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EVs Fall Much Shorter of EPA Estimates Than Gas Cars in Our Real-World Testing

17 points by clouddrover 3y ago

ggm 3y ago
Ones a stop start city/longhaul measure. The other is a different set of assumptions. ICE cars improve on long drive constant speed and EV do relatively better on stop start because of the from zero torque on electric motors.
- jondwillis 3y ago
  And also regenerative braking is a huge efficiency gain that has no equivalent for ICE engines.
  - asfgiodnionio 3y ago
    Of course it does. We've had hybrids for decades now.
- asfgiodnionio 3y ago
  This is already explained in the article, fourth paragraph: >One reason the paper suggests for why EVs fail to match expectations is how the range is calculated. While separate city and highway range figures are computed behind closed doors, only a combined number is presented to consumers. The combined rating is weighted 55 percent in favor of the city figure, where EVs typically perform better. This inflates the range estimates, making it harder to match in real-world highway driving. The paper proposes publishing both city and highway range figures—as with fuel-economy estimates for gas-powered vehicles—to give shoppers a more holistic sense of a vehicle's abilities. The problem is that measuring range in a city is nonsense. People only travel long distances on highways. This is no surprise: that's what they're built for. Efficiency matters in a city because most driving happens in the city. Range matters on the highway because most long-distance driving happens on the highway.
ZeroGravitas 3y ago
Title here is missing the vital "Highway" word, and the main reason is that the EV number inccludes city driving too. Having said that, their highway testing seems less "real-world" than the EPA tests, driving at exactly 75mph for hours at a time?
- theluketaylor 3y ago
  Long distance at high speed is the worst case scenario for an EV, so it's a pretty useful figure to know, especially when cross-shopping cars. A fixed speed range test gives you a solid floor for range, with all other uses pretty much guaranteed to meet or exceed that number. The lone exception being cold weather performance, but the easy solution there is conduct the test at multiple temperatures. Most drivers in an ICE car can get pretty close to the EPA fuel economy in the real world, but in EVs there are some pretty wild swings. Some EVs outperform their EPA number and others can't achieve it, making the EPA number not especially helpful.
pornel 3y ago
That's because it's a measure of average "fuel efficiency", not range. For range estimate they should just use maximum highway speed. This is the worst case for EVs, and also what matters most in practice. City driving is the easy case for EVs.

17 points by clouddrover 3y ago

ggm 3y ago

Ones a stop start city/longhaul measure. The other is a different set of assumptions. ICE cars improve on long drive constant speed and EV do relatively better on stop start because of the from zero torque on electric motors.

jondwillis 3y ago
And also regenerative braking is a huge efficiency gain that has no equivalent for ICE engines.
- asfgiodnionio 3y ago
  Of course it does. We've had hybrids for decades now.
asfgiodnionio 3y ago
This is already explained in the article, fourth paragraph: >One reason the paper suggests for why EVs fail to match expectations is how the range is calculated. While separate city and highway range figures are computed behind closed doors, only a combined number is presented to consumers. The combined rating is weighted 55 percent in favor of the city figure, where EVs typically perform better. This inflates the range estimates, making it harder to match in real-world highway driving. The paper proposes publishing both city and highway range figures—as with fuel-economy estimates for gas-powered vehicles—to give shoppers a more holistic sense of a vehicle's abilities. The problem is that measuring range in a city is nonsense. People only travel long distances on highways. This is no surprise: that's what they're built for. Efficiency matters in a city because most driving happens in the city. Range matters on the highway because most long-distance driving happens on the highway.

ZeroGravitas 3y ago

Title here is missing the vital "Highway" word, and the main reason is that the EV number inccludes city driving too. Having said that, their highway testing seems less "real-world" than the EPA tests, driving at exactly 75mph for hours at a time?

theluketaylor 3y ago
Long distance at high speed is the worst case scenario for an EV, so it's a pretty useful figure to know, especially when cross-shopping cars. A fixed speed range test gives you a solid floor for range, with all other uses pretty much guaranteed to meet or exceed that number. The lone exception being cold weather performance, but the easy solution there is conduct the test at multiple temperatures. Most drivers in an ICE car can get pretty close to the EPA fuel economy in the real world, but in EVs there are some pretty wild swings. Some EVs outperform their EPA number and others can't achieve it, making the EPA number not especially helpful.

pornel 3y ago

That's because it's a measure of average "fuel efficiency", not range. For range estimate they should just use maximum highway speed. This is the worst case for EVs, and also what matters most in practice. City driving is the easy case for EVs.