Battery capacity

[Gomev]

I am confused.

After a full charge my battery shows 439v and a displayed 169 miles of range in 'N'. I had comfort 2 carried out in December but I think I need the latest (15-01-2021) BMS update to get to 450v.

When I had the updates carried out in December my range dropped to a poor 125 miles in 'N' after a full charge. I recently reset the m/kWh cumulative and per trip and this increased the range to 169 miles at full charge.

My car goes in for service next week but I am unsure if I should request the latest BMS update as the range is back to 160+ miles, were it was when I bought the car, with pre comfort 2/BMS update.

Any advice?

If you are only getting 439V fully charged & balanced, then you definitely have the problem BMS and you need to get it fixed by the dealer ASAP before it gets even worse and takes even longer to get back to full health.

Very interesting.
Sounds likely a lot of hearsay than what Dr Dave has actually said about his car.
His car has not had the faulty update.
So why will he suddenly have a problem which is due to this faulty update?
439V will be about 125-127miles in the original settings so the most likely explanation of the figures Dr Dave gave is a delayed reset or other very simple explanations rather than assuming that @Dr Dave somehow has developed a problem that occurs with a particular software update that he clearly has told us has not been applied to his car.

I am inclined to agree with @JodyS21

@Dr Dave clearly states 439v after full charge. Anyone who has been following the BMS story, which doesn't appear to be @KasEV, knows that 439v is neither 455 or 449/450v, the only acceptable voltages after a full charge and balance. He also says 'when I bought the car, with pre comfort 2/BMS update'.

@Dr Dave also states that after resetting his cumulative the range miraculously went from 125 to 169 miles. Something @KasEV says should not happen as GOM is based on the last 10 miles or so not the driving history.

So not really hearsay, it was actually what was written.

 

[Sue H]

As I understand it to maintain a healthy battery it should not be allowed to go down too low before recharging. Also, as has been pointed out before batteries don't like the cold weather, so won't achieve the same range as in the warmer months. The range you can expect also depends on driving style and driving in Eco helps with the longevity of the battery. Hope this helps.

 

[Cocijo]

As I understand it to maintain a healthy battery it should not be allowed to go down too low before recharging. Also, as has been pointed out before batteries don't like the cold weather, so won't achieve the same range as in the warmer months. The range you can expect also depends on driving style and driving in Eco helps with the longevity of the battery. Hope this helps.

Hi, some good points. Generally you’re ok with your HV battery pack as long as you don’t leave it for too long at very low or very full charge. There are buffers built in to the BMS also for this purpose To help protect the battery from extremes. But, needs must and some owners need the range and have to fully charge and run down, which is absolutely fine and what the car is designed for. Having a relatively small battery pack means that you have to use a much larger proportion of it if you need the range. I get 1.5mpkwh+ in warm weather compared to cold so I agree with the cold weather comment! Roll on summer!

 

[Lovemyev]

“ I had comfort 2 carried out in December “.
Well - unless I have missed something here, that say’s it all to me !.
As we have already had confirmed, BMS updates and Comfort 2 updates applied after 23 Oct 2020 are extremely likely to have the “Buggy” software bug.
This is a known and accepted fact by MG.
Simple - The car needs the latest update released 15th Jan 2021 that is intended to overwrite the affected “Buggy” BMS software in the “Comfort 2” update.
If the car was still on the original “Non Infected” software, it would be displaying close to 455 volts after a full charge & balance.
Let’s just assume the car DID have the 15th Jan 2021 update applied correctly, then the voltage on the pack after a few full charge and balance processes, should now be increasing towards the new and accepted upper ceiling of 448 - 450 volts.
Charging the car with the “Buggy” software still in place, is only going to increase the imbalance / range reduction in the pack every time it is offered a charge.
Trying to balance the pack is totally futile under these conditions.
To me, if the voltage on the pack is not improving, but is stagnant or reducing even more, this is a clear indication to me that the car is still suffering from “Bug’s” in the system.
The longer the pack is affected by the “Bug’s” and the more charges it is offered, then this just compounds the problem even more.
A little ironic to think that some customers where actually charged for having the improvement package applied to their cars under the “Comfort 2” banner.
Look how that ended up !.
My car was never affected by the “Buggy” software even though it had the “Comfort 2” update, because it was done about two weeks before the problem commenced.
But my car did receive the 15th Jan 2021 BMS update regardless under instruction from MG Tech Team.
I guess the VIN number was in the list of cars that required it ?.
The car is one of the early first 1,000 cars into the country.

 

[KasEV]

I am inclined to agree with @JodyS21

@Dr Dave clearly states 439v after full charge. Anyone who has been following the BMS story, which doesn't appear to be @KasEV, knows that 439v is neither 455 or 449/450v, the only acceptable voltages after a full charge and balance. He also says 'when I bought the car, with pre comfort 2/BMS update'.

@Dr Dave also states that after resetting his cumulative the range miraculously went from 125 to 169 miles. Something @KasEV says should not happen as GOM is based on the last 10 miles or so not the driving history.

So not really hearsay, it was actually what was written.

