Ecomodder chart for range gain from cD reduction ?

[Cd]

Is there a chart somewhere that shows gain in range on an EV from a reduction in drag ?
I see the Ecomodder chart for ICE vehicles, but not EVs.

I'm curious what the range increase would be on a 1st gen Nissan Leaf if the drag was reduced from the stock .32 to .22


Using 24.5 sq ft for frontal area
.32 as the cD
3,375 as the weight
75 mph speed
For this example, the car would get 50 miles of range stock at this speed.

- Thanks

[freebeard]

Try it and see.

[jakobnev]

You just need the Crr too:
https://ecomodder.com/forum/tool-aer...resistance.php

[Cd]

Originally Posted by jakobnev

You just need the Crr too:
https://ecomodder.com/forum/tool-aer...resistance.php

Thanks, but what about other variables, such as engine drivetrain efficiency and such ?
I have seen a figure of 75 % efficiency for electric motors.

Putting in this variable gives an answer, but it is in MPG.
How would I translate that to Miles per Kw ?

[jakobnev]

How would I translate that to Miles per Kw?

With Crr 0.007 and parasitic load 300w i got 20,638.63w for Cd 0.32 and 15,384.21w for Cd 0.22.

Just divide the wH/h (i.e. w) with mph and you get wH/mile, then divide by driveline efficience, I get 367wH/mile for Cd 0.32 and 273wH/mile for cd 0.22.

The ratio is 1.34 so 50 miles should turn into about 67 miles of range.

[Cd]

Originally Posted by jakobnev

With Crr 0.007 and parasitic load 300w i got 20,638.63w for Cd 0.32 and 15,384.21w for Cd 0.22.

Just divide the wH/h (i.e. w) with mph and you get wH/mile, then divide by driveline efficience, I get 367wH/mile for Cd 0.32 and 273wH/mile for cd 0.22.

The ratio is 1.34 so 50 miles should turn into about 67 miles of range.

Only 17 more miles from such a drastic reduction in drag ? Wow.
That's not even worth the effort !

I read a thread on the MyLeaf forums where the guy added a grille block and front spats on the tires and got " around 18 miles extra range ".
I had my doubts, but knew that aero was really important for EVS.
I had my hopes up that there was this huge difference from ICE cars that made this possible.

Bummer.

[Isaac Zachary]

Originally Posted by Cd

Only 17 more miles from such a drastic reduction in drag ? Wow.
That's not even worth the effort !

17 miles more than 50 miles is a 34% improvement in efficiency. How is that not worth it?

That would be like and improvement getting you 40mpg instead of 26mpg in an ICEV.

"Around 18 miles extra range" on what Nissan Leaf? Was it one with only 50 miles typically? If that's the case, then yes, it's easy to be off without strict scientific testing. I'm not saying the Leaf owner didn't get or at least perceive 18 miles extra range. But that may not be entirely from supposed aerodynamic improvements.

[aerohead]

without boring you with the details, and using your 'Drag Queens' values for the Nissan, I came up with 99.1-miles range, at 139.2 mpg-e.
--------------------------------------------------------------------------------------
If you slowed down to 65-mph, you'd be looking at 120.4-miles range, at 180.6-mpg-e
--------------------------------------------------------------------------------------
If you further slowed to Tesla Motors 57-mph 'sweet-spot', you'd be looking at 141.5-miles range, at 212.3-mpg-e
--------------------------------------------------------------------------------------
If you did the 'Think Flight' modifications, with Cd 0.175, and Tesla's 57-mph, you'd be looking at 160.7-miles, at 241-mpg-e
--------------------------------------------------------------------------------------
This is predicated upon:
* no air conditioning
* 98% power electronics efficiency
* 98% single-speed transmission efficiency
* 93.71% motor efficiency
* calm
* level
* dry
* Interstate or state highway constant speed cruising
--------------------------------------------------------------------------------------
At 75-mph your wasting 3.219-horsepower / hour to waste heat.
8,197-Btu / hour
0.683-'tons' of heat, capable of heating a larger-than-normal tiny home.
------------------------------------------------------------------------------------
At 75-mph, the aerodynamic power-cubed law is handing you your own backside.
MOTOR TREND tried it with the Gen-II LEAF, and immediately slowed down to 65-mph. The range had fallen in great excess of what the odometer was gaining.
* SAE Standard air