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"Idle" energy usage accounting?

Discussion in 'Model S: Battery & Charging' started by wk057, Jul 1, 2014.

  1. wk057

    wk057 Senior Tinkerer

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    So I'm sitting in my Model S with the A/C blasting playing around on my laptop while I wait on someone. Been here about an hour.

    So far my idle usage has ticked away 7 rated miles, so about 2.1 kWh. Thats fine.

    However, none of my trip meters or "since last charge" meter show this 2.1kWh.

    So now I'm curious, is this the case while driving also? I do have the car "on" (neutral w/parking brake trick).

    Seems there would be significant power "missing" from these stats...
     
  2. Zextraterrestrial

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    I think it is missed and that is why some driving power #'s don't quite add up right
    not sure exactly what/ how it is missed but Whr/mi don't seem as high as they should be when stopped and using power
     
  3. qwk

    qwk Model S P2681

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    It shows while in drive, but not in park.
     
  4. essaunders

    essaunders Member

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    I think my LEAF ignores energy used during preconditioning. This isn't a Tesla thing. I wonder why they (EV manufacturers) have done the accounting this way?
     
  5. wk057

    wk057 Senior Tinkerer

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    So I did a short hop down the street (2.5 miles) and my energy usage graph was pegged off screen almost the whole way, even though I was driving conservatively...

    It finally looked normal for the last 0.2 miles.

    Usage increased 1.1 kWh, so not the balance of my idle usage, but more than I used driving the 2.5 miles.

    At the Hamilton supercharger topping off actually since it turns out I have another hour to kill...
     
  6. Sad

    Sad Member

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    Is that certain? I thought it didn't even while in drive, I did a calculation during a 42.3 kms drive (30 mins), supposedly used 9.9 kWh, however typical miles went down by 55 kms. That would imply that the typical assumed consumption would be 180Wh/km, but I think it's supposed to be around 196 (confirmed by the dotted line on the consumption screen which is just below 200). If I add 1 kWh (half of what was reported in the first post) for the airco, etc.., then this would bring the typical consumption to the expected level.
     
  7. scaesare

    scaesare Active Member

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    I started a discussion about this some time ago as well, there are some holes in where energy usage is accounted for: Energy Accounting
     
  8. qwk

    qwk Model S P2681

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    It's not that difficult to try out. It might depend on Firmware, but mine does.
     
  9. Todd Burch

    Todd Burch Electron Pilot

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    I believe it won't show on the energy graph or trip meters until after you put some distance on. As you saw, the energy usage was distributed over the next few miles of driving. Don't know why, though.

    Incidentally, this is why some people think that the tire shop, auto body shop, etc. took their car for a joyride. They see energy use pegged on the graph for the last few miles and assume it was taken for a joyride. What really happened is that the energy usage while the car was in the shop was distributed over the next few miles of driving.
     
  10. wk057

    wk057 Senior Tinkerer

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    It is an interesting accounting method.

    However in my case, the amount of energy consumed while motionless as calculated by the drop in rated miles was still less than the energy shown consumed over the next few of miles. Its something, but, still missing energy. :(
     

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