Does My 12V Battery Need Replaced?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by boulder_bum, Jan 2, 2012.

  1. boulder_bum

    boulder_bum Senior Member

    Joined:
    Mar 11, 2007
    1,371
    38
    0
    Location:
    Castle Rock, CO
    Vehicle:
    2007 Prius
    My 2007 Prius has about 76,000 miles on it.

    It appears we left the dome light on for a week while visiting relatives, and now the thing is pretty dead.

    We had a neighbor jump it and drove it around for about 20 minutes. I hoped this would let the alternator recharge the battery, but when I came home and parked it, the car didn't even have enough juice to lock the doors and it certainly won't start again without another jump.

    Should I try driving it around some more to try to recharge the battery after another jump? It costs $180 to replace, so I'm not especially thrilled at the idea of swapping it out.

    Also, this question may be silly, but I suppose it'w worth asking: what are the chances of the battery being replaced under an extended warranty?
     
    #1 boulder_bum, Jan 2, 2012
  2. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
    3,898
    1,900
    1
    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    That is because your Prius uses a safe, but very slow charging system called "Constant Voltage"
    An external charger can be used as long as it is limited to 3 amps or less. You want to put about 30 amp-hours into the battery (10 hours at 3 amps). You battery has been weakened by being discharged and is likely to need replacing - sorry.
    Virtually none.

    JeffD
     
    #2 jdenenberg, Jan 2, 2012
    1 person likes this.
  3. boulder_bum

    boulder_bum Senior Member

    Joined:
    Mar 11, 2007
    1,371
    38
    0
    Location:
    Castle Rock, CO
    Vehicle:
    2007 Prius
    Thanks. My wife is getting a new battery as we speak.
     
    #3 boulder_bum, Jan 2, 2012
(You must log in or sign up to post here.)