Limiting power?

[olliewebb]

Wonder how some people would cope driving a 40 ton truck ?

Don't think it would fit in my work car park.

I've piloted plenty canal boats though.

 

[siteguru]

The advice is to accelerate on a slip road to such a speed as to match the traffic flow on the road you are joining and merge safely not floor the bastard and see what happens whether it has 100 bhp or 500bhp.

That's all well and good, but as the photo showed earlier ... that's not always possible; some slip roads are virtually non-existent.

 

[olliewebb]

The advice is to accelerate on a slip road to such a speed as to match the traffic flow on the road you are joining and merge safely not floor the bastard and see what happens whether it has 100 bhp or 500bhp.

My point being you don't know what will happen, you could brush the throttle and it could scream away, or you could floor it and it'll feel like the handbrake is on.

Do you see the issue? And before you go on about trucks again, you know what a truck is going to do because you know the weight in the back when it's loaded.

This car doesn't tell you what's going to happen until you do it.

Imagine having an ICE car with an intermittent misfire, would you fix it? I know I would.

 

[gary333]

You can tell people don't live in a rural setting here.

Busy road, joining with no slip road at 60mph. You could sit and wait, but you might be there forever with traffic backing up behind you. What you need is a punchy car that can safely get you into a gap.

Also dual carriageways that have essentially no proper slip road too, you have to get to 70mph in the safest way, I'm gonna floor it (sorry, not sorry). An example here on the A1 to a place I go a bit with the TF:

View attachment 41399
And that's a long one.

When you go to put your foot down and you sometimes get half the power you're expecting, it's not exactly safe. This is why the car should tell you before you do.

I want strong acceleration, I don't give a monkeys about top speed, hence a high powered EV.

And to be clear I'm talking about peak travel times here, which is not when I'm driving a 23 year old MG, or a 56 year old one, and then when traffic is really bad I use the bike, because if you're sat in traffic you're not, you are the traffic.

Ultimately after two years with the car I can say it's a bit like the Genie from Disney's Aladdin, "Phenomenal cosmic power! Itty bitty living space battery." I've driven a Smart #1 Brabus and the drop in power at low SoC was no where near as much, and I'm hopeful the IM5 will be better too. Because genuinely it feels like going from a 3.0 turbo inline 6 (BMW B58) to a 1.5 turbo three pot (BMW B38) when it's cold (under 2ºc) and you're getting under 40% charge.

Maybe because I'm a lot younger than people who tend to own these cars, but when I learnt to drive I was taught to use the power of the car to get up to traffic speed asap.

Pah! You’ve got a run way sized slip road there, you wanna see this beauty when Nottingham’s race car drivers are all gunning it at 85+ here on the A52

Street View of Borrowash · Google Maps

Derby, UK

www.google.co.uk

 

[olliewebb]

Pah! You’ve got a run way sized slip road there, you wanna see this beauty when Nottingham’s race car drivers are all gunning it at 85+ here on the A52

https://maps.app.******/6LXA8nXG5P4xQ5FG7

I did say that was a long one.

 

[gary333]

I did say that was a long one.

I know mate, I was having a joke as there's loads of these junctions about where there's zero slip road and cars gunning it at well over 70mph where having a faster car is useful. Here's one of the many on the A1.

Street View · Google Maps

Explore a place in a more immersive way in Google Maps.

www.google.co.uk

 

[tsedge]

You can tell people don't live in a rural setting here.

Er... what? I live in rural Devon, about as a rural as you can get around me.

Busy road, joining with no slip road at 60mph. You could sit and wait, but you might be there forever with traffic backing up behind you. What you need is a punchy car that can safely get you into a gap.

There are loads of slip roads like that around here and I have zero problems getting up to speed with the traffic.

Getting up to speed does not require 429 horsepower and if you do deploy all of that at once, you're only going to surprise people on the road as you suddenly appear and muscle into a tiny gap when they are not expecting it, which is exactly how accidents happen.

When you go to put your foot down and you sometimes get half the power you're expecting, it's not exactly safe. This is why the car should tell you before you do.

There are ZERO circumstances when you NEED 429bhp on the public road. You might choose to deploy it all - hopefully when the roads are clear - but that is for fun, not for necessity.

You should never be doing so in busy traffic. You will just cause accidents.

I want strong acceleration, I don't give a monkeys about top speed, hence a high powered EV.

What you want is irrelevant. You have a responsibility to drive safely while minimising risk and being courteous to other drivers. It certainly doesn't sound like you do any of that - but perhaps I misunderstood?

Maybe because I'm a lot younger than people who tend to own these cars, but when I learnt to drive I was taught to use the power of the car to get up to traffic speed asap.

