Sorry BMS again!

[micky]

I think the 'Latest BMS' update settles at 449V and lowered the individual cell voltages / upper limit buffer .

I think we are up to SA020 as far as updates go for the ZSEV , it would be a nice 'pinned' topic if somebody could list the relevant patches & updates ?

hi Morr5 the latest bms is EU1

 

[Kithmo]

It’s worth mentioning. I’ve never seen 456v. Mine is always 455v. I’ve heard of some getting as high as 458v. The same with the 450v it may vary by a volt or two. This is assuming all fully balanced of course and no faulty software! I think Jody has a good point - is it possible to have the bad bms but because you very rarely rapid charge and balance regularly you don’t notice and the pack stays stable?

Mine shows 456.25v on the app when fully charged and balanced.

 

[Kithmo]

I'm on the 456v OEM BMS.

I charged and fully balanced using my Zappi yesterday evening and kept a close eye on the power being used at each stage.

Up to 98% power was 6.5 to 7.0 kw.
98% to 100% power was 2.5kw.
At this point the balance commenced.
13 minutes at 2.5kw.
4 minutes at 2.0kw
Then complete, showing 456 volts.

I have read in a number of threads that on the latest BMS the balance runs at 300w and takes hours to complete.

Is this another reason to stay with the 456v BMS OR a reason to move to the latest?

Scratches head!!!

I could swear mine balanced at around 250W not 2.5kW, for between 1-2 hours.
I'll check again next time I charge it.

 

[Lovemyev]

I could swear mine balanced at around 250W not 2.5kW, for between 1-2 hours.
I'll check again next time I charge it.

Yeah - From memory, when I had the OEM software, my balance time was around the 1 hour mark.
But I have to admit, I only fully charged when I had a long journey to make.
Otherwise, I would only charge to a level that I needed, with a little bit more of a buffer, just in case.
If I had about 80 - 100 miles of range on the GOM, this would take care of most of our local stuff, and a bit to spare.
I do more charging and balancing now after the BMS update.
But never every time I charge, that’s for sure !.
The pack displays a regular 448 volts when I fully charge, that’s good enough for me.
It has hit 449 and even 450 on two occasions, very briefly.
The predicted mileage after a full charge varies a little, but that does not concern me too greatly to be totally honest.
The car has covered 13,000 miles now and I guess it has a little degradation, given all the software updates etc it has gone through.
I have no idea on the current SOH of the pack, but it again this does not overly concern me either.
It runs and performs just fine and therefore you have to be happy with that I guess !.
Charging & balancing on a constant basis, chasing the magical unicorn figures is not really what I want to be doing personally.
The car has only been on a rapid about three times in 18 months, and they where just a quick “Splash & Dash” .
The bill for my last rapid arrived yesterday, it was for £1.32.
This gives you an example of how little my rapid charging has been over this time.
I would say that 99.9% of our charging needs, are done from on our drive, on the cheaper off peak rate.
My feet are completely and firmly planted in the “If the car is running, charging and performing okay ( range etc ) then leave it WELL alone”.
Intervention by the dealer is on the similar level as conducting surgery in my book, it should only be the considered as the very last resort ?.
It’s a common know fact that Lithium batteries degrade quickly straight from the “Get Go” then this slows down again to a more stable level really quickly.
Manufactures know this and this margin COULD therefore be built into the values reported by the battery.
Giving the manufacture a bigger head room in the pack to avoid any customer concerns as there predicted range is decreasing in the cars early life.
I affect, the car reports 100% full charged when the pack is new and then when that initial degradation sets in, the car is still set up to report 100% after a charge and therefore the owner is happy about the SOH of his battery, because it still reports 100%.
Well that’s my theory anyway ?.

 

[mglcastro83]

I had the SA020 update added yesterday and explained I also needed the BMS update as I had the faulty one installed (max voltage 429v). They say they have done it along with the SA020 update however a charge today still maxed out at 429v. Am I being impatient or may there still be an issue?

