Rethinking of regen brake lights a crucial step

That there is no visual indication of the vehicle slowing down while using regen. Concern being increased risk of rear-ending. @tarun @abhishek.balaji

Tl:dr of the video- as we use only regen without braking at the twist of the throttle we do slow down quickly enough for the vehicle tailgating us(which in India, it seems to be a common phenomenon) would probably rear end into the scooter with a large enough probability to warrant a software based solution.


Regen on a gen 3 acts quickly enough to get you from a 50kmph to near zero standstill which doesn’t register as braking on the tail lights try observing an Ather ahead of you slow down with only regen and not conventional braking(ie the disc brake biting in to provide a instant stop)


Additionally except for an Ola, regen braking or as Ather calls it twist-to-brake ie. Twisting the throttle in negative axis to general 0 position of the throttle gives far more braking potential than the roll off, on an ice bike or even e2w currently on the market(haven’t yet tested a uv f77).


You might be referring to material released by Ather far prior to the recent changes in software with stack 5.0 to what extent regen works, now it’s way below 7-10kmph rather vigorously when your under 50 to start with. True it only activates below 80% but with optimised charging most users already begin with regen on. Secondly the amount of charge regained by brake lever induced(prior to the pads actually engaging) regen is far lower than that of the %regained with throttle based regen hence even the difference in braking potential given by both is conclusively different.


Plus if you’re not from a technical background I would rather suggest you too read a bit about the degradation caused to the gear mechanism due to engine braking vs the difference of how a pmsm motor regulates revolutions for regenerative effect.


Nope I am quoting from the manual for the 450x v3 (450X_UserManual_Gen3.pdf, downloaded via the ver 8)

There is no note of this in the manual. So please cite your source.

My background is as about relevant to the discussion as what you are talking about above. Meaning not at all.

Let me summarize the discussion in at attempt to steer it back on course

Your central point is that regeneration should make the brake light come on a thread titled “Rethinking of regen brake lights a crucial step”. This is necessary according to you because

I am pointing out that slowing down in front of a vehicle that is tailgating you is very very unwise and not likely to lead to a safe outcome.

The term the manual uses is “Regenerative braking” where are you making up stuff from ?

that the primary purpose of regenerative braking is NOT to slow you down.

You will be able to scrub off speed faster / modulate it better by using the brakes to do so (and the brake levers will activate the regen). That by the way would be the proper riding technique.

As for

This is just plain wrong. I leave it to you to figure out why.

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By the criteria of tail gating any car behind you should be above 3 meters from you when at the speed of 30kmph, driving in a fast moving traffic of Mumbai with far lesser space would also come under same umbrella term, which is often the case.


If the primary purpose of regenerative “braking” is not to slow down why would I want a rolling potential working against the direction of the kinetic force applied.


This is true in practice. Regen braking continues to work below 20 Kmph even though the manual states otherwise. This is for my Gen 3.0


Where do you dream up this stuff from ? I do not recall any mention of speed and separation

Ah! so you have not read the manual while accusing me of reading the wrong one. I have copy pasted from the manual for your convenience - you don’t bother to read that either.

By the way I had asked you for a source to support these bogus claims

the bogus claims I am calling you out on

  1. The claimed deviation from what is described in the user manual.
  2. that brake lever induced regen starts before the pads have engaged is again not documented in the manual. I have no idea how you quantified the “% regained” so I will ignore that.

Talking strictly from the manual it mentions when it activates yet fails to mention to what point it’s unto from the point of activation so your estimation of it stopping after 20kmph is presently another of your own presumptive fallacies.


If speed and separation are not the problem then why would you even have a problem called tailgating(aka a driver driving so close to you that any deceleration caused by you or factors around you to affect the risk of rear-ending). In the above case speed and separation are directly proportional in increasing or decreasing the said risk while an indicator strip acts as an external factor influencing the probability of it.


I don’t think there’s any constructive thought or discussion here.

Because you are not clear on why regen can not / should not be primary braking method.

Should you want to ride around slowing down at random rates in front of traffic i can only point out that it is dangerous driving.

If you want to argue that twisting the throttle grip forward is a braking method of choice, and should light up brake lights, i don’t agree. It’s pointless

I agree it does work to about ~5km, quite different from the documented behaviour. This after riding around in a parking light using only the twist forward method of scrubbing speed.

It is nowhere as quick as using the brakes, it is not as predictable and consistent as the brakes. It has no modulation.

The twist forward means of slowing down is of no consequence to me, it’s a feature on the bike i can live without. Especially given that regen is also activated by the brake levers per the manual.

And the regen braking works only the rear wheel. There’s way more effective / powerful braking force through the front wheel

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Hence I would like to point you towards the discussions around one pedal driving which come up while discussing e4w in regards to the said statement and hope that sheds enough light on the problem at hand, than rider blaming when it regards to issues that involve evolving rider habits due to ingress of newer technologies or due to behaviour change to thereof.

If you’re going to tell me the Ather has one pedal i think it is time for me to quit this thread. This conversation was about four wheelers. Oh excuse me it was my “presumptive fallacy” that we are discussing a two wheeler Ather (another concept you don’t understand by the way).

It’s is neither, yet the conclusive theory regarding both end up to the same discussion if you’re not able to grasp the reasoning behind the thread to begin with, than this thread was never meant for you.

Even with two wheelers if you don’t understand how different drive trains work differently to influence rider behaviour than I’m sorry that you’ve missed the point that e2w work differently than manual or even geared automatic two wheelers and/or you’re still stuck with the ‘fallacy’ that both are equal and drive the same way; which it is not they are equivalent or equanimous yet not equal.


I know more into this scooter on the hardware level, and you are very wrong.

Forced Regen can be activated at any speed on Gen 3 as long as battery is below 80% and MCU temperatures are under control.

And yes, it is as effective as using the brakes at 60%. So yes, OP is right and brake light is important. I have had an accident with a bus rear-ending me because of this and certainly has nothing to do with “riding techniques”. Get real.


Idc about the discussion above, but if vehicle is being slowed down in any means. Let it be regen or braking. The brake light should turn on, imo.

In India 90% of the riders doesn’t know how to ride and turning the brake light makes it idiot proof.