Original MG ZS EV battery state of health

[Gazza]

So, the dealer has done a SOH check on the pack and reported it at 100% SOH ?.
I only ask because after covering 29018 miles and with a pack voltage of 445.
Plus a now predicted range of 154 miles in the default mode, this may not suggest a 100% SOH ?.
To clarify, you only cover 60 miles every day, but charge to FULL every single night regardless ?.
If you are leaving it plugged in after it reaches 100% fully charged, then you ARE balancing.
Please please don't think I am criticising your routine, I am just trying to understand what is happening, to satisfy my own ( and anybody else ) interest who likes to plot their battery condition.
On your photo, it suggests that there is NO amp's being consumed by the car, at the time you did your checks ?.
@JodyS21 you may find this thread of some interest from @Gazza because I know you where running a spread sheet on results shown, on both PRE & POST BMS updates !.
I truly would like your opinions / thoughts on this situation on Gazza's car ?.

It's on a timed charge for 4 hours...so it would only receive a max of about 28kw ...so your implying that the dealer has got it wrong or is lying and hasn't carried out the checks as stated

 

[Lovemyev]

It's on a timed charge for 4 hours...so it would only receive a max of about 28kw ...so your implying that the dealer has got it wrong or is lying and hasn't carried out the checks as stated

No - It's just that your results don't really match what I would have expected to see after the Jan 15th 2021 BMS update, that's all.
So you are charging to 100% every night, but is this long enough for the car to complete a balance cycle ?.
You are using a wall box, not the Granny ?.
Both will perform a balance cycle of course, but the balance cycle start time differs of course.
The lower voltage on the pack may indicate that your cells are out of balance ?.
445 volts is a strange figure, that's all ??.

 

[JodyS21]

20000 miles 2 years old...just had second service and battery still 100% on service sheet

Hmm reckon they really read the data or just wrote down 100!?

 

[JodyS21]

It's on a timed charge for 4 hours...so it would only receive a max of about 28kw ...so your implying that the dealer has got it wrong or is lying and hasn't carried out the checks as stated

Your figures don’t really make sense.
If you have a fully charged balanced (or pretty much balanced) battery, you would be seeing 448/449/450 or 455/456volts, not 445volts which you are seeing.

If you definitely have fully (AC) charged, then within say 12hours, started the car without the brake pedal pressed; and 445v is displayed, it very much suggests your battery is not very balanced.

I very very very much doubt you have 100% SOH after 29,000miles and 2years old.
The voltage isn’t affected by the SOH, just the capacity.

Our car has now done about 22k miles, 15months old, today after full charge (& trip reset!) the GOM (N3) shows 155miles. I need to plug in and read the latest SOH, not done it for a while, expect it’ll be about 95% now.

 

[N2STY]

This really where the car should display SOH that way there is no argument and its just easier for everyone involved full transparency gives owners peace of mind

 

[JodyS21]

Evening all,

I have recently noticed over the last few weeks that upon full charge and battery equalisation the GOM, which used to read 163miles, now consistently reads 157miles. All latest updates are on. No dodgy BMS. Weather this week has been pleasant. Battery voltage reads 449v and current / accumulated journey have been reset.

It’s the exclusive model, is a 70 reg plate (so 17 months old) and has 7500 miles.

Am I missing something or have I experienced battery degradation?

Thoughts greatly appreciated.

I would recommend buying a £10 ocdb dongle and getting the real data with an android app.

 

[N2STY]

Reading the SOH from a third party app is great but when you take it to the dealer it has to be there software and there honesty

 

[Lovemyev]

Your figures don’t really make sense.
If you have a fully charged balanced (or pretty much balanced) battery, you would be seeing 448/449/450 or 455/456volts, not 445volts which you are seeing.

If you definitely have fully (AC) charged, then within say 12hours, started the car without the brake pedal pressed; and 445v is displayed, it very much suggests your battery is not very balanced.

I very very very much doubt you have 100% SOH after 29,000miles and 2years old.
The voltage isn’t affected by the SOH, just the capacity.