 

[Lovemyev]

I had the SA020 update added yesterday and explained I also needed the BMS update as I had the faulty one installed (max voltage 429v). They say they have done it along with the SA020 update however a charge today still maxed out at 429v. Am I being impatient or may there still be an issue?

You will need to carry out a number of charge and balance cycles on either a wall box or Granny charger before the range starts to recover.
A rapid unit will not rebalance the pack.

 

[Cocijo]

I had the SA020 update added yesterday and explained I also needed the BMS update as I had the faulty one installed (max voltage 429v). They say they have done it along with the SA020 update however a charge today still maxed out at 429v. Am I being impatient or may there still be an issue?

Didn’t the dealer explain everything to you? I would go back to them and ask them to. Your fully charged voltage should be c449v. It will take many rebalances to get back to this voltage (200+). In the interim your range will be significantly reduced. With a voltage as low as yours I would ask for the dealer to balance it and supply a car while it’s completed. ?

 

[JodyS21]

Didn’t the dealer explain everything to you? I would go back to them and ask them to. Your fully charged voltage should be c449v. It will take many rebalances to get back to this voltage (200+). In the interim your range will be significantly reduced. With a voltage as low as yours I would ask for the dealer to balance it and supply a car while it’s completed. ?

Unbelievable yet again, they should’ve fully explained it to you about how long it’s take to get it resolved.
Someone will remember, the MG document to dealers said if it was below a certain voltage they should keep it and sort out the recharges for you. I’m pretty sure 429v is within the level that they are supposed to sort it out for you.

It’s roughly 10hours balancing per volt, so as Cocijo has said over 200 hours of balancing needed

 

[mglcastro83]

Unbelievable yet again, they should’ve fully explained it to you about how long it’s take to get it resolved.
Someone will remember, the MG document to dealers said if it was below a certain voltage they should keep it and sort out the recharges for you. I’m pretty sure 429v is within the level that they are supposed to sort it out for you.

It’s roughly 10hours balancing per volt, so as Cocijo has said over 200 hours of balancing needed

?

 

[mglcastro83]

Didn’t the dealer explain everything to you? I would go back to them and ask them to. Your fully charged voltage should be c449v. It will take many rebalances to get back to this voltage (200+). In the interim your range will be significantly reduced. With a voltage as low as yours I would ask for the dealer to balance it and supply a car while it’s completed. ?

That was not explained.

Yeah range has been severely reduced - meaning AA had to pick me up off the hard shoulder of the M45 a couple weeks back!

 

[mglcastro83]

You will need to carry out a number of charge and balance cycles on either a wall box or Granny charger before the range starts to recover.
A rapid unit will not rebalance the pack.

We have 7kw charge posts at work which I believe slows down to 3kw during balancing phase. Will this do or does that count as a rapid unit?

 

[JodyS21]

We have 7kw charge posts at work which I believe slows down to 3kw during balancing phase. Will this do or does that count as a rapid unit?

It’s all about if it’s an DC or AC supply.
7kW will be AC.
All AC charging will do a balance once fully charged. When balancing the power will drop down to the 100s of watts, nothing like the 3-7kW.

 

[Lovemyev]

We have 7kw charge posts at work which I believe slows down to 3kw during balancing phase. Will this do or does that count as a rapid unit?

As stated in #46 above.
You can use any 7 kw post or the supplied "Granny" in order to balance your pack.
Not a rapid charger though !.

