Slower than expected DC charging MG4 Trophy

[theboots]

I've not yet had to rely on DC charging but have done a couple so I am familiar when it is needed, we're planning a long trip at the end of Summer. The first time I was around 65% and only got 25kW from a 50kW charger. The perceived wisdom then was that my initial state of charge was a bit high, anyhoo I saw that while I would make it home it would be tight so popped into the Tesla chargers in Guildford with 32% SoC. These are 250kW super chargers, 12 bays, and I think 9 occupied the time I was there. I was only getting 38kW even starting from 32%: 13.75kWh in 21 minutes. Obviously my sample size is small but I was sort of expecting to get somewhere around double that.

 

[Jamesrr]

Yes, that appears low to me.
Just to confirm, you have the 64kWh NMC battery?

I'm not aware of any way you can throttle the DC charging rate from the car.

Strange... Hmmm

 

[theboots]

Yes, that appears low to me.
Just to confirm, you have the 64kWh NMC battery?

Yep it is a 14 month old Trophy we bought as an ex demo with low mileage. It started more or less straight away at 38kW, I locked the car and went to buy a coffee from the sports centre (chargers are in the car park) I could see from the Tesla app on my phone it was pretty steady at 38kW until I came back and stopped

 

[Jamesrr]

I'd be taking it to the dealer saying it's not charging properly. You should be getting at least 100kW at that state of charge (SoC).
To be sure, see if you can start a charge session at a Supercharger with a sub 20% SoC. Take a photo of the car screen showing that.
Then see what rate you get.
Best to have the evidence when talking to the dealer.

 

[Jamesrr]

A quick FYI... I asked our* AI "Chatbot" if there was a way...

Can you throttle the DC fast charge rate?
Based on the official MG4 manuals, there is no documented function that allows a user to directly throttle or limit the DC fast charging rate manually via the infotainment system or vehicle settings.


Key points:

• DC fast charging is managed automatically by the vehicle's battery management system (BMS) and the Combined Charging Unit (CCU), based on parameters such as battery temperature, state of charge, and external charger characteristics.
• During low-temperature fast charging, the battery heater activates automatically to optimize charging speed and protect battery health.
• There is no mention of user-adjustable settings to reduce or limit the rate of DC charging in any of the available menus or service configurations.

If your objective is to charge the battery more gently, it is recommended to use AC charging (especially at 7–11 kW), which is supported and even encouraged for battery equalisation and long-term health.


If you require a custom setup (e.g. limiting charge rate due to infrastructure constraints), you may need to rely on the charger itself (if it supports such settings) or consult an MG Authorized Service Center.


*The post by @Geekice

Post in thread 'I created an AI with all the information on MG4'

Tuesday at 11:47 PM

Hi everyone, sorry for the absence. I had decided to abandon the project because the system for managing custom GPT bots wasn’t suitable for creating GPTs that read from manuals. Lately, they’ve made some improvements to document reading, so I decided to recreate the project from scratch. Just a heads-up: it’s still in testing, but it seems much better now at reading and retrieving information from manuals.

This is the link: ChatGPT - MG4 Tech Assistant V2.

Let me know if you find some improvements in the GPT.

• Geekice

• 
• 

 

[hojnikb]

38kW seems suspiciosly like a 100A limit on the charger

 

[theboots]

I'd be taking it to the dealer saying it's not charging properly. You should be getting at least 100kW at that state of charge (SoC).
To be sure, see if you can start a charge session at a Supercharger with a sub 20% SoC. Take a photo of the car screen showing that.
Then see what rate you get.
Best to have the evidence when talking to the dealer.

I think that's my next step if the 3rd DC charge proves to be slower than expected. I'll pick another site and see what I get. I am home not and it is of course at 83% on the drive.

 

[Tight Git]

I have issues with Tesla Uxbridge a couple of times only managing 37kW and that was due to the charger throttling it as it was very busy.

If you can find a local Ionity one I'm sure it will work for you!

 

[theboots]

I have issues with Tesla Uxbridge a couple of times only managing 37kW

If you can find a local Ionity one I'm sure it will work for you!

I definitely need to try another, to be 100% before I go back to the dealer. Tesla Guildford was pretty busy so it could have been throttling me to supply the Teslas.

 

[Anon70]

Maybe try a balance charge AC session (take the charge state to less than 10% then all the way to 100%), then try a DC charge again from around 20%. The charge curve on my XPower is up to 140kW/h between 10% and 50% then drops to the 70kW/h ish speeds between 50% and 80%, then drops to the 30kW/h after that.

I have had one Telsa charger session that was really slow and just put that down to that individual charger or what the grid was sending it at the time