Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

TACC and Braking

mjtgroup

Member
Feb 4, 2012
116
10
Question: When one is using the TACC and the car brakes, are you using regenerative braking or the brakes. In other words, are you wearing down the brake pads as if you were manually braking the car? Or is it a combination of both? Think I know the answer but hope I am wrong . . .
 

Max*

Charging
Apr 8, 2015
6,670
3,719
NoVa
Both.

It'll always try to use the regen first, but often if the car brakes too hard, it'll switch to friction brakes.

When I see red tail lights, and start letting go of the accelerator to coast to a stop. TACC follows the car, the car brakes, TACC doesn't usually have enough time to only use regen.
 

Cyclone

Cyclonic Member ((.oO))
Jan 12, 2015
5,056
1,141
Charlotte, NC
Both.
When I see red tail lights, and start letting go of the accelerator to coast to a stop. TACC follows the car, the car brakes, TACC doesn't usually have enough time to only use regen.

I am set up the same. In my car, 90% of my braking is regen. However, when I have a loaner and use TACC, probably only 20-30% of my braking is regen.
 

Max*

Charging
Apr 8, 2015
6,670
3,719
NoVa
I am set up the same. In my car, 90% of my braking is regen. However, when I have a loaner and use TACC, probably only 20-30% of my braking is regen.

You had a loaner recently, it still did that? I felt like the past few updates (not .5.21) made it rely on regen a lot more, or maybe it just felt that way to me.

I also notice it HEAVILY depends on the driver in front of you. If he's jerky - your car will be jerky; if he coasts smoothly to a stop - your TACC experience will be much smoother.
 

Cyclone

Cyclonic Member ((.oO))
Jan 12, 2015
5,056
1,141
Charlotte, NC
You had a loaner recently, it still did that? I felt like the past few updates (not .5.21) made it rely on regen a lot more, or maybe it just felt that way to me.

I also notice it HEAVILY depends on the driver in front of you. If he's jerky - your car will be jerky; if he coasts smoothly to a stop - your TACC experience will be much smoother.

Yes, it did that in .253. But it was MUCH better than the same loaner under .188.

I think the road system in Charlotte is just not optimal for TACC. TACC (in .253 at least) HATES merging lanes. In my commutes, I hit 4 Interstates and it makes TACC go nuts as I exchange from one to the next and have lane merges. Then we have surface streets with a 55 MPH speed limit, and TACC hates those with all the roads that turn in and off the main road. So it's cruising at distance 4 at 55 when the person in front needs to slow down for a right turn to a 25 MPH street with no right turn lane.
 
Last edited:

brianman

Burrito Founder
Nov 10, 2011
17,518
2,980
Question: When one is using the TACC and the car brakes, are you using regenerative braking or the brakes. In other words, are you wearing down the brake pads as if you were manually braking the car? Or is it a combination of both? Think I know the answer but hope I am wrong . . .
I've never seen TACC use friction brakes and I've got at least a thousand miles under my belt with TACC. This includes a 95mph to ~50mph deceleration test that was only a dozen car lengths or so that I recently did. (My passenger was unhappy with me.)
 

brianman

Burrito Founder
Nov 10, 2011
17,518
2,980
I've never seen TACC use friction brakes and I've got at least a thousand miles under my belt with TACC. This includes a 95mph to ~50mph deceleration test that was only a dozen car lengths or so that I recently did. (My passenger was unhappy with me.)
My TACC only goes to 90mph?
1. Set TACC to 70mph.
2. Accelerate with your foot to 95mph.
3. Release the accelerator pedal as you approach 50mph traffic (in your direction, not oncoming ;)).
 

Max*

Charging
Apr 8, 2015
6,670
3,719
NoVa
1. Set TACC to 70mph.
2. Accelerate with your foot to 95mph.
3. Release the accelerator pedal as 50mph traffic is approaching.

lol, gotchya

- - - Updated - - -

What do you set as your following distance? At 2 and 3 that I usually use (3 regular driving, 2 trafficy driving) TACC definitely uses friction brakes in situations where I could easily avoid it.
 

brianman

Burrito Founder
Nov 10, 2011
17,518
2,980
What do you set as your following distance? At 2 and 3 that I usually use (3 regular driving, 2 trafficy driving) TACC definitely uses friction brakes in situations where I could easily avoid it.
4
My passengers tend to prefer 4+ and traffic tends to "allow" 4- in my general area. When travelling (road trips), 2 or 3 is somewhat mandated by the rudeness/disregard-for-safety in some areas (i.e. you get cut off).
 

Max*

Charging
Apr 8, 2015
6,670
3,719
NoVa
4
My passengers tend to prefer 4+ and traffic tends to "allow" 4- in my general area. When travelling (road trips), 2 or 3 is somewhat mandated by the rudeness/disregard-for-safety in some areas (i.e. you get cut off).

Hmm... I might try 4 [as you stated] at the risk of constantly being cut off.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top