Car unusable. Possibly battery failure or electronics issue. Advise sought...

[Richy Rich]

Hi All,

I've been looking at these forums for a while but never had anything to say, until now.... I've made this post entitled "Car unusable. Possibly battery failure or electronics issue. Advise sought..." hoping people might be able to come to my aid.

A brief bit of history:

I have a MG ZS EV, about 1.5 years old. For a while the range has dropped much quicker than expected (or the car predicts), usually giving about 60% of the suggested range overall, on normal mode, driving partly at 30 mph and partly with the ACC at 65mph tops on dual carriageways. I figured this was bad, but thought that maybe this is normal and anything over 30mph causes the prediction to be wrong. Recently, when I 'fully charge' via the 3 pin plug, I am told I have ~ 128 miles. With the standard charger it gets to ~160 miles. Again, maybe this is normal as the 3 pin can deliver less power.

Anyway, what happened recently was that I had a 21 mile journey to make to the airport. I had a range of 58 miles and figured that I would fast charge on the way back home (a mistake, in hindsight). Knowing my car, I knew that I would have to charge like this, but knew there was a fast charge station very close to the airport so it would be ok. So, even with driving carefully, mostly at 50-55 mph) the range plummeted, and at ~25 miles range (4 miles from the airport), I got red battery warning telling me there was some sort of failure, and it also stopped doing the regenerative charging (with errors for this as well). I then got consistent warnings and power drops as the range fell away and periodic power drains were repeatedly implemented (I think this is normal on low battery) and figured that I would head to the fast charge point and give it a boost before continuing to the airport. I had some time spare for this...

So, then the car would not charge via the fast charger, I was told with a very fast message flashup that the charge wasn't authorized. I tried all sorts of combinations of when to connect and lock the car etc., and used a 2nd charge point but still, it would not accept it. For info - I have used them before, although not at that site). I have this car through my work, so was able to call to have the car recovered to my property, while I headed onto the airport to catch my flight. It was dropped off and started charging.

The current issue:

When I come home and try to move the car, I get a stream of warnings telling me that all sorts of warnings/faults have come up, and the gear/drive selector will not select a gear - it doesn't light up. The faults are ABS, Stability control, Traction control, Autohold, EBP system, Hill Decent Control, Hill hold unavailable, LKA system unavailable. I've attached some pictures to show this.

I tried starting the car by holding down the power button, but then I found that I couldn't turn the car off.... I had to hold the power button down again to do that and cycle the normal process to get it off properly. I've also tried disconnecting the 12V battery for an hour to see if that helps to reset the process, but it doesn't.

So, I'm not sure what is wrong, not how to fix the issue I'm currently having. Any advice would be gratefully received.

Kind regards,

Richard

Edit - Car is working again. For anyone with a similar issue, reading through this topic may be helpful. For a quick fix, manually disconnect the handbrake, and then move the car a little, then restart the car and all should be good. Possibly your 12V battery needs charging. If you're having a similar range issue, you might have got bad BMS software and require having it put right at the dealer, and may need to do some long charges (after fully charging) to right the battery as well. Thanks everyone.

 

[JCFlippen]

I am sure experienced MG owners will post soon. In the mean time I suggest charging the 12v battery while it is disconnected. Your reduced range may be a BMS issue as my ZS EV shows 137 on N with full charge in these temperatures. Eco mode is 151 on full charge and voltage is 455v.

 

[Cocijo]

Apart from the obvious advice to get your dealer to sort it for you;
The error messages could be due to a low 12v battery so fully charge this first.
Fully charge the HV battery on AC charger and allow to equalise (MG grille light goes out).
With heater off turn car on to ready and report on HV battery voltage - depending on this it will indicate that you may have faulty bms software that needs updating.
you should check this with your dealer anyway, so it’s probably best to let them sort it for you.
Good luck.

 

[Richy Rich]

Thank you for your advice, and yes, I will be going through the 'proper' route to get this sorted. I just wanted to start the process from a sensible discussion, and hopefully get the car drivable first.

It sounds as though I should charge the 12V battery as an immediate step and check the main battery voltage. May I ask, how do you check the voltage of the main battery? I've read people referring to that and the BMS on other posts, but I've not managed to find out how to do it. I presume there is a menu option that I haven't spotted.

 

[djenson]

Hi All,

I've been looking at these forums for a while but never had anything to say, until now.... I've made this post entitled "Car unusable. Possibly battery failure or electronics issue. Advise sought..." hoping people might be able to come to my aid.

