Only charging at 45kW max. on 350kW charger.

[Geoffree]

We rarely have to charge away from home but went to Edinburgh and back last weekend. Found that charging the battery was disapointing slow. On IONITY 350kW it only managed a maximum of 45kW (even when at 10% battery) despite all the other cars charging were more than 80kW. The Porche Taycan was charging at 350kW!
Is there a problem with the CCS charging on my MG4 (SE)?

 

[Bam Bam]

We rarely have to charge away from home but went to Edinburgh and back last weekend. Found that charging the battery was disapointing slow. On IONITY 350kW it only managed a maximum of 45kW (even when at 10% battery) despite all the other cars charging were more than 80kW. The Porche Taycam was charging at 350kW!
Is there a problem with the CCS charging on my MG4 (SE)?

Have you got the SR SE?

We do and the official maximum is about 88kW. However, we've only had about 70kW on our few DC charging stops, with the speed dropping off from there as it filled up.

I wonder if it is something to do with the fact that the charger is 800V and the car is 400V meaning that it has been halved for some strange reason. As you say, the other cars were getting more. Another thought is that the site might have had a total charging limit and yours was the car that was missing out.

It seems like the DC charging works, but I can see that the speed would be disappointing.

 

[siteguru]

Unless you'd preheated the battery then I can understand you only getting a charging speed of 45kW (assuming you have the 51kWh LFP SE SR, as do I).

 

[Bam Bam]

Unless you'd preheated the battery then I can understand you only getting a charging speed of 45kW (assuming you have the 51kWh LFP SE SR, as do I).

Good point - I hadn't considered the cold weather which is the most obvious reason!

 

[Bam Bam]

"cold-gating" it is sometimes called.

For instance by Bjorn Nyland who lives in Norway where this is more of an issue.

 

[Geoffree]

Unless you'd preheated the battery then I can understand you only getting a charging speed of 45kW (assuming you have the 51kWh LFP SE SR, as do I).

Yes, I did think that it might be the cold, but when I tried to turn on the battery heating it said that it was warm enough. It had been driven for a few hours so I guess it was warmed up.
I have a MG4 SE

 

[ReintjeWA]

Doesn't it take a bit of charge before the full comes on? Comparable to how it slows down at >80%, or is that an NMC thing?

 

[hojnikb]

Maybe the charger was limited to 125A for some reason?

Either that or the battery was still too cold.

 

[Geoffree]

Doesn't it take a bit of charge before the full comes on? Comparable to how it slows down at >80%, or is that an NMC thing?

Yes, it does start at a bit slower rate, but 45kW was the maximum. Drops off to about 20kW when close to 80% :-(

 

[siteguru]

I have a MG4 SE

Yes, but which SE? (There are 2 variants ... SR = 51kWh LFP, and LR = 64kWh NMC). The charging curves are very different between the 2.

 

[Geoffree]

I have the 51kWh SE, although now 50kWh according to the service report

 

[Geoffree]

Just found tech spec for the MG4 SE SR.
Maximum rapid charge capability, DC is 117kW (LR & Trophy are 135 - 144 kW)
Estimated charging time (150kW DC public rapid charger)10 to 80% 37 minutes
[My car took about 90 mins for 10 - 100%]

 

[Bam Bam]

Just found tech spec for the MG4 SE SR.
Maximum rapid charge capability, DC is 117kW (LR & Trophy are 135 - 144 kW)
Estimated charging time (150kW DC public rapid charger)10 to 80% 37 minutes
[My car took about 90 mins for 10 - 100%]

That is what MG claimed in the original brochure but it doesn't seem to be what anyone gets in practice.

EV database has it as 87kW

MG MG4 EV Standard Range

All details and specs of the MG MG4 EV Standard Range (2022). Compare price, lease, real-world range and consumption of every electric vehicle.

ev-database.org

SiteGuru noted this nearly two years ago.

