At night you can watch the brake lights working in yourvrear view mirror as they reflect off road signs.
brake lights during regenerative braking
An interesting (USA) video on absense of brake lights while slowing down.
but also talks about the situation in Europe (about 22 mins in).
- update: sorry, he appears to have got the European situation completely wrong. So it's not really that interesting after all.
[I quite like his videos / presentation style, but I imagine some might find him annoying.]
I've still never got round to checking for sure if/when my 30kWh leaf shows the brake light - I really ought to do that (since I've got into the habit of going into B mode to slow down, rather than pressing the brake pedal).
- update: sorry, he appears to have got the European situation completely wrong. So it's not really that interesting after all.
[I quite like his videos / presentation style, but I imagine some might find him annoying.]
I've still never got round to checking for sure if/when my 30kWh leaf shows the brake light - I really ought to do that (since I've got into the habit of going into B mode to slow down, rather than pressing the brake pedal).
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On 24 kWh Leaf, they don't. B mode never turns on brake light. Only brake pedal is used it turns on.if/when my 30kWh leaf shows the brake light
I was hoping he would go into more visual direction, for example less pixels = low regen, more pixels = harder braking. But unfortunately the standards and regulation seems lacking to even start consider anything better.
Top question on my EV bingo card. It must be at least a week since this was last asked.
If you lift off in an ICEV the brake lights don’t come on.
Depending on what you’re driving the rate of deceleration could well be more than regen in a BEV.
So in a BEV with regen active, the brake lights will come on appropriately depending on that rate of deceleration. What’s not to like?
Depending on what you’re driving the rate of deceleration could well be more than regen in a BEV.
So in a BEV with regen active, the brake lights will come on appropriately depending on that rate of deceleration. What’s not to like?
That's certainly what SHOULD happen. There's no logic for anything else. The driver behind doesn't care whether it's regen or friction, only that you're decelerating hard enough to need to take notice.in a BEV with regen active, the brake lights will come on appropriately depending on that rate of deceleration. What’s not to like?
The regs are simple and have come up here several times before, search on "Brake Lights".
Example >
www.speakev.com
Example >
Brake lights whilst using regen
I'm looking into which manufactures have used some common sense regarding brake lights illuminating during regenerative braking. I have mini electric and in both low and high regen modes the brake lights illuminate as soon as the needle drops even the slightest bit onto charge block which to me...
www.speakev.com
Yes, 5.2.22.4 is exactly the paragraph he cites in the video. As you'll have seen at around the 24 minute mark when you watched the video, it used to say that regenerative braking shall not illuminate the brake lights. The version shown above was from an ammendment proposed in 2019, and only recently adopted ???Thanks for the heads up. Pretty straightforward really…
It would be interesting to know exactly when the wording changed.
EtA: Hmm - https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/R13hr2e.pdf is dated 2011 and does seem to have the "new" wording. Guess he's just plain wrong, then ?
Seems like it. He's quoting from a long superseded version of the UNECE regulation from 31 August 2010....Guess he's just plain wrong, then ?
I hope so. I will have to arrange a few test runs and report back.Guess he's just plain wrong, then?
I dont think the LEAF30 does bring on the brake lights, even in B, because its regen simply isnt strong enough to require it.
It tapers off the regen power as speed falls to ensure the deceleration limit is not exceeded.
It tapers off the regen power as speed falls to ensure the deceleration limit is not exceeded.
Stellantis vehicles are tuned so the maximum deceleration in B mode is just weak enough not to require brake lights. I think of B mode as changing down a gear to enhance engine braking in a manual fossil car, and then it sort of makes sense. I only really use it to keep the speed down on a long downhill. As the brake pedal causes regen first, only operating the mechanical brakes when you press harder, there's no point in using B most of the time. I prefer to show my brake lights when I'm braking! It's a different concept to one pedal driving, and more familiar for those used to fossils.
The Leaf 40 and 62 don’t illuminate the break lights on B mode, but they do on e-pedal.
The LEAF will light the brake lights in e-pedal mode, because it uses the friction brake some of the time.
Brake light operation clever way to keep an eye on it.
Don’t people just need to adapt their understanding? It’s in the name - brake light i.e. a light that comes on when you press the brake. If you’re not pressing the brake the light doesn’t come on. If the car ahead is decelerating under its own steam, it doesn’t come on.
My automatic ICE car does exactly the same as the EV - I take my foot off the accelerator approaching a roundabout and the car slows with the auto changing- down. This is so that I’m in the right gear to enter the roundabout without stopping if there’s no traffic. No brake light ever appears but I’m slowing significantly. Same thing approaching traffic lights or a junction.
Some people have always had a simplistic concept of what the brake and accelerator are for i.e. they are stop and go pedals. They never develop the concept of engine/gearbox braking being more efficient. But it’s their problem when they get behind an ICE auto or a regen‘ EV and can’t understand why a car that’s slowing down isn’t showing brake lights.
