EV Terminology, Measurements, and

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To our resident scientists.

It's clear that the new Electric cars need some new terminology, measurement methodologies, and displaying of available information.

This thread is a gathering place for all those "we need to come up with a term for X because this is all new in an EV" and the "they should have done this cause it's an EV" and "Why didn't they show us X because it's an EV and all that data is there and we want to compare"

This is how an EV does not fit into the "standardized tests" developed for ICEs over the last century.

Examples:

Dan Neil

We currently don't have a good term for EVs' distinctive concentration of mass, with batteries slung low as possible and centroid to the vehicle. While traction batteries are heavy, and mass is bad for acceleration and agility, the lower center-of-gravity often compensates with higher levels of cornering, especially when a car wears rubber like the Signature Performance edition's sticky 21-inch summer tires. How about "corner-levering mass"?

CapitalistOppressor

...Plus, as stated in the test notes there are driving techniques you can use with an ICE vehicle that you can't with an electric which improve the skid pad results. Still though, modulating the engine to help you around turns is a real life technique used in races, so the skid pad results of MSP are applicable.

loganss

Wish they would have put the mileage of the car and a shot of their energy usage graph from the screen. ....

 

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From JB

Power rating in EVs is not the right picture. The torque profile is so different. An internal combustion engine vehicle is rated in horsepower. That’s what it’s good at. With EVs, you need to think about newton meters at the wheel. And then kilowatts.
Power doesn’t just come from software. It’s hardware too. You need more current. You need a more capable drive inverter to give you higher motor currents at lower speed.

The magnitude of the torque is hardware and software. The feel and the dynamic and how it’s controlled are software.

 

[vfx]

There are so many ways to look at it. There really could be several MPGe ratings:

-Total energy required, or "well to wheel" efficiency (includes refining/shipping on the gasoline side, and the electrical analog: mining/generation/transmission & charging losses). This number alone can vary drastically...are you using solar power generated atop your roof, or a dirty coal plant?

-Cost-based: Cost for x miles of electricity vs. cost for x miles of gasoline.

-Vehicular efficiency (thermodynamics-based): This is the miles per kWh of electricity consumed from the battery vs. miles per kWh of gasoline energy equivalent.


Todd
There are many others...they can all convert into "MPG-like" values but they all tell a story of a particular aspect of the thermodynamics that compare the efficiency of one vehicle vs. another. The EPA uses wall-to-wheel (pump-to-tank) based MPGe. But if someone asks how efficient the Model S's drivetrain is, I'll tell them that the entire 300 mile battery pack has the equivalent of 2.5 gallons of gasoline energy equivalent.

 

[TEG]

The standard "0-60" benchmark times so often published to compare performance are frequently hard to achieve with many ICE cars.
They may get the professional "pinch hitter" driver who knows how to "dump the clutch" just so at 5K+ RPMs to extract that best 0-60 time that goes into the report. But for EVs, the performance is so predictable, consistent and easy to achieve. Teslas have 0-60 times that are "world class" but it doesn't emphasize how easy they are to achieve. Plus you don't have the drama of exhaust noise, and such. Sometimes I wish the published 0-60 times were some sort of average of many runs (not just the best time), and not to be done just by some professional performance extraction specialist. It would be nice if there was some way to better emphasize that a particular "0-60" in an EV is really a "better" 0-60 than the same value published for an ICE vehicle.

By the way, even though the LEAF acceleration is only modest, I find I can get away with full-pedal starts almost all the time without anyone getting up in arms due to lack or control or excessive noise. I find the quiet/smooth/controlled/predictable nature of the EV acceleration makes it so much more accessible and usable...

 

[vfx]

/// and not to be done just by some professional performance extraction specialist./...

And a full accounting of Launch control. The procedure of switches and how long it takes to initiate the sequence to ready. And disclosure that the driver is not even doing the accelerating.

Model S: 0 secs

Bugatti: 6 seconds

 

[jerry33]

And disclosure that the driver is not even doing the accelerating.

Does that mean you don't get a ticket?