25/01/21: Just had latest BMS software. Observations...

[rbpasapera]

Is it after the latest Jan update? I am only 449 after full charge and equalisation

Yes it's after latest Jan update.

 

[WalkingBootWeather]

Just completed granny charge since my mammoth journey yesterday. It took around 17 hours to fully charge from 7% and a further 6 hours to balance battery. Now reading Voltage 449, N range 159, E Range 173 with everything off.

 

[MAS]

I only get 454 volts albeit I’m over 14000 miles in and so could have lost a little battery capacity.

Mark, you are getting high Voltage because you have not got your BMS Jan 2021 update yet. I had a call from Glyn Hopkin Romford and wanted to book me in for MG recall for BMS update. I told her i have got mine done already on 25/01/2021, which she confirmed after speaking to MG East London. It seems they started to call from recent sales and working backward. She said they were sent VIN numbers from MG for BMS update recall.

 

[Mike]

Hi @Mike .
I am a little surprised to see that before the BMS update, your voltage was around 433 volts and now after only one single charge you are now at 445 volts !.
Other owners are are struggling to get there voltage above 449 volts.
So, clearly there is inconsistencies here with no clear explanation why ???.
Given the usage and mileage on your car Mike, then the theory that 450 volts should be seen as the NEW norm.

Errr.... I said 443V, having just checked

No inconsistency that I can see.

How I understood what @MilesperkWh said was that he would expect 455V to come back in the warmer weather after all the correction balanced had taken place and after a few rapid charges.

Batteries do not hold as much charge in cold weather.

An example... my daughter walked up Helvelen a few years ago in the snow. Her phone was in her outside pocket. When she took it out at the top it would not work. By the time she had gone down the mountain having put it in an inside pocket, it was working again. Yes, an extreme example, and one that shouldn’t happen to an EV, unless it is really, really cold, which is why they all have battery heaters in them.

Take today for example. I drove 41 miles and used less than 30%, but it was 10°C. I averaged 3.7 miles/kWh! Mixture of mostly 30mph speed limits with a little motorway.

 

[Mark Holmes]

Mark, you are getting high Voltage because you have not got your BMS Jan 2021 update yet. I had a call from Glyn Hopkin Romford and wanted to book me in for MG recall for BMS update. I told her i have got mine done already on 25/01/2021, which she confirmed after speaking to MG East London. It seems they started to call from recent sales and working backward. She said they were sent VIN numbers from MG for BMS update recall.

Hi MAS mine still has the same BMS software from when I bought the car in March 20, the only update I had applied was the comfort 2. Mine is due in soon for the first service and I’m going to ask if the new BMS update needs to be applied as I’m happy with what I’ve got, but I don’t know what other benefits are meant to be achieved by having it.

 

[MAS]

Hi MAS mine still has the same BMS software from when I bought the car in March 20, the only update I had applied was the comfort 2. Mine is due in soon for the first service and I’m going to ask if the new BMS update needs to be applied as I’m happy with what I’ve got, but I don’t know what other benefits are meant to be achieved by having it.

Technicians and dealer dont seem to know much, other than going by directive form MG and getting paid for their labour

 

[mj224]

Hi MAS mine still has the same BMS software from when I bought the car in March 20, the only update I had applied was the comfort 2. Mine is due in soon for the first service and I’m going to ask if the new BMS update needs to be applied as I’m happy with what I’ve got, but I don’t know what other benefits are meant to be achieved by having it.

Not wanting to light any fires, but this worry about new software is a bit unsettling to me. My car was bought at the end of November 20, it works well, winter range of 120+ miles. Just works so well for me, as per Mark H, I too am very happy with what I've got...

 

[Smendon]

So, just plugged in and I had 88% on the battery. Going to balance charge tonight and see whether my voltage increases higher than the 444v that I had on my last two charges
Pic below of the mileage and voltage when I plugged in.
View attachment 1312

Car charged and balanced. Took less time than it did over the weekend, but rather than showing me 444v, it’s now showing 443v??
Any idea why the voltage has decreased since my last balance charge rather than go up? (FYI it’s currently 7 degrees outside, so wouldn’t say that’s too cold)

 

[WalkingBootWeather]

So my observations following the latest BMS update on a car that was purchased in Jan 2020, and had the buggy October 2020 BMS installed on 2nd Nov 2020. Note I have driven around 600 miles since the Jan 2021 update was installed and have now completed balancing charges on I think 6 occasions:

