EPA ratings vs Independent Tests

  • Thread starter Thread starter GvilleGuy
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A few thoughts:

Bjorn Nyland has a great testing regime for 90 and 120 km travel.

Since they mix highway and city driving, EPA and WLTP are good for determining fuel/environmental costs but terrible at highway travel speeds which is what we want to actually know with the word “range.”

The Porsche spends most of the EPA test in its inefficient (but awesome) first gear. Hence the major discrepancy. In the WLTP which uses idealized but consistent ratings there is no such issue. It’s still not a good rating of highway travel.

Edmunds and other traditional outlets are doing a horrible job with EVs. They have the resources to provide us with better info, but instead they muck it up with poor understandings of the vehicles.

Case in point, they ran a Model Y/ Taycan range test and only charged the Model Y to 90% because Tesla recommends a daily charge limit. Well so does Porsche, and they recommend an 85% limit. This is truly basic stuff.
 
The difference with the EPA tests is the "fudge factor" they apply afterwards if you don't do all the tests. You can download the complete report from the EPA site. They use a rolling road which they dial up to the manufacturer supplied figures. They run the car through various scenarios till the battery is dead. They then average the results (eg. highway/city), then multiply by a factor to make it more "real world". The MINI actually got around 160 miles in their tests. They multiplied by their standard 0.7 factor to get 110 miles.

This fudge factor is the problem. In real world tests you will always get worse than a rolling road, but people like Edmunds (carwow, insideevs etc) report the actual distance traveled. In good conditions, 150miles is possible. Carwow got 154 miles, on the motorway. The 0.7 factor is really the kicker. Different cars probably need a different factor. Teslas are close to correct, however a lot of the European cars (Taycan, MINI) are significantly better than the 0.7 factor. Maybe 0.9 would be better.

Maybe also this figure aims to smooth out the temperature specific to the US. Some people in this forum have reported as low as 75 miles at -15F. An average of 110miles would mean a good temperature range of around 145 miles. I would be willing to give them that, however it does make the figure quite meaningless. It would be better to have a cold and hot figure so you get a better indication.

@polyphonic - I don't think Edmunds is doing a bad job. I am getting almost exactly what they reported. This has been consistent for 5 months, so not a one off economy run.
 
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