Brake Pads and "Regenerative Braking"

Brake Pads and "Regenerative Braking"

My Model S is, unfortunately, still being built and I have a rather interesting, but basic question. Since the Model S' electric motor "turns into" a "generator" when the driver starts to remove his or her foot from the accelerator, effectively reversing the electromagnetic field that would otherwise drive the car forward to recapture some kinetic energy, does that mean the brake pads will need to be changed less often? In theory, that makes sense because "regenerative braking" isn't using the physical breaks at all. Thanks!

riceuguy | 29 aprile 2013

Yes...Tesla has indicated that brake pads have an expected life of at least 100k miles for this reason.

rodhoffman | 29 aprile 2013

I rarely use the actual brakes - this is why people refer to the car as a one pedal machine!

tm | 29 aprile 2013

That's actually quite incredible! I honestly can't wait, how long did it take for you guys to actually have your car delivered after Tesla's site started saying, "Tesla Factory is building your Model S"?

riceuguy | 29 aprile 2013

9 months, but it's much shorter now! That message is just a and ask when it will be ready!

Brian H | 29 aprile 2013

It used to be a few months; it now may be as little as a couple of weeks. What it really means is that parts and place in line have been committed. If your car happens to match a battery batch currently in production/process, you could get it very fast.

rchiang | 29 aprile 2013

I drove my car this weekend for about 60 miles and I notice I only pressed the breaks like 4 times after that only when I had to completely stop at the light. But over all its a very light use of the breaks.

tm | 29 aprile 2013

@rchiang - That's great to hear, can't wait, thanks!

Brian H | 29 aprile 2013

Impossible. The MS has no "breaks".

The brakes are used only in slow or emergency stops, usually.

noel.smyth | 29 aprile 2013

i use the brakes about 10% of the time I would have in an ICE and usually when the car is under 5 MPH to get to a complete stop. Hard stopping is the other use which I dont have to do very often. This experience is with standard regen of course, if you opt for the lighter regen mode you would expect to use more.

inverts | 29 aprile 2013

I had a Prius before, also with regen braking, but much whimper. I was still on my original break pads after 187K miles. With the MS I break MUCH less .... The car holds easily with regen on a 6% grade!
That's also why TM can include free break pad changes in the service package, because they will never have to install a single one!

txjak | 29 aprile 2013

Another thing you'll find is a little different is that when going downhill with cruise control, the car won't go over the speed setting, it will use regen to keep to the speed from exceeding the speed you set, if necessary. Nice.

Brian H | 29 aprile 2013

considering how little kinetic energy the car has (comparatively) at 5 mph, that represents far less than 10% of normal stress/wear! I'd guess 40-50X less than the average stop. So maybe 1/10 the time, at 2.5% stress, or about ¼ of 1% wear!!


Noah.S | 29 aprile 2013

A related issue is that some people have reported that their brakes are squeaky, because rust has accumulated on them from lack of use!