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Charge Model S 12V battery from ICE

Discussion in 'Model S' started by Thiago, Aug 15, 2017.

  1. Thiago

    Thiago S75D

    Joined:
    Aug 15, 2017
    Messages:
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    Location:
    St Julien en Genevois - France
    Hello all,

    So I went on holiday and vampire drain brought the car to complete zero, including the 12V battery.

    Now, long story short, I can access the 12V battery through the frunk but only have a jumpstart cable to connect to a ICE car, like you would do on a ICE to ICE jumpstart.

    Question: am I completely mad to attempt to jumpstart my 2017 MS 12V battery from a ICE 12V battery using a standard jumpstart cable?

    Thanks
     
  2. murphyS90D

    murphyS90D Member

    Joined:
    Jul 2, 2016
    Messages:
    192
    Location:
    Horsham, PA
    It will work fine. Hopefully you know how to open the frunk with a dead 12 volt battery. You don't need the ICE to be running. As long as the Tesla battery hasn't developed a shorted call the car will come alive as soon as the connection is made Open a Tesla door to keep the car alive and then disconnect the jumper cable. The Tesla HVB will charge the 12 volt battery.

    My preference is to connect a smart battery charger, that knows what an AGM battery is, and use it to fully charge the 12 volt battery while the car sleeps.
     
  3. Thiago

    Thiago S75D

    Joined:
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    Location:
    St Julien en Genevois - France
    I will need to plug the car as soon as I can see open the charging port because at the moment, they are both dead.
     
  4. murphyS90D

    murphyS90D Member

    Joined:
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    192
    Location:
    Horsham, PA
    The HVB is not dead. Without 12 volts it is completely disconnected from the car by contactors. It is below the minimum to charge the 12 volt battery however.
     
  5. Thiago

    Thiago S75D

    Joined:
    Aug 15, 2017
    Messages:
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    Location:
    St Julien en Genevois - France
    I just thought I'd share my experience here... A bit.
    So I plugged the cables onto the 12v battery of my MS and on my girlfriend's Polo and voilà, it charged just like I was hoping.
    Can't deny it was not a bit apprehensive but in the end I was able to charge the 12v battery enough to open the car and move it to a charging location.
    A call to the insurance would have resulted in around 100 euros. But instead it was just the cost of the cable.
    Well, because I didn't find any other thread with this problem, I thought better to share.
    Au revoir
     
    • Like x 2
  6. crazy_deba

    crazy_deba Member

    Joined:
    Jan 30, 2018
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    Location:
    Seattle
    >>>
    Could you please share how you got access to the 12 v battery

    Rgds

    Deb
     
  7. Thiago

    Thiago S75D

    Joined:
    Aug 15, 2017
    Messages:
    26
    Location:
    St Julien en Genevois - France
    I
    I have a facelift model S. When you open the drunk, you'll see a plastic cover near the windshield. Start popping it out and the 12C battery will be lurking in.
     
  8. crazy_deba

    crazy_deba Member

    Joined:
    Jan 30, 2018
    Messages:
    6
    Location:
    Seattle
    Thank you Thiago. I tried but then ended up seeing another cover I am guessing i need to remove that to get access tot he battery.

    I saw this video on youtube. May be you can confirm if this will work. I have a Facelift Model S 75d
     

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