MG4 - Loss of power in cold weather with over 30% battery

[tsedge]

Whatever is wrong with my car, it's put me off MG for good and it's put me off EVs in general because everything is a compromise with them and the only benefit used to be the price per mile but that ship sailed a while ago and its never coming back.

Don't let one experience colour your view of EVs in general - that is not a good strategy.
Everything is a compromise, ICE cars included.

If you can charge at home, there's nothing remotely as cheap to run as an EV. That's a fact. Now, if you can't then fair enough.

They say most EV batteries can only handle 1000 charging cycles, if you are charging yours daily then that gives you around 3 years before its goosed.
I hope you dont plan to own it.

Don't listen to "they" because they are talking complete bollocks. EVs last longer than the equivalent ICE vehicles and many EV battery packs will have a second life in stationary storage - nothing something you can say about an ICE engine.

I get that you are unhappy - fair enough, perhaps you weren't given the right information and were sold something unsuitable for you. But you should know there are millions of happy EV owners who are saving money and one day soon an EV might be the best fit for you.

 

[Rich D]

New to the forum here.
I want to share my experience since owning the car since Sept 22. The car is a SE standard range.

It’s now been in the garage 8 times for “software updates” & has been towed in by the AA 3 times after breaking down on the motorway & dual carriageways.

I’ve experienced the car surging without pressing the accelerator (it’s already had a new brake pedal).
Last week the car would make a loud clunk sound followed by acceleration on its own.

This week was the latest where the car had 100% battery was used twice before the 3rd trip, battery at 80% and was on the motorway. Car reduced its power after 5 miles, then eventually went into limp mode. Luckily it crawled off the motorway & into a lay-by. The HV Battery then surprisingly Showed 0% & the car wouldn’t move at all.

The car is a Lemon & an absolute disgrace

 

[Rolfe]

That sounds like a dreadful experience. Did the trouble not show itself early enough so that you could reject the car? I know that a few other people who had lemons were able to walk away from them because they were able to act within the time frame.

Welcome to the forum, by the way.

 

[Tig170]

New to the forum here.
I want to share my experience since owning the car since Sept 22. The car is a SE standard range.

Sorry to hear this, same here, however not had a single issue.

 

[Rolfe]

Most of us haven't, but we all know that some people have. If the car shows its evil side within six months you can do something, but if it behaves sweetly for that period then starts doing the dirty, it's a lot harder.

 

[Tig170]

Most of us haven't, but we all know that some people have. If the car shows its evil side within six months you can do something, but if it behaves sweetly for that period then starts doing the dirty, it's a lot harder.

Agree, it will maybe be a simple dodgy connection, but I'm not convinced that the current technical staff at the dealers / SAIC have the experience / knowledge to resolve these challenges, as it appears that all they are really doing is following what the computer says, rather than real fault finding diagnostics? - looking @Rich D 's problem it looks like a 12V battery fault? (have they taken off the battery and completely cleaned the terminals?)

 

[Rolfe]

Being rescued by the AA three times because the car has broken down while being driven (as opposed to cars that won't charge) is not a common experience. Something serious is going on here.

 

[fnegroni]

New to the forum here.
I want to share my experience since owning the car since Sept 22. The car is a SE standard range.

It’s now been in the garage 8 times for “software updates” & has been towed in by the AA 3 times after breaking down on the motorway & dual carriageways.

I’ve experienced the car surging without pressing the accelerator (it’s already had a new brake pedal).
Last week the car would make a loud clunk sound followed by acceleration on its own.

This week was the latest where the car had 100% battery was used twice before the 3rd trip, battery at 80% and was on the motorway. Car reduced its power after 5 miles, then eventually went into limp mode. Luckily it crawled off the motorway & into a lay-by. The HV Battery then surprisingly Showed 0% & the car wouldn’t move at all.

The car is a Lemon & an absolute disgrace

Can you check the voltage on the 12V battery? At rest and when it’s being charged (once the main HV battery is back to a charged state)

 

[Rich D]

Can you check the voltage on the 12v battery? At rest and when it’s being charged (once the main HV battery is back to a charged state)

This was the first break down, we experienced actually the 12V battery died and the car immediately came to a standstill. It’s since had a new 12V battery and software update. The new battery runs at 13.9v when operating so it’s not the cause.

 

[Rich D]

Slight update.
The car has been in the dealership for 10 days now and they are unable to diagnose the problem. It’s now being scheduled to go to MG direct in Birmingham to continue the investigation. Likely to have a courtesy car for another 2 weeks.

Issues were;
Jolting & accelerating on its own
High voltage battery dropped from 80-0 in the space of 10 miles on a mild day having used the car twice before that trip.
I’m going to exclude driver aides from the issue log!

This is the 8th time it’s been into the dealership following recalls and breakdowns of which 3 have been assisted by the AA.

 

[Rolfe]

That is a lemon. Is there any way you can reject it?

 

[Loveclose]

I've read air this issue on the forum a great deal over the past 24hrs....

Makes me wonder when this power issue will occur with my vehicle!!

It's good to know of it in case it happens.

Has it happened to a Trophy vehicle?? Seems to have affected SE vehicles more??

Sincerely hope the issue gets sorted for those still fighting it....

 

[tsedge]

I've read air this issue on the forum a great deal over the past 24hrs....

Makes me wonder when this power issue will occur with my vehicle!!

It's good to know of it in case it happens.

Has it happened to a Trophy vehicle?? Seems to have affected SE vehicles more??

Sincerely hope the issue gets sorted for those still fighting it....

I don't know if we know definitively but this kind of issue does seem more common with the SR with the LFP battery, rather than LR/ER/XPower with NMC battery.

That may be because LFP tech is newer to MG and is still having bugs worked out.

(SE/Trophy is the trim level).

 

[Rich D]

It’s been a long time coming, but today after nearly 3 months I’ve got my car back, they tried to get away with just changing the 3 control modules, but this didn’t fix the issue.

now fitted a brand new LFP battery.
I’m only 5 miles in so I’m not going to say anymore.

I must say the communication between the dealer and MG Longbridge which is the UK repair centre is appalling.

 

[mechfurkan]

Same thing happened to me, yesterday I've been driving almost 30-40mins around 70-90kph. After that i tried to accelerate and connect to highway, my battery was exactly %35 and the car increased the speed around 120-122kph and whole acceleration gone..

The preheating wasn't active, but ambient was pretty hot. My car is SE SR with LFP battery.

In my opinion the "Sport Mode" should deactivate this "power limiting".