Charging speeds

This is the charging curve I got from a 160 kWh charger the other day. Worth mentioning it was 0 °C. Cold makes the charge slower. Hadn't seen this stepped behaviour before, but probably it is because most of the chargers here in Spain do not give you a graph with the charging speed. It was a long trip, it was cold and I had to maximise autonomy.

elenuial said:

This is the charging curve I got from a 160 kWh charger the other day. Worth mentioning it was 0 °C. Cold makes the charge slower. Hadn't seen this stepped behaviour before, but probably it is because most of the chargers here in Spain do not give you a graph with the charging speed. It was a long trip, it was cold and I had to maximise autonomy.

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That's about what I see on ultra rapid chargers, they don't seem to like the MG5 for some reason, especially in the cold.

5teep said:

That's about what I see on ultra rapid chargers, they don't seem to like the MG5 for some reason, especially in the cold.

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Nothing to do with the rapid charger, it’s the MG5’s BMU that limits the charge rate due to low cell temperature.

Overall goal is HV battery longevity, not performance.

Chatting with a guy servicing a charger and he informed me the Grid turns down power available in periods of high demand.

It also appears on at least one charging station I've used a few times the rate of charge reduces the more EVs connect.

Pebblefeline said:

Hi everyone

Happy festive season

I just wanted to ask what rapid charging speed people are seeing on the pfl 5

Mine tops out around 50kW these days but used to get up to 75+.

Doesn’t seem to matter what charger, seems to be since I had the Tesla update, though it may also be the current colder weather.

Just interested

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I've thought the same about mine. After the update in Dec 23 I've been convinced charging speeds are lower, but couldn't find a way to confirm this, until I found myself on three occasions charging next to an identical model and year MG5. On all three occasions the other car was drawing a higher rate of charge at a higher state of charge. I didn't ask if they'd had the update, but here are the charging speeds I was seeing at two of them last summer:

Cobham Services M25
My car – 50kW @ 30%
Other car – 70kW @ 57%

Leicester Donington Park M1
My car – 59kW @ 30%
Other car – 81kW @ 40%

I used to get higher rates pre update and on one occasion managed 92kW @ 37% at Reading East Gridserves in May 23. Happy days!
I've resigned myself to the fact that I just need to plan for longer stops now.

TimBA said:

I've thought the same about mine. After the update in Dec 23 I've been convinced charging speeds are lower, but couldn't find a way to confirm this, until I found myself on three occasions charging next to an identical model and year MG5. On all three occasions the other car was drawing a higher rate of charge at a higher state of charge. I didn't ask if they'd had the update, but here are the charging speeds I was seeing at two of them last summer:

Cobham Services M25
My car – 50kW @ 30%
Other car – 70kW @ 57%

Leicester Donington Park M1
My car – 59kW @ 30%
Other car – 81kW @ 40%

I used to get higher rates pre update and on one occasion managed 92kW @ 37% at Reading East Gridserves in May 23. Happy days!
I've resigned myself to the fact that I just need to plan for longer stops now.

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I don't know anymore than the next whether the update has slowed things down but the fact that your 2 examples show that your car at the same percentage, 30%, was charging at two different rates at least demonstrates that there are more factors involved than just SOC.
How warm were your batteries ? How warm was the outside temperature ? How many cars were charging ? Were the chargers shared distribution or individually supplied ?

I agree with @Gomev, in cold weather, cell temperature is the main deciding factor when it comes to rapid charging rates, (ignoring potential infrastructure issues)

By design, the battery cells are kept around 10C or ambient (whatever is higher), but once connected to a rapid charger the BMU will activate the battery heater automatically and turns it off when the cells reach around 30C.

Therefore the longer your charging session last, the warmer the cells will get, as they are also heated by the current flow. I take it that the MG5’s you compared with were plugged in ahead of yours?

You can manually turn on the battery heater to have the cells at optimum temperature just as you plug in, but in reality the exact timing is difficult to achieve without an OBD dongle to read out temperatures.

Last but not least, heat dissipation is square to battery current, therefore multiple rapid acceleration followed by kers 3 regen will heat up the cells nicely (beware of whiplash though)

Gomev said:

I don't know anymore than the next whether the update has slowed things down but the fact that your 2 examples show that your car at the same percentage, 30%, was charging at two different rates at least demonstrates that there are more factors involved than just SOC.
How warm were your batteries ? How warm was the outside temperature ? How many cars were charging ? Were the chargers shared distribution or individually supplied ?

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Donington Park was August and slightly warmer, which may explain both cars drawing higher rates.
At Cobham, the other MG5 plugged in after me; at Donington the other one started well after me as I had to help him with the Gridserve App.
In both cases both cars will have been at the same ambient temperature (obviously!) and have driven quite a few miles along a motorway.
The software fix in Dec 23 was also to resolve the issue of the battery heater switch not staying 'on' but flipping back to 'off'. It now switches correctly, though I am not convinced it makes any difference (and yes, I do switch it on at least 30 mins before charging, especially in this weather).

TimBA said:

Donington Park was August and slightly warmer, which may explain both cars drawing higher rates.
At Cobham, the other MG5 plugged in after me; at Donington the other one started well after me as I had to help him with the Gridserve App.
In both cases both cars will have been at the same ambient temperature (obviously!) and have driven quite a few miles along a motorway.
The software fix in Dec 23 was also to resolve the issue of the battery heater switch not staying 'on' but flipping back to 'off'. It now switches correctly, though I am not convinced it makes any difference (and yes, I do switch it on at least 30 mins before charging, especially in this weather).

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Interesting, the only explanation that I can think of is that your battery heater doesn’t work properly or it’s function was affected by the upgrade.

Maybe test it the next time ambient temperature is well below 10°C: before you drive off, select the “Motor RPM/Voltage/Current” screen, then turn on the battery heater manually; the current should increase by 7-8A (@400V).

Best to simultaneously monitor the battery temperature with an OBD dongle/app as 30 min may not be long enough to heat the cells to optimum levels.

BTW is your MG5 a PFL by any chance?

Oddly I had the same thoughts about the upgrade, my charging speeds seemed to drop after it was done

Then I was recently at a charging point with a jag Ipace and a kona and I was running faster than either of them at similar soc

So now I am confused

My take away is that the number of factors affecting charge speed is really high