MG5 KERS 3 & Brake Light Operation - Safety Recall?

[sido]

So I should not decelerate because someone behind me is speeding is that really what you think? I am trying to get out of the way without breaking the speed limit.

 

[MarkLynn]

I really think they mean to decelerate could be dangerous unless some warning is given "mirror signal maneuver" springs to mind, that done no issues should arrive from changing lanes or reducing speed when the need arises.

 

[smokie]

So I should not decelerate because someone behind me is speeding is that really what you think? I am trying to get out of the way without breaking the speed limit.

Absolutely you shouldn't. why would anyone in their right mind consciously, deliberately, needlessly and maliciously decelerate in front of a faster moving car?

You already implied above in your scenario you yourself may have consciously pulled out in front of faster traffic. (If it was not consciously then you are, of course, not paying enough attention and/or having respect for other road users).

If that's the way you drive then I suppose you need all the brake lights you can get!! And beware of road rage.

Simple and safer for all if you indicate, move out of the way then decelerate. And I'm not really one for preaching about safety, as you may have noticed in other threads.

Actually I am now wondering if you are being serious but unfortunately you come across as though you are.

 

[sido]

I often forget when posting to this forum to provide all the details so as to avoid confusion. My original post was related to my experiences on the A30 heading into Cornwall. The dual carriageway has a 70 mph speed limit most traffic in the inside lane is travelling between 50 and60 mph, it is normally heavy with caravans and delivery trucks and cars with fluctuating speeds needing to overtake to maintain 65 mph or faster. The outside lane normally empty except for overtakers and the odd stuck at 70mph and will not move drivers. When you look in your mirror, signal seeing nothing behind you and pull into the outside lane to overtake you are often surprised in a matter of seconds, to find a car suddenly right behind you who was clearly travelling well in excess of the speed limit, at this point, to get back into the inside lane you have no option but to slow down as you signal and move towards the inside lane otherwise you will pass the gap you are aiming for In the slower moving traffic. By this time four or five speeders are behind the car that was immediately behind me and they disappear into the distance as I plod on with repetitive overtaking and returning to the inside lane. I trust this clearer and more detailed account of my experiences firstly confirms I am serious and that I do take appropriate measures to maintain my own and others safety on that road.

 

[biffo]

One point I will make, having been someone who spent a considerable amount of time exceeding the speed limit on motorways by at least 50%++ on too many occasions to count - it's not the responsibility of the driver who is obeying the speed limit to anticipate your insane actions - if you are driving dangerously (i.e. in excess of the speed limit and/or conditions), then it's your responsibility to anticipate someone may, quite justifiably, pull out in front of you at 70mph. No one should be expected to have the foresight that a car in the distance will close the gap faster than legally allowed - unless they have blue lights flashing. Sure - doing it as recklessly as the oncoming car is being doesn't make it right however.

Perhaps this is why a set of brake pads once lasted about two months for me - dropping from 130mph+ to 80mph as passing slip roads became the norm - luckily I gained a sense of my own mortality

Anyway - now that I very rarely exceed the speed limit, I would have no issues pulling into a faster lane on the motorway at 65-70mph so long as there was an adequate gap for cars behind to see my indication and adjust their excessive speed to my manoeuvre - no one is suggesting that you should make a lane change which will cause an accident, but cars travelling above the legal speed limit have a responsibility for their actions. In the same way I have no issues irritating cars behind when I slow down as the speed limit changes - sometimes I think I'm the only person who can see the 60mph to 50mph transition on the M74 for example, and every other driver literally can't see (or doesn't care enough to pay attention to) 30mph signs.

I'm rambling & getting off topic of KERS - there is nothing worse than a reformed criminal I guess!!

 

[Vipar]

My Mitsubishi has 1-5 kers you have to drive downhill when in 5 and you certainly know when kers is engaged even in 1 stop lights do not come on when using kers.

 

[bobs2293]

I can confirm the brake light operates in KERS2 as well as KERS3.

 

[Joe McAndrew]

Well I at long last had this recall done yesterday at 1st service. Prior to yesterday my KERS worked even at 100% in the sense that the car slowed when throttle was removed and the needle indicated that the car was recharging the battery. Whether or not any charge was actually going back in I don't know but the car slowed and the meter indicated energy returning to the HV Battery. Also when driving from 100% I could get 4 miles before it got to 99% and the rate of drop to say 95% was fairly slow.

Today after the update and a charge to 100%, the car has no KERS at all and I need to brake manually until KERS kicks in at around 96%! Added to that the drop from 100% to 96% is much quicker!

In short, what a garbage update that has been!

 

[Neil Fellows]

Today after the update and a charge to 100%, the car has no KERS at all and I need to brake manually until KERS kicks in at around 96%! Added to that the drop from 100% to 96% is much quicker!

I thought this is how it should work anyway, since its impossible to add charge to a battery that's at 100% already? I seem to recall before the update, my KERS wouldn't work either if the battery was at 100%.

I'm pretty happy I've had it done since I've always been a little nervous using KERS 3 at night with a tailgater. At least they'll see a brake light now!

 

[Jomarkh]

Well I at long last had this recall done yesterday at 1st service. Prior to yesterday my KERS worked even at 100% in the sense that the car slowed when throttle was removed and the needle indicated that the car was recharging the battery. Whether or not any charge was actually going back in I don't know but the car slowed and the meter indicated energy returning to the HV Battery. Also when driving from 100% I could get 4 miles before it got to 99% and the rate of drop to say 95% was fairly slow.

Today after the update and a charge to 100%, the car has no KERS at all and I need to brake manually until KERS kicks in at around 96%! Added to that the drop from 100% to 96% is much quicker!

