Vin Numbers for Faulty BMS update identification

I have a further update. One of the dealers has agreed to do The update Of the revised BMS patch, but as a chargeable update at half an hours labour.. thanks to everyone for help, advice and info. It is much appreciated.
 
Further update on the BMS. Having booked in and agreed to pay to have it installed the dealer added into the workshop put it onto the computer and are now saying that they cannot install the update unless they get permission from Mgb because the car is not on the list for the latest BMS patch to be installed. As it happens they’ve now confirmed that the steering column is faulty and is going to need replacing and they are asking MG for permission to install but I have to say I am baffled by this reticence to actually just do what the customer asks. My car was only registered five months ago and probably should’ve had the latest update installed before being put on the road but now it is on the road we have to ask Mjs permission. It just gets stranger every day.
 
Further update on the BMS. Having booked in and agreed to pay to have it installed the dealer added into the workshop put it onto the computer and are now saying that they cannot install the update unless they get permission from Mgb because the car is not on the list for the latest BMS patch to be installed. ......... My car was only registered five months ago and probably should’ve had the latest update installed before being put on the road but now it is on the road we have to ask Mjs permission. It just gets stranger every day.
Sounds more like your dealer doesn't understand what they are supposed to do.
 
Thanks, the volts quoted are all on the basis you say. Other than the 439 I quoted when driving this morning. The 439 I took before charging this afternoon from 90% was on the basis you say. The charge time was about 45 minutes to Full charge then 3.25 hours for equalisation . However I did a full equalisation charge the night before anyway. So you think I need to get the new patch loaded? The strange thing is that the comfort pack is on the car already.
Your figures are the same as mine, my dealer swears I have all updates according to MG, I think they are talking Bo******
 
Further update on the BMS. Having booked in and agreed to pay to have it installed the dealer added into the workshop put it onto the computer and are now saying that they cannot install the update unless they get permission from Mgb because the car is not on the list for the latest BMS patch to be installed. As it happens they’ve now confirmed that the steering column is faulty and is going to need replacing and they are asking MG for permission to install but I have to say I am baffled by this reticence to actually just do what the customer asks. My car was only registered five months ago and probably should’ve had the latest update installed before being put on the road but now it is on the road we have to ask Mjs permission. It just gets stranger every day.
Can you take it to another dealership.
I don't know where you are location wise etc, but everyone would recommend Chorleys. I'd try giving them a call and explaining your situation and ask if they would do it, if so a day trip out to take it there.
 
Can you take it to another dealership.
I don't know where you are location wise etc, but everyone would recommend Chorleys. I'd try giving them a call and explaining your situation and ask if they would do it, if so a day trip out to take it there.
His location is on the left of his post, same as yours and mine, assuming entered correctly of course. :) Chorley quite a way from St Leonards.
 
His location is on the left of his post, same as yours and mine, assuming entered correctly of course. :) Chorley quite a way from St Leonards.
My location is indeed on the South Coast. It seems that the dealers do not understand the update system. I took the forums article in about the BMS updates which gives the patch numbers and everything, but they are saying they can only install it with permission explicitly from MG to do so, although they did say that they might be able to get MG to pay for it.

This was a large dealer, well known and well organised, they knew about a fault with the steering column, so I do not think they are messing around.
 
Further update. Hopefully Caffyns Ashford MG are installing the latest BMS patch tomorrow. Just wondering how I will know that they have put in the right one?
Today put on charge on my 7kw pod point at midday for 50% recharge and currently 9 hours later still equalisation not finished although dash shows fully recharged at 456volts with 154 miles in the tank. I have not used any rapid chargers lately so wonder what the reason is for this very slow equalisation. Any thoughts appreciated.
 
Today put on charge on my 7kw pod point at midday for 50% recharge and currently 9 hours later still equalisation not finished although dash shows fully recharged at 456volts with 154 miles in the tank.
On the factory BMS our car would balance in around 45 mins to just over one hour.
It would appear that your pack is out of balance.
I would not be overly concerned because tomorrow they intend to install the latest BMS update dated 15th Jan 2021.
Wow ........ That sounds a LONG way back now !.
They should charge and balance at the dealership, before returning the car.
You already know what to expect on voltage / predicted range after the update of course ?.
Expect the balance process to take about 2 hours, when the pack is in good order, when the update has been applied.
 
