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Help: need advice for 12 volt battery warning

Discussion in 'Model S: Battery & Charging' started by theflyer, May 18, 2018.

  1. theflyer

    theflyer Member

    Joined:
    Feb 1, 2015
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    Location:
    Northern Virginia
    I'm out pretty much in the middle of nowhere in Custer South Dakota for the Tesla rally. When I awoke this morning, the car is throwing the "12 volt battery needs service" warning.

    I called roadside assistance and the only thing they could say was a generality that the car should work for 2 to 3 weeks in this condition. They couldn't say whether that depends on driving it just a little each day or if I could put on thousands of miles in that two to three weeks and still be okay.

    It doesn't sound like the mobile team could get here until next week but I'm waiting for a call back from them.

    My journey it's supposed to take me to Seattle after the rally. I could obviously get the car serviced there but I'm concerned I wouldn't make it before the battery fails completely. I could completely rethink my trip and go down to Denver instead but even that is a pretty long drive through not much of anything.

    I could just hole up here in Custer and wait for mobile teams and again completely rethink my trip.

    Questions:
    Any real-world experience out there as to how long I can assume the car will continue to operate in this condition?

    Given the options above, Which choice would you suggest?

    Are there any options I'm not considering?

    Thanks in advance
     
  2. smsprague

    smsprague Member

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    555
    Location:
    Prescott, AZ
    Mine was fine for the 10 days, until a Ranger changed it out.
     
  3. theflyer

    theflyer Member

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    Location:
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    Thank you. Tesla pulled my logs and technicians in Denver are doing a detailed review. They'll call back with their thoughts on which options are viable.
     
  4. Brass Guy

    Brass Guy Member

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    Holbrook, MA
    Mine was fine for a week or 2, until I changed it out myself.
    Driving it more will not cause it to fail sooner, the 12V is constantly powered from the main battery while the car is "on." It may even make it last longer.

    All that battery really has to do is power up the computers and close the main contactors so you can drive. In the unlikely event there it won't power up, you should be able to get a jump from any 12 car (even a motorcycle), or pick up a cheap booster pack from somewhere. There should be a 12V jump terminal somewhere, you should find it just in case. Mine is behind the "nose cone," but if you have a "refresh" model I don't know where it is. I bet if you use "Keep Climate On" every time you get out, the main contacts will never close; then you wouldn't have to jump it again.
     
  5. theflyer

    theflyer Member

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    Location:
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    Great info. Thanks. I'm pre-refresh so my jumper should be in the same location.

    Why do we even have this battery? Couldn't these functions be accomplished off the main battery? Are there advantages to having this stock car battery?
     
  6. Brass Guy

    Brass Guy Member

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    Location:
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    The main battery is connected only when needed; which is for driving, heating, cooling, and charging the 12V battery when it drops a certain amount. I'm not sure why it's disconnected otherwise, it may be a regulation and/or a safety issue.
     
  7. theflyer

    theflyer Member

    Joined:
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    Location:
    Northern Virginia
    Teslas techs feel I'd be able to complete my entire trip but they are able to replace it while I wait in Denver on Monday so I will rework my trip plans. I have very flexible plans through that part of the trip so no big dramas.
     

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