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Discussion Starter · #1 · (Edited)
So at the weekend I ventured into Wales with the family and needed to rapid charge for the first time since getting the MG5 last year.

On the first go I stopped at the MFG in Bristol and easy peasy tap and go but noticed it stopped at 95% on returning.

My second attempt in Newport before returning home I stopped at an InstaVolt and again it stopped at 95%

Hopefully it'll be a long time before needing to rapid again (57p a kWh 馃様) but is there anyway to override to 100%?

I found another quirk that the miles per kWh tops out at 20 馃槄

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The MG5 does some strange things on a rapid over 90%.
You are lucky it did not show an HV fault.
Best not to rapid over 90% plus the charge rate drops off between 80-90%.
What percentage did you start the charge at and how long was it connected?
 
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Discussion Starter · #4 ·
The MG5 does some strange things on a rapid over 90%.
You are lucky it did not show an HV fault.
Best not to rapid over 90% plus the charge rate drops off between 80-90%.
What percentage did you start the charge at and how long was it connected?
What's the HV fault issue?

I was watching the second time right at the end dropped to around 7kW for 85-95%

I have a shot from 68% at 4:25pm. The end summary has 4:22pm start so must have been about 65%.

Ended at 95% at 5:05pm

So 30% in 43 mins.

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Discussion Starter · #5 · (Edited)
The first time at the MFG was roughly the same start point. Probably about 60% to the 95%

Not sure on how long it took but it was running about 60kW as I left. It can only peak at 80kW so pretty decent.

The InstaVolt was rubbish but it was the Newport location most likely as the one next to it had a calibration issue.

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Discussion Starter · #6 ·
InstaVolt
拢10.33 cost and 57p a kWh = 18 kWh

MFG
拢6.01 cost and 49p a kWh = 12 kWh

Weirdly I think MFG under charged me for it at six quid, unless it wasn't 49p 馃

The InstaVolt 18kWh seems about right.

57kWh usable so 1% is 0.57

18/0.57 = 31.5% but about 30% actually added
 

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Discussion Starter · #7 ·
BMS must be stopping the charge due to heat or after reaching a desired pack voltage. Do not use rapid beyond 85 or 90, and use home Charge Point to force rebalancing.
As far as I'm aware there's nothing to program in the car to stop at 85 or 90% so you would have to be physically next to it.

It looks like MG have set a limit at 95%

What issue would be taking it to 100% on DC at a few kW Vs taking it to 100% on AC at a similar speed? (Other than hogging a charger)
 

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As far as I'm aware there's nothing to program in the car to stop at 85 or 90% so you would have to be physically next to it.

It looks like MG have set a limit at 95%

What issue would be taking it to 100% on DC at a few kW Vs taking it to 100% on AC at a similar speed? (Other than hogging a charger)
I frequently charge my Ioniq to 100% on a rapid. Is there any evidence it doesn't balance the cells on DC? The last couple of % takes ages on DC, just like AC and drops to 1 or 2kW. So I assume it is balancing the cells still.
Perhaps your MG doesn't balance the cells on DC (or they are out of balance) so stops at 95%. Have you charged to 100% on AC recently?
I find that if I haven't charged to 100% on AC or DC in a while, the last bit takes a lot longer whilst it balances.
 

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Discussion Starter · #9 · (Edited)
I frequently charge my Ioniq to 100% on a rapid. Is there any evidence it doesn't balance the cells on DC? The last couple of % takes ages on DC, just like AC and drops to 1 or 2kW. So I assume it is balancing the cells still.
Perhaps your MG doesn't balance the cells on DC (or they are out of balance) so stops at 95%. Have you charged to 100% on AC recently?
I find that if I haven't charged to 100% on AC or DC in a while, the last bit takes a lot longer whilst it balances.
Well I'm always charging to 100% at home on my Indra EVSE.

There's no stop at x% so it'll always go to full. But that's what I want so no issues.

Those two times this weekend are the only ever times I've DC charged.

The car is a three year lease too. I reckon it'll probably be less than ten times DC charged with me tbh. More interested in why it can't 100%

I think you're correct in that it can only rebalance under AC so leaves the last 5%

Was getting a nice 5 miles per kWh with the decent weather and smooth driving, but could have been a different story with harsh weather so didn't want to take the chance.
 

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The MG5 rapid charging software is questionable and lots of people have reported issues over 90%. That's why people advise you not to do it. We'll never actually know why - SAIC aren't interested in dialogue or feedback.

In any case, you're wasting your time. If you charge from 20% you'll add the same amount of energy in half the time.
 

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I frequently charge my Ioniq to 100% on a rapid. Is there any evidence it doesn't balance the cells on DC? The last couple of % takes ages on DC, just like AC and drops to 1 or 2kW. So I assume it is balancing the cells still.
Perhaps your MG doesn't balance the cells on DC (or they are out of balance) so stops at 95%. Have you charged to 100% on AC recently?
I find that if I haven't charged 100% on AC or DC in a while, the last bit takes a lot longer whilst it balances.
Yes, the advice is for the specific car. If BMS doesn't want to go beyond 95%, there must be a reason, and we should not push it.
 

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Well I'm always charging to 100% at home on my Indra EVSE.

There's no stop at x% so it'll always go to full. But that's what I want so no issues.

Those two times this weekend are the only ever times I've DC charged.

The car is a three year lease too. I reckon it'll probably be less than ten times DC charged with me tbh. More interested in why it can't 100%

I think you're correct in that it can only rebalance under AC so leaves the last 5%

Was getting a nice 5 miles per kWh with the decent weather and smooth driving, but could have been a different story with harsh weather so didn't want to take the chance.
All batteries would degrade. The degradation would be faster if the pack voltage is constantly high.
 

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Battery balancing can only be done on AC Type2.
 
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What's the HV fault issue?

I was watching the second time right at the end dropped to around 7kW for 85-95%

I have a shot from 68% at 4:25pm. The end summary has 4:22pm start so must have been about 65%.

Ended at 95% at 5:05pm

So 30% in 43 mins.

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Discussion Starter · #15 ·
From reading that does sound like a faulty charger rather than the car tbh.
 
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