I bet you weren't in a 429bhp car when you were learning. Obviously your instructor did not mean full send in an XPower.

Like I said, I have no problem with you enjoying your car when the traffic is light in good conditions when you pose a minimal risk to others.

But if you are connecting that level of power as being necessary to join busy traffic or overtaking on busy roads, or on a regular busy commute rather than a weekend drive, then in my opinion you need to seriously re-evaluate your driving before you hurt someone.

 

[Everest]

what he said ^^^

 

[olliewebb]

Er... what? I live in rural Devon, about as a rural as you can get around me.

There are loads of slip roads like that around here and I have zero problems getting up to speed with the traffic.

Getting up to speed does not require 429 horsepower and if you do deploy all of that at once, you're only going to surprise people on the road as you suddenly appear and muscle into a tiny gap when they are not expecting it, which is exactly how accidents happen.

There are ZERO circumstances when you NEED 429bhp on the public road. You might choose to deploy it all - hopefully when the roads are clear - but that is for fun, not for necessity.

You should never be doing so in busy traffic. You will just cause accidents.

What you want is irrelevant. You have a responsibility to drive safely while minimising risk and being courteous to other drivers. It certainly doesn't sound like you do any of that - but perhaps I misunderstood?

I bet you weren't in a 429bhp car when you were learning. Obviously your instructor did not mean full send in an XPower.

Like I said, I have no problem with you enjoying your car when the traffic is light in good conditions when you pose a minimal risk to others.

But if you are connecting that level of power as being necessary to join busy traffic or overtaking on busy roads, or on a regular busy commute rather than a weekend drive, then in my opinion you need to seriously re-evaluate your driving before you hurt someone.

My issue is still around the nature that sometimes you get full power, and then other times you don't. Like I said, it's like having a ICE car with an intermittent fault that cuts power.

The amount of reduction in power is really silly in my car, there's a chance it might be faulty but I've run out of energy to care any more with it going back. To the point where I've seen under 60% power at around 40% SoC. And like I keep saying, you do not now how much power the car will let you have until you try and accelerate, all I want is a warning from the car, I'd happily drive around it if that's just the nature of it. The classic "they all do that sir".

A 40% reduction puts it at what? Around 250bhp, in a 1800kg+ car that's not really all that much when you're supposed to have nearly double that, and especially when the last time you drove it the car was giving you all the shove. Anyone who's driven higher performance cars will know that the difference between 250bhp and 430 is quite significant.

Like I say, one minute you brush the throttle and you get a nice shove, another time you can floor it and it's like driving a car with the handbrake on. That's not safe. I've had it when it's been sluggish one second and then later in the day even without charging it seems to be back to full power again.

The only common factor is cold weather, it's fine in spring/summer even at low SoC. So you go to heat the battery and the car or app tells you it doesn't need to be heated.

I will say I've had a clean license for 20+ years, and take driving (and riding) very seriously. I'm very rarely giving it full beans, but it can be useful and even actually safer (reducing time on the opposite side of the road overtaking extremely slow moving vehicles like tractors) time to time.

 

[tsedge]

My issue is still around the nature that sometimes you get full power, and then other times you don't. Like I said, it's like having a ICE car with an intermittent fault that cuts power.

The amount of reduction in power is really silly in my car, there's a chance it might be faulty but I've run out of energy to care any more with it going back.

I'm with you on this aspect. It does sound like you may have a fault and it is your right to get what you thought you paid for. There certainly are some lemons out there and if you had one, that is bad luck you didn't deserve.

 

[olliewebb]

I'm with you on this aspect. It does sound like you may have a fault and it is your right to get what you thought you paid for. There certainly are some lemons out there and if you had one, that is bad luck you didn't deserve.

Thanks.

When I test drove the IM5 I did make sure I ran it down to a low SoC, and it was a fairly cold and wet day. It actually felt faster than my XPOWER, not as much traction of course, but I can live with that having driven a M140i through a few winters on Cup 2 tyres.

 

[Cabansail]

This does seem to be a thread with people taking small issues to an extreme to make a point.

Yes I live in a rural area, but not like what you seem to call the driving conditions in the UK with motorways.

Joining a Motorway on a slip road is often an issue for some, as they tend to do it wrong. The power of the car (imho) is not the major factor. The think I see most often is people who drive down the slip road and only plan their join as it merges. Some then push their way in and rely on other traffic to give way to avoid a collision. Others will then stop with an indicator on and a very large speed differential (this is where high acceleration could help) The proper way is to plan the merge at the top of the ramp and then match speed and timing to join there. I can do this in the XPower, but could also manage this in a loaded Landrover. It more about your awareness and being ahead of the vehicle than the performance of the car.

