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Porsche puts wireless EV charging into production

100 points · 107 comments · cisc

  1. cromka · · focus · HN ↗
    “and claims a charging rate of up to 11 kW and with an efficiency of about 90% for easy overnight charging.”

    That’s a some 9kW lost on a 80kW battery. I get the convenience, but I think the best use for those would be when standardized and installed in public parking spots, for a brief charge bump, not to charge fully at home, e.g overnight, which is what Porsche aims for.

    1. Rygian · · focus · HN ↗
      Charging rate of 11 kW, with efficiency of about 90%, means that the charger sucks around 12.2 kW of power from the grid, of which 1.2 kW is continually lost*, and only 11 kW is effectively being stored in the battery at any point in time.

      I don't understand the mention about battery capacity (80 kWh, which would translate to around 7½ hours of charging at 11 kW, if a battery could charge at a uniform rate) or where the "9 kW lost" figure comes from.

      *Which is probably useful to melt snow above the device, when installed outdoors on cold climates.

      1. idiotsecant · · focus · HN ↗
        unit confusion
      2. onlyrealcuzzo · · focus · HN ↗
        The average person is spending about $1.50 to $2.00 in electricity per day to drive a car.

        This would cost $0.15 to $0.20 per average trip to NOT plug in.

        Average person spending $100k on a car would likely pay that without a second thought.

        1. scottm01 · · focus · HN ↗
          The Cayenne seems to need about 315Wh / mile. I assume a substantial number of them are sold in California, where rates are often above $0.50/kw. I think $1.50 would get you about 9 miles.

          I drive a more efficient PHEV and spend much more than $1.50/day.

          1. vel0city · · focus · HN ↗
            Average cost of electricity is around 18¢/kWh. $2 of electricity at 18¢/kWh is about 11kWh. 11000 / 315 = 34.9. The average US driver does about 40 miles of driving a day. Its a pretty close gut-estimate figure to a median US driver paying an average price per kWh with this particular car.

            > I drive a more efficient PHEV and spend much more than $1.50/day.

            Cool story bro. I drive a more efficient EV and spend less than $1.50/day. Isn't it fun to share anecdotes?

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