Dc charging at 250kw station

[halogen]

Hello. Today i took my mg4 51kwh to ultra super fast charger. Its rqted at 250kwh.
I plugged it in qt 58% soc.
But im only getting max at 63kwh speed. There was an ioniq 5 charging at the time too.
Im curious.
Isnt the 51kwh batt mg4 is rated at max 117kwh speed?

when 2 cars are sharing a charging station does the power output halved?
If so. Why am i not getting the max 117kwh speed as advertised. Mqybe someone knows the technicality?
Thank u

 

[Rolfe]

The 117 Kw raing was always a myth, it never did that. Speculation on the forum is that during development they thought they could achieve it, but never did. Later specs have a more realistic number quoted, possibly 85 Kw. There is video footage of people achieving 88 Kw on the SR, and I've seen 85 Kw on mine.

It will depend on your state of charge and the temperature too. You'll only get the maximum rate at a low state of charge, say under 50%, and when the battery is warm.

In fact the car charges reasonably fast, if not as fast as the LR. This is because it holds a fairly high rate of charge quite well up in the charging cycle, so you get a decent rate for a fairly long time. The original (fictitious) charging curve with the 117 Kw on it only achieved that for a very short time, and in fact the real charging time is probably as good as it would have been with that curve, overall.

 

[Jomarkh]

Hi, there may well be a bit of power sharing and the quoted max could be for 800V the two car using it are both 400V.

 

[Rolfe]

If two cars were sharing 250 Kw then you'd still expect to get 125 Kw, all else being equal. However you will not get 125 Kw on the SR because it doesn't charge that fast. It doesn't charge at 117 Kw either despite some earlier literature claiming that it does.

Its maximum charging power is about 88 Kw. To get that you have to be at a low state of charge, and to have a warm battery. The photo in the OP shows a car visibly over 50% charge, maybe as much as 60%, and you are not going to get 88 Kw at that level. 62 Kw is about what I'd expect at that state of charge - I'd be hoping for 85 Kw or better down below 50%. Overall the charging time isn't bad though, because it maintains the 85-88 Kw peak for quite a long time, and as I said, 62 Kw isn't bad when you're up around 60% charge.

I found this graph of charging curves that includes the MG4 SR. It's the red line that doesn't jump up and down like a jack-in-the-box. You can see what charging power you can expect at various states of charge, with a warm battery.

 

[halogen]

yes this makes sense...i watched bjorn's video charging test.. he started at 10% and its above 80kwh...then when its charged until about 60% ( where i was) the kwh charging speed is identical to mine. i guess 117kwh speed is a myth. ... thanks guys for the replies.
awesome community.


Bjorn's video.

 

[fnegroni]

Some chargers are better than others.
And let me just say this here…

Some companies don’t want to give you max speed no matter how much you beg for it.
Because it costs money.

I’ve seen 91kW on my SE SR while at a Tesla supercharger in France.

 

[Rolfe]

I thought that around 90 should be possible, although I've never seen it. (I've only charged at an ultra-rapid six times in total though.)

 

[siteguru]

Some companies don’t want to give you max speed no matter how much you beg for it.
Because it costs money.

Would you care to flesh out that theory please? (Cost per kWh is the same regardless of how fast it is delivered. In fact getting it delivered fast gets that car off the charger so another car can get on. More kWh delivered = more revenue).

 

[leafowner]

Would you care to flesh out that theory please? (Cost per kWh is the same regardless of how fast it is delivered. In fact getting it delivered fast gets that car off the charger so another car can get on. More kWh delivered = more revenue).

The cost of the infrastructure to deliver the power to the location can be much much more expensive.

 

[AB71]

Hello. Today i took my mg4 51kwh to ultra super fast charger. Its rqted at 250kwh.
I plugged it in qt 58% soc.
But im only getting max at 63kwh speed. There was an ioniq 5 charging at the time too.
Im curious.
Isnt the 51kwh batt mg4 is rated at max 117kwh speed?

when 2 cars are sharing a charging station does the power output halved?
If so. Why am i not getting the max 117kwh speed as advertised. Mqybe someone knows the technicality?
Thank u

Yes I saw it on a video somewhere the more cars using the chargers the slower it gets.