Then there is the loss of power when the battery has a lower charge. This does seem to be more pronounced in the higher performance EV's than those with a lower power to weight ratio. It is something I have noticed but it has not been a problem. From my observation the power does not suddenly reduce but instead reduces slowly over a long period. The only time it has caught me unaware was driving home from work one night and going to overtake a slower car. There was only one lane and it's about 400m up a steep hill. The low battery warning had come on and I was under 20%. I was expecting the explosion of power and it was quite reduced. Still more than enough to make the maneuver but not as fast. It felt like just the rear motor was on. Not a problem as I had other options. It would have been unsafe only if I was in a position that without full grunt I was compromised. That would not be safe driving.

 

[blueman671]

Haven’t checked this in a while but unsure why my genuine question about the car’s battery/power has been hijacked so that the ‘holier than thou’ crowd can preach about how much safer they are than everyone else.

I tested the car’s acceleration today at 21% and it didn’t reach 60 until 7+ seconds.

No matter how you spin it, that isn’t safe, and it isn’t acceptable from a ‘what you paid for’ stand point.

If there is a gap in traffic when pulling from a junction/slip road/roundabout/hard shoulder and you’re sat in a car with 400+ bhp then, as long as you’re a competent driver, you can gauge whether you can join the moving traffic safely and get up to speed. If you go to do that and find after committing to the move that the car is going to half its power output, that is incredibly dangerous.

Scaling that down for those that seem to be scared of their own shadow, sitting in a 1 litre Corsa with 100bhp and attempting a perfectly safe overtake or roundabout/junction exit, and suddenly having 50bhp at your disposal will also leave you a sitting duck.

You don’t ‘need’ 400+bhp. Using said horsepower is also not indicative of being a dangerous driver. If you think it isn’t possible to accelerate hard and retain control of your car and respect other road users, you are a nervous driver and I’ll assume you stay glued to the middle lane yelling ‘maniac’ as people overtake you at 71mph.

Needing the power isn’t the issue. It’s having the power and suddenly losing it that is. With no visual indicator. It’s no different to limp mode on an ice car when a sensor goes, but at least you get an EML so you know something is off before your right pedal becomes redundant.

For whoever asked, the diesel that was faster was an m340d with more a lot more power and torque. Got to 60 a few tenths slower but from accelerating from 30mph+ it would leave the xpower in the dark - even with 5 miles left in the tank.

For those who think their car isn’t affected, I’d suggest running it to 20% and timing a 0-60 run. It’s a software issue, so all cars will be programmed the same. Weather and tyres being the only major variable.

For the bubblewrap-wearing brigade, when the car is fully charged in the morning I’ll give you all a wave as you sit in the middle lane with your hands at 10 to 2

 

[Cabansail]

You really come across as a very aggressive driver.

Unless you have a fault the power does not disappear suddenly. It reduces over a period. It is well known this occurs and you should take it into account. It is similar when planning a flight youknow your aircraft is heavy at the start and will have lower performance than later in the trip when fuel is burned. This change is taken into account for a safe flight. The same applies but in this case the performance will slowly decrease. If you are placing yourself in a situation where the safety margin relies on you having 400bhp and is compromised with only having less, then you are not being safe.

 

[T1 Terry]

I can see the point regarding no warning the throttle response is being reduced, no doubt we have all driven an ICE powered car when planting the foot to overtake and swinging out at the same time so uou don't run into the car in front, only to have complete dead response initially and now you are going too fast to pull back in behind the car you were overtaking, yet not the expected performance to safely make the overtaking move ...... once you sort that small panic situation, you are never quite sure the next time you plan an overtaking move ..... will it go or won't it ...... it does make a fun drive very unsettling if you are second guessing the cars performance at any given time .....

The IM series use an LFP chemistry battery and not as susceptible to low temperature when high current is demanded ..... that sort of fuels the thought it is battery temperature related and the battery not able to supply the high current without a cell dropping voltage to the point of permanent damage ..... so the software protects the battery ........

The only way to know for sure is a data logger monitoring cell temp and voltage along with current draw, that will show a cell voltage drop when a peak current draw is demanded and the software limiting the current draw at that particular point of high current demand ......

From there, you could identify if it is cell temp related or an individual cell voltage dropping that is causing the problem ..... armed with tat information, the fix is much easier to tackle ...... does battery heat need to be better monitored and auto heating switched on .... or is there just a weak cell in the pack ......

T1 Terry

 

[T1 Terry]

In Australia, drive by weight is applied to a fair extent as rule 1, unless you drive a BMW of course ...... as you approach the freeway you look over to the right and see what is approaching in the lane you want to merge with ...... if it's a double A trailer or B triple or quad, they have the right of weight, they will be at X point on the freeway after Y time has passed, whether you are there or not ...... only a BMW driver believes differently .......