Post in thread 'Maximum DC charging power for the Standard Range (LFP) battery'

Apr 16, 2024

The SR was advertised with 117kW charge rate, but it has never ever achieved that ... 88-90kW is the maximum anyone gets. That said, the 10-80% charge time is still achieved, even without the higher peak charge rate. That's because the lower peak charge rate is available over more of the SOC range ... the 117kW rate was only available (per graphs we've seen previously) over a very small SOC range, thus the overall average charge rate works out the same.

• siteguru

• 

 

[Bam Bam]

Actually MG are still claiming this in the latest brochure, not just the original one.

Pretty poor from MG I think to advertise a figure that is so wrong.

 

[siteguru]

[My car took about 90 mins for 10 - 100%]

How long did it take to reach 80%?

Trying to reach 100% on a DC charger is pointless - the last 10% tends to take as long as the 10-80%.

 

[Jamesrr]

... IONITY 350kW it only managed a maximum of 45kW (even when at 10% battery) despite all the other cars charging were more than 80kW. The Porche Taycam was charging at 350kW!

The Taycan is an 800V architecture car and designed to support 350kW charging on suitable 800V chargers.

The MG4 is 400V architecture and the SR/51kWh LFP battery version tops out at 88kW charging, albeit the most I've seen on ours is 70ish kW for a little while.
It's not our long distance car so we hardly ever DC charge it.

Our Trophy ER/ Essence 77 is spec'd to 144kW charging and I regularly get 130-140+ on Tesla Superchargers. It is our long distance car and I regularly DC charge it.

Is there a problem with the CCS charging on my MG4 (SE)?

Doubt it very much, however that's based on the very limited sample size you provide

 

[Jamesrr]

I wonder if it is something to do with the fact that the charger is 800V and the car is 400V meaning that it has been halved for some strange reason.

There's no strange reason kW limit is halved! It's physics P=VxI

360kW chargers are 800V X 450A. They are typically current (I) limited so a 400V car can only get up to 400V x 450A = 180kW

As you say, the other cars were getting more. Another thought is that the site might have had a total charging limit and yours was the car that was missing out.

Stations do have total power limits. Tesla sites are configured so that each supercharger plug provides full power irrespective of how many plugs are in operation, whereas KemPower units are configured to "load share" their total capacity across the plugs.
Both approaches have their pros and cons.

It seems like the DC charging works, but I can see that the speed would be disappointing.

True. I wouldn't choose an SE SR as a touring car however if you accept the slower charge speed and range you can make do.

In warmer weather I suspect that 40kW would be up at the 70kW level.

 

[Jamesrr]

How long did it take to reach 80%?

Trying to reach 100% on a DC charger is pointless - the last 10% tends to take as long as the 10-80%.

Exactly! Past 80% things really slow down. 90% to excruciating levels.

There's one leg on my "regular" 2 day 1500km trek from Sydney NSW to the beach house in SA where I used to charge up to 85% to minimise the range anxiety but these days the only time I charge past 80 is if I can't get back in time to stop it from my comfort break pitstop

 

[Jamesrr]

Actually MG are still claiming this in the latest brochure, not just the original one.

Pretty poor from MG I think to advertise a figure that is so wrong.

The Australian brochures have only ever claimed 88kW and still do.

https://cdn.shopify.com/s/files/1/0580/0476/6795/files/MG4_Product_Brochure_2025_v2.pdf?v=1751962542

*Not sure if this link is going to be valid in perpetuity...

 

[Bam Bam]

There's no strange reason kW limit is halved! It's physics P=VxI

Indeed.

360kW chargers are 800V X 450A. They are typically current (I) limited so a 400V car can only get up to 400V x 450A = 180kW

I mentioned it as being a surprise because I couldn't see why this would apply to a car whose maximum is well below the halved amount.

The amps were seemingly still available, unless they weren't for some other reason (the maximum site capacity as mentioned).

On reflection the point others made that the car was restricting the supply due to the cold (cold-gating) is more likely.