New BMS installed last week. As informed by the group mileage dropped on recharge and voltage seems to be 449 instead of 456/7. ECO mode range with other stuff off 164, normal range 145. As stated previously hopefully range will recover after several recharges.
 
New BMS installed last week. As informed by the group mileage dropped on recharge and voltage seems to be 449 instead of 456/7. ECO mode range with other stuff off 164, normal range 145. As stated previously hopefully range will recover after several recharges.
Now you have the latest update, don't forget to reset both of your trip counters to get a more accurate prediction of range, before taking a long journey.
With BOTH trips reset, you should be seeing 448 - 450 volts and around 163 miles of range in the default NORMAL mode and Regen level 3.
Ensure ALL 12 volts items are switched off ( especially the HVAC ) and boot up the car with your foot OFF the footbrake.
 
Thanks for comment. I thought trips were reset by the update being loaded as everything showed no miles covered or am I misunderstanding here. Also I expected to initially lose range indicated as that is what we were told to expect, and a recovery over a number of equalisation charges, or do I have that wrong. I thought it was behaving as expected.
 
Thanks for comment. I thought trips were reset by the update being loaded as everything showed no miles covered or am I misunderstanding here. Also I expected to initially lose range indicated as that is what we were told to expect, and a recovery over a number of equalisation charges, or do I have that wrong. I thought it was behaving as expected.
That is all correct.
But one thing to note, that after the new BMS has been applied, how the car predicts your predicted range, is based on the accumulative range trip recordings.
So if you have been using the car for local short trips, with the HVAC etc running, let’s say for a couple of weeks now.
it will be recording the mileage and how the car is driven etc in the accumulative total.
If you then had a long trip to make and you needed a full charge and balance, resetting both trips prior, will give you a better indication of your predicted range.
If you don’t reset the trips, the predicted figure you are shown before you set off, will be either under or over what you should be expected to see.
E.G. - 163 ish miles of range with around 448 - 450 volts after a full charge & balance on a A/C supply.
Other members who have had the latest BMS update, have also noted the behaviour regarding more frequent trip resetting, to get a more accurate predicted range on the GOM.
It’s not a problem, it just something worth remembering.
 
Thanks for that further clarification I think I have now Twigged something which I didn’t previously appreciate. By zeroing the trip meter before charging and equalisation or immediately afterwards you then see the pure state of the battery based on the original computations of its capacity without the influence of averages being applied to the figures from the cars previous performance. I’ve got it at last but I now fully grasp what you were meaning. Thanks for your very helpful explanation which helped to clarify the position finally. Just to reiterate with the battery in new condition and everything switched off on boot up with no miles on the truck metres what would you expect to see in normal and economy mode.
 
My accumulated trip has a mind of its own. Since the last charge and reset it's showing 2.4 m/kWh. All the short journeys I've done since resetting it were between 2.7 and 3.1, so a 2.7 at minimum, how does it come up with 2.4 ?
I've resigned myself to the fact that none of the figures on the GOM or the trip mean anything in the real world and just use the battery gauge like a fuel gauge and fill up when I get to the last bar.
FWIW reset trip and charge last time showed 158 miles in Normal at 3 deg C.
 
My accumulated trip has a mind of its own. Since the last charge and reset it's showing 2.4 m/kWh. All the short journeys I've done since resetting it were between 2.7 and 3.1, so a 2.7 at minimum, how does it come up with 2.4 ?
I've resigned myself to the fact that none of the figures on the GOM or the trip mean anything in the real world and just use the battery gauge like a fuel gauge and fill up when I get to the last bar.
FWIW reset trip and charge last time showed 158 miles in Normal at 3 deg C.
Original factory software ?.
That would be about right.
The GOM records and reports differently after the 15th Jan 2021 update.
I ran on the original factory software for 12 months from Jan 6th 2020, then had the comfort 2 update applied around October of 2020 - no bugs present !.
GOM / trips remained the same from day one to this point.
Then on the 15th 2021 the car was submitted for its first service and the drivers door wiring loom replaced under a service bulletin.
Long story, but the car failed to boot after the loom change ( not the cause ) and completely shut down.
Stuck on the workshop ramp for about three days.
The dealer uploaded the data pack from the car, up to MG Tech Team.
They then instructed the dealer on what to do to fix the problem.
This involved firing the update cannon at the car !.
As a result, it received the Friday the 15th Jan update, on Monday 18th Jan 2021.
It must have been one of the first customers cars to receive the latest BMS update.
As a result, after a week of using the car I noticed that the GOM was recording in a different manner than before the update.
Other owners who have received the BMS update, have also noticed this phenomenon.
 
