Buggy BMS software

[mraines]

Hi Im a car owner from israel, when I purchased the car it was already delivered to be with the BMS bug .I got fix on Jan 18 and since the update I follow the instructions and let it charge and balance all night.
Today I noticed a the full battery voltage increase to 440V from 437v that I had prior to update. I hope to see it improving soon. The Israeli dealer told me to be patient as it's suppose to take a while

 

[Lovemyev]

There is no advantage of charging on a "Granny" charger from low charging levels really.
To balance the pack, you DO have to charge via an A/C supply of course.
If you are using a 7kw or a slow "Granny" it matters not, because when the battery is almost full, the car will throttle back the charge right down to a trickle charge, in order to balance the pack is my understanding.
It has been suggested that balancing can take place from about 90 - 92% SOC.
Running the pack down low, only makes the whole cycle even longer.
To be honest, I personally think some of us ( including myself ) have bigger issues here.
The whole charging process itself is taking WAY to long I.M.H.O.
Charging from a low SOC and needing to use the car for a long journey the next day, makes it almost impossible now.
The car taking well over 10 hours to charge and balance is totally impractical.
It appears that my car is now only allowing the car to pull just under 4.0 kw from the 7.0kw wall box.
Therefore the charge time alone has now doubled !.
I have asked other owners to check they cars.
This would go a long way to explain why the car is now taking so long to charge, than it did before.

 

[DriverInNorway]

There is no advantage of charging on a "Granny" charger from low charging levels really.
To balance the pack, you DO have to charge via an A/C supply of course.
If you are using a 7kw or a slow "Granny" it matters not, because when the battery is almost full, the car will throttle back the charge right down to a trickle charge, in order to balance the pack is my understanding.
It has been suggested that balancing can take place from about 90 - 92% SOC.
Running the pack down low, only makes the whole cycle even longer.
To be honest, I personally think some of us ( including myself ) have bigger issues here.
The whole charging process itself is taking WAY to long I.M.H.O.
Charging from a low SOC and needing to use the car for a long journey the next day, makes it almost impossible now.
The car taking well over 10 hours to charge and balance is totally impractical.
It appears that my car is now only allowing the car to pull just under 4.0 kw from the 7.0kw wall box.
Therefore the charge time alone has now doubled !.
I have asked other owners to check they cars.
This would go a long way to explain why the car is now taking so long to charge, than it did before.

 

[DriverInNorway]

I had the same problem and if you read my thread on that, you can see that it is the dealers responsibility to deliver you the car with a fully functional batter. The dealer here is doing all the charges and dissipations until the battery is restored. If your car is under 6 months old, it is covered by Consumer Protection Law and the dealer has the option of one chance to repair it to your satisfaction. Don't accept the car back until the battery has been reconditioned to its correct state.

 

[AV2EV]

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

Avoid the December BMS update. Had a lot of problems after the BMS update in early December - the range dropped about 100 km - the real range now is about 140 km only. Every day I get multiple warnings "Slow Charge the Vehicle" although I have slow charged the vehicle almost every night. One cannot trust the numbers of remaining km at all. One has to divide it by 2 to get the realistic range after the update. The other day it showed a "Low Charge" warning at 96 km... Moreover, the voltage is down to 428 and even 419 volts. Something stinks here.
The car has been at the dealership for more than 20 days, I’m using their car - at least this is nice. They are struggling to get it back to normal.
I'm not the only one - met a guy with similar problems from another city - his car is in the MG garage for two weeks already.
Yesterday they called me from the MG garage Jerusalem and said that my car will soon be ready - the truth is, however, as I was told that there are other clients lining up with exactly the same problem and they need their demo car back...

 

[DriverInNorway]

Yes, that is the same situation I am in, in Norway so it is an MG wide problem. The dealer told me it would take up to a month for the battery to recover. They are doing this process through multiple discharge/charge cycles until it is able to hold the correct and balanced voltage across all the cells. At least in both our cases they have taken the car back, acknowledged the problem and are fixing it while we have a replacement. Even if there are other people waiting, I wouldn't return the car unless it is proved to you that it is fixed. I believe the best way to tell this at the dealership is to see what the fully charged voltage reports and compare it to what other people are seeing after the most recent BMS update and the recovering charge cycles. Then I guess it will be through actually driving the car and seeing if the range and charging is improved.

 

[Lovemyev]

Yes, that is the same situation I am in, in Norway so it is an MG wide problem. The dealer told me it would take up to a month for the battery to recover. They are doing this process through multiple discharge/charge cycles until it is able to hold the correct and balanced voltage across all the cells. At least in both our cases they have taken the car back, acknowledged the problem and are fixing it while we have a replacement. Even if there are other people waiting, I wouldn't return the car unless it is proved to you that it is fixed. I believe the best way to tell this at the dealership is to see what the fully charged voltage reports and compare it to what other people are seeing after the most recent BMS update and the recovering charge cycles. Then I guess it will be through actually driving the car and seeing if the range and charging is improved.

After the dealer has applied the new Jan 15th 21 update, they will carry out a full charge and balance procedure.
This is likely to be an over night process.
MG would have given the dealer a target figure that they expect the car should hit, before releasing it back to the owner.
After my car had the new update applied, the pack hit 249 volts and a predicted range of 162 miles in normal mode.
The outside temperature on the day was only about 4 degrees.
Under current travel restrictions, it is difficult to tell what the consumption of energy is like.
But over the last few weeks, it is returning about 3.1 miles / kWh.
So given the cold weather and the drain taken by almost constant use of the electrical item ( heater / wipers / lights etc ) it feels some where about right.
The longer the “Buggy” software has been installed, the longer it is likely to take to get your HV battery back to normal.
Each charge and then use is just putting the pack more and more out of balance.
Rapid charging is making the problem even worse with each charge.
The HV pack is becoming more unbalanced with each and every charge now.
The sooner the better you can get the old software over written the better !.
Good luck !.