MG4 Restricted speed - weird

[Ayoull]

Stop focussing on hills.
It does it on the flat too.

I'm not trying to be pedantic but you'll be very hard pressed to find a "flat" road there is virtually always an incline, and while I appreciate you're frustrated, people are making valid suggestions to see if there is a rhyme or reason as to the "fault", but you appear obstructive and resistant to testing any potential solutions or theory.

 

[bowfer]

Says the guy who just posted a hill climbing example!

Which I've acknowledged, I was talking about driving style, you brought hills into it ***!

Wrong spy there, wasn’t me who posted the hill climb video.

 

[Ayoull]

MGs fix for power loss

 

[tsedge]

Wrong spy there, wasn’t me who posted the hill climb video.

Sorry, I apologise, it wasn't you.

 

[bowfer]

Normal mode, 87% battery.
100% power until around 85mph, then plummeted to 58% power and wouldn’t go any faster.
I’ll try the same thing on sport mode tomorrow.

 

[wandle MG4 trophy]

It has to be said that driving at 85 mph is dangerous. If you want to kill yourself, so be it but you risk killing or maiming innocent people.

 

[bowfer]

It has to be said that driving at 85 mph is dangerous. If you want to kill yourself, so be it but you risk killing or maiming innocent people.

Private test track, mind your own business.

 

[Macadoodle]

Normal mode, 87% battery.
100% power until around 85mph, then plummeted to 58% power and wouldn’t go any faster.
I’ll try the same thing on sport mode tomorrow.

I think you're pushing the c rate of the battery at those speeds, especially if it's cold. It maybe simply cant output over 3 c for any length of time at the moment, might be different mid summer.
The LFP cell definitely doesn't dump current as readily as the ternary one.
Looks like the 64 pack is going to handle a 6c discharge rate in the upcoming AWD version so it's clearly far superior in this regard.

I hammered mine up a half mile hill today, pretty steep, 70 % charge, no problems whatsoever, still pulling well at the top, I really think its current demand/ temp/ SOC that determines the standard range's idiosyncrasies and this power limiting.

Has anyone with a long range experienced throttling like this ?

 

[stevegus]

Private test track, mind your own business.

You are going to be so missed here once you leave

 

[Ayoull]

The LFP cell definitely doesn't dump current as readily as the ternary one.

If you look at LFP Vs NMC battery chemistries the crystalline structure of both is very different, LFP essentially forms tubes that Lithium has to run down as if on rails.

Where as NMC the lithium can travel on any direction, it's one of the reasons LFP is so thermally stable and NMC isn't, but could also be a limiting factor in power delivery as the lithium must travel through the battery in one direction only where as NMC it can take many routes.

 

[bowfer]

I think you're pushing the c rate of the battery at those speeds, especially if it's cold. It maybe simply cant output over 3 c for any length of time at the moment, might be different mid summer.
The LFP cell definitely doesn't dump current as readily as the ternary one.
Looks like the 64 pack is going to handle a 6c discharge rate in the upcoming AWD version so it's clearly far superior in this regard.

I hammered mine up a half mile hill today, pretty steep, 70 % charge, no problems whatsoever, still pulling well at the top, I really think its current demand/ temp/ SOC that determines the standard range's idiosyncrasies and this power limiting.

Has anyone with a long range experienced throttling like this ?

Interesting.
The scenario I get it most on is about the same distance, around 1/2 mile up a hill.
God knows how I’d describe the gradient, suffice to say it’s onto a bypass and therefore not that steep, as I’m sure there are probably regulations about how steep these things can be and still have lorries joining them.
To be fair if it only arise at higher speeds it wouldn’t be such a big deal, although that’s really just making excuses for MG and putting up with a clear flaw/fault.
The fact it did it before, and may still do it now, at far lower speeds is the real issue.
Even the biggest Karens of the forum would object to being restricted to 58-63mph max speed as they enter a 70mph road, as I have been in the past (and suspect will be soon once I let the battery run down).

