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Comment by gameoverhumans | Hacker News Reader

As I understand it, electric cars are actually surprisingly polluting, which is a consequence of their battery weight and particulates from tires:

https://dynomight.net/tires/

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Brakepads are not an issue on EVs. They barely use frictional brakes.

My car is at 150000 miles and it's still on the original set of brakepads. Some EVs actually have a problem with that, their brakes are used so infrequently that rotors start to rust. So automakers added firmware that periodically applies frictional brakes.

The blog in your link seems to conclude that electric cars pollute less than petrol cars overall. Still, if the blog is true, it's still surprising that such a large amount of air pollution comes from tyres and brakes. A little Googling does support this claim.

It could have something to do with the fact that in order to regen-brake a 1800kg car at your typical 0.5g at 100 km/h you need some 270kW of motor/generator power. This is the main reason your Teslas and Polestars have these otherwise outlandish engines, and if you already have it, why not accelerate at traction limit, creating all these aerosols and what not.

It is extremely atypical to be braking at 0.5g. That is an emergency braking situation, in which case, it is perfectly reasonable to be engaging the mechanical braking.

Modern cars emergency brake at 0.87-1.08g. Maybe 0.5g is not your everyday braking, but not something you'd remember in a few weeks. https://www.sae.org/publications/technical-papers/content/20...

I wasn't making any kind of comparison to petrol cars! I guess it seemed like I was and that explains the downvotes, perhaps?

All I was trying to do is add some support to the claim that battery density does matter in cars (contrary to ancestor assertion). Less weight = less strain on brakes and tires = less nasties in the air and our lungs.

Brakes? Surely not, EVs hardly use them.

Tyres, absolutely. Equivalent size EVs are heavier (due to the batteries) which creates more tyre wear. My brakes, however, wear far less than on a petrol car due to regenerative braking.

Just for reference, some cars’ curb weights in kg;

  Standard Range Model 3: 1617
  Long Range RWD Model 3: 1779
  Long Range AWD Model 3: 1900
  2022 Toyota Camry XLE:  1630
  2021 Audi A6:           1970

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