Latest E400 BMS update appears to have reduced usable capacity.

[mariano3113]

The pack 37510-E4203R has 96 cells and is for the 2015-2017 models.
The pack 37510- E4302R has 100 cells and is for the 2018-2019 models.

Given that the fire safety recall adds the 2018-2019 BMS hardware and wiring harness to the 2015-2017 cars I'm not sure why they bother keeping the two versions.

Yeah why would they still do 2 different battery variants.

I assumed since the "Battery warranty for US is a replacement battery with >70% battery capacity....then even putting the smaller Refurbished battery in a 2018-2019 would fulfill Warranty promise and save them some "cells" to have move packs available.

 

[JejuSoul]

My assumption would be that giving everybody the same replacement packs would simplify their software maintenance. Having to write a BMS 'fix' is much easier if you only need to test it on one variant.

My guess for the recent BMS 'fix' fiasco is that they did only test it on one variant but applied it to many.

 

[chilibt]

Th summer Before the second update (that is after the first update last winter), my battery cell voltage was 4.18VDC, After the second update it is 4.10. My range is also 16% less that before the two updates. What I do NOT have is the Pre-update Cell voltage , that is prior to the first update in the BMS software.
What cell Voltage history do others have prior to any updates?

 

[JejuSoul]

Th summer Before the second update (that is after the first update last winter), my battery cell voltage was 4.18VDC, After the second update it is 4.10. My range is also 16% less that before the two updates. What I do NOT have is the Pre-update Cell voltage , that is prior to the first update in the BMS software.
What cell Voltage history do others have prior to any updates?

Can you confirm this is a MY2018 30kWh Soul EV. With original pack or a replacement.?
Do you have any readings of the SOH?

Note:
I have two 2015 Soul EV both with replacement packs.
Both have now had the BMS fix. Both now have the 2018-2019 BMS hardware and wiring harness.
My battery packs have 96 E400 cells not 100.
The BMS software and algorithm they use is not the same as MY2018 30kWh Soul EVs.
In particular the standing voltage at full charge for a new battery is 4.14V
This suggests the size and loss over time of the 'early years' buffer for the 2015 cars is different from the 2018 cars. I cannot estimate that difference because I don't have any data.

 

[chilibt]

Yes it is a 2018 , original battery, dealer SOH was 100% prior to second update (September 3). The previous SOH at the dealer 2 or 3 years ago was 100%.

The soul spy SOH in August was 100%. but it has not given a SOH reading from just before the 2nd update (September). It has 96,000 KM and is going in next week for a Transmission Oil change and to see if everything is good prior to the warranty expiring at 100K Km (Canada).

 

[JejuSoul]

About the 'early years' buffer.
The BMS divides the battery pack into three parts.
Usable Capacity, an 'early years' buffer and a 'safety buffer'.
The 'safety buffer' is required to protect a lithium ion cell from severe degradation at the very top and bottom of the voltage range. This buffer is never lost.
The 'early years' buffer was a construct added by the manufacturer to protect resale values in the first 3 years.
This buffer is lost over time by widening the voltage spread as the battery degrades to maintain the usable capacity at the same value as new.

It seems the BMS algorithm has been modified to alter the behavior of the 'early years' buffer during the BMS fire-safety recall. ( At least for the two 2018 cars in this thread. My two 2015 cars don't show this for now. )
We don't know the reason for this.
Maybe it is somehow related to fire-safety.
Maybe the BMS just thinks the car is new again and will reduce the 'early years' buffer over the next 3 years.
Maybe it is just a software bug and they will fix it at some point.
I don't think we are ever going to know. Kia is never going to tell us.

Also maybe this change will be positive overall by increasing longevity.
I doubt they did it for this reason though because all our cars will be out of warranty soon and after that Kia couldn't care less about battery longevity.

 

[IanL]

I'm afraid I do not understand " by widening the voltage spread as the battery degrades to maintain the usable capacity at the same value as new." How is this widening achieved?

