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Brake lights & regenerative braking 🔴

Posted: Sat Nov 21, 2020 8:13 pm
by Coopear
Something which often goes through my mind when I’m driving my ID3 is
“I wonder what my brake lights are up to right now?”

When I’m driving and press the brake pedal I expect the brake lights come on, but what about:
- When I’m coasting up to a junction and the car progressively increases RB
- When I’m coasting from one speed limit to a lower limit and RB shaves a couple of mph off
- When I’m driving in B and take my foot of the accelerator

What’s going on at the back?

Re: Brake lights & regenerative braking 🔴

Posted: Sat Nov 21, 2020 10:25 pm
by Deleted User 192
Good question 👍

I assume that the brake lights come on in the first two of those three situations, possibly B mode too.

Go for a drive at night, to an area with no street lights, and check your mirrors 😉 (or ask a friend to follow you)

Re: Brake lights & regenerative braking 🔴

Posted: Sat Nov 21, 2020 10:36 pm
by RDR
I wonder if they have a deceleration sensor? will be interesting to see our I3 does where it puts the brake light on when detecting moderate deceleration works well.

Re: Brake lights & regenerative braking 🔴

Posted: Sat Nov 21, 2020 11:18 pm
by Coopear
Yeah I think it will need someone following but that’ll take some arranging. I thought someone might have done the hard-work for me already ;)

Re: Brake lights & regenerative braking 🔴

Posted: Sun Nov 22, 2020 4:33 pm
by F11_MWG
I had a friend follow my GTE and the brake lights come on in B model, so I'm sure the ID3 will be the same. I hate the idea that the driver behind will think I'm an idiot braking all the time!!

Re: Brake lights & regenerative braking 🔴

Posted: Sun Nov 22, 2020 10:12 pm
by pdk42
On EVs during regenerative braking, the brake lights come on when a certain deceleration threshold is reached (which I think is 0.1g).

Re: Brake lights & regenerative braking 🔴

Posted: Sun Nov 22, 2020 10:22 pm
by pdk42
The threshold is between 0.7m/s^2 and 1.3m/s^2 - so about 0.1g:

Brake.png

Ref: http://www.unece.org/fileadmin/DAM/tran ... 13hr2e.pdf

Re: Brake lights & regenerative braking 🔴

Posted: Mon Nov 23, 2020 6:49 am
by Deleted User 192
Very clever 👍

Re: Brake lights & regenerative braking 🔴

Posted: Wed Dec 08, 2021 4:30 pm
by DickieBoy
Has anyone tested out when these limits are reached in real world driving?

Do say in B do the brake lights come on all the time when you lift off the accelerator?

What about D?

Re: Brake lights & regenerative braking 🔴

Posted: Wed Dec 08, 2021 5:22 pm
by Deleted User 192
DickieBoy wrote: Wed Dec 08, 2021 4:30 pm Has anyone tested out when these limits are reached in real world driving?

Do say in B do the brake lights come on all the time when you lift off the accelerator?

What about D?

Depends how much you lift off the accelerator in B and how fast you're going at the time, as those influence the level of braking force applied.

If doing 30mph and lifting your foot entirely off the pedal, the brake lights will come on.

If doing 70mph and only lifting your foot a little, they probably won't come on.

Re: Brake lights & regenerative braking 🔴

Posted: Wed Dec 08, 2021 10:54 pm
by Chivers
...and if you stop at traffic lights and touch the RES button for the auto cruise control on the steering wheel [to put on the handbrake and get ready to move off] the brake lights stay on. :cry:

Re: Brake lights & regenerative braking 🔴

Posted: Thu Dec 09, 2021 9:31 am
by G43FAN
Chivers wrote: Wed Dec 08, 2021 10:54 pm ...and if you stop at traffic lights and touch the RES button for the auto cruise control on the steering wheel [to put on the handbrake and get ready to move off] the brake lights stay on. :cry:
Do you have Auto Hold disabled?
Sorry I am kind of confused by your comment. I have never touched the RES button to stop at traffic lights (or anywhere) the car does it itself, as did my Tiguan. But that was with Autohold enabled.