Recent BMS update

Cocijo said:
Surely the dealerships must get release notes from MG for software updates. I’m thinking that the latest update is designed to further protect the HV battery pack and improve longevity. It seems to reduce top end voltage. The bugs contained in previous updates have further clouded the issue but it may well be that this latest update was coming anyway. If you were fortunate enough not to have the bug filled update then the battery balance fiasco may well not apply to you. Come on MG provide some clear guidance to your customers!
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I am getting confused. Had all of the updates done to date. Heard about another BMS due now. Is that correct? Has anyone else had this done? Was it worthwhile? They need to have the car in for about 2 hours. Wondering if it’s needed.
 
Hi John, you’re not alone feeling confused! Many feel the same. As it stands - as I understand it - the latest BMS update is the one issued mid-January 2021.
Unless you have range/power issues and/or the old bug-filled software - the recommendation is to wait until your next service when the dealer will apply the update then - no need to get it done straight away. If you do have issues then contact your MG dealer and get them sorted.
The latest BMS update reduces top-end HV battery pack voltage (450v compared to 455v previously) and extends the lower end providing slightly more top-end battery pack protection without detriment to range.
There are of course quite a few parts to the software updates and this has led historically to a few ‘variations’ in what has been applied. I hope that this helps.
 
John Arnold said:
I am getting confused. Had all of the updates done to date. Heard about another BMS due now. Is that correct? Has anyone else had this done? Was it worthwhile? They need to have the car in for about 2 hours. Wondering if it’s needed.
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Definitive list of updates

This is a timeline of pertinent (mainly software) update packages to the ZS EV - that we are aware of. You can use this to try to ascertain what you have or not on your car. Please provide updates / corrections / comments as appropriate. I will keep this post edited and updated as necessary...
www.mgevs.com www.mgevs.com

I was hoping we could get this 100% complete and made as a sticky post, as so many people continue to ask pretty much the same question
 
Paulie68 said:
Just to confirm, the Jan 2021 BMS update does not automatically give you charging on AC whilst unlocked, mine is updated and all working as expected, lower terminal voltage etc. but still needs to be locked to AC charge.
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They've missed one of the module updates then that enables this feature I would guess.

We understand there are several (maybe 15 or so) different modules (ecus) that can be updated, each has to be selected (and then configured correctly) by the engineer.
If you def have the latest BMS update, then that would suggest, that the AC charge unlocked functionality is part of a different module/ecu update that hasn't been applied to your car. Or I guess it could be the configuration part that's not been done correctly on the BMS module/ecu.

This is exactly what is REALLY annoying so many of us.
If the car goes in for updates, they should make 100% sure that EVERY item has been updated correctly to the latest version.
The system they use, does not do this and it must not have the functionality to check afterwards that it has ALL been updated correctly.
This is leaving everyones cars slightly different, which is an absolute support nightmare.
 
Richie said:
Just to add my little observation for equalisation.
We had BMS update Oct 14th and Dec 1st then again late Jan for latest one. Not too many trips so not much charging been done but never got more that 403v per charge. Yesterday I did two 32 mile round trips and managed 3.4 & 3.6 m/kw. Its now 06.05 and the cars been on charge for 12hrs 25mins, initial SOC was 11% and 17 Miles now added 79% with 122 miles. EV charge rate now is 1A/230W showing on the app at 90% and 104 miles. Will leave it charging to see how long it will take to complete. Am I to expect it to show 100% and still go on to equalise (pulsing light) or should that be it? I'll check the V's when I get up 🛌💤
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If you have latest BMS then charge it to 100% and the see what voltage is with all ancillaries switched off. You’re aiming for 449/450. When baa as lancing the car for first time after latest BMS if your voltage is out you can expect the car to charge to about 93% and then it will start balancing the cells which for me tool 10hours 40 mins on top of the charge time to 93%.
 
JodyS21 said:
They've missed one of the module updates then that enables this feature I would guess.

We understand there are several (maybe 15 or so) different modules (ecus) that can be updated, each has to be selected (and then configured correctly) by the engineer.
If you def have the latest BMS update, then that would suggest, that the AC charge unlocked functionality is part of a different module/ecu update that hasn't been applied to your car. Or I guess it could be the configuration part that's not been done correctly on the BMS module/ecu.

This is exactly what is REALLY annoying so many of us.
If the car goes in for updates, they should make 100% sure that EVERY item has been updated correctly to the latest version.
The system they use, does not do this and it must not have the functionality to check afterwards that it has ALL been updated correctly.
This is leaving everyones cars slightly different, which is an absolute support nightmare.
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Yep, its nuts... I don't mind the having to be locked on AC charging, so I'll leave it until the next service, but its a pretty poor show.