Also, in Aust, we tend to move to the right lane when travelling down the freeway as we approach a blending lane to make sure it isn't a BMW drive in a loaner car and likely to pull out in front of you like it is their god given right ......

Different states have far better educated drivers regarding joining a freeway as well ...... the really annoying ones are those that slow down in the blending lane and look for a slot to fit in .... it stuffs it up for everyone else ......

Victoria, Melbourne area in particular, have this insane set up where a traffic light brings you to a complete stop and only allows 1 vehicle at a time to enter the blending lane ...... from a standing start Try that one in the heavy vehicle ...... rule 1 then applies, I need that spot, I'm heavier than you are, either get out of my way or smile as you go under

T1 Terry

 

[tsedge]

Haven’t checked this in a while but unsure why my genuine question about the car’s battery/power has been hijacked so that the ‘holier than thou’ crowd can preach about how much safer they are than everyone else.

In your complaints you revealed driving practices and a driving mindset that puts people at risk.

The problem seems to be you think you are a better driver than everyone else and others are useless, scared of the road and best put firmly behind you with your right foot.

That's a mindset that gets other people hurt, which is why you are getting these comments. It isn't about you, but the harm you could cause.

It is the exact opposite of what you are saying: you are the one who seems to think he is better than the rest, coming across as if you are God's gift to driving.

And now you are repeatedly calling people names that belittle their supposed driving habits, which again reveals how you think about other drivers and therefore how you act on the road.

But you just can't see it.

The power reduction issue has been acknowledged and explored and explained at length. You have a right to be unhappy and take that up with MG.

 

[Tuareg]

A couple of very immature 'drivers' posting on here who seem to have minimal experience with roadcraft which they should go and spend a lot of time assimilating before they cause problems for other road users.

 

[LenEV2016]

tested the car’s acceleration today at 21% and it didn’t reach 60 until 7+ seconds.

No matter how you spin it, that isn’t safe, and it isn’t acceptable from a ‘what you paid for’ stand point.

I get that your car may have a fault and you are annoyed by it, ours has had it's fair share and I get that feeling but saying a cars 0-60 time isn't safe because it didn't reach 60 in just over 7 secs isn't a safety issue.
I get that it is less than advertised but it's still the acceleration of a normal reasonably quick EV, as long as you are aware that the power limits as the % gets lower then you drive accordingly. Nobody needs 0-60 times of 3.4 secs just to drive safely.
And it's nothing to do with being holier than thou

 

[blueman671]

You really come across as a very aggressive driver.

Unless you have a fault the power does not disappear suddenly. It reduces over a period. It is well known this occurs and you should take it into account. It is similar when planning a flight youknow your aircraft is heavy at the start and will have lower performance than later in the trip when fuel is burned. This change is taken into account for a safe flight. The same applies but in this case the performance will slowly decrease. If you are placing yourself in a situation where the safety margin relies on you having 400bhp and is compromised with only having less, then you are not being safe.

I really couldn’t care less what meritless conclusion you draw about my style of driving, thank you.

I also don’t care if the power doesn’t ‘suddenly’ disappear. I don’t drive at full throttle for hours at a time so wouldn’t feel the power reducing, would I? If I set off with 50% charge and the car drives normally, then 2 hours later on the same drive I go to overtake a tractor and the car has lost half of its power with no prior warning, I’m glad to know that’s my fault.

It makes it impossible to understand your own car and its limits. No different to if the gear ratios suddenly changed in a manual, or the turbo suddenly stopped spooling, or the brakes suddenly stopped and your stopping distance tripled. Having a constantly variable throttle pedal is not a safe feature.

If it snows and you know your is capable of driving in the snow thanks to it’s 4wd, only for the front motor to stop working mid-drive and leave you in a rwd car unable to pull up a hill, that is also placing you as a driver in an avoidable and dangerous situation.

Likening an MG4 to flying a jet is such an amazing comparison, they couldn’t be more similar! Good to know that when planning my commute in a budget EV I need to calculate at what point the car will go into limp mode as part of my pre-drive checks. I’ll make sure my co-pilot brings this to my attention as we reach that part of the drive.

As with all car forums, you tend to find some people struggle to hear negative things about a car they so dearly love. It’s a cheap, unrefined, Chinese-made MG4 - it’s going to have faults and poor design features. Someone (clearly multiple people) raising that should not make you defend the car blindly when there is a glaring issue with it.

Regardless of whether you think I’m a dangerous driver or not, I paid more money to get the more powerful model of the car. That’s what I should have, 100% of the time.