 

[Coulomb]

The cost of the infrastructure to deliver the power to the location can be much much more expensive.

Yes: seriously large transformers, feeder cables, etc. The cable from plug to charger has to be water cooled. Plus a lot of the time, until the average EVs gets a more powerful battery, a lot of expensive equipment will be under-utilised.

Plus possibly a touch of "those Porsche drivers can afford it".

 

[Mickky]

I don't think the charging speed quoted is a myth ,just you started at to high a battery state of charge and probably a cold battery the charge speed for the trophy battery certainly isn't a myth see pic

 

[andymgzs]

Hello. Today i took my mg4 51kwh to ultra super fast charger. Its rqted at 250kwh.
I plugged it in qt 58% soc.
But im only getting max at 63kwh speed. There was an ioniq 5 charging at the time too.
Im curious.
Isnt the 51kwh batt mg4 is rated at max 117kwh speed?

when 2 cars are sharing a charging station does the power output halved?
If so. Why am i not getting the max 117kwh speed as advertised. Mqybe someone knows the technicality?
Thank u

Raise it with MG. My 2020 44.5 KWh car will only achieve a max charge speed of 32kw. Max rated is 76kw. MG replied they don’t Guarantee charge speed and have since ignored the issue.
My guess is they have dialed it back in an update - car is now useless for road trips.

 

[AdeSc]

I have to say, MG4 Trophy, South Mimms services, a GridServe location I cannot remember and a GridServe in Norwich, maximum I’ve seen at Norwich Is 143kW, all others, maximum 137kW so far. It’s normally on a run when I get these numbers, all other times, on a Zappi at home at just under 7kW.

 

[Rolfe]

To clarify again, the most you will get from the SR car (LFP battery), which is the car the OP has, is about 90 Kw. You will only get that when the car is at a relatively low SoC, and as the battery fills up the power will drop.

This graph suggests (red line) that the drop-off will happen starting around 30% charge. The OP's car is behaving perfectly normally. (Although some early literature indicated 117 Kw max, this has never been achieved, and in fact the total charging time of the car as it is, is not significantly slower than the hypothetical short-lived 117 Kw would have managed, because the 90 Kw can be maintained for longer and doesn't drop off fast.)

It's not scorching fast, but it's a perfectly decent charging speed for most purposes. If minimum charging time on long journeys is a priority for you, don't buy the SR.

 

[AdeSc]

To clarify again, the most you will get from the SR car (LFP battery), which is the car the OP has, is about 90 Kw. You will only get that when the car is at a relatively low SoC, and as the battery fills up the power will drop.

View attachment 20827

This graph suggests (red line) that the drop-off will happen starting around 30% charge. The OP's car is behaving perfectly normally.

Presumably, this does not apply to the Trophy, or does it? I've seen, on multiple occasions,143kW on mine.

 

[Rolfe]

No, it doesn't apply to the Trophy, which (along with the LR) has a completely different battery. The SR has an LFP battery which charges more slowly than the NMC batteries on the long-range models. This thread is about the SR, the 51 KWh model, as laid out in the OP.

 

[PeteC]

Presumably, this does not apply to the Trophy, or does it? I've seen, on multiple occasions,143kW on mine.

The Trophy and LR will charge at a higher rate than the SR.

 

[AdeSc]

No, it doesn't apply to the Trophy, which (along with the LR) has a completely different battery. The SR has an LFP battery which charges more slowly than the NMC batteries on the long-range models. This thread is about the SR, the 51 KWh model, as laid out in the OP.

Understood, thank you.

 

[tsedge]

While the enquiry is about SR, just for comparison in case anyone is making up their mind about SR vs LR based on charge rate, if the charger supports it, I get (with a warm battery - eg after a long journey):

Peak around 135kW
Starts dropping around 50% SOC
50kW at 80% SOC
30kW at 90% SOC
Then steady drop off downwards from there

With the LR battery, charging to 95% is realistic and something I'll do on a long journey (eg leave home with 100%, drive for 4 hours / 180 miles, charge from 20-95%, return home).

However, battery must be warm and I typically only get the highest rates on Tesla chargers.