In short, what a garbage update that has been!

Hi, so before the update are you saying that you were able to put the car into kers3?
Kers2 will give some regen.
Mine will only go into kers3 at about 95/96%.

 

[smokie]

Mine goes into 3 at 100%. Whether is is actually putting the regen into the battery is another matter. I still don't have the feeling of sharp braking under KERS which some have.

 

[BugEyed]

Well I at long last had this recall done yesterday at 1st service. Prior to yesterday my KERS worked even at 100% in the sense that the car slowed when throttle was removed and the needle indicated that the car was recharging the battery. Whether or not any charge was actually going back in I don't know but the car slowed and the meter indicated energy returning to the HV Battery. Also when driving from 100% I could get 4 miles before it got to 99% and the rate of drop to say 95% was fairly slow.

Today after the update and a charge to 100%, the car has no KERS at all and I need to brake manually until KERS kicks in at around 96%! Added to that the drop from 100% to 96% is much quicker!

In short, what a garbage update that has been!

Sounds to me like they have changed the behaviour of the BMS to avoid charging into the buffer at 100% either from the mains or KERS. That's probably a good thing for battery life but less good for range and drivability.

 

[biffo]

Hi, so before the update are you saying that you were able to put the car into kers3?
Kers2 will give some regen.
Mine will only go into kers3 at about 95/96%.

Mine goes into KERS3 at all battery levels - before and after this update. Sometimes the regen feels less, usually when battery full or perhaps when cold - but display always shows '3' when I select it.

 

[Joe McAndrew]

Just to clarify it goes, I can still put the car in KERS 3 but there is no noticeable KERS action in the form of braking until 96% and therefore no charging of the HV Battery (whether it was actually accepting it previously or not who knows?).

The car therefore has no noticeable slowing down other than natural slowing until the battery discharges to 96%. I am therefore clearly losing some efficiency over that first 4% and am having to use brakes where before I could almost 1 foot drive and would only touch the brake pedal if the car had to come to a halt.

 

[Dino]

I’ve never been able to put the car into KERS 3 until I’m down to 98% or less, if I try at 100 or 99% I get a message saying something like regenerative braking mode isn’t available. MG5 SR and had the update done the end of last year.

 

[BarryH]

It is a BMS calibration. What the BMS shows as 100% is not the "True" 100% SOC and is just the level at which the top charge buffer starts and similarly 0% Empty isn't a fully discharged battery. These 0% and 100% SOC only give you the accessible range. I have a 44 kWh Gen 1 ZS and originally at full or near full charge when pressing Start I would often get a warning screen saying that KERS Braking would not be available as the HV Battery was fully charged but there was a BMS update around 2 years ago which recalibrated the Battery Pack so that the MAX Battery voltage at which the BMS said 100% (ie Full) was lower than before and the voltage to which the battery could discharge and at which BMS said 0% (ie 3 dashes) was also lower than before. This had the effect that the is Regen braking ie KERS effect over far greater range of SOC. In practice, on the rear occasions that I drive immediately after topping up to 100% I get the warning and I get KERS Braking in about ½ mile of setting off. But if, as I usually do, I charge overnight on Octopus Go then by the time I drive it in the morning the cell voltages will have settled enough for me not to get the message.

So It is most likely just a matter of a BMS change.

With regards to loss of efficiency until you get to 97% I doubt that is something you'll see unless you would normally do a lot of heavy braking in those first few percent of charge. In fact, less KERS is arguably a more efficient use of the power in the car's battery since KERS isn't 100% efficient (round trip efficiency of KERS is only about 60% at best) and lift and coast, ie using the momentum of the vehicle to cover more ground, is high 90's percent efficient use if the kWh put into the motor.

However, there is no denying that it can be a little disconcerting to lift off and have the car coast on when you weren't expecting it, and later have KERS kick in, but it isn't necessarily going to make a big difference to the range.

 

[shayjeffs]

I’ve never been able to put the car into KERS 3 until I’m down to 98% or less, if I try at 100 or 99% I get a message saying something like regenerative braking mode isn’t available. MG5 SR and had the update done the end of last year.

I think what I’m finding is that after a load balance charge I can put it into Kers3 at 100%. But if I just do a charge to 100% without leaving it on to balance I get the same message as you when I try to put it in Kers3. At about 98% I can do it. So is it something to do with balancing the battery?

 

[BarryH]

I think what I’m finding is that after a load balance charge I can put it into Kers3 at 100%. But if I just do a charge to 100% without leaving it on to balance I get the same message as you when I try to put it in Kers3. At about 98% I can do it. So is it something to do with balancing the battery?

Yes, it is possible that if the battery pack isn't balanced then one cell could be 'high' and the BMS would prevent KERS as it could otherwise overcharge the high cell. Balance or Equalisation Charges are a really important part of EV ownership not just to prolong the life of the battery but also to ensure you get the full driving range.

 

[TheArcher]

I'd much prefer dealer updates than OTAs. Check out a YouTube video by Chris in Battery Life when he had to update his VW ID3. It looked as if the car was unable to be driven for hours (not that I'm going to watch it again).

 

[BarryH]

I'd much prefer dealer updates than OTAs. Check out a YouTube video by Chris in Battery Life when he had to update his VW ID3. It looked as if the car was unable to be driven for hours (not that I'm going to watch it again).

I'm not sure you've posted on the best thread for your comment on OTA Updates, but it is perhaps worth noting that OTAs are not all equal for all car makers. Some ie Tesla can provide OTA to pretty much any and every software system on the car whereas others are far more limited in what they can or will do and can be just the infotainment system and no more.