MG4 Trophy LR MY2022 AC Charging Speed

[Diver]

Hi all,

I've had my 2023 MG4 Trophy Long Range since March, and I'm pretty certain it's the MY2022 model - no rear wiper & "pins" in the charging port to support 22kW (11kW limited).
I'm experiencing some difficulties with AC charging speeds.

I charge once a week at work from ~40% up to 80%.
There are 2 charging points, both capable of 22kW AC as it's a 3-phase supply.

Initially, when using the Type 2 cable that came with the car, it would only charge at 3.7kW (claimed on Monta app) / ~3.3kW (MG iSmart app.)
"Must be a 1-phase 16A cable" I thought.
Checked the cable rating and no, it's 1-phase 32A lead - images attached showing rating & lack of pins in the connectors; suggests 1-phase, though please correct me if I'm wrong.
Swapped over to the other charging point, same story.
Checked the settings in the car: AC current selected.
So why on Earth am I only drawing 3.3kW, surely I should be seeing around 7kW?

Enter my colleague with his Tesla.
I borrow his cable and test it on both charging points.
Immediately charging at near 11kW (Monta) / ~9.7kW (iSmart) at both points, which is to be expected when accounting for losses / car limitations.
Happy days, the car will take 11kW as suspected (from what I can tell this requires either a 16A 3-phase or 32A 3-phase cable such as the Tesla one used?)
So now I'm thinking the cable rating is wrong, and it is only a 1-phase 16A.
I carry on using the provided cable and continue charging at a painfully slow 3.3kW.

Fast forward a few weeks, I plug in one Friday morning as usual.
Same cable, same charging point, only this time the car decides it wants to take 7.4kW (Monta) / 6.6kW (iSmart).
Bizarre, but surely this means I must have a 1-phase 32A cable? Again, correct me if I'm wrong.
Swapped over to the other charging point, also 7.4kW.
Conditions remain unchanged, it's maybe a few degrees warmer is all, and it's not been cold for a while.

This 7.4kW charging rate carries on for 2-3 weeks, which brings us to the present.
The car decides it wants to drop back down and only accept 3.3kW again, on both charging points, for the past two Fridays.
Tesla colleague is facing no such issues as he continues to reap the full 22kW - or whatever his model will take.
It's not an issue with the points themselves, nor any faulty or loose cable / port connections, at least not at surface level.
The car is always locked & switched off, air conditioning off also.

My questions to you then, ladies & gentlemen:

Could the car be throttling the charging speeds, and if so, why?
Is it likely to be an easily resolved software issue, or something more sinister and potentially battery component related?
Which avenue is best to explore to get the car / issue investigated? i.e. local dealership, service centre etc.

Apologies for the long-winded post, I'm still fairly new to the scene and want to be as thorough on the original thread as I can be.
Any solution or information is much appreciated, thanks.

 

[Coulomb]

Could the car be throttling the charging speeds, and if so, why?

I believe that there is a setting in the charging menu of the car somewhere, though I might be thinking of a Hyundai or Kia.

That cable is definitely 32 A, single phase; there is no metal in the L2 or L3 pins.

Some electronics in the car decides what the maximum charge current of the AC charging cable is, based on a resistor in the housing of the cable's plug. It seems like the sensing of that resistor is intermittent. So you might be having trouble with your EVCC or perhaps the OBC. There seems to have been a batch of poor quality EVCCs used around the time of the pandemic or its aftermath; that's possibly the reason.

If it's the cable, you could test it with a multimeter; you should see 220Ω ± 3% between the proximity pilot pin and the earth pin. Remember that the tips of the charging pins are insulated, except for the earth pin, so you need to get one of the multimeter probes behind that insulation.

Good luck demonstrating that to the service centre, assuming it's not a setting in the car's menus. Intermittent issues are always the hardest to resolve.

It could be that you are getting poor contact in the car's charging socket and/or the charging cable. Spraying with a non-residue contact cleaner (not moisture displacing oil) may help.

 

[Martinonline]

The charging current car can be changed via the battery page on the info screen. Touch the battery icon to get there.

 

[Jomarkh]

Hi, what kWh do you get from a 7kW destination EVSE?

 

[Diver]

The charging current car can be changed via the battery page on the info screen. Touch the battery icon to get there.

It's always on AC current as per attachments - flicking between 16A & AC current has no effect on speed, it stays around 3.3kW.

Hi, what kWh do you get from a 7kW destination EVSE?

Unsure, not tested, only ever charged at work. Should I expect ~6.6kW or slightly less?

I believe that there is a setting in the charging menu of the car somewhere, though I might be thinking of a Hyundai or Kia.

That cable is definitely 32 A, single phase; there is no metal in the L2 or L3 pins.

Some electronics in the car decides what the maximum charge current of the AC charging cable is, based on a resistor in the housing of the cable's plug. It seems like the sensing of that resistor is intermittent. So you might be having trouble with your EVCC or perhaps the OBC. There seems to have been a batch of poor quality EVCCs used around the time of the pandemic or its aftermath; that's possibly the reason.

If it's the cable, you could test it with a multimeter; you should see 220Ω ± 3% between the proximity pilot pin and the earth pin. Remember that the tips of the charging pins are insulated, except for the earth pin, so you need to get one of the multimeter probes behind that insulation.

