarpirate, Jul 1, 2013.

  1. yarpirate

    yarpirate New Member

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    My Prius has sat in my driveway since March (in Minnesota). About a month after I parked it, I tried starting it with no success.

    Today, I tried putting a 12v battery charger/maintainer on the leads under the hood, and it would not complete the circuit (my charger only starts charging when it's complete). I believe this may be because of mice chewing through the wires, but does anyone know of any other possible ways this could happen? My first instinct is to test the continuity between the battery leads in the trunk and the battery leads under the hood to see if the wires between them are good, but I'm not exactly sure how to go about doing that.

    I'm sort of at a loss, and this is far beyond my normal mechanical skills. Any suggestions would be greatly appreciated!

    Thank you.
     
    #1 yarpirate, Jul 1, 2013
  2. bisco

    bisco cookie crumbler

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    perhaps the battery is too far gone. you could try connecting directly and see what happens.
     
    #2 bisco, Jul 1, 2013
  3. Jon Hagen

    Jon Hagen Active Member

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    Many battery chargers will not charge a totally dead battery. You can parallel connect another charged 12V battery to your dead one, which should allow the charger to start. After an hour or so, your dead battery should regain enough charge to allow the charger to work with the other battery removed
     
    #3 Jon Hagen, Jul 1, 2013
  4. yarpirate

    yarpirate New Member

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    I'm assuming that would require me to access the trunk and get at the 12v battery... Unfortunately the battery is dead and the button on the fob won't do anything, nor will the handle on the hatch itself. Will I need to crawl over the rear seats to get to the battery, or can I open it from the inside?
     
    #4 yarpirate, Jul 1, 2013
  5. bisco

    bisco cookie crumbler

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    crawl into the back and there is a mechanical release on the inside of the hatch. check your owners manual.
     
    #5 bisco, Jul 1, 2013
  6. Jon Hagen

    Jon Hagen Active Member

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    You can hook the parallel connected battery at the jump start point under the hood. Use jumper cables to connect the second battery at the jump start point under the hood, then connect the charger to the added battery.
    Your charger will charge both batteries. After an hour or so, your Prius battery should be charged enough so you can remove the extra battery and connect your charger directly to the jump start terminal under the hood.

    Be very sure you connect the second battery +post to the boost start terminal and connect the - post to a good ground under the hood.
    If your reverse connect the second battery, for even an instant, it can do very expensive damage to the Prius electronics.
     
    #6 Jon Hagen, Jul 1, 2013
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    My suggestion is that the 12V battery needs to be replaced, having been in a discharged state for 3-4 months.
     
    #7 Patrick Wong, Jul 1, 2013
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