Our car has now done about 22k miles, 15months old, today after full charge (& trip reset!) the GOM (N3) shows 155miles. I need to plug in and read the latest SOH, not done it for a while, expect it’ll be about 95% now.

Similar on our original Gen 1 model @JodyS21 .
Over two years old, BMS update done in 2021 covered almost 20,000 miles, almost zero rapid charging.
Full charge and balance, usual protocol followed.
154 miles of predicted range in normal mode.
No OBD reader, but I estimate our SOH was around 93 - 94% SOH ???.

 

[JodyS21]

Reading the SOH from a third party app is great but when you take it to the dealer it has to be there software and there honesty

Unfortunately we know for a fact that most of the MG dealers (in regard to the EVs) are very unknowledgeable / untrained / don’t care / “lie”!

Fortunately we can read exactly the same data that they can via ocbd, so can check for definite what they tell us.

 

[N2STY]

Unfortunately we know for a fact that most of the MG dealers (in regard to the EVs) are very unknowledgeable / untrained / don’t care / “lie”!

Fortunately we can read exactly the same data that they can via ocbd, so can check for definite what they tell us.

I understand that but it still down to them to check they wouldn't bleave third party information it's just a pain when a little software update could show you on your car

 

[JodyS21]

I understand that but it still down to them to check they wouldn't bleave third party information it's just a pain when a little software update could show you on your car

I don’t think they really want us to see/know the battery state of health, otherwise they’ll get more complaints etc

 

[Alb]

I can see it from both sides.
Openly displaying this parameter would trigger what is most likely unjustified concern from the myriad of owners who don't actually understand what it means. Access in a nested menu sounds a much better idea.

 

[Lovemyev]

Owners car's that have received the BMS update ( like our car ) have a new base line to work from.
We know after the update that the historical data has been wiped and reset to zero.
The new ideal figure to aim for was a predicted range of 163 miles of range and the pack sitting on 448 - 450 volts after full charge and balance.
As the car continues to be charged and used, with more miles added, I believe the system is then starting to relearn what is the true SOH of the HV battery has now become.
It is my own belief, that it then slowly erodes that ideal predicted range of 163 miles little by little.
12 months after the update, has the figure now stabilised down to more realistic SOH ?.
Our car had displayed similar returns of other owners now, after a full charge and balance it returned around 154 - 153 predicted miles of range.
This had been slowly reducing from 163 down to this recent 153 miles of predicted range.
I can understand the debate of :-
"Should customers be using third party equipment to drill down and investigate the SOH of their HV batteries ? ".
Well, some of you already know that I never purchased a OBD reader to access the battery data.
But in all fairness, owners are able to get a pretty good handle on there SOH by just looking at the figures, without the use of a dongle.
Starting point 163 miles, now after another 12 months of charging more miles covered, the predicted mileage was 153 miles.
This indicates a reduced range of 10 miles now, given the same full charge and balance.
Quick "Back of a fag packet" ( non smoker by the way ) man math's.
10% of 163 miles = 16
An apparent loss of 10 miles of range now from the base figure of 163 miles, indicates a rough SOH of around 94% ish ??.
That's a rough guess, but not a million miles off I don't think !.
So, owners who are interested in their battery SOH are able to get a handle really quickly on any possible battery degradation.
I guess the 99 dollar question here is of course !.
Will the predicted range figure continue to decrease at the same rate, or will the pace of reduction slow down from this point in time ?.
Who know's ???.
In our case, the car was just over 2 years old and had covered almost 20,000 miles.
99.9% of our charging needs where all done from home on a 7kw wall box.
I have seen other owners post their new predicted ranges with similar aged cars and mileage covered.
It would appear then, that this is a fairly consistent pattern ?.
Is there any point in plotting this behaviour on your excellent tracker @JodyS21 ?.
It would be interesting to hear from any owners who are running on the factory software, to compare what ( if any ) the SOH their batteries are reporting.
Are they seeing similar returns on their SOH after similar time and mileage covered ?.
I really welcome your views and opinions on this subject @JodyS21

 

[N2STY]

So are you say 115 miles would mean a loss of 30% then it's warranty time?

