BMS update- feedback from MG

[Trevor]

Sent to dealer

Please confirm how long it is expected to take before the battery equalises properly (after 15 Jan BMS update), and if there are any scenarios that can be implemented to facilitate reaching this point quicker.

As you can imagine, I am still suffering with range issues. Although the car was charged up to 142 miles whilst in the garage, I can only charge it to approx 100 miles, but I'm only getting about 45 miles driving range, and not prepared to tolerate this much longer.

I have already done the following:
2x greater than 24 hour charges
5x overnight charges on granny charger
5x daytime charges (avg 6 hrs each) on a 22kW charger

Thankfully I have a charger near work, but as a slightly disabled person, this walk is uncomfortable and inconvenient. Let alone arriving at the charger today to find the front flap was frozen closed and I had to park the car in the sun for a couple of hours before I could return it to the charger.

Furthermore, I cannot fully charge the car during my cheap (4.7p per kWh) rate and am having to pay public charge rates every day. I cannot finance or use an underperforming vehicle and will be requesting a warranty change of battery if this is not fully operational very soon.

--------------------------- Reply from MG --------------------------

We are not going to replace the battery.

As long as the updates have gone in, the car will recover. I appreciate that it has been inconvenient and will continue to be so until fully recovered, but it will recover.

Even though you cannot provide the SNOW case, I have no problem with you typing out a transcript of the case, obviously leaving out the names and details of the technicians involved.

Brief transcript notes of case

Customer complaint low range on the full battery ,battery range 30 miles with message connect slow charger and HV battery w/l on dash , VDS test reset all DTC and recharging battery for 20 hours , road test and reset VDS DTC PIEDE-00cell voltage difference suspect software issue

instructed to carry out BMS reprogram ,once updated allow an overnight slow charge so a equalisation can take place , the range will recover however this could take a month or two depending on how unbalanced the battery is

 

[Chrisb]

I think that's really bad, you would at least think they could give you courtesy whilst it was made right, the cars not fit for purpose really!

Have you looked on the speakev forum at what Mike said about rebalancing after the BMS update this morning, he says it takes 100 hours of balancing per 10v it is out, yours sounds well out, so that could be a very long time.

My car never had the faulty update, but it is due service next month, I'm thinking of telling them to leave the BMS update as mine is fine, if it ain't broke don't fix it!

 

[AbuG]

Which dealer is this?
Should offer to drop off your car and loan you another while they can assess it... possible another issue other than BMS software.

 

[Trevor]

Which dealer is this?
Should offer to drop off your car and loan you another while they can assess it... possible another issue other than BMS software.

I do wonder if something else is going on. Every day I get "Please connect slow charger" which I don't hear others reporting. I only have a granny charger and do regular long slow charges. I also once got "HV battery fault" on screen, but apparently battery is ok and will recover. I've done a lot of charging since BMS update and HV voltage this morning showed 432V, which is up from 429V a week ago. This could take forever...

 

[Trevor]

I think that's really bad, you would at least think they could give you courtesy whilst it was made right, the cars not fit for purpose really!

Have you looked on the speakev forum at what Mike said about rebalancing after the BMS update this morning, he says it takes 100 hours of balancing per 10v it is out, yours sounds well out, so that could be a very long time.

My car never had the faulty update, but it is due service next month, I'm thinking of telling them to leave the BMS update as mine is fine, if it ain't broke don't fix it!

Thanks - that's an interesting read from Mike. Looks like I have a very long road ahead (with little charge ).

I'd leave the update until some positive feedback received. I won't be rushing to test MG's software releases (not that I asked for the update)

 

[DriverInNorway]

My car is very similar at the moment. It was delivered in November and has not had any software updates yet. Currently I get around 30km useful range. It is -19 C but there is no warning from the dealer that range should be this reduced. I have a 7kw wallbox and I plug the car in every night. I assume it does a complete charge and balance with the wallbox as it is an intelligent charger. So I am surprised that the car said today to do a slow charge. That is all I ever do I believe as the car and charger control how much current is flowing into the battery. After a full charge it says around 190km. I do 10 minutes of heating, to melt the ice and warm the car, the drive 23km to work and it is down to 100km range when I arrive. After a few km the range is down to around 90km and power limiting to 20% occurs which means a maximum uphill speed of 50km which annoys other drivers in a 70km zone. Also, today after driving off, HV batter fault appeared and power was cut. Removing my foot from the accelerator recovered the fault but any moderate acceleration produced the same fault. This happened 3 times. I am taking the car to the dealer this week but hope they come back with a better response that you received.

 

[Mark Holmes]

My car is very similar at the moment. It was delivered in November and has not had any software updates yet. Currently I get around 30km useful range. It is -19 C but there is no warning from the dealer that range should be this reduced. I have a 7kw wallbox and I plug the car in every night. I assume it does a complete charge and balance with the wallbox as it is an intelligent charger. So I am surprised that the car said today to do a slow charge. That is all I ever do I believe as the car and charger control how much current is flowing into the battery. After a full charge it says around 190km. I do 10 minutes of heating, to melt the ice and warm the car, the drive 23km to work and it is down to 100km range when I arrive. After a few km the range is down to around 90km and power limiting to 20% occurs which means a maximum uphill speed of 50km which annoys other drivers in a 70km zone. Also, today after driving off, HV batter fault appeared and power was cut. Removing my foot from the accelerator recovered the fault but any moderate acceleration produced the same fault. This happened 3 times. I am taking the car to the dealer this week but hope they come back with a better response that you received.

