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Comment by Cthulhu_ | Hacker News Reader

Why would you think it's BS? The Model S gets over-the-air updates all the time; if I recall correctly, they increased the ride height a while ago through an update after a car drove over a metal wotsit, causing a puncture in the battery compartiment and a fire.

They can probably update the settings for the brakes as well, as long as the underlying mechanicals support it.

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I think the implicit question is "can an OTA somehow improve braking performance - why isn't it optimal already?" not "do Tesla OTAs change other aspects of the car?"

Electric motors and generators are essentially the same thing run in different directions. Run electricity through a motor and it generates motion while putting load on the power. Move a generator and it creates resistance as it extracts electricity. This also answers both how they can change it and why it is not already optimal. Actively using the motors to break causes it to use energy instead of recovering it. Hybrid drivers have long known to break gradually when possible to maximize battery recharge. It is possible they had an electric neophyte as a test driver. Fair enough if they were supposed to test from the perspective of someone new to hybrids and electric cars trying a Tesla as their first.

Not sure if you read the article but what they were testing is pretty much emergency braking from 60mph to full stop.

So the goal is not regenerate the battery (and it doesn't matter if the driver was "an electric neophyte"), it's to brake hard and to repeat the process a couple of times to see if you get brake fade.

From the article: Our testers get a car up to 60 mph, then slam on the brakes until the car comes to a stop. They repeat this multiple times to ensure consistent results. Between each test, the vehicle is driven approximately a mile to cool the brakes and make sure they don’t overheat.

Whoops. My mistake for giving into the temptation to segue after my explanation of what I did know.

What does "gradually braking to optimize battery recharge" have to do with an emergency stop?

There are plenty of reasons why you would default to a lower ride height. What would be the purpose of intentionally making your brakes worse than an f150?

I don't think anyone's suggesting it was intentional. Parameters for managing the brakes may just have been set badly, or the anti-locking algorithm written poorly. A possible explanation is they may have optimised it to improve handling while braking.

I never said I thought it was BS. I was curious what the physical mechanism to change the braking characteristics was. If there was no physical mechanism that I assume it's BS.

The car most definitely has software controlled anti-lock braking equipment, and likely has software controlled electric brake cylinders. Both of those things could plausibly be updated via an OTA update.

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