Buggy BMS software

[peter]

Hi.
I've been a little concerned with my car range ever since I got it (Oct 2020).
Today I had a trip from 100% to empty (flashing battery and range display at "---") and only got 80 miles.
However I was driving carefully and had 2.9 m/kWh which should have given a 122 mile range with 42kw battery.
I was reading other threads about potential BMS bug limiting the range which seems to coincide with the date I bought my car.
Are there any other ways I can test whether I'm impacted by this?
I see some threads talk about a voltage display but I'm not sure where I see this or how to interpret it, is there anywhere which explains this? Thanks.
I'm also going to charge car from empty to full overnight and check on my ohme app how many kWh it was able to put into battery.
I guess next step would be to contact the dealer? Thanks for any advice

 

[Mark Holmes]

Hi.
I've been a little concerned with my car range ever since I got it (Oct 2020).
Today I had a trip from 100% to empty (flashing battery and range display at "---") and only got 80 miles.
However I was driving carefully and had 2.9 m/kWh which should have given a 122 mile range with 42kw battery.
I was reading other threads about potential BMS bug limiting the range which seems to coincide with the date I bought my car.
Are there any other ways I can test whether I'm impacted by this?
I see some threads talk about a voltage display but I'm not sure where I see this or how to interpret it, is there anywhere which explains this? Thanks.
I'm also going to charge car from empty to full overnight and check on my ohme app how many kWh it was able to put into battery.
I guess next step would be to contact the dealer? Thanks for any advice

Yes book you car back in for the latest BMS update as I’m sure this is your problem

 

[Chrisb]

When you've fully charged your voltage on the dash menu should read 455v.

 

[Lovemyev]

The “Buggy” software in the BMS affected cars that had a BMS update or Comfort 2 update applied AFTER the 24th Oct 2020.
If you collected your car BEFORE this date, then you should not be affected.
However, your poor return on your range may suggest otherwise.
Another customer complaint with the “Buggy” software, is that the red battery low warning is being displayed when they appear to still have 50 miles of range left.
Another symptom is that the car is taking a lot time to balance the battery after a charge on a home wall box.
Some cars are taking over 7 hours to balance the HV pack, clearly this is not correct.
With the correct software, the balancing of the pack should only take roughly about one hour, when the main charging cycle had ended.
From a low SOC to full charged and balanced, should take about 6 ish hours on a 7kw wall box.
My car would display the yellow warning when the car hit roughly about 35 miles of range left on the previous software.
I now the latest BMS update, released on 15th Jan 2021 but have not had the chance to carry out any testing yet due to C19 restrictions.

 

[peter]

Spoke with dealer this morning. They had a list of Chassis numbers which were impacted by the issue and confirmed my car was on the list.
Booked in for an update on Friday. Fingers crossed fixes the issue!

 

[Lovemyev]

Spoke with dealer this morning. They had a list of Chassis numbers which were impacted by the issue and confirmed my car was on the list.
Booked in for an update on Friday. Fingers crossed fixes the issue!

Keep us posted Pete !.

 

[AndyNWuk]

I am getting 448 volts after a full charge, is this near enough? Or should I still be looking to contact the dealer for the latest update?

Andy (Blackpool)

 

[Cocijo]

This is becoming the BMS forum! There’s real concern about this issue. Andy, from what I’ve seen on the forum and from my own car - after a full charge and any battery equalisation that then takes place (which is a normal process) - with minimal drain (i.e. no major electrical components switched on) the HV battery will show 455v. under normal conditions. Some have advised that it may take a few cycles to get back to this if it has had a previous issue (mine for example has always shown 455v). I hope that this helps.

 

[AndyNWuk]

Thanks Cocijo, I had the BMS update done just before Christmas which then allowed my car to be charged while unlocked.

I will give my dealer a call tomorrow - Chorley Motors in Burnley, to see what they say and advise.

Will keep you posted.

Andy (Blackpool)

 

[Paulie68]

This is becoming the BMS forum! There’s real concern about this issue. Andy, from what I’ve seen on the forum and from my own car - after a full charge and any battery equalisation that then takes place (which is a normal process) - with minimal drain (i.e. no major electrical components switched on) the HV battery will show 455v. under normal conditions. Some have advised that it may take a few cycles to get back to this if it has had a previous issue (mine for example has always shown 455v). I hope that this helps.

The latest January update now seems to be giving a terminal voltage of 450v, so they seem to have moved it down a little.

 

[Cocijo]

The only other thing that I would say is that when approaching the dealer it is always advisable to describe the problem that you have and not try to solutionize. So, for example - the problem may be - ‘I’m getting very poor range since the update, Not - ‘my battery voltage should show 455v after charging and it needs another update’. Keep any knowledge that you may have up your sleeve for later use if you need it. Just my thoughts on approach ?

