Technology

The insideevs article reports 239 miles for a Model 3 Performance while clicking all the way through to the actual source of the testing "Whatcar" reported 324 miles for a M3 LR. What car indeed. I don't believe these low numbers.

I'm sure Tesla has been overly aggressive with the range numbers. Especially people in colder climates must be getting far less than advertised. But these low-effort articles are not the best of sources.

In traffic, the largest reduction of efficiency comes from accelerating and the braking. You use energy to start moving (proportional to m V^2) and then you dump that energy into heat in your brakes to stop. The second comes from idling where you use energy to keep the engine rotating. As others have mentioned, EVs use regenerative braking so a substantial portion of the energy used to slow and stop the car is used to recharge the battery. EVs have no need to keep an engine running so unless you’re running the a/c there are minimal demands on a stopped/idling EV.

On the highway, you have the internal friction in the drivetrain to overcome, the constant deformation of the tires, and - most importantly - wind resistance, which is proportional to cd x rho x V2.

Cd (drag) and rho (air density) are low, but that V (speed) squared means driving at 75mph incurs 25x the energy use as driving at 15 mph. An EV gets no sage harbor here - plowing through a fluid (air) is essentially the same work.

To give you a sense of numbers, my vehicle (F150) gets less than 10mpg the 5 miles to my local pool/gym. The speed limit is 25 mph but there are stop signs every block or two. Lots of braking loss. On back roads with gentle curves and a 45 mph limit I get close to 30 mpg. That’s the sweet spot between overcoming transmission friction and air resistance. On the highway at 60 mph I get 22-23 mpg. At 78-79 mph I get 19 mpg. These are all generally on flat stretches using the 6 min average on my dashboard.

(Sorry for the long post…I’m an engineer and mechanical efficiency and aerodynamics are my happy place)

Traveling at high speeds just takes a lot of power regardless of fuel, but ICE cars are so inefficient in city driving it makes highways look good in comparison. 25-50mph might be more efficient, but every time you brake that kinetic energy is turned into waste heat, totally negating the benefit of driving slower.

EVs on the other hand have regenerative braking systems. Rather than using friction to slow the car down, they just use the motors by applying resistance to the wheels. The kinetic energy is used to charge the battery while slowing the car down. You get the benefit of slower speeds without much braking loss, so this is where EVs shine.

Frequent lite braking allows the regenerative brakes to do all or almost all the work, meaning you recover a good chunk of the energy you’re using in city/stop-and-go traffic.

Infrequent braking or hard braking (which requires the service brakes) means less energy recovered, so shorter range.

In addition to what atmur said, EVs don't have the baseline inefficiencies an internal combustion engine requires just to keep itself running. ICEs waste a huge amount of energy just running, which gets lost as heat, vibration, and noise. EVs have the advantage of being able to run just as much as needed, so you don't throw away huge amounts of energy at low speeds.

The efficiency curve of an ICE vehicle generally peaks somewhere around 70-90km/h, due to a combination of wasted energy at low speeds and gearing ratios. EVs peak much lower, generally in the 35-55km/h range. This is due to not having the low speed overhead of an ICE, but still being subject to high speed inefficiencies like rolling resistance and drag.

Top Gear were completely phony though, they purposefully ran the battery flat before the demo. This is known. Elons a douche but so is Clarkson.

ikr they deserve exactly normal damn it

Which is true, many countries have planned bans on the sale of new ICE cars by 2035. Which is good, even now electric cars are starting to be competitive without subsidies.

I would maybe extra-tax ICEs instead of banning them, so you still have your exotic cars with vroom sounds...