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this post was submitted on 06 Jan 2024
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The EPA highway test is 55mph or something around that. These real world tests are all 70mph+
The only way you do better or equal on a 70mph test is
Advertise a smaller range than you actually have
Gear the motor for high speed and have worse performance at lower speeds (EVs typically do better at low vs high, but you could make low even worse)
Have a multi gear motor like Porsche and I think some Audi. Then you don't have to optimize the motor on 1 gear, but it substantially increases cost (but it's a porsche) and complexity and repair costs.
The EPA just needs to make a 70mph test part of the test cycle and make them advertise that.
The gearing in the Taycan/E-Tron GT aren't for efficiency, but for speed. Electric motors don't really lose efficiency as they spin faster, but they do start to lose the ability to move the car faster against the exponentially increasing wind resistance. This isn't an issue for most cars (they top out around 110mph), but for something like the Taycan it's important (tops out around 155mph).
The 70mph situation is more that manufacturers de-rate their cars. Both the Taycan and the Lyriq (a SUV brick) are well-known for demolishing their EPA ranges in 70mph cruising tests. Even the EV9 (the brickiest brick) exceeded the EPA range in this same test.
Unrelated to my other reply - but I think it'd be interesting to see how much other manufactuers de-rate their cars, by having independent testers also run an EPA test just like they run real world tests.
I'd love to see them run reports saying XYZ car has an actual epa range of XYZ even though they report ABC
This is right from energy.gov
https://www.energy.gov/eere/amo/articles/determining-electric-motor-load-and-efficiency
They also run more poorly below 50%.
To get a good city/highway range they would need to try and keep the motor above 50% for city, while also keeping it ~~under~~ around 75% for highway. How you move that gearing will impact range at higher speeds or lower speeds. Maybe it's not as much as I think, but it definitely comes into play, and the Taycans geared motor helps some amount.
Tesla has definitely honed their motors to maximize the EPA range vs higher speeds in addition they aren't de-rating like some other manufactures do.