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How is km/h charging calculated? Please help by showing how YOUR car charges

Discussion in 'Hong Kong' started by DITB, Jan 6, 2015.

  1. DITB

    DITB co-founder

    Nov 13, 2012
    Hong Kong
    From other threads, I am doing testing with charging: Single vs dual charger installed, 1 vs 3 phase, Tesla vs non-Tesla charger (all AC)

    While doing that, I was wondering how rated and typical range is calculated.

    It is obvious that when selecting "Distance" in the units screen of settings, it is using average, not instant, as the km/h starts low and only stabilises after charging for quite a while, at least 15 minutes maybe even more. Selecting Energy rather than distance, shows instant power in kW, unfortunately with no decimal point. It can be calculated more precisely, though, as in point 1. below.

    For a given charge, at a certain kW charger, do our cars indicated the same km/h charging (Distance/Typical), or is it dependant on the driving history of the car?

    Please help me find out - it's very easy, just do this for me next time you are charging:

    1. While charging, note the combined amps and voltage, to find the precise kW of charging, ie for a 3-phase charge, it could be (32A+32A+32A) x 218 V = 20,928 W or 20.928 kW. If the voltage is fluctuating, use the average value.

    2. Select "Distance" and "Typical range" in the units screen under settings

    3. Let the charging stabilise, like 30 minutes charging or more, but before it starts to taper (battery getting full, for AC charging, up to 80% full should still be full speed)

    4. Divide the kW you calculated in 1. above, with the indicated (and stabilised) km/h charging, ie 20,928 W / 94 km/h, to get 222.6 Wh/km

    Please do the above calculation when you are charging (not supercharging please as it tapers almost right away).

    Report back here with

    a) Charger location
    b) Type (ie HKEVPower single phase 32A)
    c) Single/dual charger installed
    d) kW indicated in car (when selecting Energy)
    e) Amp (1 or 3 phase, 3 phase has a small 3 in a circle)
    f) Average voltage (if showing 217-219, just choose 218, no need to time it)
    g) km/h indicated (before tapering begins).
    h) Optionally, do the calculation above from point 4., or just provide the numbers then I can do it

    Thank you for your help :)
  2. Vmax

    Vmax Member

    Mar 1, 2014
    Hong Kong
    a) private location
    b) HKEVPower 32A 3phase
    c) Dual charger installed
    d) 20kW indicated in car
    e) 32A 3phase
    f) Average voltage 215V
    g) 92km/h
    h) 224.3 Wh/km
  3. DITB

    DITB co-founder

    Nov 13, 2012
    Hong Kong
    Thanks, Vmax, quite close to my figures. I charged with 32A single phase yesterday, failed to do a calculation of it myself (duh!).

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