Battery problem advice

[Gwynfor Hughes]

Car still in dealers and yet to find the solution.
A contributory factor for the delay may be short staff in the dealers.
The installer I believe was referring to charging on a domestic plug in Europe as being or becoming illegal.
I'm surprised that no warning has shown on dashboard regarding balancing being required.
With regard to charging I normally leave on over night and disconnect the following morning.
I'm so confused by all this.

 

[chowbenter]

It should/must be charged AND balanced using an AC charger once per month

I'm going to have to get into a regimen of balancing the battery once a month, I think I've only done it once since January We don't use the car everyday or do high mileage & I only charge it to 50-70% because of that, I've just plugged it in now & will let it charge to 100% & see if it goes into balance mode.
Thanks for the heads up.

 

[JodyS21]

Car still in dealers and yet to find the solution.
A contributory factor for the delay may be short staff in the dealers.
The installer I believe was referring to charging on a domestic plug in Europe as being or becoming illegal.
I'm surprised that no warning has shown on dashboard regarding balancing being required.
With regard to charging I normally leave on over night and disconnect the following morning.
I'm so confused by all this.

It actually sounds like you’ve been inadvertently letting it balance without knowing it if that is your normal charging routine

 

[Iain]

It should/must be charged AND balanced using an AC charger once per month

Hi Jody. I wonder where you get the advice for charging and balancing once a month from. I am not criticising just interested.
I have never used a rapid charger and tend to charge when battery is around 20%, charging up to about 80% if possible.
With no rapid charging and mostly fast charging, as and when required, I do not see the need for monthly balancing.
I have not seen any official advice regarding how often balancing should be carried out and had always assumed it depended on amount and type of charge (ie rapid) rather than a fixed monthly schedule.
I would welcome any further thoughts and advise.
By the way I love and agree with your statement regarding a great car.

 

[JodyS21]

Hi Jody. I wonder where you get the advice for charging and balancing once a month from. I am not criticising just interested.
I have never used a rapid charger and tend to charge when battery is around 20%, charging up to about 80% if possible.
With no rapid charging and mostly fast charging, as and when required, I do not see the need for monthly balancing.
I have not seen any official advice regarding how often balancing should be carried out and had always assumed it depended on amount and type of charge (ie rapid) rather than a fixed monthly schedule.
I would welcome any further thoughts and advise.
By the way I love and agree with your statement regarding a great car.

Hi Iain.
It's in the manual somewhere about the AC charging/balancing, never looked myself but others have said it.

Rapid charging doesn't just cause the cells to imbalance, it happens as a by-product of all charging & draining done.

I don't know at what point the message to AC charge/balance is displayed on the dash.

The trouble with not doing/allowing a balance to occur regularly, is that it only re-balances the cells VERY slowly, so the longer you leave it the longer it will take to complete a balance when you finally do one - and it's limited to 10 hours (I believe it was) of balancing within a charging session.
The more out of balance the cells become, the lesser range you'll have and power etc maybe restricted earlier. It will only charge the car until the first cell hits the max allowed voltage and, it will only allow power to be drained from the battery until the first cell hits the lowest allowed voltage.

I think as well, unless the car is charged to 100% and probably balanced, the car (BMS) won't know what's fully going on with the state of health etc of the battery so its calculations may become more out of step.
This may well not be an accurate analogy! But imagine a 1 litre container being constantly emptied a bit and partially refilled, how much is left in the jug would be very hard to figure out/keep track of, by periodically filling it completely you reset your baseline to know the amount left in it.

 

[LeoRBK]

Hi Jody. I wonder where you get the advice for charging and balancing once a month from. I am not criticising just interested.
I have never used a rapid charger and tend to charge when battery is around 20%, charging up to about 80% if possible.
With no rapid charging and mostly fast charging, as and when required, I do not see the need for monthly balancing.
I have not seen any official advice regarding how often balancing should be carried out and had always assumed it depended on amount and type of charge (ie rapid) rather than a fixed monthly schedule.
I would welcome any further thoughts and advise.
By the way I love and agree with your statement regarding a great car.

