MG4 losing power

[RewqNo]

Hey.

I have a MG4 SE. The car has been idle since saturday. When I started to drive today it gave 100% power up to about 50-60 kmph and then it dropped down to 56% power. Battery was around 76%.

After driving about 10 min it could give 100% at 120 kmph.

It is -5c outside. Does the battery need to get warm before giving 100% power all the way?

 

[fnegroni]

is this the first time you have experienced this power loss at sub zero temperatures?

 

[RewqNo]

is this the first time you have experienced this power loss at sub zero temperatures?

I have experienced it before, but not sure if it was below zero

 

[tsedge]

Hey.

I have a MG4 SE. The car has been idle since saturday. When I started to drive today it gave 100% power up to about 50-60 kmph and then it dropped down to 56% power. Battery was around 76%.

After driving about 10 min it could give 100% at 120 kmph.

It is -5c outside. Does the battery need to get warm before giving 100% power all the way?

A cold battery may limit power output, because if it is too cold a high power drain could damage it. The SR battery chemistry (LFP) is a little more sensitive to low temperatures. So what you suggest is possible, although hasn't been mentioned by many people - so it might not be this.

This is one of the reasons for battery heating (main one being faster charging) - you could switch this on before your journeys (at the cost of some range).

However, there has also been a fault with some SR cars in the past that isn't temperature related - it tends to show up not as a power limit but a speed limit on the car (won't exceed a specific speed, which changes on different journeys). If you are seeing this, your car needs some updates to fix and it is not likely temperature related - so approach your dealer for a fix.

 

[Rolfe]

You could have a read at this if you make a coffee and put your feet up.

MG4 Restricted speed - weird | MG4 EV (2022 to 2025) Forum

Big shot in the dark that anyone else has experienced this, but worth a go. My drive home involves a short blast up a dual carriageway from a set of lights, bit of a Grand Prix to be honest. Twice now I’ve floored the car up it and it’s resolutely refused to do more than 71-75mph. It’s not a...

www.mgevs.com

It's possible yours is not the same issue. But if it is, then the spoiler alert for the thread is that in the end the fault seems to have been cured by a software update that became available last summer.

 

[stevegus]

You could have a read at this if you make a coffee and put your feet up.

MG4 Restricted speed - weird | MG4 EV (2022 to 2025) Forum

Big shot in the dark that anyone else has experienced this, but worth a go. My drive home involves a short blast up a dual carriageway from a set of lights, bit of a Grand Prix to be honest. Twice now I’ve floored the car up it and it’s resolutely refused to do more than 71-75mph. It’s not a...

www.mgevs.com

It's possible yours is not the same issue. But if it is, then the spoiler alert for the thread is that in the end the fault seems to have been cured by a software update that became available last summer.

But then you would have to read pages and pages of Bowfer whining and saying how much better a Born is….

 

[Rolfe]

Well, I would suggest skipping those bits...

 

[siteguru]

Well, I would suggest skipping those bits...

I suspect that's the forum defaulting from MG4 to the first item in the profile list ... MG4 SE SR.

 

[Rolfe]

Are you sure that's the post you meant to quote?

 

[siteguru]

No it isn't - and I'm sure it wasn't me ... the forum threw a wobbly. I actually quoted (or at least thought I had) the post where you mentioned someone having the wrong car in their profile. ?‍

 

[Rolfe]

Yes, I thought that's what you must have meant to quote, but that doesn't even seem to be in this thread. Weird.

 

[RewqNo]

Just a quick update. This morning i tried battery heating from the app. Set it to 06:00, i started driving at 06:30. No problems. So it must be that the battery is to cold so give max power. It was -10 c. Just like you wrote.

All good. Thank you ?

A cold battery may limit power output, because if it is too cold a high power drain could damage it. The SR battery chemistry (LFP) is a little more sensitive to low temperatures. So what you suggest is possible, although hasn't been mentioned by many people - so it might not be this.

This is one of the reasons for battery heating (main one being faster charging) - you could switch this on before your journeys (at the cost of some range).

However, there has also been a fault with some SR cars in the past that isn't temperature related - it tends to show up not as a power limit but a speed limit on the car (won't exceed a specific speed, which changes on different journeys). If you are seeing this, your car needs some updates to fix and it is not likely temperature related - so approach your dealer for a fix.