MG4 Restricted speed - weird

[Rolfe]

How long before you noticed?

 

[bowfer]

How long before you noticed?

Collected the car 5/11, first noticed the issue start of December.
I’m not sure time has any relevance, in the sense that I’m not sure there’s a period after which you could consider yourself safe.
I mean, why does it take weeks/months to manifest at all?
Why isn’t it there from the second you collect the car?

 

[Rolfe]

I don't know, because nobody knows. What sort of mileage had you done by then?

Of course you're right, but you could still be wagging a finger and saying "it could still happen you know" when the car is 15 years old and has done 200,000 miles at this rate.

 

[Ian Key]

Could be a couple of duff cells in the battery pack or loose/corroded connections so when the battery is asked for full power the management system detects its not getting what it expects and backs off.

 

[Macadoodle]

Anyone know if the LFP battery is a cell to pack configuration ? If there's 100 something large cells in series just one break in the 'chain' definitely would have a major effect.

 

[Richmorr]

Anyone know if the LFP battery is a cell to pack configuration ? If there's 100 something large cells in series just one break in the 'chain' definitely would have a major effect.

 

[Macadoodle]

Looks like all versions are cell to pack then .

 

[Rolfe]

I vaguely know what a blade battery is. I know blade batteries are LFP but are all LFP batteries blade?

 

[Richmorr]

I vaguely know what a blade battery is. I know blade batteries are LFP but are all LFP batteries blade?

No you can get different style of LFP batteries, blade battery is a technology from BYD.
CATL provides both NMC and LFP for the MG4.

I have never seen a cylindrical LFP battery even Tesla in there Standard range plus uses a cell to pack type.

 

[Rolfe]

So people who describe the MG4 SE SR as having a blade battery are mistaken?

 

[Richmorr]

So people who describe the MG4 SE SR as having a blade battery are mistaken?

As far as I’m aware, yes. if you look at the images of a blade battery then watch the video you’ll see the both completely different. Only similarity I'm aware of is the chemistry LFP.

BYD makes the blade battery too it’s there technically it will be the battery tech used on the dolphin. Our battery are from CATL

 

[Rolfe]

Thanks.

 

[squirrelz]

Well whatever the garage did last week, seems to have fixed it for now.
Car goes like stink, 100% power where it would previously have not given over 70%, and shows no sign of cutting the power back to 30-ish %
I'll give them a ring next week and find out what they did.

 

[Rolfe]

That's wonderful! If you can find out what they did it could be a huge benefit to members still struggling with the issue.

Are you certain? Was it reproducible enough before that you can be sure it's not doing it now?

 

[squirrelz]

Yes, it was "throttling" the power most of the time before, you'd get maybe 1-2 seconds of 100% power, then you'd be down to around 60-70%, and then when you reached somewhere around 60-75mph, it would cut the power to around 30%.
This was happening on every drive, totally reproduceable.
It feels like a totally different car now. My only wonder is whether it was the garage that fixed it, or whether the few charges we've done to 100% allowed the battery to balance the cells and that sorted it.

 

[Rolfe]

Fantastic! I don't remember, did you confirm that your car is an SE SR?

I doubt if charging to 100% would have been enough to cure that, I'm sure Bowfer and other members with the problem tried everything. Interested to hear what your garage says.

 

[squirrelz]

Yep, 72 plate SE SR, one of the early ones with the privacy glass

 

[Rolfe]

Pretty much the same as Bowfer's (ex) car then. If this is a real fix, it's a big deal.

 

[squirrelz]

The garage claimed that one of their techs is the best MG EV tech in the country, but I've learned to take garage's claims with a lorry-load of salt

 

[Rolfe]

Tell us about your undertray...