You will find this advice under the sub-head "HV Battery" of the head "Maintenance".

You would hope that dealers make it a point to walk through maintenance for EVs during handover since it is new technology for most.

 

[Cocijo]

I’m afraid most dealers don’t understand it themselves.

 

[Lovemyev]

I’m afraid most dealers don’t understand it themselves.

Your totally correct of course !.
“What day of the week is it today ?” .

 

[chowbenter]

I'm going to have to get into a regimen of balancing the battery once a month, I think I've only done it once since January We don't use the car everyday or do high mileage & I only charge it to 50-70% because of that, I've just plugged it in now & will let it charge to 100% & see if it goes into balance mode.
Thanks for the heads up.

I charged it to 100% yesterday & it went into balance mode for around two hours, I did some errands in the car this morning & plugged it in again on my return to charge up to 100% from 97%. It went into balance mode again for almost five hours with the MG badge a steady light. I wasn't expecting that after yesterdays balance.

 

[Lovemyev]

I charged it to 100% yesterday & it went into balance mode for around two hours, I did some errands in the car this morning & plugged it in again on my return to charge up to 100% from 97%. It went into balance mode again for almost five hours with the MG badge a steady light. I wasn't expecting that after yesterdays balance.

It would appear that you are running on the OEM original factory software then, because your voltage after a charge suggests it.

 

[chowbenter]

It would appear that you are running on the OEM original factory software then, because your voltage after a charge suggests it.

Yes from what I've read on this forum it didn't get the full 'Comfort 2' update, it wont charge unless the car is locked either.

 

[rbpasapera]

Hi Jody. I wonder where you get the advice for charging and balancing once a month from. I am not criticising just interested.
I have never used a rapid charger and tend to charge when battery is around 20%, charging up to about 80% if possible.
With no rapid charging and mostly fast charging, as and when required, I do not see the need for monthly balancing.
I have not seen any official advice regarding how often balancing should be carried out and had always assumed it depended on amount and type of charge (ie rapid) rather than a fixed monthly schedule.
I would welcome any further thoughts and advise.
By the way I love and agree with your statement regarding a great car.

Pages 292-293 on the handbook pdf file:

 

[Iain]

Many thanks for info rbpasapera. I thought I’d read most of the manual but had missed that. Cheers Iain

 

[JodyS21]

I charged it to 100% yesterday & it went into balance mode for around two hours, I did some errands in the car this morning & plugged it in again on my return to charge up to 100% from 97%. It went into balance mode again for almost five hours with the MG badge a steady light. I wasn't expecting that after yesterdays balance.

Not really sure what to say, it's rather surprising it did that!!!!

So, the car chose to balance for only about 2 hours to get it to a nicely fully balanced state.

A brief drive was done using about 3% of the battery capacity (5miles or so). It was then recharged from 97% to 100%. That tiny amount of use got it in a state of unbalance whereby it took 5 hours to rebalance the battery pack....... LOL......
Obviously it is possible with unstable chemistry to get into that state, but..... do we really think it did, or could it be some kind of software bug that caused this weird situation.
As you said you are running a rather old BMS software version, I wonder if it a bug - that has been fixed since????

 

[Lovemyev]

Not really sure what to say, it's rather surprising it did that!!!!

So, the car chose to balance for only about 2 hours to get it to a nicely fully balanced state.

A brief drive was done using about 3% of the battery capacity (5miles or so). It was then recharged from 97% to 100%. That tiny amount of use got it in a state of unbalance whereby it took 5 hours to rebalance the battery pack....... LOL......
Obviously it is possible with unstable chemistry to get into that state, but..... do we really think it did, or could it be some kind of software bug that caused this weird situation.
As you said you are running a rather old BMS software version, I wonder if it a bug - that has been fixed since????

Just something worth considering here.
If the OP charged from around 96 - 97% then the charge would have commenced at only 3.5 kw's.
Therefore taking a while to hit 100% - then balancing would have started taking place.
So, if we are just looking at the time the whole total time the cycle had taken, then it will appear a little on the longer side maybe ?.
Just a guess on my part.

