BMS update- feedback from MG

[WalkingBootWeather]

MG had sent a further update out

A further update to BMS since 15th Jan? If so would be interesting to know what it fixes or improves over the Jan update.

 

[WAC 768]

A further update to BMS since 15th Jan? If so would be interesting to know what it fixes or improves over the Jan update.

This is what they said and is all the information i have..

 

[JodyS21]

This is what they said and is all the information i have..

Wowsa, be interesting to see what this is - if there really is another one.
Hopefully the very helpful Miles may know.

 

[Mark Holmes]

Wowsa, be interesting to see what this is - if there really is another one.
Hopefully the very helpful Miles may know.

What another BMS update released on the 15th Jan two days ago.....really?!

 

[Cocijo]

Surely not?

 

[JodyS21]

What another BMS update released on the 15th Jan two days ago.....really?!

you mean a couple days ago - 15th feb

Surely not?

Who knows lol.....

 

[Lovemyev]

Surely not?

I would be extremely surprised if this was the case !.
My guess is, they are referring to the Jan15th BMS update myself.
Which could mean either the OP did not get the 15th Jan update or it was not applied correctly.
“Miles Is The Man” to answer this question.
“What say you” - @MilesperkWh !.
Many thanks

 

[Gomev]

@WAC 768 did say in the post that had Jan update and been back and told a FURTHER update...interesting as the way that is written does infer 2 updates.

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.

 

[WAC 768]

@WAC 768 did say in the post that had Jan update and been back and told a FURTHER update...interesting as the way that is written does infer 2 updates.

Based upon what the service department said then yes, but who knows....

 

[Gomev]

Pure speculation but I wonder could the 'further' update relate to the reduced power problem others are reporting ?

 

[AV2EV]

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...

Had a lot of problems after the BMS update in early December - the range dropped about 100 km - the real range after the update remained about 140 km only. Couldn't trust the numbers of remaining km at all. Every day - multiple warnings "Slow Charge the Vehicle" although I have slow charged the vehicle almost every night.
The car was at the dealership for more than 20 days, and they did the daily charge/empty cycles - only after 21 days the car was back to normal.

 

[PeteJ]

I had my car serviced 2 days ago which included the BMS update. After charging overnight with my 'Granny' charger I see 540v and a range of 132miles, the temp was -1c.. Looks good to me.

 

[Cocijo]

I hope that’s 450v!!

 

[PeteJ]

Sorry being a bit optimistic it should be 450v

 

[Trevor]

Had a lot of problems after the BMS update in early December - the range dropped about 100 km - the real range after the update remained about 140 km only. Couldn't trust the numbers of remaining km at all. Every day - multiple warnings "Slow Charge the Vehicle" although I have slow charged the vehicle almost every night.
The car was at the dealership for more than 20 days, and they did the daily charge/empty cycles - only after 21 days the car was back to normal.

I'm making progress - voltage has increased from 426V to 446V. I should hit 450V within 2 weeks. I'm still only getting about 90 miles under similar conditions to last Feb where I would get 110 miles. I'm hoping this comes good.

 

[DriverInNorway]

I'm making progress - voltage has increased from 426V to 446V. I should hit 450V within 2 weeks. I'm still only getting about 90 miles under similar conditions to last Feb where I would get 110 miles. I'm hoping this comes good.

My car is still at the dealers. Maybe they have forgotten.

 

[JMX]

Update on my experience having been quite badly affected by the BMS in late 2020 and with the Jan 2021 update 'fix' - the max voltage has been stable for the last 2 weeks and 10 full charges at 449.25v The max/min voltages have a difference of 20mv which has not changed and the balance takes 4 hours every night. Is anyone else seeing this? Range is largely back to normal, but could do without 4 hours of balancing charge each night.

 

[Mike]

Update on my experience having been quite badly affected by the BMS in late 2020 and with the Jan 2021 update 'fix' - the max voltage has been stable for the last 2 weeks and 10 full charges at 449.25v The max/min voltages have a difference of 20mv which has not changed and the balance takes 4 hours every night. Is anyone else seeing this? Range is largely back to normal, but could do without 4 hours of balancing charge each night.

That all looks normal to me based on my last charge which was almost 4 weeks ago. The car has barely been driven since then and I don’t yet have a home charger. A broken right leg has rather put a stop to my driving

 

[Lovemyev]

Range is largely back to normal, but could do without 4 hours of balancing charge each night.

I am witnessing a similar pattern.
At my last & balance the HV pack reported 450 Volts, the highest I have ever seen.
The range in the default mode is around the 161 miles mark.
The balancing is still taking between 3.5 and 4.0 hours still.
I have completed about 6 or 7 full charge / balance cycles, after I received the 15.01 BMS update on the 18.01.21.
My HV pack was never affected by the "Buggy" software, it received the latest BMS update because my car was in for the 1st service etc at the time.

 

[JodyS21]

I am witnessing a similar pattern.
At my last & balance the HV pack reported 450 Volts, the highest I have ever seen.
The range in the default mode is around the 161 miles mark.
The balancing is still taking between 3.5 and 4.0 hours still.
I have completed about 6 or 7 full charge / balance cycles, after I received the 15.01 BMS update on the 18.01.21.
My HV pack was never affected by the "Buggy" software, it received the latest BMS update because my car was in for the 1st service etc at the time.

I'm not convinced there's a obvious reason for how long the balance takes.
Except when due to the problem BMS it's way out of balance and goes for 10 hours.

My car has always been ok & balanced every charge etc, yet it seems to be pretty random how long it balances for - always not ages just a few hours.

I guess it's all chemistry so nothing definitive in how evenly the battery cells discharge, different days after the same journey they'll be very slight differences in cell voltage balances. We are only talking a handful of milli-volts but it can be enough to be a couple of hours difference in balancing time.

If your battery is already at a well balanced state, I don't think it's really necessary to let it do a full balance after every charge. The difference in voltage/SoC/range isn't much if it's at a reasonably balanced state.
It's quite possible that the subsequent discharge following a charge, could end up balancing the cells a bit more; so why waste the electricity/pennies that it takes to do a balance every charge...
That said when I can do a scheduled 7kwh charge soon, I'll prob effectively just set the start time to when my off-peak rate starts and then let it go as long as it likes and balance!