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What goes into the trip kwh usage calculation?

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Just did a 600 mile trip in LR MY.

Trip computer states the following:

603 miles | 183 kWh | 302 Wh/mi

I left the trip at 100% charge (74Kw in the pack). I supercharged during the trip for total of 125Kw. I arrived back with 7% battery. This means that I have put in total of 199Kw. Taking out 7% I had left (5Kw) it means I used up 194Kw for the trip, while the trip computer states I used 183Kw. That is a discrepancy of about 6% (or at 302Wh/mi 36.42 miles of range).

The trip was done in one shot, so the car didnt have time to sit and have vampire drain.

Why such a discrepancy? Are things like A/C, music, phone charging, battery cooling not counted as part of trip power usage?

Someone may mention BMS calibration. I supercharge only on big trips couple times a year. This car has seen less than 10 superchargers total, I keep battery charged at home between 50% and 70% always.

I also noticed on this trip that when I pulled in to the first supercharger I went from 100% down to 6%, but only pulled 64Kw by that point. With 74Kw pack I should have pulled around 70kw by that point.

Tesla advertises 326mile range, based on this trip (assuming 74Kw battery) I got 245mile range (so 75% of advertised range). I know that they advertise based on perfect conditions and going 55Mph, still fun facts are fun :)

I am more concerned with the discrepancy between what I put into the car and what the car says I put in/used.
 
I *think* the trip meter will count energy used while the car was in Drive. I do think that heating/cooling during that time is included. However, while you're in Park, for example while you're charging and still using heating or AC etc, that energy would not be counted. Same if the car runs Sentry mode, that ~200-250w constant draw would not be accounted for.