BMS Version is there a better one available

[Aussi55]

Hi,

Having had the chance to do my first full charge and equilisation I was wondering if there is a better version available.

The HV voltage is 449v with the GOM range showing 148 miles in normal mode regen 3, heating switched off.

Car is August 2020 and has had one service.

I don't get lots of bongs and can only charge the car when locked.

Does that indicate any other update worth having?

Many thanks in advance.

 

[JodyS21]

You have the "latest" 450V BMS then that suggests.
There is an update (EVCC ECU module) that allows AC charging unlocked, it seems hard to get a dealer to do the update though.

You haven't reset the trips to reset the GOM calculation, in N3 under no load (0amps) it will should show 163 miles, unless you have lost some battery State Of Health (which is likely from Aug 2020) in which case it could be a few miles less.

 

[Aussi55]

Hi,

Many thanks for your reply.

I did reset the accumulated trip before charging so I can keep track of my distance and associated charge info.

I will double check everything just to be sure.

Thanks again.

 

[JodyS21]

Hi,

Many thanks for your reply.

I did reset the accumulated trip before charging so I can keep track of my distance and associated charge info.

I will double check everything just to be sure.

Thanks again.

Def double check that, if you did reset trips and it shows 148 miles then that is very bad news....

 

[ARealHuman]

I had the latest BMS version put on at my first service at the end of August. I had the "non-faulty" version prior to that. One thing I have noticed is it's easier to equalise the cells - previously I would do an overnight charge, then plug it in again the following night if I wanted to equalise. Now it seems to equalise on all instances of charging overnight.

 

[JodyS21]

I had the latest BMS version put on at my first service at the end of August. I had the "non-faulty" version prior to that. One thing I have noticed is it's easier to equalise the cells - previously I would do an overnight charge, then plug it in again the following night if I wanted to equalise. Now it seems to equalise on all instances of charging overnight.

@Kithmo This matches what you’re seeing with your old BMS version doesn’t it, suggests getting upgraded to the new 450v BMS may help your imbalance

 

[Zoomy]

The revised BMS lowers the cell voltage thus increasing the pack life, but at the cost of lower range. It didn't though amend the stats in the GoM, so SoH and range ETA is off. You can run to "-1%" though before it shuts down.

 

[Kithmo]

@Kithmo This matches what you’re seeing with your old BMS version doesn’t it, suggests getting upgraded to the new 450v BMS may help your imbalance

If the dealer offered it free, I would, but if they want paying for it I won't.
If I hadn't used the app, I would never have known about my 40mV imbalance.
As the car charges up then balances for between 10 minutes and half an hour I would think all is tickety-boo.

 

[Zoomy]

Added point there Kithmo is the quality of updates and with the new cars, is the ability to do OTA and so the impact risk is more significant from being able to touch more of the owner population at once.

 

[JodyS21]

Added point there Kithmo is the quality of updates and with the new cars, is the ability to do OTA and so the impact risk is more significant from being able to touch more of the owner population at once.

I’m not quite so sure the OTA updates are all what they imply.
I asked someone abroad who has the existing app functionality, they can do OTA updates but he said it is restricted to updating the infotainment system software & not to update any ECUs.
So I think we’ll have to wait to see what the new system actually does regarding OTA.

 

[JodyS21]

The revised BMS lowers the cell voltage thus increasing the pack life, but at the cost of lower range. It didn't though amend the stats in the GoM, so SoH and range ETA is off. You can run to "-1%" though before it shuts down.

The amount they’ve taken off the top buffer has been added (subtracted!) to the bottom buffer, so it seems to be the same amount of real SOC available to use.
We’ve done a few tests on the 455 & 450v BMS versions at full and run completely empty.

 

[Headgas1]

The amount they’ve taken off the top buffer has been added (subtracted!) to the bottom buffer, so it seems to be the same amount of real SOC available to use.
We’ve done a few tests on the 455 & 450v BMS versions at full and run completely empty.

Hi I did a check on mine after a full charge and equalisation and it was 448v and 161 miles it was a particularly cold evening am i right in thinking that would account for it being a little bit down on the figures ?

 

[JodyS21]

Hi I did a check on mine after a full charge and equalisation and it was 448v and 161 miles it was a particularly cold evening am i right in thinking that would account for it being a little bit down on the figures ?

I do not believe the temperature makes any difference to the GOM, it is purely based on WLTP / previous trip data.
I guess maybe the battery just didn’t fill up completely because it was cold...

 

[Headgas1]

I do not believe the temperature makes any difference to the GOM, it is purely based on WLTP / previous trip data.
I guess maybe the battery just didn’t fill up completely because it was cold...

Fair enough

 

[rbpasapera]

I do not believe the temperature makes any difference to the GOM, it is purely based on WLTP / previous trip data.
I guess maybe the battery just didn’t fill up completely because it was cold...

Or the battery has the SOH at 98-ish%

 

[JodyS21]

Or the battery has the SOH at 98-ish%

Very very true.
@Headgas1 Your car is pretty new isn’t it?

 

[Headgas1]

Very very true.
@Headgas1 Your car is pretty new isn’t it?

Very very true.
@Headgas1 Your car is pretty new isn’t it?

March 2020

 

[JodyS21]

Oh I didn't realise, as you were new on the forum I just assumed the car was new.

In that case, as @rbpasapera said, your 161miles GOM will likely be because your battery State Of Health is no longer at 100%

 

[Headgas1]

Oh I didn't realise, as you were new on the forum I just assumed the car was new.

In that case, as @rbpasapera said, your 161miles GOM will likely be because your battery State Of Health is no longer at 100%

yes well there is a second hand car market unfortunately we can’t all afford brand new cars
Edit.. It could be that the battery isn’t fully balanced but I tend to agree that the SOH is no longer 100% but it’s not far off so I’ll take that

 

[Headgas1]

Oh I didn't realise, as you were new on the forum I just assumed the car was new.

In that case, as @rbpasapera said, your 161miles GOM will likely be because your battery State Of Health is no longer at 100%

If my o level maths is correct 100%=163 x%=161
so x%/100% 161/163 x = 98.77%