Thanks for that further clarification I think I have now Twigged something which I didn’t previously appreciate. By zeroing the trip meter before charging and equalisation or immediately afterwards you then see the pure state of the battery based on the original computations of its capacity without the influence of averages being applied to the figures from the cars previous performance. I’ve got it at last but I now fully grasp what you were meaning. Thanks for your very helpful explanation which helped to clarify the position finally. Just to reiterate with the battery in new condition and everything switched off on boot up with no miles on the truck metres what would you expect to see in normal and economy mode.
It is ( for me away ) a little hard to explain how this difference on how the GOM reacts, after the BMS update.
But you are bang on with your understanding.
Okay I will try and explain what you should expect to witness on the GOM now by using this example.
You arrive home from your previous journey and you have conducted a few different types of trips in different weather conditions over a ten day period that has demanded high usage of the heater etc.
You have also “Topped Up” the battery a couple of times also.
The next day you intend to make a long journey that is likely to stretch the limit of the range of the pack.
So what do you do, before you shut down the car the day before, go into BOTH of your trips and reset BOTH of them !.
Makes sure you have turned off the HVAC and any other 12 volt demands.
Now shut down the car and carry out a full charge and balance.
Following morning, unplug and enter the car.
Apply NO pressure to the footbrake and press the start button once, then after a few seconds, press it again.
You may get a yellow warning ⚠️ on the dash panel about the HV battery is not connected.
Disregard this, it’s because the car is not in the fully ready mode and the pack is not fully engaged yet.
( Note - AFTER you have completed all of the following checks, you can then press the start button again and the car will shut down, or apply pressure to the foot brake and hit the start button once more, this will now fully boot up the car, ready for driving ).
Okay now to continue - scroll through the menu on the dash panel until you get to the section that displays your HV battery.
Your voltage on the pack should be anything from 448 - 450 volts.
The predicted range / miles should be figures around 161 - 163.
163 is the highest reading that you are doing to see after the update.
This is accepted new base line figure, for cars AFTER the BMS update.
This 163 miles is the recognised figure when the car is in default normal mode and Regen level 3.
There does not appear to be a set down standard for what Eco mode would show post BMS update.
I am not a big user of Eco mode, but I would expect the figure to be an additional 20ish miles of additional range over the normal 163.
It is my firm belief that when the BMS has been first applied, it completely wiped out any previous data stored.
Therefore 163 is the base line and from then it will learn the current SOH of the HV pack.
If you are a low user case and have a young low mileage vehicle, then you see likely to see regular predicted ranges of 163 miles after a reset.
This what I witnessed in the first few weeks.
Then as it started to understand the SOH of the pack, it started to reduce the prediction figure slowly, bit by bit !.
More mileage, more charging ( A/C) and a car almost 2 years old with 16,500 miles and it is now displaying 155 miles of predicted range after a reset of the trips.
Clearly after the BMS update has been applied, it forms a picture over time of the true SOH of the pack I believe.
A relative of mine has the same car about 5 months younger than our car, he has over covered about 7,000 miles and still hits 163 on the GOM.
Clearly my pack is reporting some degradation over the two years etc.
I am guessing a SOH of around 94 - 95%.
Sorry this post is so long, but I guess you have a full handle now on what you see going forward.
 
Last edited:
Great final explanation and clarification thanks again. After charge and balance all zeroed, car has just shown 164 miles for normal and 182 for econ. However what is the actual words behind the acronym GOM.
Whilst understanding what it refers to I do not know the words.
Do you know the battery degradation stipulated in the warranty statement, and is that over 7 years or more. I wonder what a replacement battery would cost, has anyone reported that anywhere?

Thanks again
 
Support us by becoming a Premium Member

Latest MG EVs video

MG3 Hybrid+ & Cyberster Configurator News + hot topics from the MG EVs forums
Subscribe to our YouTube channel
Back
Top Bottom