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What is the kWh draw of various charge methods? (For solar application)

Discussion in 'Model S: Battery & Charging' started by carrerascott, Feb 12, 2014.

  1. carrerascott

    carrerascott FUEL FTR

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    Getting solar array to power our garage soon, already have one for the house (they are on separate meters). Wondering what the draw is on various charge methods... we have a HPWC and a 14-50 in the garage. The solar array for the garage will be a 3.6kW system. (House is a 9.4kW system). Question is, for charging during daylight ours, I want to try to limit the charging so that most or all is covered by the solar panels. Obviously it doesn't matter at night since it will be using the grid then, but wondering how I should limit the Amps going from the HPWC during the day, or perhaps use the 14-50.

    Thanks for any info/advice!
     
  2. djp

    djp Roadster 2.0 VIN939

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    Amps * Volts = Watts

    40A * 240V = 9.6 kW

    If you want to limit to 3.6 kW that would be 15A at 240V.
     
  3. carrerascott

    carrerascott FUEL FTR

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    Thanks. I just had a thought to instead add the new panels to the house system so we'd be at about 13kW, and just run a dedicated circuit from the house power to the garage for charging. Seems to make more sense since the garage charging is only a few specific hours per day.
     
  4. idoco

    idoco Member

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    Also realize that the kWh rating (13kWh) in your case is the maximum rating for the panels. In reality, depending on the time of day and year, you are getting less. At peak hours, on a good day, I see 85-90% average during the summer and 70% average in the winter.
     
  5. essaunders

    essaunders Member

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    the charging standard (J1772-2010) allows for the EVSE to vary the pilot in near-real time. the car shall follow (within some small time frame) that pilot. you can build an EVSE. there is no reason you can't build an EVSE that varies the pilot in response to an external input. you can meter the actual power from your solar. So, just tie it all together: build an EVSE that tracks your solar production during the day and sets the pilot based on other rules at night.
     

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