1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Do I need a new 12v Battery?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by newts, Oct 27, 2008.

  1. newts

    newts New Member

    Joined:
    Jan 30, 2004
    78
    3
    0
    Location:
    Newt Hampshire
    Vehicle:
    2004 Prius
    I had an oil change and inspection done at a local (Toyota trained) garage and since then it has acted strange. Not sure exactly but it seems the red key blinks more before it is started and the car beeps as soon as I open the door but before anything is started.

    Around the same time I noticed that closing all the windows at once really slowed the motors down (engine off). Also I get the red bang-triangle ("of death") for a second when I start but then it goes out and the car is fine.

    I didn't use the car this weekend (the best gas mileage is using a bike and not gas at all...) and the car wouldn't start. I got the dashboard fireworks and that was about it.

    I put the charger on the car and it started fine. The gas gauge was one bar for a few minutes until it noticed the full tank of gas again.

    So it appears the battery is bad and this is an 04 so maybe it is used up? The only reason I want to question it is if there is something that could be "on" or set that is draining the battery and not just a weak battery. As far as I can see all the lights are off. Anything else?

    jv
     
    #1 newts, Oct 27, 2008
  2. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,074
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    It sure sounds like it's time for a new battery.

    Tom
     
    #2 qbee42, Oct 27, 2008
  3. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    The weirdishness you're seeing has preceded 12V battery failure for
    a number of folks posting here.

    This coupled with the frequent recommendation that the OEM 12V battery be
    replaced every 4 years strongly suggests that it's time for a new battery.
     
    #3 Rokeby, Oct 27, 2008
  4. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,192
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    +1 to both above
     
    #4 efusco, Oct 27, 2008
  5. newts

    newts New Member

    Joined:
    Jan 30, 2004
    78
    3
    0
    Location:
    Newt Hampshire
    Vehicle:
    2004 Prius
    Great, that sells it for me. Now to call for some quotes and do the buy/make decision if I do it or have a mechanic. If I do it I can try to keep my memory and settings intact. If they do it they own the problem if they f' it up.

    Thanks.
     
    #5 newts, Oct 27, 2008
  6. firepa63

    firepa63 Former Prius Owner

    Joined:
    Jul 23, 2005
    1,761
    208
    0
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Once the 12v battery is disconnected you will lose your settings, such as radio presets, AC/Heat settings, etc. It's no big deal to reset them. Just make sure you install the proper battery with correct venting.
     
    #6 firepa63, Oct 27, 2008
  7. rigormortis

    rigormortis Active Member

    Joined:
    Feb 14, 2007
    1,340
    26
    0
    Location:
    san jose, ca
    Vehicle:
    2007 Prius
    rigor's canned reply
    ----------------------
    the batteries with the correct venting are going to cost $140 or something?? or more?
    before spending that money, how about removing the battery and taking it down to your local dealership or automotive store just to have tested and get a print out. this is free
     
    #7 rigormortis, Oct 27, 2008
  8. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,192
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    If you connect a 12v source to the terminals under the hood during the change you can preserve all your settings. For some of us it's a little bit of a big deal b/c we're lazy!
     
    #8 efusco, Oct 27, 2008
  9. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,192
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    that's certainly an option...but I'll say just this, he's got an '04, thus it's likely nearly 5 years old. Many of us got just 4 years out of our original 12v so it's highly likely that it's near the end of it's life no matter what the printout says. Add to that that his symptoms are exactly consistant with those of others, myself included, that had a 12v nearly expired, and I say it's a waste of time to bother with taking it out, having it tested, then putting it back in and again going through the process of ordering a replacement. If the print out shows it to be good how often are you going to go through this remove/test/replace thing before actually replacing it...?

    For my money I'd just cut bait now knowing I had another 4-5 years in my new battery and not have to worry about the old one dying unexpectedly.
     
    #9 efusco, Oct 27, 2008
  10. newts

    newts New Member

    Joined:
    Jan 30, 2004
    78
    3
    0
    Location:
    Newt Hampshire
    Vehicle:
    2004 Prius
    My thinking exactly. Thanks for the help.

    jv
     
    #10 newts, Oct 27, 2008
  11. rigormortis

    rigormortis Active Member

    Joined:
    Feb 14, 2007
    1,340
    26
    0
    Location:
    san jose, ca
    Vehicle:
    2007 Prius
    i am on my second original 12 volt battery. and i have only driven 43,000 miles on a car that is only 20 months old. if its one thing i have learned from toyota dealerships is that even though they say they do a 21 volt inspection, they do not actually look at the 12v battery at all. it is completely ignored.

    also i have discovered that certain cd changer errors can affect your car stereo causing it to forget its presets while the car is on and in full ready mode. (has happened 5 times), just playing the wrong cd can make you lose your settings, i do not understand the big deal about preserving them. the prius keeps some things in flash memory you know... the prius is fully capable of taking a dive and losing its own settings on a malfunction without its owners doing something like disconnecting the 12. all by itself

    i do not know, maybe its just me, but if i am going to spend the money for an overpriced battery, or a kit, i would want a print out, maybe i am just cheap

    at the time of battery failure i only had 21,000 on it

    people with conventional cars would rush right out and have thier battery or alternator tested for free, prius owners seem
    to be different. i do not understand why some people with a $60 battery would rush out and test it, but people with a $150 prius battery would just assume the worst and buy a new one

    this could rule out a drain issue too.. and i believe someone in this thread wanted to check to see if it was the battery or an electrical drain.


     
    #11 rigormortis, Oct 28, 2008
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,472
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The OP's vehicle and battery are 4+ years old and the OP lives in the frigid Northeast. It is likely that the battery will fail sooner vs. later even if no driveability symptoms are currently noted.

    Since the fuel gauge lost its memory, this is a strong clue that the 12V bus voltage sagged due to low battery voltage. Further, I've seen posts where the poster had the battery tested and found to be OK, yet the battery failed soon thereafter anyway.

    Given the specific circumstances described by the OP, I agree that battery replacement is warranted.
     
    #12 Patrick Wong, Oct 28, 2008
(You must log in or sign up to post here.)