Good luck demonstrating that to the service centre, assuming it's not a setting in the car's menus. Intermittent issues are always the hardest to resolve.

It could be that you are getting poor contact in the car's charging socket and/or the charging cable. Spraying with a non-residue contact cleaner (not moisture displacing oil) may help.

I've heard whispers of issues ref EVCC / OBC, assume this will require investigation at service centre if all other options are exhausted?

I'll test the cable with a multimeter & update.
Hopefully get my hands on some contact cleaner also, would you recommend spraying both cable ends as well as port on car?

Thanks all,

 

[Coulomb]

would you recommend spraying both cable ends as well as port on car?

Yes, it can't hurt.

 

[TomLane]

Hi, you paid for a car with a 7 year warranty, drop it in, collect a loan car, when it is fixed swop back and the dealership will tell you what was wrong.
Update the forum so others are aware and wiser.
Good luck
Tom
PS: I bet you it's the BMS board issue which controls charging speed and balancing as well as other things.

 

[Museruk]

Might not be relevant - but I have only just got my MG4 Trophy back from the dealership (Stoneacre Derby) after it took them nearly 3 weeks to solve my charging issue.
The car would only allow a very limited charge to be taken by the car - note not the power level, but limited time of charge before the car refused to allow any further charge (typically 2 to 4kWh)
This was independent of the charger (I have a Zappi 7kW charger) whether I used the Granny charger supplied by MG or the Zappi.
After waiting over a week for a replacement CCU (Combined Charge Unit), when fitted it made no difference!
They then did some software updating (didn't tell me exactly what was changed) - but it was definitely software!
When I complained about how long it had taken, they apologised and blamed MG Technical Support UK stating that MG only have one support person to cover the whole of the UK and that they sometimes have to wait up to 3 days to get help from them.
Obviously not good news and I am now (although I really enjoy driving this car!) seriously considering selling the car (after only owning it from new for just over a year).
MG support seems to be grossly inadequate and the software generally is not good (lane keeping assist is also another very annoying issue we have to put up with).

 

[craggy]

Hi. It sounds like the charger for a while was only working or set at 11kW which would explain why your 1-Phase 32A cable was only 3.6kW and the Tesla’s 3-Phase 32A was getting you 11kW.

 

[derek401]

Hi I have just got my MG4 trophy long range and only accepts 6.6kW at an 11kW charger. I have read that this car can take 11kW and wondered if I should buy a 3 phase cable. After reading up more it says my car socket should have 5 pins but it doesn’t. So now confused and maybe the max it can take in AC is 7kW . Any help is much appreciated.

 

[craggy]

Hi I have just got my MG4 trophy long range and only accepts 6.6 at an 11kw charger. I have read that this car can take 11kw and wondered if I should buy a 3 phase cable. After reading up more it says my car socket should have 5 pins but it doesn’t. So now confused and maybe the max it can take in AC is 7kw. Any help is much appreciated.

If the bottom 2 holes are empty then yours is a 7kW single phase max version. If I remember correctly the early ones had 11kW but newer are all 7kW.

 

[DixieTGS]

The following thread about cable limitations is worth checking out:

Thread 'Maximum Charging Guide - Type 2 EV Cables' Maximum Charging Guide - Type 2 EV Cables

 

[Coulomb]

If I remember correctly the early ones had 11kW but newer are all 7kW.

I believe it depends on the market. My Australian Jan 2024 built Extended Range (77kWh) is definitely 11kW.

 

[Corindikev]

The 77kW Essence (Trophy ER) is the only current version with 3 phase AC charging in Australia/NZ. Early 2022 UK models had 3 phase but that was changed in 2023 to single phase. The most likely reason is that most homes only have a single phase supply so having 3 phase capability is not very useful and in fact detrimental in that scenario.

 

[siteguru]

BTW, the single phase charger cars are rated to 6.6kW. The 3-phase charger cars are rated to 11kW 3-phase and 7kW single phase. (The onboard charger links 2 of the charger phase units when a single phase supply is detected, thus can achieve a higher charge rate than the dedicated single phase charger).

 

[derek401]

Thanks for everyone's responses. I did a lot a research but missed the bit about what charge the car would expect. It will just take longer for me to charge at work than I anticipated.

 

[amdmad]

Thanks for everyone's responses. I did

We have Monta charge at work . Mine flatlines at 3.7 all the time it's plugged in !!

 

[craggy]

We have Monta charge at work . Mine flatlines at 3.7 all the time it's plugged in !!

Are they 11kW charging units? Are you using a 32amp single phase lead?

 

[amdmad]

Friend as a Honda any1 . Hers pulls the full 11kw . Not sure about lead ?

 

[craggy]

Friend as a Honda any1 . Hers pulls the full 11kw . Not sure about lead ?

Check the label on 1 end. Or the writing on the wire itself. If it’s 16/32amp 1 phase or the wire says 3 x 6mm² + 2 x 0.5mm² then the most you will get from an 11kW unit is 3.6-3.7kW. You will need a 32amp 3 phase to get 7-11kW. (5 x 6mm² + 2 x 0.5mm²).