 

[JodyS21]

Owners car's that have received the BMS update ( like our car ) have a new base line to work from.
We know after the update that the historical data has been wiped and reset to zero.
The new ideal figure to aim for was a predicted range of 163 miles of range and the pack sitting on 448 - 450 volts after full charge and balance.
As the car continues to be charged and used, with more miles added, I believe the system is then starting to relearn what is the true SOH of the HV battery has now become.
It is my own belief, that it then slowly erodes that ideal predicted range of 163 miles little by little.
12 months after the update, has the figure now stabilised down to more realistic SOH ?.
Our car had displayed similar returns of other owners now, after a full charge and balance it returned around 154 - 153 predicted miles of range.
This had been slowly reducing from 163 down to this recent 153 miles of predicted range.
I can understand the debate of :-
"Should customers be using third party equipment to drill down and investigate the SOH of their HV batteries ? ".
Well, some of you already know that I never purchased a OBD reader to access the battery data.
But in all fairness, owners are able to get a pretty good handle on there SOH by just looking at the figures, without the use of a dongle.
Starting point 163 miles, now after another 12 months of charging more miles covered, the predicted mileage was 153 miles.
This indicates a reduced range of 10 miles now, given the same full charge and balance.
Quick "Back of a fag packet" ( non smoker by the way ) man math's.
10% of 163 miles = 16
An apparent loss of 10 miles of range now from the base figure of 163 miles, indicates a rough SOH of around 94% ish ??.
That's a rough guess, but not a million miles off I don't think !.
So, owners who are interested in their battery SOH are able to get a handle really quickly on any possible battery degradation.
I guess the 99 dollar question here is of course !.
Will the predicted range figure continue to decrease at the same rate, or will the pace of reduction slow down from this point in time ?.
Who know's ???.
In our case, the car was just over 2 years old and had covered almost 20,000 miles.
99.9% of our charging needs where all done from home on a 7kw wall box.
I have seen other owners post their new predicted ranges with similar aged cars and mileage covered.
It would appear then, that this is a fairly consistent pattern ?.
Is there any point in plotting this behaviour on your excellent tracker @JodyS21 ?.
It would be interesting to hear from any owners who are running on the factory software, to compare what ( if any ) the SOH their batteries are reporting.
Are they seeing similar returns on their SOH after similar time and mileage covered ?.
I really welcome your views and opinions on this subject @JodyS21

That’s correct, we have seen that the SOH% ties up directly with the GOM reduction from 163 miles. So you can figure out the SOH pretty accurately just by the (reset) fully charged GOM reading.

Maybe what we need (now there’s been more time for data) is data plotting a graph of X=mileage, Y=SoH%
I don’t think there’s any value from what we’ve seen of plotting an X axis of time (instead of mileage)
??

 

[JodyS21]

So are you say 115 miles would mean a loss of 30% then it's warranty time?

Yes.
163 * 0.70 = 114.1

 

[Lovemyev]

I don’t think there’s any value from what we’ve seen of plotting an X axis of time (instead of mileage)
??

Yeah - Agreed, fair point !.

 

[rpannell]

I don’t think there’s any value from what we’ve seen of plotting an X axis of time (instead of mileage)
??

I suspect that it is both a mixture of time and use. This is supported by some of the Tesla curves that suggest that time since manufacture is as important as mileage. I remember a ZSEV taxi driver on here some time ago and he had done about 50,000 in the first year and the SOH was still showing 100%.

 

[Kithmo]

SOH on display would be more useful for second hand buyers.

 

[N2STY]

Cool so working off 161 miles to give a little buffer the original zs
157 = 97.5%
153 = 95%
149 = 92.5%
145 = 90%
And so on every loss of 4 miles is 2.5% or is that to simple?