Regeneration brake lights

[Exdro]

Well, Les, I'd say it was a design fault if it does not meet the legal requirement, regardless of what the ZS and later MG5 demonstrate. It seems to me that the key question is....Is there a legal requirement for UK cars to have brake lights that are activated over a certain level of regenerative braking and does the existing MG5 conform to it? Either way, let's hope the newer "5" has got it.

There seems to be quite a difference in the way that the MG5 and the ZS have been set up. As far as I can tell from reading various posts. MG5 brake lights do not come on when KERS is activated. They do on the ZS under KERS 3. Is this because there is less braking or regen on the MG5?
There is no regeneration when slowing with Cruise Control on the ZS, but there is on the MG5. Am I correct or have I mis-read or misunderstood some posts.?

 

[5teep]

It should be a legal requirement for all EVs to activate brake lights on regen. I drove for the first time in the dark last week and could not see my brake lights coming on in the MG5.

 

[5teep]

There is no regeneration when slowing with Cruise Control on the ZS, but there is on the MG5. Am I correct or have I mis-read or misunderstood some posts.?

There is regen when using cruise control on the 5 but it's not nearly as strong as when in manual.

 

[Adee]

There is regen when using cruise control on the 5 but it's not nearly as strong as when in manual.

I'm completely with you, 5teep, that there should be brake light activation on regenerative braking and, personally, I would be happy if this were triggered on a particular level of deceleration. If this requirement is written in law, then I'd say the MG5 does not meet legal requirements, but I don't know if it is.

When you say cruise control, I assume you mean adaptive cruise control? My MG5 (Excite) does not have ACC but I do use an ICE car that has this facility and the brake lights can be seen to illuminate on the dashboard when the cars' brakes are applied under ACC. If you are using ACC in an electric car, can you be sure whether the car is using regen braking or actual (mechanical) braking when the brake lights are illuminated? My guess is that it is still mechanical braking that is activating the brake lights and possibly not regenerative braking?? But I can't test this as I don't have ACC.

 

[5teep]

No Adee none of them have ACC I think and that's a good thing. The 5 will regen when slowing down in cruise control but because the cruise doesn't usually slow very fast the regen is not so much.

 

[biffo]

From the latest podcast. Miles has confirmed the MG5 Long Range uses regen as part of the ACC (unlike the ZS EV which uses brakes) - he saw the voltage/charge levels change I think. Don’t remember him confirming brake lights for ECC.

 

[Adee]

As an aside...I am not a fan of using cruise control in KERS3 setting for the simple reason that if you cancel the cruise control by using the CC lever, the KERS3 braking comes on in full force which may not always be what you want (unless you are prepared for it and are aiming to match the throttle setting at the same time)!!

 

[Kompins]

Recently I did a bit of research into this brake light activation issue; after discovering that the regulations state that brake lights should be activated if de-acceleration is equal to or exceeds 1.3m/s², using a GPS accelerometer I recorded 2.4m/s² consistently using KERS 3. I contacted MG Motors a few weeks ago and had the following prompt response:

'After looking into this, we can confirm the MG5 EV would require this feature to be fully functioning in order to pass regulations.... and I can confirm your initial question in relation to regenerative braking has been forwarded to our engineering team for further advice.
We will keep you updated, thanks for your patience.'

Excellent response from MG Motors UK and it will be interesting to see what they come up with.

 

[Alb]

I was driving in the dark recently and I'm sure I saw signs of brake light illumination in my rear view mirror during KERS3 (non braked) deceleration. It could have been an illusion but it did grab my attention at the time.

 

[Sark21]

I have seen the dealer sticker which is mostly white at top of back window turn red when break lights come on in dark during regenerative breaking.Thats on the ZS

 

[Jeff]

I can confirm that the brake lights do not come on on kers3 when braking on the Mg5 for safety I just touch the brakes to warn following vehicle

 

[Ozzie1989]

Recently I did a bit of research into this brake light activation issue; after discovering that the regulations state that brake lights should be activated if de-acceleration is equal to or exceeds 1.3m/s², using a GPS accelerometer I recorded 2.4m/s² consistently using KERS 3. I contacted MG Motors a few weeks ago and had the following prompt response:

'After looking into this, we can confirm the MG5 EV would require this feature to be fully functioning in order to pass regulations.... and I can confirm your initial question in relation to regenerative braking has been forwarded to our engineering team for further advice.
We will keep you updated, thanks for your patience.'

