12V starter battery drained - risks of charging it?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Jan M, Mar 6, 2019.

  1. Jan M

    Jan M New Member

    Joined:
    Mar 6, 2019
    2
    0
    0
    Location:
    Danbury
    Vehicle:
    2012 Prius c
    Model:
    I
    My wife drove her 2013 Prius C last night and parked it in a garage .... leaving it there running. Our teen age son noticed 4 hrs earlier that car is running in a garage ... and turned it off but leaving the key in ignition.

    Earlier this morning dashboard lights and stats (last trip time length, miles, cost of gas etc working but unable to start, crank the engine.

    Called dealerhip: get it towed there they advised.
    Looked up bunch of YouTube clips some of them by dealers.

    Using smal DieHard charger (connected plus to red port in fuse box on driver side and negative as recommended on videos and by Toyota dealer video included)

    But after about 2 hours of charging with internal lights at ceiling lighting up when getting in a car and only check engine icon lightened I am unable to sense any juice in the battery. Car has 55000 miles, almost 6 yrs old, garaged in our CT weather.

    What to do?
     
  2. Jan M

    Jan M New Member

    Joined:
    Mar 6, 2019
    2
    0
    0
    Location:
    Danbury
    Vehicle:
    2012 Prius c
    Model:
    I
    Charger went from initial yellow light (charging) to pulsating green "fully charged" but that is not certainly the case
     
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    93,091
    42,184
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    welcome!

    couple of issues. prius battery is agm. you need an appropriate smart charger to charge it properly.

    even then, if it has internal damage, it will have to be replaced. 6 years is a pretty good run.
     
  4. ztanos

    ztanos All-around Geek!

    Joined:
    Jan 10, 2013
    3,329
    1,136
    40
    Location:
    Cumming, Georgia
    Vehicle:
    2012 Prius c
    Model:
    Four
    Try disconnecting the battery for 30 mins and then trying again.
     
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    4,306
    4,225
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    Did it run out of gas?

    If the car still has fuel, then the 12v battery may be too far gone for a charge to help.

    If the car did run out of gas, you may have bigger problems.
     
    Mendel Leisk likes this.
  6. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    43,986
    31,548
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Check the battery voltage for starters, with a digital display multimeter, and post. Due to charging it'll likely be reading higher than "real" voltage, but you've got to start somewhere. Check it at the jump point, and directly at the posts if you can. I believe it's tough to get to the battery in the c?
     
    Jim Bob Khooter likes this.
  7. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,282
    2,150
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Classic symptoms of a worn out battery.
    6 years is a bit past their normal life.
    Get a new battery. Be sure it is charged before installing.

    If you have a Pep Boys auto parts store nearby, they seem to come recommended for Prius batteries.
    And a dealer will be a bit more expensive.

    P.S. In a hybrid vehicle, the 12 V battery does NOT turn the starter like with a conventional car. It only boots up computers but the end result is about the same when it goes dead.
     
  8. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,282
    2,150
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    No you don't. Any "good" charger will work just fine.

    It might only charge it to 95% capacity instead of 100 but in most applications, that is not an important difference.
     
  9. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    43,986
    31,548
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    The difference in chargers, as far as I know, is an AGM capable charger will be able to charge at slightly higher voltage rating. My older CTEK 3.3 doesn't have that, while my newer CTEK 4.3 does. Either will charge fine, just the 4.3 is maybe a bit more effective/faster.
     
  10. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    93,091
    42,184
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    put a volt meter on her, and see what comes back
     
    Mendel Leisk likes this.
Loading...