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Charging rate stops at 47A?

Discussion in 'Model S: Battery & Charging' started by u00mem9, Aug 7, 2016.

  1. u00mem9

    u00mem9 Member

    Joined:
    Jun 8, 2016
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    500
    Location:
    USA
    Refresh car and HPWC set at 48A...but charge rate adjustment stops at 47A. It doesn't really make a difference, but any idea why won't it go to 48A?
     
  2. gavine

    gavine Petrol Head turned EV Enthusiast

    Joined:
    Apr 1, 2014
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    Location:
    Southern New Jersey
    Same issue here. I have a theory. The on-board charger is ultimately rated by kW, not amps.....kW is volts-times-amps. The normal household voltage is 240 and at 48A that would be 11,520 watts. My house shows 245V on the charge screen so I believe the car drops the amps down to 47 to keep the kW in the 11.5 range (245 x 47 = 11,515).
     
  3. rhumbliner

    rhumbliner Member

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    Sep 24, 2015
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    Las.Vegas Jackson.Hole
    Same issue here. @gavine, your theory certainly makes sense. But then I'm not an electrical engineer. :(
     
  4. ThisIsTrue

    ThisIsTrue Member

    Joined:
    Nov 29, 2016
    Messages:
    127
    Location:
    'Western Slope' Colorado
    That sounds plausible. My HPWC has a 60A breaker, and I do see 48A routinely when I charge at home, even though the setting in the car tops out at 47A:

    HomeCharging.png
     

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