• Car now charges on AC even when unlocked
• Still seeing 449V when fully charged and everything off. Previously I was getting 454V
• Still taking several hours to complete balancing on a granny charger
• Range does not appear to have been unduly affected, and appears to have improved from what I was getting pre-Jan 2021 update. Car displays about 159 miles in N and 173 miles in E mode with everything off, in temperature of about 5 degrees. In reality I'm getting about 120 miles range driving sensibly with heating on in N. I could probably get 140 miles in cool temperatures if I was prepared to drive very carefully with minimal heating.
• Regen in level 3 feels slightly stronger than before
• Rapid charge speed may be slightly higher than before. I have yet to experience sub 30kw charge speeds since the update.
• Rapid charging now appears to taper down to about 15kw from 85% whereas it was 82% before update

These observations are subjective and may change as weather improves and I complete more driving and equalisation charges but perhaps provide a reference for others.

 

[Lovemyev]

So my observations following the latest BMS update on a car that was purchased in Jan 2020, and had the buggy October 2020 BMS installed on 2nd Nov 2020. Note I have driven around 600 miles since the Jan 2021 update was installed and have now completed balancing charges on I think 6 occasions:

• Car now charges on AC even when unlocked
• Still seeing 449V when fully charged and everything off. Previously I was getting 454V
• Still taking several hours to complete balancing on a granny charger
• Range does not appear to have been unduly affected, and appears to have improved from what I was getting pre-Jan 2021 update. Car displays about 159 miles in N and 173 miles in E mode with everything off, in temperature of about 5 degrees. In reality I'm getting about 120 miles range driving sensibly with heating on in N. I could probably get 140 miles in cool temperatures if I was prepared to drive very carefully with minimal heating.
• Regen in level 3 feels slightly stronger than before
• Rapid charge speed may be slightly higher than before. I have yet to experience sub 30kw charge speeds since the update.
• Rapid charging now appears to taper down to about 15kw from 85% whereas it was 82% before update

These observations are subjective and may change as weather improves and I complete more driving and equalisation charges but perhaps provide a reference for others.

As you have charged roughly about six times now ( A mixture of rapid and A/C I assume ) then the common voltage number of around 449 volts is a common factor here.
The magical unicorn number of 455 volts appears not to be making itself known.
Nobody ( as of yet ) has seen any improvement on voltages above 450 is my understanding.
There is some speculation that 455 volts will only return ( if ever ) when the warmer weather returns, however I find it strange that “Pre Update” cars are still displaying 455 volts in the same weather conditions ?.
Question :- When cars are presented for their annual service, will they automatically get the latest BMS update, in order to standardise all cars to the same software condition ?.
Therefore we will all end up with 450 ish volts on the pack.
MG released a “HV Fuse Protection” update which all cars are going to receive at one point or another.
This was because there had been a couple of ZS EV’s that had suddenly just stopped because the HV fuse protecting the pack had failed.
Is this why they have reduced the voltage on the pack now down to 450 (ish) volts ?.
I have no idea - just guessing.
If there is any truth in this pure guess, then charging to full and balancing multiple times is never going to result in achieving the 455 volts we are all lead to believe we SHOULD be returning to ?????.
Is 450 volts the new 455 volts I wonder !.

 

[Mark Holmes]

As you have charged roughly about six times now ( A mixture of rapid and A/C I assume ) then the common voltage number of around 449 volts is a common factor here.
The magical unicorn number of 455 volts appears not to be making itself known.
Nobody ( as of yet ) has seen any improvement on voltages above 450 is my understanding.
There is some speculation that 455 volts will only return ( if ever ) when the warmer weather returns, however I find it strange that “Pre Update” cars are still displaying 455 volts in the same weather conditions ?.
Question :- When cars are presented for their annual service, will they automatically get the latest BMS update, in order to standardise all cars to the same software condition ?.
Therefore we will all end up with 450 ish volts on the pack.
MG released a “HV Fuse Protection” update which all cars are going to receive at one point or another.
This was because there had been a couple of ZS EV’s that had suddenly just stopped because the HV fuse protecting the pack had failed.
Is this why they have reduced the voltage on the pack now down to 450 (ish) volts ?.
I have no idea - just guessing.
If there is any truth in this pure guess, then charging to full and balancing multiple times is never going to result in achieving the 455 volts we are all lead to believe we SHOULD be returning to ?????.
Is 450 volts the new 455 volts I wonder !.

All good points, but who really knows!!

 

[Lovemyev]

All good points, but who really knows!!

Nobody - That’s the whole point !.
No information then causes speculation.