My observations have led me to believe that, when new, the SoH is artificially understated by defining it at a lower capacity than the actual usable capacity, and preventing the BMS from outputting a value in excess of 100%. Thus the initial degradation is invisible to the user and maintainer alike. Perhaps this is what you mean by the early buffer?

Since the BMS update, my BMS still reports 100% SoH, so I would argue that there is no evidence of a change in that respect. What I have observed is a change to the actual useable capacity, by reducing the value of voltage at which the full 100% charge is defined. Thus the displayed SoC has been re-scaled. At the same time, it would appear that the SoC data supplied to the Nav system to facilitate the GOM calculations has been "alternatively processed" such that the reduced capacity is not apparent to the user. My data suggests that the GOM was previously markedly pessimistic, but is now closer to "realistic".

The bottom line is that I estimate my useable capacity has been artificially reduced from 30kWh to about 27 kWh. Living on a small island, and charging infrequently, it's not a problem, but I do object to the apparent deceit.

 

[JejuSoul]

...
My observations have led me to believe that, when new, the SoH is artificially understated by defining it at a lower capacity than the actual usable capacity, and preventing the BMS from outputting a value in excess of 100%. ...

No. This is false.
SoH is a measure of usable capacity. It can never go above 100%
The 'early years' buffer is a portion of the total capacity that is not available at the start.
This is achieved by stopping charging at a lower voltage when the car is new. eg 4.10V
At a later date the voltage spread is widened to maintain the usable capacity. eg 4.18V
Any value for SOH that is greater than 100% is a false construct.
This false construct had some meaning back in 2015 because the car would report the degradation from the 'early years' buffer. Since 2018 the car no longer does this. Hence since then any value for SOH that is greater than 100% should never be used.
Nothing is known about the size of the 'early years' buffer or the rate it is lost for cars from 2018 onwards.
It seems that it has changed. But that is as much as we know.

From my last comment.

It seems the BMS algorithm has been modified to alter the behavior of the 'early years' buffer during the BMS fire-safety recall. ( At least for the two 2018 cars in this thread. My two 2015 cars don't show this for now. )
We don't know the reason for this.
Maybe it is somehow related to fire-safety.
Maybe the BMS just thinks the car is new again and will reduce the 'early years' buffer over the next 3 years.
Maybe it is just a software bug and they will fix it at some point.

I have been talking about the 'early years' buffer. The adjustment to this would be temporary and may have an overall positive impact in the long-term.

But if they adjusted the 'safety buffer' to somehow reduce the fire risk, this would be a permanent loss of range. Although again it may improve longevity.

We don't know what they did. I don't why this doesn't show up on my cars. I suspect the replacement battery on the 2015 has a smaller buffer than yours. If they adjusted it then the difference would be more pronounced on mine than yours.

 

[chilibt]

I agree it is deceit, only to protect the company. After 5 years of great performance and no battery issues (state of health always 100%) they removed 20% of my range with the first update. Then the second update corrected this to removing 16% from the pre software update.

Now my range estimator is all messed up and it is junk. It tells me I have 200 Km and after a planned trip begins of 120km back to home, I cannot make it home and have to get an unscheduled charge (all driven at 80Kmh no heat or A/C). I have been lucky, twice there was a working charger in this remote area. I never experienced anything so bad in the 5.5 years of ownership.

If you purchased a TV with 150 channels available, and after 5 years the TV gets an "software update" making only 120 channels available there would be lawsuits galore, similarly, this is like blocking off a gas tank in a ICE car so the last 16-20% is not available after a warranty update to 5 year old cars.

I believe this software induced degradation of EV batteries is new in the world of warranties and consumer protection. Companies will try and avoid responsibility for manufacturing/product problems, and in this case take away our battery capacity to reduce the risk of ever having to honour any warranty claims.

This cars reduction of range and unpredictable range estimates make it a dangerous mix to travel in the winter. Being suddenly stranded with no options will hurt someone one day.
I hope there is someone who can advise us on legal options, as it is not a battery issue, it is just a software issue.