@Gomev
You may be right. But I do not get the impression that @Dr Dave voltage or range has been progressively decreasing from what Dr Dave wrote. Also if you battery pack is in a good state of health you will notice that voltage at 125miles N mode on GOM in current weather conditions is about 439 volts on the current meter. The most likely situation with @Dr Dave car in my opinion is a delayed reset and if he rechecks his voltage now after full charge it will be up to the 450 mark.
May be @Dr Dave will update us if his car is progressively losing voltage and range but from what he has said so far he has notice 439 volts only once and that was at the time of resetting his GOM when it was showing 125 miles.
Anyway there is no need to argue with the premise of the argument being "it is all over the Web"... so anything that sounds remotely similar must be it.
I am surprised at how you came to the conclusion that I have claimed that a reset will not cause the GOM to change from 125 to 163 when I have not in anyway said anything to that effect.
Interesting to see how you are making all sorts of deductions and extrapolations

 

[KasEV]

I'm very happy for you that the GOM in your car is clever enough to guess what driving you're going to do next and show you an accurate figure.

I will continue to not trust & go by the GOM in my actual car (which does the same long journey 3 days a week) otherwise my wife will be stuck at the side of the motorway regularly with a flat battery.

Enjoy your MG ZS EV experience.

@JodyS21
Have your GOM checked if it is that bad.
You seem to be having a rough time with the ZS EV. Bad BMS.... Bad GOM and all....
I was among the first 1200 ZS EV to be sold in UK. I believe my car was about 700 when it was registered in Dec 2019.
I know a few who have had their cars from 2019 who are all enjoying the car with no problems with charging, GOM etc and updates all straight forward and OK.

 

[KasEV]

“ I had comfort 2 carried out in December “.
Well - unless I have missed something here, that say’s it all to me !.
As we have already had confirmed, BMS updates and Comfort 2 updates applied after 23 Oct 2020 are extremely likely to have the “Buggy” software bug.
This is a known and accepted fact by MG.
Simple - The car needs the latest update released 15th Jan 2021 that is intended to overwrite the affected “Buggy” BMS software in the “Comfort 2” update.
If the car was still on the original “Non Infected” software, it would be displaying close to 455 volts after a full charge & balance.
Let’s just assume the car DID have the 15th Jan 2021 update applied correctly, then the voltage on the pack after a few full charge and balance processes, should now be increasing towards the new and accepted upper ceiling of 448 - 450 volts.
Charging the car with the “Buggy” software still in place, is only going to increase the imbalance / range reduction in the pack every time it is offered a charge.
Trying to balance the pack is totally futile under these conditions.
To me, if the voltage on the pack is not improving, but is stagnant or reducing even more, this is a clear indication to me that the car is still suffering from “Bug’s” in the system.
The longer the pack is affected by the “Bug’s” and the more charges it is offered, then this just compounds the problem even more.
A little ironic to think that some customers where actually charged for having the improvement package applied to their cars under the “Comfort 2” banner.
Look how that ended up !.
My car was never affected by the “Buggy” software even though it had the “Comfort 2” update, because it was done about two weeks before the problem commenced.
But my car did receive the 15th Jan 2021 BMS update regardless under instruction from MG Tech Team.
I guess the VIN number was in the list of cars that required it ?.
The car is one of the early first 1,000 cars into the country.

@Lovemyev
You are right. The issue is a Buggy Update so how does one suddenly have the problem if the person has not had the Buggy update?

 

[Dr Dave]

@Gomev
You may be right. But I do not get the impression that @Dr Dave voltage or range has been progressively decreasing from what Dr Dave wrote. Also if you battery pack is in a good state of health you will notice that voltage at 125miles N mode on GOM in current weather conditions is about 439 volts on the current meter. The most likely situation with @Dr Dave car in my opinion is a delayed reset and if he rechecks his voltage now after full charge it will be up to the 450 mark.
May be @Dr Dave will update us if his car is progressively losing voltage and range but from what he has said so far he has notice 439 volts only once and that was at the time of resetting his GOM when it was showing 125 miles.
Anyway there is no need to argue with the premise of the argument being "it is all over the Web"... so anything that sounds remotely similar must be it.
I am surprised at how you came to the conclusion that I have claimed that a reset will not cause the GOM to change from 125 to 163 when I have not in anyway said anything to that effect.
Interesting to see how you are making all sorts of deductions and extrapolations

Since the comfort 2 update I have only got 439v. Previous to the update I had 450v. I will report what happens when it goes in for service next week and I get the updated BMS.

 

[Lovemyev]

@Lovemyev
You are right. The issue is a Buggy Update so how does one suddenly have the problem if the person has not had the Buggy update?

No "Buggy" update applied to the car - then no problem !.
The issue only develops as a result of the "Bug" update being applied to the car and then getting into the system, it does not get in there on it's own.
If your car matches the same criteria of dates / certain type of BMS / Comfort 2 update identified as problematic by MG - then it needs the latest BMS update ( 15th Jan 2021 ) to rectify the situation.

 

[KasEV]

Since the comfort 2 update I have only got 439v. Previous to the update I had 450v. I will report what happens when it goes in for service next week and I get the updated BMS.