A brief bit of history:

I have a MG ZS EV, about 1.5 years old. For a while the range has dropped much quicker than expected (or the car predicts), usually giving about 60% of the suggested range overall, on normal mode, driving partly at 30 mph and partly with the ACC at 65mph tops on dual carriageways. I figured this was bad, but thought that maybe this is normal and anything over 30mph causes the prediction to be wrong. Recently, when I 'fully charge' via the 3 pin plug, I am told I have ~ 128 miles. With the standard charger it gets to ~160 miles. Again, maybe this is normal as the 3 pin can deliver less power.

Anyway, what happened recently was that I had a 21 mile journey to make to the airport. I had a range of 58 miles and figured that I would fast charge on the way back home (a mistake, in hindsight). Knowing my car, I knew that I would have to charge like this, but knew there was a fast charge station very close to the airport so it would be ok. So, even with driving carefully, mostly at 50-55 mph) the range plummeted, and at ~25 miles range (4 miles from the airport), I got red battery warning telling me there was some sort of failure, and it also stopped doing the regenerative charging (with errors for this as well). I then got consistent warnings and power drops as the range fell away and periodic power drains were repeatedly implemented (I think this is normal on low battery) and figured that I would head to the fast charge point and give it a boost before continuing to the airport. I had some time spare for this...

So, then the car would not charge via the fast charger, I was told with a very fast message flashup that the charge wasn't authorized. I tried all sorts of combinations of when to connect and lock the car etc., and used a 2nd charge point but still, it would not accept it. For info - I have used them before, although not at that site). I have this car through my work, so was able to call to have the car recovered to my property, while I headed onto the airport to catch my flight. It was dropped off and started charging.

The current issue:

When I come home and try to move the car, I get a stream of warnings telling me that all sorts of warnings/faults have come up, and the gear/drive selector will not select a gear - it doesn't light up. The faults are ABS, Stability control, Traction control, Autohold, EBP system, Hill Decent Control, Hill hold unavailable, LKA system unavailable. I've attached some pictures to show this.

I tried starting the car by holding down the power button, but then I found that I couldn't turn the car off.... I had to hold the power button down again to do that and cycle the normal process to get it off properly. I've also tried disconnecting the 12V battery for an hour to see if that helps to reset the process, but it doesn't.

So, I'm not sure what is wrong, not how to fix the issue I'm currently having. Any advice would be gratefully received.

Kind regards,

Richard

When is the last time you did a balance charge on the car?

 

[JCFlippen]

A balance charge takes place after you have charged to 100% and then leave charger connected. If you have not done this then it could possibly be why you have such low range. Balancing can take many hours after full charge or even many separate goes after 100% charging.
Worth trying before going to dealer.

 

[djenson]

I am sure experienced MG owners will post soon. In the mean time I suggest charging the 12v battery while it is disconnected. Your reduced range may be a BMS issue as my ZS EV shows 137 on N with full charge in these temperatures. Eco mode is 151 on full charge and voltage is 455v.

From my understanding of the BMS issue, it only affected cars that came in for a software update after collecting the cars. The BMS issue or just not balancing the car would make sense for there problem though:

HV battery goes out of balance, slowly affecting total range -->

Battery's gets extremely out of balance as OP is on low range and some cells go below the safety threshold making the BMS freak out and put the battery in a 'limp mode' of sorts. Battery light comes on -->

OP goes to a DC fast charger. THis doesn't resolve the issue because the car cannot balance the battery on a DC fast charger, so the car rejects a charge -->

Car disconnects the HV battery as it gets too out of range, Meaning the 12v battery isn't charged, and motor cannot be used. As 12v battery drain, modules in the MG start to disconnect, making the dash turn into Christmas lights.

It could also just be a fault HV battery thats just got bad cells in it. I think OP should try leaving the car on an AC charger for 48H, and see if that resolves some of the issues. Either way, they should go to dealer ASAP to check that the HV battery and BMS are in good working order.

edit, after reading Richys post again, I've noticed you say you had the car charging while you went to an airport, Meaning the car would have been plugged in for a long time anyway. Makes me think BMS issue more likely or totally different issue?

 

[Lovemyev]

Sounds like your car has been "Screaming" a buggy BMS for a long time.
The slow, but increased reduction in range is one of the classic symptoms.
Another symptom is the car not being able to provide full power under demand.
Continuing trying to put more and more charge into the battery ( especially from a Rapid ) just makes matters worse, and puts the pack more and more out of balance.
Pure guess work here, but I believe that your pack has become SO far out of balance now, it has now decided to shut down to help protect itself.
If this is indeed case, it requires the BMS updating ASAP.
Then it will take a large number of A/C charges to bring the pack back to its normal state.
NOT RAPID D/C CHARGES !
The buggy BMS problems have been covered at great length on this forum.

