Tesla Model 3

[wdb]

Originally Posted by NeilBlanchard

The Model 3 is not brake by wire. Like almost every other car in the world, it has computer controlled ABS; but the braking is purely mechanical / hydraulic. It doesn't even have what virtually all other EV's have, which is regenerative braking integrated onto the braking system.

I haven't been able to find any details on the Model 3 specifically but the Model S has computer controlled regenerative braking and a computer controlled electric brake booster for the mechanical brakes. So, okay, technically not a pure brake by wire system. But it's also a far cry from even a standard antilock braking system. Lots and lots of decisions being made by bits.

[samwichse]

https://www.reddit.com/r/teslamotors...s_that_teslas/

The original article is in German, so here's a nice summary from Reddit.

A German engineering firm brought over 4 Tesla M3's for a tear down for an unnamed German automaker.
Some interesting highlights:
*Tesla Model 3 LR estimated to contain $18k in parts, cost $10k to assemble if production rate is 10k/wk (it's not, yet)
*The amount of Cobalt in the battery is far lower than other manufacturers, making the cells way cheaper.
*Everything very symmetrical to facilitate L/RHD production.
*Only 4 kinds of bolts used on the chassis (!)
*Many parts are designed specifically to be easier for a robot to assemble them

The battery thing explains some of the sour grapes coming from Mercedes about the Tesla semi about the proposed battery pack size/price "violating the laws of physics."

[Fat Charlie]

Originally Posted by samwichse

*Only 4 kinds of bolts used on the chassis (!)

I love Tesla.

[NeilBlanchard]

https://teslamotorsclub.com/tmc/thre...e-pedal.70780/

https://forums.tesla.com/it_IT/forum...erative-brakes

https://model3ownersclub.com/threads...st-drive.4501/

https://www.quora.com/Does-pressing-...erative-brakes

Bottom line is that no Tesla model has regen integrated on the brake pedal. Tesla only has regen when you lift your foot off the accelerator pedal.

[samwichse]

Originally Posted by NeilBlanchard

https://teslamotorsclub.com/tmc/thre...e-pedal.70780/

https://forums.tesla.com/it_IT/forum...erative-brakes

https://model3ownersclub.com/threads...st-drive.4501/

https://www.quora.com/Does-pressing-...erative-brakes

Bottom line is that no Tesla model has regen integrated on the brake pedal. Tesla only has regen when you lift your foot off the accelerator pedal.

On your last link, the most upvoted answer is, this... is it not correct, then?

Andrew Qian
Andrew Qian, likes machinery, knows physics
Answered Apr 14, 2016 · Author has 570 answers and 1.1m answer views
The Tesla has what is called "brake-by-wire", meaning the pedal doesn't actually connect to the brakes. This is becoming a very common setup on hybrid cars, because the electric motor can usually provide a very significant braking force which needs to be controlled electronically anyways. The new Acura NSX for example has brake by wire as well.

What a brake-by-wire system should try to do is of course emulate the feeling of a normal brake pedal, aka the harder you press, the faster you slow down. In a hybrid or electric car, what you want to do is use electric braking to save wear on the brakes and charge the battery, until the point where the electric motor can't provide any more braking force, then begin to apply the friction brakes.

The limitations of electric braking are:

At low speed, the motor simply cannot generate much power
At very high speed, a small amount of force translates to a lot of power, which the battery can't absorb
Thus, the friction brakes are not engaged as long as the brake force required is less than the min of what the battery can take and what the motor can generate, but any more than that, you will activate the friction brakes. The Tesla is a very powerful car so I would expect it to be in full electric regen braking most of the time.

[MetroMPG]

Thanks, Neil. Learned something new today!

[MetroMPG]

New data is now showing that about 23 percent of reservation holders have received refunds. The data comes from Second Measure, a company that analyzes credit-card transactions, as reported by Recode.net.

https://www.greencarreports.com/news...del-3-deposits

[wdb]

Originally Posted by samwichse

On your last link, the most upvoted answer is, this... is it not correct, then?

I was avoiding that because it is a vote and not a fact. I believe that, at the end of the day, Tesla brake pedals connect to a hydraulic system. If all else fails pressing the pedal will still actuate brakes. But "all else" in a Tesla is a lot more than it is in more conventional cars.

[NeilBlanchard]

"Brake by wire" is not the same as regenerative braking, and that answer conflates them somewhat.

I think it is surprising, and somewhat close minded to not have regen on the brake pedal - and even more so to not have default coasting.

[redpoint5]

It must be a fairly difficult engineering challenge to blend regen in with mechanically actuated braking. The only way I can figure to do it would be brake by wire, which I'm not sure is legal or safe.

Brake feel consistency is very important regardless of state of charge.

The Prius has a wonky brake transition from regen to friction that isn't smooth and still catches me somewhat by surprise.