# Drive efficiency in Model X

A nice idea for Model X owners will be to have a different Drive efficiency calculations as now are the same for Model S and Model X (based on 20kWh/100km).

As you know Model X is larger and weights more than Model S and Typical range should be calculated different and maybe based in something between 22kWh/100km and 23kWh/100km

### Answer

The kWh calculations are already unique to each vehicle. It uses the rated miles available at a 100% completed charge (or extrapolated from 90%+ completed charge) along with the battery size for the vehicle to determine how much energy was used. This "factor" is then used to calculate the kWh used based on how many rated miles were actually used on the drive. The reason that the factor needs to be adjusted is because TeslaFi currently assumes the battery size to be the advertised kWh available but we know that the majority of time that number is lower. For example a 85 kWh may actually have 77.5 kWh available.

Also, the maximum rated range for the vehicle is constantly updated each time a max range charge is completed and it's stamped to each data point stored in TeslaFi. This way kWh calculations performed on any data point are based on the battery state at that point in time and recent changes will not effect prior data.

Hopefully this helps a little. There's more to it, but this is the easiest way to explain it.

Actually Drive Efficiency, as I understand it, is a very simple calculation in TeslaFi: actual mi/km driven divided by rated mi/km used. This would not vary from vehicle to vehicle, since the rated miles are vehicle-appropriate.

@cperez, I have found that with my Model X (90D), putting a Correction Factor of .9193 in the TeslaFi settings panel gets a pretty close match between the vehicle's displayed Wh/mi (or km in your case) and what TeslaFi shows.

To find where to enter this, choose the Settings (gear) from the footer menu, and look for the "kWh & Wh/mi (km)" entry. Type .9193 in the box (default is 1), and that will give you a start. The good news is that anything you enter here will apply the correction to all previous drives.

To come up with this, I used the following procedure several months in a row:

- In the car's trip counter ("Trips" on the car's main screen), reset one of the trip counters to zero at the start of a month. (I name it "Month to Date")
- At any time of the month, you can compare the Wh/km displayed on your vehicle for the month to date with the Wh/km displayed for the current month in the "Calendar" section of TeslaFi. Tweak the .9193 up or down as needed to make them match (it won't be exact because the way the car calculates is slightly different from the car's method, but it should be within 1-2 Wh/km -- it was off by 10% before I did this)

I hope this helps.

Thank you very much for the advice! I will review my settings and will adjust them based on your recommendations but my idea was to change 'Drive efficiency' for Model X as it's a very different car than Model S.

I think that Drive Efficiency calculations are the same for both cars, so Model S always perform better as it's a very different car. Model X weights more and have a different CX so it consume more kWh/km than Model S. If the base calculations are the same (based on 20kWh/100km) drive efficiency will be wrong as Model X will be more of the time below Model S efficiency.

Customer support service by UserEcho

The kWh calculations are already unique to each vehicle. It uses the rated miles available at a 100% completed charge (or extrapolated from 90%+ completed charge) along with the battery size for the vehicle to determine how much energy was used. This "factor" is then used to calculate the kWh used based on how many rated miles were actually used on the drive. The reason that the factor needs to be adjusted is because TeslaFi currently assumes the battery size to be the advertised kWh available but we know that the majority of time that number is lower. For example a 85 kWh may actually have 77.5 kWh available.

Also, the maximum rated range for the vehicle is constantly updated each time a max range charge is completed and it's stamped to each data point stored in TeslaFi. This way kWh calculations performed on any data point are based on the battery state at that point in time and recent changes will not effect prior data.

Hopefully this helps a little. There's more to it, but this is the easiest way to explain it.