Motor or Efficiency Loss over time

[jpet]

That's just it. My past experience, and other local drivers with sigs, and my 'test' against a identically configured P85, driven in identical circumstances and weather, indicates a minimum 15% difference, that's why I'm taking issue with it. On average, I think most people drive MS as if they are enjoying it (hence 220Wh and not 200Wh as an average) - I do too, but with lots of long distance driving, I drive to arrive.

I understand you're taking issue with it, I would too. Wheel alignment would be the first thing I would have Tesla take a look at. This can make a significant difference. If there is such an issue, you should also experience excessive and/or uneven wear of your tires but it will take a couple of 1000 kms before you can see this.
What you can do yourself is double check your tire pressure: 45 psi (3.1 bar) for the 19" and 42 psi (2.9 bar) for the 21".

PS - Have you compared your Battery Survey with data from the US/Canada lifetime efficiency thread? I seem to recall 330Wh/mi down to 300 was a standard range for my area, flat terrain.

The sheet was originally started over here in Europe, but now it is global with 8 participants from Canada and 40 from the US. I wish more owners would use it because it gives us good statistics we don't get from Tesla. Location is quite relevant since speed limits and temperature vary between your region and mine. This is reflected in the statistics:

 

[kennybobby]

+1 on verifying the alignment. First order culprit that needs to be eliminated for sure.

But another consideration may be the P motor upgrade. The newer motors have a longer and larger-diameter rotor shaft and spline gear than the obsolete version. This higher inertia will require slightly higher torque to spin up at a given speed, so it needs more current to produce that torque. Torque is proportional to current^2, so if it needs 3.16% more torque, then it will draw 10% more current. It's true that W = V * A, but the A is now different with the bigger P motor.

The P motor has the capability to run and deliver higher power levels for performance, but that doesn't help any in eco-mode driving trying to stretch the range. There are pictures of the bigger shaft for comparison--maybe some clever person will calculate the inertia difference.

 

[qwk]

The top picture is of the small motor rotor. The bottom is of big motor rotor post summer of 2013. There isn't' much difference, if any between the shafts of the 2012/early 2013, and the newer rotors(big motor).

 

[jpet]

@andyro, did you get the results of the wheel alignment that was performed when your DU was replaced? If not, here are 2 messages I came across that might be of interest to you...

 

[andyro]

Tesla service reviewed this case on January 6th. On road testing the car, they noted significant DU noise (something I have grown used to, the early sigs all had that distinctive whine) - well, that whine is bearing noise - the source of the drag. A new (third now) DU was installed, and I get exactly the performance the car had originally.

Service noted that alignment that would cause that much drag would be obvious when driving, and the car likely would't track straight. Screenshot from an aggressive drive with the problem solved, 10deg. C, windy, speeds of 120-150km/hr and cruising at 115km/hr for over 100km - consumption is in the 'rated' range. I am once again, a very happy customer. I have raised this issue on a number of service visits for over a year, but it was difficult to communicate exactly what was going on, as driving can be extremely subjective and cause all the difference in efficiency - however in this case I knew something was up because my long inter-city trips were no longer possible after my 2nd drive unit was installed. In short, attaining the 'rated range' even at 100km/hr should be possible, even at 10deg. C. I can now cruise at 115km/hr and just be hovering at 20kW consumption - which is what I understood as 'normal' for my first year of ownership.

 

[apacheguy]

I've often wondered if the milling noise contributed to increased frictional losses in the motor. Surprised to see the effect was so large tho.

 

[LargeHamCollider]

Happy to see this is finally resolved, shame it took so long.