Reduced range following garage visit! Hurrah!

[shawncullen]

So, had a knocking on my steering wheel. Took it into local dealer. Not sorted yet. They are ordering a part. However the car is fine to drive so I do have it back. However: before the car went in my GOM would show 213 on a full charge. On my first full charge since having it back, it’s down to 156! Showing 449v. Is it simply because they’ve reset everything and the miles will come back up shortly? I don’t know if they’ve done anything with the BMS - hope not! Will speak to them Monday to see but just wondering if anyone had any thoughts?
Shawn

 

[micky]

So, had a knocking on my steering wheel. Took it into local dealer. Not sorted yet. They are ordering a part. However the car is fine to drive so I do have it back. However: before the car went in my GOM would show 213 on a full charge. On my first full charge since having it back, it’s down to 156! Showing 449v. Is it simply because they’ve reset everything and the miles will come back up shortly? I don’t know if they’ve done anything with the BMS - hope not! Will speak to them Monday to see but just wondering if anyone had any thoughts?
Shawn

hi shawncullen as its showing 449 volts that indicated you have the latest bms did they update this when in the garage if so the old voltage must have been on 455 volts on full charge before..

 

[Lovemyev]

So, had a knocking on my steering wheel. Took it into local dealer. Not sorted yet. They are ordering a part. However the car is fine to drive so I do have it back. However: before the car went in my GOM would show 213 on a full charge. On my first full charge since having it back, it’s down to 156! Showing 449v. Is it simply because they’ve reset everything and the miles will come back up shortly? I don’t know if they’ve done anything with the BMS - hope not! Will speak to them Monday to see but just wondering if anyone had any thoughts?
Shawn

We are talking ZS EV - I guess ???.
If so, 449 volts after a full charge would suggest the BMS update has been done.

 

[shawncullen]

Yup - zs ev - thought I’d tagged that! Doh!

 

[BarryH]

Yes, the latest BMS is 449 volts on a full charge. I think the BMS needs a few charge cycles to recalibrate. I would do a few miles and get the HV battery down to 1 or 2 bars then fully chartered with a Ballance charge about 6 hours on an AC charger overnight should do the job. The latest BMS not only lowered the Full-Charged voltage to 449 volts which meant you get Regen sooner from 100% charge but also lowered the voltage at which the car is at 0% ie it allowed a deeper discharge. I have found I'm getting about 10 miles extra range operating the battery in this range possibly because Regen is available sooner from full and when I Rapid Charge the actual battery voltage is lower at the start of the charge so the car seems to charge for longer at the highest rate.

The weather has a lot to do with what range you'll see on full-charge and recently temperatures have varied quite a lot from day-to-day. I've been seeing Full-Charge showing anything from 187 to 165 miles where as about a month ago I'd see 215 miles.

 

[Lovemyev]

But if the BMS has been done, then you would expect the GOM to read 162 miles after a full charge & balance.
Unless the pack was out of balance of course ?.
Just check if they have reset both of the trip recorders on the car.
A predicted 215 on the GOM is an inflated / non achievable figure anyway.
A strange feature of the new BMS is that it over reports a predicted range on the GOM with even a small amount of mileage reported on the GOM.
Resetting both of trip records will bring the predicted range more into an achievable range.
A number of owners running on the latest BMS update, have picked up on this strange phenomenon.
If you are displaying a predicted range of +200 miles on the GOM after a fully charge and balance, before you start your next journey, reset both your recent trip and the accumulative trip.
As you do this, watch the impact on the range of the GOM.
Wow ….. where did that range just go ?.

 

[shawncullen]

Thanks for this. Will run it down and slow charge and see what happens! Don’t mind getting BMS update just wish they’d tell you they’ve done it! ??

 

[Cocijo]

Unless I’m missing something - which is entirely possible!!
1/we haven’t established what full voltage the pack had before the dealer visit. This should tell if it’s been updated from say 456v to 449v
2/if it’s now showing 449v it doesn’t need much balancing if on the 449v bms
3/you don’t need to run the hv pack down to one or two bars to balance - down to around c93% is enough then charge and balance if needed.
4/the previous predicted range was based on historic trip records - if you really like to see this (although fairly fictitious) i’m sure that you can build your trip back up to somewhere near again.
5/with 449v on latest bms you don’t really have an issue.