 

[Kithmo]

I've had no updates since I bought mine in July, it had the comfort 2 applied before I got it new and I've just charged it up to full, for the first time in over a month and I have 455v and 156miles on the GOM in Normal mode with the HVAC off. Because I have no FOMO I'm sticking with what I've got.

 

[Cocijo]

It sounds very similar to mine.

 

[Paulie68]

I've had no updates since I bought mine in July, it had the comfort 2 applied before I got it new and I've just charged it up to full, for the first time in over a month and I have 455v and 156miles on the GOM in Normal mode with the HVAC off. Because I have no FOMO I'm sticking with what I've got.

You might want to get the fuse protection update done if nothing else, if the HV fuse does blow, you'll be stranded and the car will be incapacitated for some time!

 

[Kithmo]

You might want to get the fuse protection update done if nothing else, if the HV fuse does blow, you'll be stranded and the car will be incapacitated for some time!

I'll wait until the dealer calls me, if my VIN was in the affected range I'm sure they would have by now.
I wouldn't be stranded far away anyway, I hardly ever go more than 3 or 4 miles from home and that's what the AA cover is for.
I'm a firm believer in "if it ain't broke, don't fix it" and don't suffer from FOMO on things.

 

[Paulie68]

I'll wait until the dealer calls me, if my VIN was in the affected range I'm sure they would have by now.
I wouldn't be stranded far away anyway, I hardly ever go more than 3 or 4 miles from home and that's what the AA cover is for.
I'm a firm believer in "if it ain't broke, don't fix it" and don't suffer from FOMO on things.

Fair enough, they probably won't call you though, mine didn't, they will automatically apply the fuse update the next time your car is in the dealership as they've been advised to by MG

 

[Lovemyev]

Fair enough, they probably won't call you though, mine didn't, they will automatically apply the fuse update the next time your car is in the dealership as they've been advised to by MG

I would agree with that !.
Mine had the Comfort 2 update on the 19th Oct 2020 and the HV Fuse update ( SA017 ) had already been released at this point, they did not apply the update at the same time.
But if you read the SA017 - It clearly says that this update should be applied when the car is presented for yearly service, or if the car enters the workshop for any other work.
Clearly this did not happen.
After the experience my local dealer had with my car, they appear to be a little windy about making any changes unless requested to !.
I am still of the personal opinion that 445 Volts on the HV pack after a full charge and balance is what we are aiming for here after the so called new BMS update released on 15th Jan 2021.
However, it is only my own personal belief that a few charge / balances will need to be done to achieve this figure.
There is about three or four people ( myself included ) who have now had the update, and are now reporting 450 volts on first boot up on collection.
I also think, that depending when and how long the "Buggy" was applied to each individual car, will also affect on how long it takes to balance different owners packs.
I have no evidence to back up this theory of course, but it does make a little sense I guess ?.
The longer the "Buggy" update was in the car and was being charged and used, the more the cells have been put out of balance and therefore it could take a few more cycles to correct the imbalance.
The car that had the "Buggy" update done only a few weeks ago and is now corrected, may respond to the rebalance a little more quickly ?.
I am really keen to offer more information on my findings, but C19 restrictions are making this impossible at the moment.
Surly MG are keenly awaiting the feed back on this latest attempt to get this problem sorted, but the lack of use by a lot of affected owners is slowing progress right down.
We only have the feed back from limited owners that are able to use their cars right now, so it is a slow job.

 

[peter]

An update following the dealer update on Friday. So far not a great improvement.
I charged from 2% battery to 100% after the update. Ohme app tells me the battery only took in 31kwh so still missing around 10kwh of capacity.
After the full charge voltage was showing at 437 so short of the expected 450.
I know it takes a few charges to get back to full capacity but was hopeful I would see some improvement. However results above are about same as before the update.
I'll be doing another full charge tonight starting at 5% battery.
Does anyone have any recommendations on how to balance in most efficient way.
I.e. is it best to charge empty to full?
Is 3kwh better than 7khw charging rate for this purpose? Anything else that might help?
I'll try a few more charges but may need to go back to dealer again if it doesn't start at least moving in right direction.

 

[Mark Holmes]

No just do only a few miles and then straight back on to charging and leave it as it will only equalise once it reaches 100%, so few miles and straight back on charge.

 

[Cocijo]

As I understand it. You don’t need to drain right down and recharge. Drain to max of 93% some have suggested then charge and let equalisation complete and repeat. 7kw and below is best I’m told.