 

[MAS]

That's the main cause of confusion, Technician at the dealer don't seems to know or want to commit to a voltage figure that can be used as a benchmark. 449V is what I have got after BMS update for a new car with 200 miles driven.

 

[Lovemyev]

That's the main cause of confusion, Technician at the dealer don't seems to know or want to commit to a voltage figure that can be used as a benchmark. 449V is what I have got after BMS update for a new car with 200 miles driven.

Thank you for that information, that leaves me in very little doubt now.
1. That 449 volts is now the “New” 455 volts that MG wants to run the ZS EV on considering the MG 5 runs on a lower voltage of around 395 volts I think.

2. Unless we are to see an increase to 455 volts as the weather improves.

But I am a little sceptical of this theory.
I would dearly like to be proven wrong here.
Yes, we will see an increase in range of course due to the kinder conditions.
But voltage ??????.

 

[WalkingBootWeather]

As you have charged roughly about six times now ( A mixture of rapid and A/C I assume ) then the common voltage number of around 449 volts is a common factor here.
The magical unicorn number of 455 volts appears not to be making itself known.

I have undertaken 6 equalisation charges in addition to 4 rapid charges and 2 fast charges that didn't get to 100%. The battery has been down as low as 7% in this time so has had a good chance to get balanced.

I suspect we will be limited to 449/450 volts, but even if this is true I'd accept a 1% potential difference or 1-2 mile range reduction to solve other issues and provide longevity.

If I can cross the Pennines at this time of year, doing 102 miles in a single leg, departing with 88% and arriving with 7%, I can live with that. In my mind, 100 miles for 80% battery capacity represents reasonable progress between stops. Sure 150 miles for 80% would be better but I wouldn't pay thousands of pounds extra for a benefit that might theoretically save me a few hours per year.

 

[Gomev]

Good job none of my ICE cars ever had an indicator that told me the BHP available, that would have been very disappointing.

 

[Jeps]

Just watched an old video from Bjorn Nyland where he is trying an MG ( before he bought his own) when that had charged to 100 % it showed 458 volt, the weather was around 30 degrees, so maybe warm weather play a role in getting the highest possible figures!

 

[rbpasapera]

As you have charged roughly about six times now ( A mixture of rapid and A/C I assume ) then the common voltage number of around 449 volts is a common factor here.
The magical unicorn number of 455 volts appears not to be making itself known.
Nobody ( as of yet ) has seen any improvement on voltages above 450 is my understanding.
There is some speculation that 455 volts will only return ( if ever ) when the warmer weather returns, however I find it strange that “Pre Update” cars are still displaying 455 volts in the same weather conditions ?.
Question :- When cars are presented for their annual service, will they automatically get the latest BMS update, in order to standardise all cars to the same software condition ?.
Therefore we will all end up with 450 ish volts on the pack.
MG released a “HV Fuse Protection” update which all cars are going to receive at one point or another.
This was because there had been a couple of ZS EV’s that had suddenly just stopped because the HV fuse protecting the pack had failed.
Is this why they have reduced the voltage on the pack now down to 450 (ish) volts ?.
I have no idea - just guessing.
If there is any truth in this pure guess, then charging to full and balancing multiple times is never going to result in achieving the 455 volts we are all lead to believe we SHOULD be returning to ?????.
Is 450 volts the new 455 volts I wonder !.

I think the magic number will be 450v, at least I'm getting the same mileage that I got before the BMS update.

 

[Cocijo]

Here are my thoughts and I must add I’m far from an expert on battery capacity and voltages.
455v in 44.5kw/hr battery produces 97.8amps
If the current remains the same but voltage drops to 450v then capacity falls to 44kw/hr losing 0.5kw/hr on capacity or say 1.5miles. MG are also able to tweak the usable capacity so that it remains roughly the same. I’m not sure if monitoring small voltage changes provides any real value - if there is a 5v difference on some cars the real-world impact would be negligible if any. ?

 

[WAC 768]

Purchase mine in late Dec 20 and never fully charged.... Having had the BMS update done last Thursday, it's clearly improved things for one, using the same rapid charge point @1C, in just under 1hour SOC went from 16 - 93%, compared against similar @4C SOC went from 16% - 72% in the same time and for both i went direct circ 6 mile. Averaging now 3.2 apposed to 2.5 previously even when the temp is just above 0C, with the heating on etc..

Having completed my first full change using the granny charger + balance (latter took 3 hours) it's looking like 450V maybe the new 455V?