 

[Lovemyev]

Also, you don't have to run the pack really low, before trying to balance the pack again.
Once you have dropped the battery gauge down by one of the white bars, you can put it back on charge again, if you so desire.
The car will charge at 7kw's below at any level SOC of about 95%.
At around 97% the car will reduce the charge down to 3.5 kw's.
When the pack reaches 100% DON'T unplug the lead !.
This is when the balance process has commenced.
The demand will only be about 600 Watts, then when the balance is almost complete, it will finally reduce down to 175 Watts before shortly finishing.
While the car is charging, the MG badge in the front grill will give out a slow pulsing glow, when the balance process has started, the MG badge will omit a STEADY constant glow.
When the balance completes, it will automatically shut down the supply from the 7kw post / wall box or 3.5 Kw Granny lead.
Don't worry if the balancing appears to take a long time, because it will !.
My first charge and balance after the update had taken almost 12 hours to complete.
The balancing cycle / time will reduce as the HV pack returns to normal.
JUST the balance cycle ( after a full charge ) should take around 2 hours ( ish ) to complete on the latest BMS update.
On the previous OEM software, a balance would only take about 30 mins to 1 hour.
More space has been created at the top of the pack on the latest update, this may account for the longer time to balance ?.
If you have a energy meter and can be bothered ( like myself ) you can see this charging pattern of events mapped out ( ask sad me, how I know ).
As others have said, the dealer can carry out the re-balancing for you, but they will need your car for a while !.

 

[mglcastro83]

As stated in #46 above.
You can use any 7 kw post or the supplied "Granny" in order to balance your pack.
Not a rapid charger though !.

?

 

[mglcastro83]

Also, you don't have to run the pack really low, before trying to balance the pack again.
Once you have dropped the battery gauge down by one of the white bars, you can put it back on charge again, if you so desire.
The car will charge at 7kw's below at any level SOC of about 95%.
At around 97% the car will reduce the charge down to 3.5 kw's.
When the pack reaches 100% DON'T unplug the lead !.
This is when the balance process has commenced.
The demand will only be about 600 Watts, then when the balance is almost complete, it will finally reduce down to 175 Watts before shortly finishing.
While the car is charging, the MG badge in the front grill will give out a slow pulsing glow, when the balance process has started, the MG badge will omit a STEADY constant glow.
When the balance completes, it will automatically shut down the supply from the 7kw post / wall box or 3.5 Kw Granny lead.
Don't worry if the balancing appears to take a long time, because it will !.
My first charge and balance after the update had taken almost 12 hours to complete.
The balancing cycle / time will reduce as the HV pack returns to normal.
JUST the balance cycle ( after a full charge ) should take around 2 hours ( ish ) to complete on the latest BMS update.
On the previous OEM software, a balance would only take about 30 mins to 1 hour.
More space has been created at the top of the pack on the latest update, this may account for the longer time to balance ?.
If you have a energy meter and can be bothered ( like myself ) you can see this charging pattern of events mapped out ( ask sad me, how I know ).
As others have said, the dealer can carry out the re-balancing for you, but they will need your car for a while !.

Good stuff to know re: not having to drain the battery. I bit the bullet and got an EV without owning a drive way knowing work had free chargers I can use 5 days of the week. Essentially, make sure the charge points at work aren’t ice’d, do my normal day and hopefully the MG badge is no longer lit when I’ve finished work. Then rinse and repeat 200 times.

I’ll also scope out what the dealer will do for me but as they didn’t even offer it as an option the other day I don’t think they’d be too keen.

Whilst up in Shrewsbury Budgens MG were really good and offered all of that off the bat. Very helpful group. Unfortunately, just not up there long enough to do it.

 

[Kithmo]

Good stuff to know re: not having to drain the battery. I bit the bullet and got an EV without owning a drive way knowing work had free chargers I can use 5 days of the week. Essentially, make sure the charge points at work aren’t ice’d, do my normal day and hopefully the MG badge is no longer lit when I’ve finished work. Then rinse and repeat 200 times.

I’ll also scope out what the dealer will do for me but as they didn’t even offer it as an option the other day I don’t think they’d be too keen.

Whilst up in Shrewsbury Budgens MG were really good and offered all of that off the bat. Very helpful group. Unfortunately, just not up there long enough to do it.

If you don't have a drive and hence a home charger, I would inform the dealer and ask them to do the balancing for you, with a courtesy car in the meantime. It could take a very long time to get up to the proper, balanced, voltage when you don't have charging facilities at home.