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Discussion Starter · #1 ·
I have an MG ZS EV from last year, a pre-reg model picked up at the beginning of September from Richmond Portsmouth. It's having its first service next week. I'm not sure how on the ball they are but what do I need to check with them should be done for a car of that generation?

  • Service action bulletin 17 - HV fuse
  • charging with unlocked doors

Anything else? Will the door wiring loom have been done and is there a bulletin number for that?

Apologies if the information is elsewhere, I have looked, but it's a bit confusing and I'm trying to avoid having to find the right number at SAIC and calling them!
 

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I'm not sure how on the ball they are but what do I need to check with them should be done for a car of that generation?
If you aren't having range or charge issues then personally I would refuse the BMS updates (there's a lot of posts on the issues so I won't get into it all again other than to say: even with the latest update which was meant to fix the previous F ups... I am yet to read of or speak to anyone that has managed to get their equalisation/balance charge back to a reasonable time)
 

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.. I am yet to read of or speak to anyone that has managed to get their equalisation/balance charge back to a reasonable time)
I was unfortunate to have the bad BMS installed in October giving me 443 volts and an out of balance battery. On discovering the problem my dealer installed the latest BMS - 0210622EU1 and rebalanced the battery for me. The car now charges and performs as it should.

So there you are evidence for you, of a car with an equalisation/balance charge back to a reasonable time, as confirmed using my OBD II

Cell max voltage 4.188
Cell Min voltage 4.175
Imbalance 0.013v
Fully charged voltage 450.75v
SoH 100%
 

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The main thing is whether the dealer's technicians have been properly trained and have a good reputation, and know how to update the car properly. I'd search the Facebook page for their name if you don't know whether they can be trusted or not.
 

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So there you are evidence for you, of a car with an equalisation/balance charge back to a reasonable time, as confirmed using my OBD II
Oh really... thats reassuring I've been holding off on the latest update until people were reporting the rebalance time getting back to spec.

Just to confirm, are you confident your equalisation/balance time is back to the original expected times (30 to 60 mins)?

Thanks
 

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Well Sue, I use the Southampton branch and I think they are now up to speed. As a group they have sold a lot of ZS EVs including 6 one day to a hotel in the New Forest! They have had mine 4 times, 2 updates, including the wiring loom a failure of the 7kw charging which appeared to be a software glitch and a service last May. My range wobbles around 140 to 160 so they didn’t destroy that and I think my max voltage is about 450.
As I say they have sold a lot of the ZS EV at one time about 12 months ago half their MG sales were ZS EV.
 

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Discussion Starter · #7 ·
Thanks guys. Yes Brian, the local branch sold loads too and must have pre-regged loads to get some dealer bonus. Mine hasn't been back in yet which is why I'm so uncertain as to where I stand. I'll list all the points and add the BMS as something to check too, although I've noted no issues there. I'd certainly like to get the charging with the doors unlocked.
 

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Oh really... thats reassuring I've been holding off on the latest update until people were reporting the rebalance time getting back to spec.

Just to confirm, are you confident your equalisation/balance time is back to the original expected times (30 to 60 mins)?

Thanks
I mainly use 7kw for charging as all ecar charging is free in Northern Ireland. If you do a lot of hi-speed charging the car will go out of balance more quickly and take longer to rebalance. The latest BMS 0210622EU1 Feb 2021 will not affect the balance rate any more than the original BMS
1125600R15 the 2019 BMS 016600R17 or the 10/01/2021 BMS 123062A01.

If you have BMS 1016620R40 (the bad, now withdrawn BMS) this will give a low voltage (around 439v at full charge) and does not allow the car battery to balance, if so you would need to visit your dealership immediately as the problem only gets worse.

Unfortunately there is a lot of misinformation regarding battery balancing in relation to the MG ZS EV.
 

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The latest BMS 0210622EU1 Feb 2021 will not affect the balance rate any more than the original BMS
1125600R15 the 2019 BMS 016600R17 or the 10/01/2021 BMS 123062A01.
I can only go off what other members have stated but there are numerous reports on here and other groups where people have went from previously having a normal/spec equalisation charge time of 30-60 mins to now having to wait many hours (on every charge)
 

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I can only go off what other members have stated but there are numerous reports on here and other groups where people have went from previously having a normal/spec equalisation charge time of 30-60 mins to now having to wait many hours (on every charge)
I do wonder then why all cars from the MG production line, as from February 2021 all have the latest 0210622EU1 BMS. You would think if this BMS had a detrimental effect on equalisation charge time MG would, by now, have released yet another update.