When you’re taught to drive you‘re told to leave a gap behind the car in front (a) in case they emergency brake and (b) in case they slow down by engine/gearbox braking (something common with ICE autos and now, with EVs as well). And that with (b) you have to keep alert because there’s no brake light indicating their speed is dropping.
My automatic ICE car does exactly the same as the EV - I take my foot off the accelerator approaching a roundabout and the car slows with the auto changing- down. This is so that I’m in the right gear to enter the roundabout without stopping if there’s no traffic. No brake light ever appears but I’m slowing significantly. Same thing approaching traffic lights or a junction.
Some people have always had a simplistic concept of what the brake and accelerator are for i.e. they are stop and go pedals. They never develop the concept of engine/gearbox braking being more efficient. But it’s their problem when they get behind an ICE auto or a regen‘ EV and can’t understand why a car that’s slowing down isn’t showing brake lights.
When you’re taught to drive you‘re told to leave a gap behind the car in front (a) in case they emergency brake and (b) in case they slow down by engine/gearbox braking (something common with ICE autos and now, with EVs as well). And that with (b) you have to keep alert because there’s no brake light indicating their speed is dropping.
The regulations are clear, but what is not clear is the implementation of these across the various BEVs now on UK roads.
Because the middle deceleration values state "may" it allows interpretation by the manufacturer. Some may do this, whilst others may not.
I drive my Kia Niro EV in Eco mode and i-Pedal (one-pedal driving) all the time. Unless I'm caught out by someone doing something daft on the roads, I rarely touch the brake pedal and on those occasions I do it is likely to stop quickly so brake lights will illuminate.
So for the rest of the time, as I'm slowing to varying degrees but none of which are more significant than say engine/gearbox braking in an ICE, I doubt my brake lights ever turn on.
I have noticed at times when regen is strong-ish, such as when you used to go from 4th to 2nd in a manual ICE car ready to accelerate again, the car behind me quickly gets close as clearly they've been a little taken aback by my speed reduction without any brake light illumination.
Brake lights are either off or on. Some cars have a stronger brightness for emergency braking, but that is usually accompanied by hazard warning lights so it's clear an emergency stop is underway.
Personally, I would prefer all manufacturers implement both the 2nd and 3rd rates of regen deceleration to illuminate the brake lights. I am going to fire off an email to my Kia dealer to ask how the Niro EV deals with this, just so I know for myself.
Because the middle deceleration values state "may" it allows interpretation by the manufacturer. Some may do this, whilst others may not.
I drive my Kia Niro EV in Eco mode and i-Pedal (one-pedal driving) all the time. Unless I'm caught out by someone doing something daft on the roads, I rarely touch the brake pedal and on those occasions I do it is likely to stop quickly so brake lights will illuminate.
So for the rest of the time, as I'm slowing to varying degrees but none of which are more significant than say engine/gearbox braking in an ICE, I doubt my brake lights ever turn on.
I have noticed at times when regen is strong-ish, such as when you used to go from 4th to 2nd in a manual ICE car ready to accelerate again, the car behind me quickly gets close as clearly they've been a little taken aback by my speed reduction without any brake light illumination.
Brake lights are either off or on. Some cars have a stronger brightness for emergency braking, but that is usually accompanied by hazard warning lights so it's clear an emergency stop is underway.
Personally, I would prefer all manufacturers implement both the 2nd and 3rd rates of regen deceleration to illuminate the brake lights. I am going to fire off an email to my Kia dealer to ask how the Niro EV deals with this, just so I know for myself.
In another current thread in the Ioniq 6 forum section, an American guy has claimed that in i-pedal mode the brake light of that family of cars only shows when the foot is lifted away from the pedal totally. And as retardation can be quite high in that mode he is concerned about being rear-ended by a follower not paying full attention. I tend to agree if his claim is shown to be correct so I will carry out a few road tests in my Ioniq 5 and report back.
Many years ago I built an inertia brake light that was completely self contained and used a 6v dry 'lantern' battery as power. It was a small box that sat on the rear parcel shelf. The system was based on a mercury switch that was set at an angle so that when the car was slowing down the mercury ran forward in a glass tube and bridged two connections to light the bulb. I can't remember quite why I made this but I did. It worked well but was superseded by a second generation device that used a floppy spring and bob weight that turned a potentiometer to make the lamp brighter the harder the retardation became. Then latched to keep the light on at its brightest if retardation was actually a crash. I tried to sell this idea but nobody was interested.
Obviously, cars and other devices now use accelerometers to detect the rate of acceleration or deceleration so that fine tuning the lighting of a brake light is easy apart from when the real pedal is being pushed. But have they all got that algorithm right? That's the real debate.
Obviously, cars and other devices now use accelerometers to detect the rate of acceleration or deceleration so that fine tuning the lighting of a brake light is easy apart from when the real pedal is being pushed. But have they all got that algorithm right? That's the real debate.
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