 

[chowbenter]

Not really sure what to say, it's rather surprising it did that!!!!

So, the car chose to balance for only about 2 hours to get it to a nicely fully balanced state.

A brief drive was done using about 3% of the battery capacity (5miles or so). It was then recharged from 97% to 100%. That tiny amount of use got it in a state of unbalance whereby it took 5 hours to rebalance the battery pack....... LOL......
Obviously it is possible with unstable chemistry to get into that state, but..... do we really think it did, or could it be some kind of software bug that caused this weird situation.
As you said you are running a rather old BMS software version, I wonder if it a bug - that has been fixed since????

No it hasn't been back into the dealers as it's been working just fine, It isn't due it's first service until January 2022. I've only ever charged it once to 100% since January just after I picked it up prior to yesterday so the cars never had a chance to balance after a 100% charge before, Whether that has anything to do with the odd balancing times I don't know, I kept walking to the garage to check on it every half hour to see if it was still balancing & it still had the solid light lit on the MG badge

 

[Lovemyev]

I kept walking to the garage to check on it every half hour to see if it was still balancing & it still had the solid light lit on the MG badge

If you have a home energy meter in your home, you can save on a bit of leg work.
When the car first commences the balancing process, it will be pulling around 500 Watts, then when it is close to completing, it will then reduce down to 300 Watts and then finally down to 175 Watts just before actually completing.
Yeah - It is sad that I have noticed this happening !.
I did have some issues on my car when it returned home from the BMS update and it’s first service.
It’s charging habits became weird to say the least upon its return.
Therefore I was documenting it’s charging behaviour via my home energy meter.

 

[Bazzer44]

Must confess,got the car in Jan 2021, used all manner of chargers, rapid,fast and home Rolec
Never bothered about balancing , but generally fully charge overnight on home Rolec
Up to last night best I ever got was 161 on eco after overnight chzrge
Experiment Yesterday, put it on granny charger , but took it off before bed , it showed 169 on eco at 95% charged
Went to free podpoint locally today and in one hour fully charged showing 161 in normal and 179 in eco , did not reset any of the readings , so hey ho was happy before but am happier now

 

[Lovemyev]

Must confess,got the car in Jan 2021, used all manner of chargers, rapid,fast and home Rolec
Never bothered about balancing , but generally fully charge overnight on home Rolec
Up to last night best I ever got was 161 on eco after overnight chzrge
Experiment Yesterday, put it on granny charger , but took it off before bed , it showed 169 on eco at 95% charged
Went to free podpoint locally today and in one hour fully charged showing 161 in normal and 179 in eco , did not reset any of the readings , so hey ho was happy before but am happier now

If you are leaving your car charging all night from your 7kw wall box, then it is likely to be balancing the pack without even knowing it @Bazzer44 .
Your 163 miles of predicted range in normal mode sounds fine !.
To be 100% sure, resetting both trip meters without pressure on the foot brake, is the most accurate reading.
What voltage is the pack displaying AFTER a full charge and balance, when the trips have been reset ?.
This will give an indication of what software you are running on.
A voltage of 455 - 456 would suggest the original ( OEM spec ) or a reportage voltage of 448 - 450 volts would suggest the newer BMS update has been applied.
I am going to guess at 455 - 456 volts original OEM software ????.

 

[Bazzer44]

If you are leaving your car charging all night from your 7kw wall box, then it is likely to be balancing the pack without even knowing it @Bazzer44 .
Your 163 miles of predicted range in normal mode sounds fine !.
To be 100% sure, resetting both trip meters without pressure on the foot brake, is the most accurate reading.
What voltage is the pack displaying AFTER a full charge and balance, when the trips have been reset ?.
This will give an indication of what software you are running on.
A voltage of 455 - 456 would suggest the original ( OEM spec ) or a reportage voltage of 448 - 450 volts would suggest the newer BMS update has been applied.
I am going to guess at 455 - 456 volts original OEM software ????.

Spot on