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New 12v battery won't keep a charge

Discussion in 'Gen 3 Prius Main Forum' started by Barbara1977, Mar 16, 2023.

  1. Barbara1977

    Barbara1977 New Member

    Joined:
    Mar 16, 2023
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    Location:
    USA
    Vehicle:
    2011 Prius
    Model:
    N/A
    Our 2011 Prius front end was destroyed by a deer, great body shop mechanic has put it back together, looks great but the new 12 V battery in the back won't keep a charge. He thinks there may be a "parasite" draining it somewhere. It doesn't throw a code, and when it's running on the road, it's great. Hybrid battery charges to full as it should. Talked to a Toyota mechanic who said "this problem doesn't come up very often". Where do we even start to look?
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Start with a complete health check of the battery.
    If it’s okay, measure the draw with the car off to see how many milliamperes it is drawing.
    If it’s much over 20, you’ll need to pull the fuses one at a time to see which circuit is the problem.
    But start by making sure the dome light is off with the doors closed
     
    Grit likes this.