 

[vcantrill]

Was this problem resolved?
Think I may have simpler problem.
Car will start and drive after going though all warning.
Car is changed 90% of the time via granny charger, but yesterday fast charger at service station was used. After charge to 80% drove home with no warning lights or problems.
Was put on granny charger will 75 miles left from 5pm till 8.30am. My wife used car for work this morning after setting off noticed warning lights also charge mileage was only 144.
Any advice welcomed.

 

[Kithmo]

First thing I would do is check the 12v with a volt meter and the car off. If the voltage is 12v or over then it should be ok, if not charge the 12v with a 12v charger.
I that doesn't make any difference and it's a HV balancing problem then the following.
From the photos, it appears you can put the car in READY mode and I believe some dealers were balancing batteries by leaving the cars in READY mode after updating the bad BMS. So I would try leaving the car in READY mode (without driving it) and see if the battery balances itself out enough to get it into a position where you can put it on a 7kW or the granny to finish the balance.

 

[vcantrill]

First thing I would do is check the 12v with a volt meter and the car off. If the voltage is 12v or over then it should be ok, if not charge the 12v with a 12v charger.
I that doesn't make any difference and it's a HV balancing problem then the following.
From the photos, it appears you can put the car in READY mode and I believe some dealers were balancing batteries by leaving the cars in READY mode after updating the bad BMS. So I would try leaving the car in READY mode (without driving it) and see if the battery balances itself out enough to get it into a position where you can put it on a 7kW or the granny to finish the balance.

Ok thanks for advice.

 

[Richy Rich]

Hi everyone, thanks very much for your input! Combining Djenson and Lovemyev and I think I can now spot a history of the car performing worse in range, and when under load. As I genuinely don't put the car under a lot of load, its not easy to notice, but I have occasionally thought to myself that an EV should shift a bit more of the mark than this does if and when I put my foot down.

So I think I may have been having a BMS issue for a while - without knowing it - I never knew this was a thing... (ignorance is not bliss). I would have assumed that the occasional long 7kw charge at work would go into that BMS correcting mode, but with frequent home working, shorter office days and granny charge top ups, it may well not have for some time. Maybe the long granny charge simply wasn't long enough to put it right. Also, the car doesn't get used a great deal, 3.5K miles in 1.5 years isn't a lot, so maybe that contributes in some way.

The story djenson articulates pretty much sums up my position. I have returned home on a pretty low battery before - <5% before recharging so that might have thrown it a bit as well (from what I now understand).

I will recharge the 12V battery and seek to get the car checked over and the BMS updated / corrected etc. I did have an update and comfort 2 pack installed a while after receiving the vehicle to remove the bongs at the same time the 'gearbox' was changed as it was making a scraping noise when at low power - that's fixed so no need to go into that one

Thanks again, I'll report after I charge the battery... after I find a charger

 

[djenson]

I did have an update and comfort 2 pack installed a while after receiving the vehicle to remove the bongs at the same time the 'gearbox' was changed as it was making a scraping noise when at low power

Maybe the faulty BMS software was installed into your car at the same time. Good luck getting it fixed!

after I find a charger

An AC charger is anything that isn't a DC fast charger, so could even be the 3 pin socket charger. ID personally go to the local charger to get it to 90+%, then leave it on the granny at home for a long while. Just wanted to make it clear because it sounds like your about to go on a mission to the local charger away from home haha

 

[Ian MG5]

Hi
I have a Mg5 LR
I read somewhere in the hand book ,when I first got the car, that after it reaches 100% charge it can take upto 7.5 hours to finish equalisation
I have read on some threads that if you do an equalisation charge regular it doesn’t take as long
I do an equalisation charge once a month (I don’t know how long it takes as I do it at work and I work 12 hour shifts)

 

[Richy Rich]

Maybe the faulty BMS software was installed into your car at the same time. Good luck getting it fixed!

I could see that my range issues started after the work was done, so maybe that is something. I'll ask to have the latest BMS software anyway.

I use the granny charger quite a lot, so have assumed that if my 12V battery is at fault, then I have to use a battery charger as you would to charge the battery in an ICE car. If it charges the 12V with the granny charger then it should not really have been at fault unless drained significantly just recently. I didn't manage to find a friend with a 'usual ICE charger' that I could reach today, so will stick the car back on the granny charge overnight and see what happens.

