We have started discussing EV range test results in July 2019, when What Car? presented very different results from those EPA certifies for Tesla. Our investigation suggested EPA numbers were more reliable, which changed after Car And Driver said how they are performed. Ben Sullins decided to join the conversation after Edmunds said all Tesla vehicles failed to meet their EPA ranges in their real-world range tests.
If you do not remember what Car And Driver brought up, it was a rule on EPA tests. It determines that some automakers can perform a longer range test to try to present better numbers. Tesla and Audi do that. The issue with such a strategy is that such tests are made to allow customers to compare how vehicles perform under the same conditions. If EPA allows any exception, that concept is broken and you start to compare apples to bananas.
Edmunds made its tests in real-world conditions, focusing on city driving (60 percent), which is more beneficial to electric cars. That’s right the opposite for combustion-engined vehicles: they burn more fuel in the city because of the constant stop-and-go and the fact that the engine is running even when the car is stuck in traffic.
Under the same conditions, the electric motor works only when it is necessary, which makes it more efficient. That is why hybrid vehicles have better fuel consumption in the city than on the highway. Regarding electric cars, that’s also why the Hyundai Kona Electric managed to reach 1,026 km (637 miles) at speeds of about 30 km/h (18.6 mph).
The EPA test was designed with ICE vehicles in mind, so most of the driving is on highway conditions (55 percent). Electric cars are very efficient machines that get more penalized by aerodynamic drag than combustion-engined vehicles. The higher the speed, the more drag they have to beat.
Laboratory tests allow all vehicles to be evaluated under the same conditions. The issue is that aerodynamics plays such an important role with electric vehicles that you cannot apply a single correction factor to all of them. The ones with better drag coefficients will have better energy-efficiency numbers, which will help them go further with the same amount of energy.
Mass also plays an important role in vehicle efficiency, as well as the motors used. Finally, electric vehicles have something no pure ICE car can offer: regenerative braking. Each manufacturer applies it in a way. Volkswagen thinks that coasting is more efficient, for example. Recovering energy is something unique to EVs that most tests have to take into consideration to reflect what they truly offer.
Edmunds’s attempt to compare electric cars in real-world conditions can be criticized due to temperature and route differences. EVs work better in warm environments and any difference in the weather can have a great impact, such as a windy day.
That said, would their results be wrong to point out that Tesla overestimates the range of its vehicles? Sullins tried to investigate that and recognized that the Edmunds tests pointed out to inconsistency in EPA's results. A 10 percent variation would be acceptable, according to Sullins, but not the ones the Porsche Taycan and the Tesla Model 3 Performance presented.
The youtuber tried to use real-world data obtained by TezLab, a smartphone app he developed. Just like Edmunds's tests, the information obtained by Sullins does not help because it does not allow for comparisons: we have no idea about the conditions in which the ranges were obtained.
In an ideal world, we would have a giant closed test track always with the same temperature. All cars tested there would be operated by robots doing the same sort of driving in all cars. If they could or should run longer, it would be always on the same itinerary, preventing variations on that.
Since that would cost an insane amount of money, tests use dynamometers. Still, EVs need them to contemplate the precise effects of mass, aerodynamics, temperature, and regenerative braking for fair and comparable results.
All current discussions prove we are not there yet. EVs deserve specific testing rules that take them into full consideration and are able to determine how energy-efficient they really are. Like platforms, using something created for ICE vehicles does not work well for electric cars.