Oh, and there are no engineers working in MG dealerships! They're technicians, whatever that means, but I'm pretty certain none have an engineering degree!
 
MilesperkWh said:
To get the charging whilst unlocked, you need the EVCC (onboard charger) updating, then the BMS after.
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This is interesting. My car (Dec 2020 )had an update yesterday. Unfortunately I don't know which one but I believe it to be the latest BMS one. Car managed to take 6kWhs on the Octopus Go early this morning from the EO mini pro. However it would not do a scheduled charge from the app today until I used my Shelly remote reboot system. Is MG likely to roll out the EVCC charger update to allow scheduled charging anytime soon?
 
I had the January 16th BMS update installed on 1st February. I have now fully charged and balanced 7 times and seen balance time improve from over 9 hours to 5 hours last night.

My fully charged voltage has improved and is sitting now at 449v. This is what the new BMS target is against the duff BMS.

Now achieving 3.8kw per hour average on last few local trips. At 9° outdoor temp

GoM reset and over last 2 charges getting better estimated range. See today's photos after full charge from 85% and full balance
GUESS OMETER TODAY SHOWED
Economy 182
Normal 165
 

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MG ZS EV WEST YORKSHIRE said:
If you have latest BMS then charge it to 100% and the see what voltage is with all ancillaries switched off. You’re aiming for 449/450. When baa as lancing the car for first time after latest BMS if your voltage is out you can expect the car to charge to about 93% and then it will start balancing the cells which for me tool 10hours 40 mins on top of the charge time to 93%.
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Following on from my earlier replies my App top rate was 92% and it stopped charging with 0A/0W after 12.5 hours on charge. Although when disconnected and driven the car said 100% and 162 miles and 432V
 
Paulie68 said:
Just to confirm, the Jan 2021 BMS update does not automatically give you charging on AC whilst unlocked, mine is updated and all working as expected, lower terminal voltage etc. but still needs to be locked to AC charge.
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Just to say that my car would never charge with the doors unlocked in the 12 months of ownership.
But after having the 15th Jan 21 update it WILL now charge with the doors unlocked !.
 
MG ZS EV WEST YORKSHIRE said:
If you have latest BMS then charge it to 100% and the see what voltage is with all ancillaries switched off. You’re aiming for 449/450. When baa as lancing the car for first time after latest BMS if your voltage is out you can expect the car to charge to about 93% and then it will start balancing the cells which for me tool 10hours 40 mins on top of the charge time to 93%.
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Same here !.
From an SOC of 92% to full charge and balance - 11.00 hours !.
 
I’m still just using granny charger so cannot see any power figures yet to figure this out...

When it’s put on charge and the car dash gives you the SoC, miles, time to charge; is this time just how long it should take to get to 100% charge but WITHOUT the time it then takes to balance?

We’ve charged overnight so far & when I’ve looked not that long (<2hours) after the estimated time on dash, mine’s finished charging completely - no MG lighting, green&red flashing on granny charger
 
Richie said:
Following on from my earlier replies my App top rate was 92% and it stopped charging with 0A/0W after 12.5 hours on charge. Although when disconnected and driven the car said 100% and 162 miles and 432V
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The mg zs EV stops balancing after about 10 or so hours but as the voltage nears 447-449v the balance charge takes a lot less than 10 hours
 
I'm still using Granny charger. Soc and estimated time on dash is just to take car to 100% . When the MG badge stops pulsing its reached 100%. Keep it connected and light will stay lit during balancing. Keep charger connected until badge light goes out completely. Can take hours to balance. Mine has been improving from 9 hours to about 5 after 7 full balance charges since new BMS update done on 1st February 2021.
 
RossN said:
I cant imaging how much more money and hassle it is doing all this for you guys with a ZS.
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It took about 5-7 days to recover my voltage so not so much money when charging at 5.5p plus I’ve just received an FOC £90 first year service on 1st March. Car runs like a dream on latest BMS too ! Happy days
 
Paulie68 said:
Money is next to nothing, the car only uses 300w whilst balancing. Hassle? Well i'd expect most are fast asleep whilst it happens overnight. :)
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I agree.
If you are on a cheap “Off Peak” rate, then that is when you are likely to be carrying out your charging.
It could become a pain if you doing a lot of charging in the day time, because you want to just charge and then go !.
But if the balancing is taking a long time and you are in a hurry, then it is likely that the balancing process is going to get skipped out due to time constraints.
Very very rarely do I charge in the day time.
Off Peak rates are so cheap and convenient as long as you have the ability to perform a delayed charge cycle.
 
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