 

[Lovemyev]

Unless I’m missing something - which is entirely possible!!
1/we haven’t established what full voltage the pack had before the dealer visit. This should tell if it’s been updated from say 456v to 449v
2/if it’s now showing 449v it doesn’t need much balancing if on the 449v bms
3/you don’t need to run the hv pack down to one or two bars to balance - down to around c93% is enough then charge and balance if needed.
4/the previous predicted range was based on historic trip records - if you really like to see this (although fairly fictitious) i’m sure that you can build your trip back up to somewhere near again.
5/with 449v on latest bms you don’t really have an issue.

I agree, we are not sure what software package you are running on, either before or after your visit to the dealer.
To be honest, if the dealer HAS applied the latest BMS update to your car, then they have correctly done what MG have instructed them to do, applying the latest service bulletin updates.
All dealers SHOULD be updating all ZS EV’s to the latest software at the time of them requiring work, or at the time of service.
Some have chosen to avoid applying these updates, or will apply them only by request.
Which is against the MG protocol.
Poorly applied updates can leave the dealer with a big head ache.
Has @Cocijo has suggested, reset BOTH of your trips, then fully charge and balance the pack.
You don’t need to run the pack down to a low SOC, you can commence a balance as soon as you loose one white bar from the GOM.
When you reboot the car after the balance has completed, with foot ? OFF the brake, and ensure all items are turned off.
Then scroll through your menu’s with the up and down buttons on the right hand side of the steering wheel.
You will find a screen that reports your voltage on the pack.
This should be around 448 - 450 volts IF you are on the latest BMS software.
456 volts would suggest the OEM original software.
Your range should be around 162 miles in normal default mode.
Unless your pack is out of balance.
If they did update the BMS - they should have explained that you should be conducting balancing of the pack to restore any imbalance there in.

 

[Cocijo]

I think updating the bms to the 450v doesn’t necessarily mean that extra balancing is needed above normal. Obviously if you had the bad bms you may be out of balance already but if you didn’t experience issues before you shouldn’t have to balance any more after the update than before.

 

[Fishettibean]

The miles on the GOM will come back, as when the BMS is updated, all usage is erased. Unless you have lead foot like i do and might see it go down ?
Also on benefit of the 449v BMS is that kers 3 regeneration is available sooner and less "use brake" warning when fully charged.

 

[Dr Dave]

Thanks for this. Will run it down and slow charge and see what happens! Don’t mind getting BMS update just wish they’d tell you they’ve done it! ??

When the BMS is updated everything is reset.

 

[Lovemyev]

When the BMS is updated everything is reset.

Arhhh ......... That's gives a bit of strength to my theory then !.

 

[BarryH]

When the BMS is updated everything is reset.

I can't remember now it was 6 months ago

 

[shawncullen]

Now up to 183 miles on the GOM so going in right direction. And seems a lot more accurate ?‍

 

[BarryH]

Now up to 183 miles on the GOM so going in right direction. And seems a lot more accurate ?‍

It's been cooler this past week and we are promised more heat next week and realistically EV's do go further on a full charge when the ambient temperature is higher. I've found 25C and above much-improved range but in winter 130 miles tops.

 

[Lovemyev]

Now up to 183 miles on the GOM so going in right direction. And seems a lot more accurate ?‍

183 is an over inflated prediction.
Nice to see, but unachievable.
Ambient temp has a BIG impact on what the car is likely to report.
BUT ....... REMEMBER TO RESET YOUR TRIPS TO GET A MORE ACCURATE FIGURE !.

 

[SCB86]

As others have said you should reset your GOM at every charge to get more accurate readings.
Mine always shows 161 miles of range in Eco with HVAC on and 179 with it off.

The miles on the GOM will come back, as when the BMS is updated, all usage is erased. Unless you have lead foot like i do and might see it go down ?
Also on benefit of the 449v BMS is that kers 3 regeneration is available sooner and less "use brake" warning when fully charged.

I don't remember ever getting the brake warning since I had the 449v BMS update.

 

[Lovemyev]

As others have said you should reset your GOM at every charge to get more accurate readings.
Mine always shows 161 miles of range in Eco with HVAC on and 179 with it off.


I don't remember ever getting the brake warning since I had the 449v BMS update.

I think I have seen the "Reduced Regen Braking" warning once, after receiving the BMS update way back on the 15th Jan 2021.
But I can not remember if this was after a full 100% charge or part 80 - 85% charge ????.

 

[Cocijo]

Is this not just because regen braking is not reduced even on a full charge on the 449v?