 

[Macadoodle]

Interesting.
The scenario I get it most on is about the same distance, around 1/2 mile up a hill.
God knows how I’d describe the gradient, suffice to say it’s onto a bypass and therefore not that steep, as I’m sure there are probably regulations about how steep these things can be and still have lorries joining them.
To be fair if it only arise at higher speeds it wouldn’t be such a big deal, although that’s really just making excuses for MG and putting up with a clear flaw/fault.
The fact it did it before, and may still do it now, at far lower speeds is the real issue.
Even the biggest Karens of the forum would object to being restricted to 58-63mph max speed as they enter a 70mph road, as I have been in the past (and suspect will be soon once I let the battery run down).

Well no, that's a scenario I would find unacceptable too. It's taken over 2000 miles for my one to surprise me with a power limit, I was demanding max power uphill over a sustained period at a relatively low SOC so I kinda forgive it now I know to expect it.
Going to return to the scene of the crime at the weekend and try the full 2 mile uphill blast with 80%.

 

[Chequers]

It has to be said that driving at 85 mph is dangerous. If you want to kill yourself, so be it but you risk killing or maiming innocent people.

It also needs to be said that if MG advertise a top speed of 100Mph then the car should be able to do that speed.

 

[bowfer]

It also needs to be said that if MG advertise a top speed of 100Mph then the car should be able to do that speed.

Exactly.
I wonder how many 4s they’d sell if they advertised the top speed as ‘well it depends…’

 

[TheHypnoToad]

It's a shame the MG4 doesn't have a true power read out like the MG ZS EV MK1 that I also have at home as it shows volts and Amps and would be able to see if there was either a current or voltage collapse indicating a battery issue, or if it holds constant.

It seems the only people that have has issues with power limiting so far are in the SR model, I have yet to hear of anyone with the LR model having this issue, so I think this may be battery related, as opposed to motor related.

One thing to be aware of is that the LR battery model has ~200HP instead of ~150HP but I'm not sure if it's the same motor on both models. If it is the same motor then why isn't the LR going into power limit mode?

It would be nice if there was a certain hill (or flat!) run that we could test both a SR and LR MG4 on, and see if they both go into power limited mode, or if it's only the SR version.

 

[tsedge]

It seems the only people that have has issues with power limiting so far are in the SR model, I have yet to hear of anyone with the LR model having this issue, so I think this may be battery related, as opposed to motor related.

One thing to be aware of is that the LR battery model has ~200HP instead of ~150HP but I'm not sure if it's the same motor on both models. If it is the same motor then why isn't the LR going into power limit mode?

It would be nice if there was a certain hill (or flat!) run that we could test both a SR and LR MG4 on, and see if they both go into power limited mode, or if it's only the SR version.

The batteries and motors are different across SR and LR.

I thought we did have a LR with this fault early on? Can't remember who it was?

 

[Ayoull]

The batteries and motors are different across SR and LR.

I thought we did have a LR with this fault early on? Can't remember who it was?

Stageshoot had this issue and his was a trophy

It seems the only people that have has issues with power limiting so far are in the SR model, I have yet to hear of anyone with the LR model having this issue, so I think this may be battery related, as opposed to motor related.

One thing to be aware of is that the LR battery model has ~200HP instead of ~150HP but I'm not sure if it's the same motor on both models. If it is the same motor then why isn't the LR going into power limit mode?

It would be nice if there was a certain hill (or flat!) run that we could test both a SR and LR MG4 on, and see if they both go into power limited mode, or if it's only the SR version.

Atleast one confirmed case with a trophy so battery chemistry is not the issue it would appear

 

[tsedge]

Atleast one confirmed case with a trophy so battery chemistry is not the issue it would appear

My money is on a sensor problem in a common control unit or a software bug that triggers more easily on the SR.

 

[bowfer]

Tried sport mode on the way home.
Same result, over a ‘certain speed’ the power meter tumbles down from 100% to around 56% and the car just stops at that speed.

 

[tsedge]

Tried sport mode on the way home.
Same result, over a ‘certain speed’ the power meter tumbles down from 100% to around 56% and the car just stops at that speed.

Thanks for trying it, one more thing eliminated.

Tried sport mode on the way home.
Same result, over a ‘certain speed’ the power meter tumbles down from 100% to around 56% and the car just stops at that speed.

Is the speed consistent that it throttles to?