If you got your car in November you may have the doggy BMS software, I’d get it in and get it updated urgently to the new software release in January 21

 

[MAS]

If you got your car in November you may have the doggy BMS software, I’d get it in and get it updated urgently to the new software release in January 21

Mark; what difference do you see since your update of BMS at first service?

 

[Mark Holmes]

Mark; what difference do you see since your update of BMS at first service?

Booked in on the 23rd of this month and so I can’t say yet...

 

[DriverInNorway]

Thanks for the responses. I will let you know what the dealer says as it is dangerous to not have the power to go up a modest hill after a full over night charge and having only driven 30km or so. I am going to take it to them tomorrow and leave it with them as it is pretty useless to me in the current state.

 

[Mark Holmes]

Thanks for the responses. I will let you know what the dealer says as it is dangerous to not have the power to go up a modest hill after a full over night charge and having only driven 30km or so. I am going to take it to them tomorrow and leave it with them as it is pretty useless to me in the current state.

Good luck with getting this matter resolved.

 

[Lovemyev]

Thanks for the responses. I will let you know what the dealer says as it is dangerous to not have the power to go up a modest hill after a full over night charge and having only driven 30km or so. I am going to take it to them tomorrow and leave it with them as it is pretty useless to me in the current state.

Your car is displaying "Classic" symptoms of the "Buggy" BMS software.
The latest BMS update, released 15th Jan 2021 is needed to correct the problem, then a series of charge / balance process on a slow post to re-align the cells in the HV battery.
Good luck !.

 

[Lovemyev]

You may find this of some interest ?.

 

[DriverInNorway]

Thanks for the responses. Yes, the dealer took it in and said it has the faulty BMS software and that it is likely it will take them up to a month to balance the battery properly before returning it to me. In the meantime, they have given me a Tesla 75d. So, really pleased with the dealer but still annoyed that MG didn't do a recall as soon as they knew the software would render batteries very imbalanced and therefore with vastly reduced range.

 

[DriverInNorway]

You may find this of some interest ?.

He did well. Well, the car did well. Much better than my 30km on a full charge. It will still be -10 at least by the time i get my car back so I will post here what my new winter ranges are with the new software and restored battery.

 

[Jeps]

Thanks for the responses. Yes, the dealer took it in and said it has the faulty BMS software and that it is likely it will take them up to a month to balance the battery properly before returning it to me. In the meantime, they have given me a Tesla 75d. So, really pleased with the dealer but still annoyed that MG didn't do a recall as soon as they knew the software would render batteries very imbalanced and therefore with vastly reduced range.

It would have been appropriate to have been called in for an update.
I was called in back in January, they called me on the phone, and I didn't know much about the BMS update at that time. But they told me to come in A.S.A.P to have it rectified.

 

[Trevor]

Thanks for the responses. Yes, the dealer took it in and said it has the faulty BMS software and that it is likely it will take them up to a month to balance the battery properly before returning it to me. In the meantime, they have given me a Tesla 75d. So, really pleased with the dealer but still annoyed that MG didn't do a recall as soon as they knew the software would render batteries very imbalanced and therefore with vastly reduced range.

Oh no, even when your MG is fixed, that Tesla range is going to be your new frame of reference. That salesman is clever

 

[Mike]

I do wonder if something else is going on. Every day I get "Please connect slow charger" which I don't hear others reporting. I only have a granny charger and do regular long slow charges. I also once got "HV battery fault" on screen, but apparently battery is ok and will recover. I've done a lot of charging since BMS update and HV voltage this morning showed 432V, which is up from 429V a week ago. This could take forever...

You will still get these until the battery has recovered more. As you were 26V out, that is several hundred mV imbalance. I’m guessing 3-400mV or possibly even more!

I take it you drive a lot and charge a lot. Did you also do much rapid charging with the duff BMS?

 

[Trevor]

You will still get these until the battery has recovered more. As you were 26V out, that is several hundred mV imbalance. I’m guessing 3-400mV or possibly even more!

I take it you drive a lot and charge a lot. Did you also do much rapid charging with the duff BMS?

Hi Mike. I have reached 440V now and the "connect slow charger" no longer appears. I am in manufacturing so have kept up the daily commute through lock down; 26 miles each way. In cooler weather, together with my heavy foot, I need to granny charge every night. I hardly ever rapid charge. I guess this daily cycle meant I was one of the heavier sufferers of the software bug.

I'm not sure whether I got the buggy software on 3 or 18 Nov (car was in twice, but I think 18th). I first noticed the problem on a long journey on 8 Dec, when I barely made it to a (off-line, but luckily rebooted) charger, only 76 miles from home. On this occasion I was driving economically anyway, and especially so once I realised the consumption rate. So, the effect really took place quickly - much quicker than its taking to recover.

 

[WAC 768]

Your car is displaying "Classic" symptoms of the "Buggy" BMS software.
The latest BMS update, released 15th Jan 2021 is needed to correct the problem, then a series of charge / balance process on a slow post to re-align the cells in the HV battery.
Good luck !.

Mine had the latest Jan BMS update and post this had the same symptoms as per DriverInNorway, so wouldn't guarantee this...
I have since had the car back to the dealer who's reapplied everything and mentioned MG had sent a further update out... Hopefully today, I will have the battery low enough to test once again if this fix has resolved the problem or not.

Confirmed problem still exists