Excellent response from MG Motors UK and it will be interesting to see what they come up with.

Any update on this? It's been nearly a month and is what I would call a pretty serious issue

 

[Kompins]

Any update on this? It's been nearly a month and is what I would call a pretty serious issue

I had a follow up on the 14th October as follows:

"We would like to let you know that below query is still being investigated by the Engineering team and we should have further findings to report back on in the coming few weeks."

I'll chase it up this week, hopefully we will get an answer soon.

 

[Freddy]

We have both the ZS and MG5 LR. Not noticed wether the lights come on during regen. But both my wife and I feel that the ZS has far stronger regen at 3, and the MG5 is only equivalent to the level 2 of the ZS, as more often than not in the 5 we are flicking the setting up to make sure it'in level 3.

 

[evmick]

We did a long journey in the dark in our MG5 EV LR last week, and in any KERS mode (including 3) the brake lights don't come on unless you press the brake pedal. You can see the lights come on in the rear view mirror when it's dark. Even in KERS 3, and braking sharply, they don't come on until you press the brake pedal.

 

[johnd973]

I really don't think the lights need to come on. Anybody who has ridden a large motorcycle will know the deceleration in an EV feels much less than what you get when you let off the throttle on a bike and the brake lights don't illuminate on those. In my experience this causes no issues at all so long as you don't let off the throttle completely when someone is tailgating you in a 4x4!

If someone runs into the back of you during regen they were probably driving too close and/or not paying attention and would almost certainly have still hit you even if the brake lights came on.

 

[Kompins]

I really don't think the lights need to come on. Anybody who has ridden a large motorcycle will know the deceleration in an EV feels much less than what you get when you let off the throttle on a bike and the brake lights don't illuminate on those. In my experience this causes no issues at all so long as you don't let off the throttle completely when someone is tailgating you in a 4x4!

If someone runs into the back of you during regen they were probably driving too close and/or not paying attention and would almost certainly have still hit you even if the brake lights came on.

My last bike was a Honda CBR1100XX so I understand where you are coming from though I don't agree. The point is the MG5 does not appear to comply with the construction regulations, see my original post. Is your insurance valid if someone runs into the back of you and says your brake lights were out?

 

[Kithmo]

My last bike was a Honda CBR1100XX so I understand where you are coming from though I don't agree. The point is the MG5 does not appear to comply with the construction regulations, see my original post. Is your insurance valid if someone runs into the back of you and says your brake lights were out?

Both those statements don't make sense to me. How would they prove your brake lights were out and if the car didn't comply with UK regulations it would not have been allowed on the roads.

 

[johnd973]

My last bike was a Honda CBR1100XX so I understand where you are coming from though I don't agree. The point is the MG5 does not appear to comply with the construction regulations, see my original post. Is your insurance valid if someone runs into the back of you and says your brake lights were out?

I cannot imagine the 5 or ZS would be on sale in the UK if they did not meet construction and use regulations. Type approval is carried out by the vehicle certification agency on production samples of vehicles before they can be sold in the UK and is quite a rigorous process.

I believe there are other EV's which also do not illuminate their brake lights under regen (Renault Zoe, Kangoo and first generation Nissan Leaf), it's not an exclusive trait of the MG's.

If someone runs into the back of you under regen then they were not maintaining a safe stopping distance in accordance with the highway code and were possibly driving with undue care and attention. I don't think the regen is strong enough that it should take anybody driving sensibly by surprise! It's no different than driving an ICE car and changing down from say 4th gear to 2nd to slow down!

 

[smokie]

They didn't come on on my Ampera either during regen, and I think that is correct otherwise brake lights would be on and off like the proverbial whore's drawer, every time you took your foot off the accelerator for more than an instant. That would be really irritating to follow.