Maybe this will help and the next time I try to start the car it won't give me the problems and will let me drive it. Either way, I'll be in touch with the relevant people to get it checked over properly.

 

[biffo]

I could see that my range issues started after the work was done, so maybe that is something. I'll ask to have the latest BMS software anyway.

I use the granny charger quite a lot, so have assumed that if my 12V battery is at fault, then I have to use a battery charger as you would to charge the battery in an ICE car. If it charges the 12V with the granny charger then it should not really have been at fault unless drained significantly just recently. I didn't manage to find a friend with a 'usual ICE charger' that I could reach today, so will stick the car back on the granny charge overnight and see what happens.

Maybe this will help and the next time I try to start the car it won't give me the problems and will let me drive it. Either way, I'll be in touch with the relevant people to get it checked over properly.

It could be that the car isn’t spending long enough on the granny charger to allow full charge and balancing. Could you charge to say 90% on a rapid and then plug into granny charger for a day or two (or more) to allow balancing? I know the balancing doesn’t need much power but the granny will take a long time to get to that stage. Maybe only useful once the updated BMS is installed though.

 

[Gomev]

Thank you for your advice, and yes, I will be going through the 'proper' route to get this sorted. I just wanted to start the process from a sensible discussion, and hopefully get the car drivable first.

It sounds as though I should charge the 12V battery as an immediate step and check the main battery voltage. May I ask, how do you check the voltage of the main battery? I've read people referring to that and the BMS on other posts, but I've not managed to find out how to do it. I presume there is a menu option that I haven't spotted.

Buttons on the right side of steering wheel, click down 3 times when the display is showing the speedo.

 

[Richy Rich]

An update for this morning - the car is going again. Thank you everybody for your time and help. I definitely need to get the software changed, that I now know.

I tried again to recharge with the granny charger and it did add more range, which is good. I did this again the morning and watched - it quickly stopped charging and shortly thereafter the MG badge colours stopped showing. I tried the car, but had the same issue. I then tried charging the 12V battery via a standard car battery charger. Seemed to work ok, but again I had the same issue with all the warnings.

But it is now 'fixed', or at least mobile again.

So, please understand that I write this in full embarrassment of what has occurred:

To make the car move... I err.... had to take the handbrake off myself, manually... then engage gear and go... Yes, I now realise that the automatic handbrake removal is one of the systems that was not working, and as such the car wasn't moving when I tried to go. I would have noticed had the car fought against it's own handbrake (it the traditional style), but it makes sense in an EV that you don't 'fight' against your handbrake.

I therefore able to move the car, and just repositioned it on my drive. I switched the car off, and when restarting I found it to turn on as normal.

Checking voltage (thanks Gomev) is 426V. Range is 143 miles, no heater, on normal mode. It told me that regen was not working, so I guess it is fully charged. Given the voltage, BMS may be faulty - I'll get this checked.

Thank again, everyone, the encouragement to keep checking and the learning I've taken from this have helped me a lot, even if it was just to keep trying to get the car moving

For anyone else with a similar issue, manually release the handbrake, engage drive, move the car, restart the car, and the warnings should go away. I should stress that you probably shouldn't drive it far after manually releasing the handbrake, as all the other systems may not be working then, including crash prevention, ABS etc., so do restart the car.

 

[Lovemyev]

Checking voltage (thanks Gomev) is 426V. Range is 143 miles, no heater, on normal mode. It told me that regen was not working, so I guess it is fully charged. Given the voltage, BMS may be faulty - I'll get this checked.

As said by myself and other members earlier in the thread, the problem "Smacks" of buggy software issue.
Likely to be caused when the comfort 2 update was applied.
The bug was contained in some of the updates done in October 2020.
Here is a brilliant "Pod Cast" that explains just what and why this happened and what needs doing to rectify the problem.
I strongly suggest you watch this video, as I think you will find that it fit's the symptoms that your car is displaying.
I do firmly believe there is a lot of other ZS EV's being driven around, that are also suffering from this type of problem and the owners have absolutely no idea.
You will have A.A. cover as part of your MG package, if you feel it is unsafe to drive the car to the dealers, then get it booked in first and then have it transported over to them.
Your A.A. cover has "Home Start" which gives you collection from your home address and onto your dealer.
Try and choose a dealer who has a GOOD proven track record of applying the Jan 15th BMS update.
the update should only take a few hours, but then may offer to keep the car a couple of days to help balance the cells in the pack.
Otherwise they SHOULD give you instructions on how to carry this out, at home over a few weeks.
NO RAPID CHARGING O.B.T.W. !.
Sooner the better you can get it booked in, I would suggest.