Time Optimized Traveling Speed: the Final Graph

[Skotty]

All the passive aggressive replies to my request, anyone can google. kind of defeats the purpose of using a graph to quickly display information. Didn't realize my response was so outrageous, seeing how everyone's odometers are in MPH, all street signs are in MPH, the cars range is rated in MILES, but hey whatever. Someone asks for help interpreting information and it brings out the most *****bag reply, lmgtfy.

This debate immediately made me think of the software developer tabs vs spaces debate. I'm a tabs guy, myself (more specifically, tabs for indentation, spaces for alignment). And anyone who says otherwise is simply wrong.

 

[SageBrush]

Here is a plot of the power use, interpolated from RWD Model 3 numbers from evtripplanner.com:

https://www.eso.org/~llundin/poweruse.pdf

How closely does the derivative match Aero forces ?

 

[lklundin]

How closely does the derivative match Aero forces ?

I am unsure how to best estimate that. I guess as a first estimate, one could assume that _all_ power use that grows with the speed cubed is due to air resistance, and the other components are due to other losses.
The coefficients of the polynomial that fits the data from evtripplanner are here:
Time Optimized Traveling Speed: the Final Graph

The partial derivative of the power consumption wrt to the speed is the driving force, i.e. the force the vehicle has to exert on the road in order for the vehicle to maintain a given constant speed (i.e. where aero and other losses match the driving force):

https://www.eso.org/~llundin/drivingforce.pdf

(NB: The driving force is also the energy consumption per distance covered, Newton = Watt * second/ meter).

 

[SageBrush]

I am unsure how to best estimate that.

My question was not asked correctly, it should have been whether the derivative of the power function is proportional to the change in Aero force. Your answer was to my intended question, so thanks for that

I'm just wondering why our two graphs have differences in terms of Wh/Km deltas as speed increases when we both seem to be using the same physical model.

By the way, I very much appreciate your interest in the thread.

 

[SOULPEDL]

Basically it says you can drive as fast as you want if you're supercharging.

It took me a while to get it... you're right. And about 95 mph if you're sharing the superchargers at half power. Wonder if Tesla knew this when they defined supercharger requirements; It's almost perfect.

Even better at high altitude