[IanT]

So tonight on my way home from work I put the Leaf into B Mode and I noticed that the break lights didn't come on when I took my foot of the accelerator.

Now, I would have thought that being in regenerative breaking mode the break lights would have come on, the car is slowing down pretty quickly but the poor person behind me doesn't actually know this, isn't this rather dangerous?

Surely this is a fault / failure on the Leaf!

 

[AndyG]

The same happens in the Volt so it's not a Leaf fault, I have read that it is something to do with the rules about how much you slow down. The car won't slow down any more than an ICE that's using gear box braking. We usually feather the brake pedal if someone is driving too close.

 

[Paul]

I know what you mean, but I've had cars where I used to brake through the gears quicker than the regen on the LEAF, never had any issues then. Tricky one, when does "slowing" count as "braking", wonder if there's even any legislation on this?

 

[Paul]

@AndyG beat me to it!

 

[IanT]

Thanks for the clarification. I just think B mode is slowing down much quicker than going through the gears. I just need to be mindful about the person behind me, as you say feather the brake.

 

[Steamrunner]

The onus is always on the person behind to leave a safe distance - hence why there's nothing specifically addressing it. Mind you, BMW have added it (dynamic brake lights) to the i3 so perhaps we'll see it more often in the future.

 

[AndyG]

I had a mark 1 Escort GT and used the gears to slow down far more than the brakes, mind you it also spent more time on opposite lock going round a corner than the correct lock!!!! (many many years ago)

 

[purpleperil]

Same on the Ampera but no worse than engine braking on some of the large cc ICE cars I've owned

 

[Andy]

I'm a bit surprised to learn that the LEAF doesn't do this ? With the strength of the regen braking on the i3 I'd be very nervous if the brake lights weren't coming on but fortunately they do. If the regen is combined with the friction brakes for heavy braking then there is a 2nd set of lights that come on as well.

 

[markweatherill]

I've read that existing systems that flash the brake lights or put them on under hard deceleration, are disabled for the UK (if not the EU).
So I'd be surprised if the UK supplied i3 would put its brake lights on to indicate rapid deceleration, but there must be some UK owners who can advise???

(I don't know if it's a good idea or not, to illuminate brake lights under any circumstances that aren't actual brake pedal type braking, but if it is a good idea, it ought to apply to all cars)

 

[Andy]

The i3 brake lights are definitely coming on under regen braking in the UK (not flashing). It's mentioned in the BMWi UK marketing, the handbook and in a lot of UK reviews.

I don't know if you've driven one Mark but there's up to 60kw of regen applied so it's stopping the car quite quickly when you lift off the accelerator. Does anyone know what that number is for the LEAF ? Maybe it's a bit lower seeing as the motor is 80kw.

 

[markweatherill]

Hi Andy, that is interesting. Either there's been a change in the relevant laws to allow this, or BMW has included it regardless.

 

[Paul]

Robert Llewellyn mentioned in the VW e-up! review that he thought the brake lights would come on as the regen on that was aggressive too.

 

[IanT]

Robert Llewellyn mentioned in the VW e-up! review that he thought the brake lights would come on as the regen on that was aggressive too.

Funny you mention this as it's what sparked my question / thought about the Leaf.

 

[Spirit Driver]

Braking forces when applying the electronic retarder in most modern trucks are far greater than the LEAF in B mode, and yet the brake lights on a truck only come on when the driver uses the foot brake.

 

[Toby Galbraith]

So tonight on my way home from work I put the Leaf into B Mode and I noticed that the break lights didn't come on when I took my foot of the accelerator.

How can you see that the brake lights don't come on?

And why would you expect them to? In an ICE car if you lift off the accelerator and stay in gear, the car slows down, but that doesn't turn brake lights on...

I remember many moons ago there was a massive motorway pile-up and some secondary school kid was publicised as having the great idea of having brake lights that come on when you lift off the accelerator instead of when you press the brake, to save a few milliseconds. Sounds reasonable in principle but is clearly not workable, since it never happened. I would say that a lot of motorway jams could be avoided if people were looking further ahead and using coasting to slow gently, instead of needing to press the brake at all. What tends to happen is that they are so up the arse of the car ahead they have to chuck out the anchors when the guy in front sneezes, triggering a ripple of panic behind.

 

[T'leaf]

Braking forces when applying the electronic retarder in most modern trucks are far greater than the LEAF in B mode, and yet the brake lights on a truck only come on when the driver uses the foot brake.

Exhaust brakes they do, and on the old telma retarders I used to try setting up so they did come on

 

[BarryP]

What tends to happen is that they are so up the arse of the car ahead they have to chuck out the anchors when the guy in front sneezes, triggering a ripple of panic behind.

SO please can drivers stop filling the safety gap I leave in front of me! And stop touching you brakes every few seconds, If you need them on a motorway you are too close.

 

[inferno]

I have had a relative comment on it too, B mode does drop speed somewhat quick

SO please can drivers stop filling the safety gap I leave in front of me! And stop touching you brakes every few seconds, If you need them on a motorway you are too close.

+1
On my commute, if I leave a gap of more than 20meters to the car in front, someone is going to assume it means theres room for another car ... at 60-70mph
I generally avoid using b mode because people are asleep at the wheel and drives too close.

 

[AndyG]

I have had a relative comment on it too, B mode does drop speed somewhat quick

+1
On my commute, if I leave a gap of more than 20meters to the car in front, someone is going to assume it means theres room for another car ... at 60-70mph
I generally avoid using b mode because people are asleep at the wheel and drives too close.

I find B mode is a good way to wake them up.
If people drive to close to me I often lift off in B and watch them in the mirror panicking, if they drive to close again repeat until they get the idea. PS I do keep an eye out just in case they are really asleep so i can accelerate out of harms way and don't do it without an escape space.