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Transition to higher voltage batteries / DC fast charging

Discussion in 'Charging Standards and Infrastructure' started by n2mb_racing, Sep 10, 2017.

  1. n2mb_racing

    n2mb_racing Member

    Jun 14, 2014
    durham, NC
    I've been wondering, how will Tesla (and other manufacturers) transition to higher voltage DC fast charging? I can only see two options:

    1. Change the battery, motor and other car systems to 800V or higher.
    Cons: You lose the ability to DC fast charge at all existing supercharger and Chademo installations that are only designed for up to 400-500V charging. All the chargers must be upgraded.
    Pros: Car internal wiring is easier.

    2. Keep the battery and motor systems at 400V. Use a DPDT contactor to break the pack in half and put it in series for DC fast charging at 800V, parallel for normal operation (400V).
    Pros: You get backwards compatibility with all existing DC faster chargers and the ability to charge even faster at new high voltage stations.
    Cons: added complexity on the car.
  2. widodh

    widodh Model S 85kWh

    Jan 23, 2011
    Middelburg, The Netherlands
    I think they will go for option 2. A bit more complex, but it does allow backwards compatibility.
  3. spottyq

    spottyq Member

    May 7, 2015
    Even if you choose to go with option 2, you still have to at least make the HVAC able to operate at both 400 and 800V. (You need cooling/heating when charging fast) and probably also the DCDC converter (though you could probably get away with a beefed-up 12V battery.)

    So basically, you have to convert everything HV except the motors…

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