I now have the benefits of the latest BMS which I am very happy with.

In the latest BMS MG have shaved the upper limit of the battery whilst releasing a similar amount at the lower limit to protect the long term use of the battery. What this also means is that you now get regen even when the car is fully charged as there is now extra space at the top end of the battery to store the additional electrons, with the available capacity remaining the same, great.
 

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I do wonder then why all cars from the MG production line, as from February 2021 all have the latest 0210622EU1 BMS. You would think if this BMS had a detrimental effect on equalisation charge time MG would, by now, have released yet another update.
I suspect they will eventually but personally I think they are a little sheepish after the last mistake (who knows). I don't know all the fine details and again can only go off what I've read but as I said earlier, I'm yet to speak to or read of anyone who has had the update that has seen their equalisation charge time return to 30 or so mins... my understanding is that even after a full equalisation charge and after only small journeys, once the car is on charge they are still taking hours to fully complete the equalisation (which clearly isn't as it should be)

If anyone is saying different and that I'm mistaken then great, I'll get my booked in for the update as soon as its confirmed.
 

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If you read threads on other makes it seems to me that there have been issues with all cars. VWs which get bricked and can’t be driven, the Jags had issues rapid charging at one time etc. I think we MG owners have done well on a vfm basis, practical cars at realistic prices and the professional car journalists who were very sniffy in their original revues missed the point that most people don’t race, they just go shopping, visit friends and relatives and want nice enough cars to do these things. The threat of high depreciation on the MG EVs hasn’t materialised given that there is much more of a market for second EVs than the petrol heads gave a thought to. And for those who had the duff BMS I feel really sorry but I thought it did resolve itself but needed quite a few charges.
 

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Oh don't get me wrong, I'm not complaining about the car... its the best car I've owned. Personally though, unless I was having issues then I wouldn't be updating the BMS with one that by all accounts still isn't 100% up to scratch. If mine was going in for a service I would make it clear that I didn't want the BMS updated (but that's just me).
 

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If you aren't having range or charge issues then personally I would refuse the BMS updates (there's a lot of posts on the issues so I won't get into it all again other than to say: even with the latest update which was meant to fix the previous F ups... I am yet to read of or speak to anyone that has managed to get their equalisation/balance charge back to a reasonable time)

I had a March 2020 BMS which was the original one, which didn't suffer from the balancing issues. I never mentioned this to dealer and just let them do what was on the service bulletin. Turns out they updated mine to the lastest BMS.

My balancing is exactly as it should be. I get faster charging on rapids and it was fast before, it chargers harder for longer too. I also had the other updates that means the car charges when unlocked, de-bonged etc.

MG have been quick to release software updates for the ZS, maybe too quick as was the case with 1 update but they've also been pretty quick to rectify when they realised the mistake.
 

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Thanks Sandy, its all very strange.. I wonder why some are getting issues and others aren't 🤔 it can't just be that they had the buggy BMS as there are people who didn't have it that are still getting the slow equalisation times.
Yes it was 1 BMS that was buggy, it was on cars sold over a set period and cars serviced during that period. The new BMS appears to be very good. I've had no issues, in fact I did a week away using only rapids and the car had very good range even though it was only charged to 100% one time (on an instavolt rapid where it charged to 100% in the time I expected it to only be hitting upper 80s).
 
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Yeah, I know about the buggy BMS but people who have received the current update to rectify it - none I know of have had there equalisation time return to 30 mins and there have been reports of people who never had either of the 2 buggy BMS or any equalisation issues now suffering slow times (again only going off what I've read on here and other groups)

If you're saying that your equalisation takes only 30 mins or so then (I think Dr Dave is also saying this) it clearly cant be the update itself so something must be going on in the background on some cars... possibly it depends on which BMS you are updating from (who knows)
 

