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12V battery and aircon

Discussion in 'Model S: Battery & Charging' started by Gig103, Oct 17, 2016 at 11:53 PM.

  1. Gig103

    Gig103 Member

    Oct 6, 2016
    Phoenix Metro Area
    I'm reading up on old threads and saw how the car has a 12V lead acid battery too (new to me) and how it is involved in some of the car electronics. What I haven't figured out is -

    If I have my car plugged in at night does this help with the 12V battery longevity?

    If I remotely turn my air-conditioning on with the app, I am going to assume that this has to use the main battery, but do the other electronics continue on 12V until I'm in the seat?
  2. Adrien

    Adrien Member

    Mar 30, 2016
    Huntington Beach
    The 12V battery is charged by the traction (main battery) pack. It's a DC to DC converter. The reason is that onboard electronics can be isolated and other reasons we won't get into. The 12V battery is basically constantly charged unless you start running low on main pack and then the DC to DC charger is shutoff, but your electronics will still run.

    You are right the air conditioning draws too much power to be run by the 12V battery, it is done by the main pack. A lead acid 12V battery, like the one in the model S likes, to be at 100%, but this is controlled by the main pack and not you plugging the car in.

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