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50 amp service down to 32 amps

Discussion in 'Model S: Battery & Charging' started by Stimyg, Jun 2, 2013.

  1. Stimyg

    Stimyg Member

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    I just got my car and had a 14-50 put in with 50 amp service, which works out to 40 amps continuous. However today I noticed that while it runs at 40 amps for a while, pretty soon the car turns itself down to about 34 to 30 amps. What are some of the reasons this might be happening? And more to the point, what can I suggest to my electrician as to how to solve this?
     
  2. wycolo

    wycolo Active Member

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    Feel all adapter plugs, the charger & cord, and the plug going into the S. Nothing should be getting particularly warm to the touch. If you find a hot spot clean any nearby connection. If there is no connection near the hot spot then there could be a problem- call service. Some of the chargers have required replacement. Ditto with the 50A breaker; these should not be getting hot. Keep charger out of direct sun & ventilated as much as possible.

    What is voltage shown on Charging Screen as the Amps decline?
    --
     
  3. FlasherZ

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

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    Temperature of the car and/or UMC can cause it to reduce power, as will the end of the charging cycle.
     
  4. Stimyg

    Stimyg Member

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    Ah that's interesting, in that it was a very hot and sunny day, and I do charge outdoors.

    Any idea what part of the UMC should ideally be kept cooler? Or is it more the car? If I got the HPWC would that help any?

    - - - Updated - - -

    And about the voltage - I don't recall exactly and it moved around a bit, but I think in the 220s?
     
  5. FlasherZ

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

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    I believe it is more of the UMC "box" itself (the contactor/ground fault/interlock circuitry).
     
  6. JPP

    JPP Active Member

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    Outdoor heat and heat of battery pack likely are influencing charging rate & current.
     
  7. brianman

    brianman Burrito Founder

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    Just to cover our bases...

    1. Do you have the dual chargers option?
    2. When it drops to 34 or 30 A, what is your SOC (state of charge)?
     
  8. Stimyg

    Stimyg Member

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    Yes, I have dual chargers. And the SOC was between 60-90%, if I recall correctly.
     
  9. brianman

    brianman Burrito Founder

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    It might have been tapering off above 80% even on a 14-50. Not sure if it does that or not. Others that have tracked it know.
     
  10. Stimyg

    Stimyg Member

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    But would the car lower its maximum attempted charging rate? Ie it was showing 32/32, not 32/40.
     
  11. FlasherZ

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

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    It lowers the "/xx" when you crank down the charging current, or when the plug isn't fully inserted, or when the car needs to reduce its maximum charge current due to temperature. You may need to attempt to press the up-arrow to attempt raising the charge current again.
     

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