@Dr Dave
I believe so far as you are aware you have not had the BMS update.
So has your Voltage and range been stable or has it been progressively been reducing?
I understand it is a few months now since your comfort 2 update and during this time has your range, voltage drastically decreased despite increased charging?
Kindly update us with your latest numbers on full charge.

 

[Dr Dave]

@Dr Dave
I believe so far as you are aware you have not had the BMS update.
So has your Voltage and range been stable or has it been progressively been reducing?
I understand it is a few months now since your comfort 2 update and during this time has your range, voltage drastically decreased despite increased charging?
Kindly update us with your latest numbers on full charge.

On full charge 439v, stable since comfort 2 update.

My main concern is others seem to be getting 449/450v at full charge. The car has only done 5200 miles in the last year. I hope the latest BMS update will get me the 450v at full charge. The car is in for service tomorrow, I have requested BMS update. I will report on the outcome.

 

[Cocijo]

Another indication that the battery pack is out of balance is being unable to get higher power when the charge drops. This differs as to when this occurs depending on the state of imbalance in the pack and protects those cells that are out of ballance with the pack from damage due to excessive draw. On a well balanced pack full power should be available even at quite low states of charge as long as the cells are balanced well.

 

[JodyS21]

On full charge 439v, stable since comfort 2 update.

My main concern is others seem to be getting 449/450v at full charge. The car has only done 5200 miles in the last year. I hope the latest BMS update will get me the 450v at full charge. The car is in for service tomorrow, I have requested BMS update. I will report on the outcome

Remember you'll need to do a fair few battery cycles/balances to get it back to 450V.
Search the forum for an idea of how many, roughly I think you're probably looking at 110 hours of balancing to get it back to how it should be.

 

[Lovemyev]

Remember you'll need to do a fair few battery cycles/balances to get it back to 450V.
Search the forum for an idea of how many, roughly I think you're probably looking at 110 hours of balancing to get it back to how it should be.

The longer the "Buggy" software has been applied to the car, the longer it is likely to take to bring the H.V. pack back to a more normal condition.
In Norway, the dealers are taking the cars back from the owners for one to two weeks, in order to apply the new BMS update, then correct the issue by charging & balancing the HV packs a number of times, before returning the cars back to the customers in a more usable condition.
This must be a logistical nightmare to be honest.
One owner was offered a Tesla as his loan car !.

 

[macd2401]

Just a thought, but folks on this thread are discussing an app for android, and an obd adapter that seems to be having success with reading battery values in the car. It may be worth looking at, because it gives you your top line voltage, and also your top and bottom cell values, giving you a good idea how far out of whack your battery is, and if its getting better with your balancing regime.

 

[KasEV]

The longer the "Buggy" software has been applied to the car, the longer it is likely to take to bring the H.V. pack back to a more normal condition.
In Norway, the dealers are taking the cars back from the owners for one to two weeks, in order to apply the new BMS update, then correct the issue by charging & balancing the HV packs a number of times, before returning the cars back to the customers in a more usable condition.
This must be a logistical nightmare to be honest.
One owner was offered a Tesla as his loan car !.

Wow!!!!
Good service in Norway.
Somehow, I am a bit doubtful that @Dr Davies problem is same as that due to the buggy bms as if it were that particular problem he will not have a stable voltage and his range will begin to significantly fluctuate. Anyway I may be wrong. Good that he the car in for the correct bms.

 

[KasEV]

Just a thought, but folks on this thread are discussing an app for android, and an obd adapter that seems to be having success with reading battery values in the car. It may be worth looking at, because it gives you your top line voltage, and also your top and bottom cell values, giving you a good idea how far out of whack your battery is, and if its getting better with your balancing regime.

@macd2401
I have been following that thread with a lot of interest but I not sure, I can say with confidence that the apps and devices that are being used are accurate. We may be need a. MG tech to give a take on these apps and devices. For now I am not investing into these devices the dashboard voltage is enough for me.
Have you got one of these devices and apps?

 

[Cocijo]

@macd2401
I have been following that thread with a lot of interest but I not sure, I can say with confidence that the apps and devices that are being used are accurate. We may be need a. MG tech to give a take on these apps and devices. For now I am not investing into these devices the dashboard voltage is enough for me.
Have you got one of these devices and apps?

Make sure it’s an MG tech who has been incorrectly applying software updates though!

 

[macd2401]

@macd2401
I have been following that thread with a lot of interest but I not sure, I can say with confidence that the apps and devices that are being used are accurate. We may be need a. MG tech to give a take on these apps and devices. For now I am not investing into these devices the dashboard voltage is enough for me.
Have you got one of these devices and apps?

The app was free, the dongle was around £10. Haven't had a chance to test it with any other apps yet since my car had to go in for accident repairs.

 

[KasEV]

The app was free, the dongle was around £10. Haven't had a chance to test it with any other apps yet since my car had to go in for accident repairs.

Oh yes, the Glasgow incident.
Sorry, I forgot.
Hope the car is back soon as good as new.
If the device is not that expensive then it may be worth a go but I have my doubts about the accuracy.