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High Power Wall Charger - Actual DC Volts/Amps Going To Battery?

Discussion in 'Model S: Battery & Charging' started by RaySuave, Apr 4, 2013.

  1. RaySuave

    RaySuave Member

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    The high power wall charger is rated at 240v 80amps AC. After the AC to DC conversion by the twin on-board chargers, does anyone know what the actual DC voltage/amperage output of the on-board chargers is that is feeding into the battery?

    I am also looking for information regarding the series/parallel configuration of the battery.

    If not, can someone point me in the right direction for this information?
     
  2. shokunin

    shokunin P85 & S40

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    The car display will show you your AC input from the HPWC in volts and amps giving you +KwH into the pack. It does not show the DC voltage (unless you're on supercharger) . On a 85Kw pack there over 7000 individual battery cells and their configuration is part of Tesla's IP. I'm sure some are in series and some groups are paralleled, but how many cells per section is not publicly known.

    Is there a reason to know what the DC voltage and amperage is after the twin chargers?
     
  3. RaySuave

    RaySuave Member

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    Thanks for your reply. The reason I would like to know is for some research Im doing regarding directly charging with DC instead of using AC.

    For the super chargers, Ive read that they pump 440V DC at 90kw into the car. So is it safe to say that the amperage would be about 205A right?
     
  4. TurboFroggy

    TurboFroggy Member

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    Figure the chargers are 95% efficient and 20KW in would equal about 19,000 watts into the pack. If the pack is 380-400 volts or so then 19,000 watts / 380 volts = 50 amps. This would only be the case if it was 20KW in or 250 volts * 80 amps = 20,000 watts. A more reasonable rate would be 230 volts * 80 amps = 18,400 watts. 18,400 / 380 volts = 48 amps.
     
  5. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    For SC's the display shows 360V @ 275A.

    Some of Tesla's safety documentation says "400V".

    One of the service managers was once able to rattle off very specific information on the battery structure, to include cells, sheets, modules, etc., but I never committed anything to memory but 7,104 cells in the 85 kWh battery pack.
     
  6. GSP

    GSP Member

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    The battery controller will tell the charger what voltage and current to provide. This is true for both on-board and off-board chargers (AC or DC input to the vehicle). The battery most likely is charger at constant current until a set voltage is reached, with the battery SOC determining the voltage required to achieve that current. After reaching the set voltage (at about 80% SOC) the battery is most likely charged at constant voltage until the target SOC is reached.

    GSP
     
  7. RaySuave

    RaySuave Member

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    Thanks for the replies, with the efficiencies and display information, I have a much better idea of what kind of power the on-board chargers are supplying. Hopefully one day I will own one a Tesla. If I find more info on the chargers elsewhere, I will post it.
     
  8. jkirkebo

    jkirkebo Model S P85+ VIN 14420 EU

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    That seems consistent. Most EVs have 96 cells in series, it seems the Model S has the same number due to the voltage. 7104/96=exactly 74.

    But 74 is only dividable by 2, so my guess is the battery is either made up of 96 bricks in series which each has 74 cells in parallell, or 192 bricks of 37 cells in parallell connected 2p96s. My main guess is for the latter. Thus you must replace 1/192th of the battery if one brick goes bad.

    The 60kWh battery must have different sized bricks because it has more than 70% of the voltage of the 85kWh batteri (seems to be
    around 85-90%). My guess is around 86 bricks of 58 or 2*29 cells in parallell.
     
  9. RaySuave

    RaySuave Member

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    It looks like the charger efficiency is around 80%, based on a few posts I have found like these where people have equipment to measure how much AC input wattage is needed for a full charge.





    SOURCE: http://www.teslamotors.com/forum/forums/charging-efficiency-0

     

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