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Comment by manmal

1 day ago

We have a heat pump with SOCP 5, but are still using 30kWh per day now.

That's 2-3 days worth without changing your use pattern, which surely you would do if you expected a long blackout period?

On most modern EVs, that's at least 3 days worth of power if the vehicle is not being driven. Larger vehicles naturally have far larger batteries.

  • Mmmh no? 90kWh battery packs are not that common. An M3 or MY LR AWD have an 82kWh. Some Mercedes and some Chinese model have a 100+kWh battery but the most common setup is between 60 and 70.

    Anyway I agree that in emergency conditions it can go a looong way for a house.

Is that 30 kW each hour of the day or 30 kW per day?

  • 30 kWh per day, while a clunky unit, is what most people would understand when talking about home consumption. It’ll be what their utility typically reports, how you’d want to size a battery, etc.

  • Sort of neither?

    It's 30kW for one hour.

    (Or 1.25kW for 24 hours, or however you prefer).

    [Link: https://en.wikipedia.org/wiki/Kilowatt-hour]

    • It's like you had a faucet with cross section of 2 square inches, and 15 seconds with that faucet wide open would fill a jug. That jug holds 30 squareinches-seconds of water.

      You may then use that water over the course of a day. That's 30 sqin-sec per day. That is not 30 square inches for a whole day. It's second per day.

      Or watt hour per week or whatever.

      Yes, it can be described like 0.00034722 sqin/day, and that corresponds to no physical object and that would be largely useless.

      Why not Joules or Liters? Because that's complicated for anything electrical.

    • Pretty sure GP understands that, their point being you can't just wave away 'per unit time' when talking about it relative to generation, it matters.

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