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If mine was going in for a service I would make it clear that I didn't want the BMS updated (but that's just me).
Just to be clear, if your dealer was correctly following the MG service protocol, then when your car was submitted for service, you would NOT be getting the option to reject any updates that have been released for that car by the manufacture.
The dealer is NOT doing themselves or YOU any favours here.
They are just incompetent and unable to follow company policy.
@Sandy has witnessed this himself, he received the update without requesting it and the very same thing happened to myself.
Let's use a small example of one of the released service bulletins.
The HV fuse update ( now been replaced by the latest BMS update ).
There had been clear evidence that the HV fuse had been failing and rendering some car as completely DEAD !.
As a result dealers where instructed to apply this update to all cars in stock and a service appointment time.
My dealer even had a car fail, while on it's PDI inspection and another car delivered on a flat bed.
Both cars where shipped to a larger dealer to deal with the problem.
So, YOU are aware of the update but say nothing, the dealer fails to check for the service bulletins ( useless ) and plays "Ostrich Syndrome" and puts his head under the sand.
The following week you find yourself stuck at the side of road, waiting for a flat bed.
Now what !.
What is the point of releasing the updates, if the dealer does not apply them ????.
Okay I will agree that the "Buggy" software issue did nothing for customer confidence in the car.
But the Jan 15th 2021 BMS update was release to over write the issues surrounding the earlier updates / problems.
If the MG service updates procedures are followed ( and they should be ) then eventually ALL - ZS EV's will be brought up to the same software spec at some point.
Speaking as somebody who did not have the "Buggy" software installed, but DID get the latest BMS update applied regardless.
Question - Did I witness any changes in the cars behaviour / habits post updates.
Yes - Is the short answer.
As you are aware, the buffer at the upper end of the HV battery ( post BMS ) has now been increased.
Pack voltage after a full charge has also been reduced from 455 - 456 volts (OEM) to 448 - 450 volts post BMS.
The regen is a lot more linear now and available much earlier stage, because the there is space in the pack for somewhere for the energy to go now.
In answer to your question over balancing times, pre and post BMS.
Pre BMS my car would take about one (ish) hour to complete after the battery reported 100% fully charged, but its important to remember the upper buffer is much smaller pre BMS update.
When the car was returned after the BMS, the first charge and balance went on forever !.
This WAS something I was not use to, or expecting !.
But after a few charge / balance cycles the time scale started to reduce quickly.
After a few weeks it settled down, yes just a little concerning at the time.
The update was done on the 15th Jan 2021 and that is 6 months ago now.
What do I see ?.
The balance process HAS increased in time from the original OEM software, I would say an average time now, is around 2 - 2.5 hours max and that is being totally honest.
Yes - This is an increase on the original 1 hour pre BMS of course, but remember the smaller buffer, it is really no big deal.
I think most owners are seeing similar time scales by what I can gather.
I have not heard of anybody balancing in one hour, but I think this is to be expected.
It also reports the predicted range on the GOM in a slightly different way to the original factory software, unless you reset the accumulated total on the trip meter "pre" long journey.
Owners have reported GOM range of +210 miles, which we all know is achievable.
This again has also been pointed out by a number of owners post BMS.
I actually think the BMS update addressed a lot more under lying issues that was less focussed on.
Like rapid charging times and charging failing at 80% SOC on certain units.
Not being able to charge with the doors unlocked when charging on a A/C unit also.
High voltage fuse protection was reviewed as well I believe.
The still car drives and performs as it did from day one, and the car is now 18 months (ish) old and has covered14,000 enjoyable miles.
 

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Zoe Devotee
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Owners have reported GOM range of +210 miles, which we all know is achievable.
Nah you've got that wrong. If it was a Kia or a Zoe ZE50 then yeah totally achievable. But if its an MG its made up lies. (y)

:ROFLMAO:

I've seen 221 miles on the GOM, but to be honest I've not tested it fully, I have ran 150miles. I covered 72.4miles and still had 121 remaining = 193 potential. So not 221 but not far off.
 

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Nah you've got that wrong. If it was a Kia or a Zoe ZE50 then yeah totally achievable. But if its an MG its made up lies. (y)

:ROFLMAO:

I've seen 221 miles on the GOM, but to be honest I've not tested it fully, I have ran 150miles. I covered 72.4miles and still had 121 remaining = 193 potential. So not 221 but not far off.
Sorry @Sandy .
This was a typing error on my part, I missed out the all important word of NOT when referring to the reported high accumulative range prediction without resetting the GOM.
That was my whole point, but I goofed up and missed out the most important word / point !.
But you already knew this I think 🤔.
Sorry folks !.
 
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