Latest E400 BMS update appears to have reduced usable capacity.

The recall was done on my 2018 MY recently. Prior to the update, my SOH was about 101%. I calculate it using displayed SOC percentage before and after charge, mileage between charges, and kWh/mile between charges. The results vary a little, because of the poor granularity of the data, but are reasonably consistent. The resulting capacity in kWh is then expressed as a percentage of 30 kWh (the usable capacity) to give the SOH. I also record GOM before and after charge, and calculate "GOM pessimism".

Since the update, the SOH has dropped to about 92%,. The GOM pessimism has reduced correspondingly. In both cases, the change is marked, not a gradual movement. The explanation I have arrived at is that the relationship between the real SOC in Ah and the displayed SOC in percent has been altered, and the GOM algorithm correspondingly altered so that the displayed range appears much as before (which it does). The data shows that the usable capacity has been reduced from 30 kWh to about 27.5 kWh, as the BMS will not charge over the 100% displayed value.

Another item of confirmatory evidence is that the 5hr 20min charge (with my wall box set to 16A) I usually employ to get approximately 50% SOC increase, now gives 58-62%. Some variation can be expected, mainly due to ambient temperature, but the noticeable step change is not linked to a marked shift in the weather. I do not believe the box is providing more Ah, so the change must arise because of an alteration of displayed %age charge.

I think KIA may have done this to extend the battery life, as the 70% SOH replacement value would appear to have been altered from 21 kWh to about 19.25 kWh. It may also have benefit in reducing the probability of dangerous overheating, which is the stated purpose of the recall.

I would be interested in knowing if anyone can confirm my observations. One way would be to compare cell voltage values at 100% SOC before and after the update.

The recent recall updated the BMS software. It is quite likely that the algorithm used by the BMS has changed. The PIDs we use to query the BMS also sometimes change.

But the GOM software is in the Navi computer. The trip data is stored here. The software for this has not been changed. The change must be that the BMS is sending different data for the SOC at the start and the end of a trip.

The SOH that should be used is from the original usable capacity of 30kWh. This is what the battery warranty applies to. It would not be okay for them to lower the 70% SOH replacement value by later artificially reducing the usable capacity.

JejuSoul said:

... It would not be okay for them to lower the 70% SOH replacement value by later artificially reducing the usable capacity.

Click to expand...

I quite agree. I will watch SoulSpy for when the reported SOH drops below 100% and then check my value for capacity. As Spy uses the SOH value computed by the BMS (which is presumably also used by KIA for warranty replacement), that should reveal whether they are playing it straight.

Do you perhaps have a record of cell voltage when fully charged before the recall was applied? Unfortunately, I do not.

Previously I have written this :- Analysis of a replacement battery.

Also of note - a MY2018 30kWh Soul EV has a final resting voltage at 100% SOC of 410.0V
This has 100 cells, each charged to 4.10V
My car has 96 cells, each charged to 4.14V

I assume this means there is a much larger buffer on the MY2018 30kWh Soul EV than a MY2015 replacement battery 27kWh Soul EV.

Click to expand...

The data came from 3 cars.
My blue 27kWh 2015 Soul EV. Original BMS. Data read 4 years ago. SOH = 96%
My white 27kWh 2015 Soul EV after replacement battery. 2nd BMS. Data read 4 years ago.
Norwegian 30kWh Soul EV. Original BMS. Data read 6 years ago.

There have been plenty of BMS updates in the intervening years. The latest being the 'Recall BMS'
that most of our cars now have. The BMS software is not the same. There is no way I can keep track of all the changes. Hence I no longer track BMS data for cars other than my own. Nor do I recommend trusting any app that gives BMS data, other than the one that Kia itself uses.

What I do recommend if you intend keeping the car for the long term is to track the range data over many seasons. This would give a real trendline of the car's usable capacity to compare the BMS data against.

Thanks, the data for the Norwegian Soul is just what I need. I will report when I have next done a 100% charge.

Well, I have done a 100% charge , and the battery voltage is 413.6, with all cells reading 4.12 volts. This was after 12 hr from full charge end. The reported SOH, stated as read from the BMS, is 100%. All data from SOULEV Spy.

This does not support my theory. I will have to search for another explanation.

Battery update (august 2024 version) removes range in 2018 Soul EV.

After the first Battery software update in February removed 20% of my range an new update was given by KIA as a "Voluntary recall" dated August 2024.
Now it has been 17 days and here is the fact for my car:
The new update maximizes the range to only 210 KM. My car was getting a summer range of 240 to 255 Km, now it is limited to a Maximum of 210Km. No highway driving, Max speed (no AC) 80 Km h.

My EV spy software showed in early August a max charge as 4.18v per cell prior to the newest update (I do not have the data from Feb, prior to the first update) Now it is limited to 4.10 volts, and never above! (both sets of data was at a cell temp of 25C-27c)

As a result of the first update(Feb 2024) I lost 20% range (max range 196). Now the new August update gave me a loss of 16% from last year. (242km avg down to 210 km). To add to the problem, the range data is terribly inaccurate. My 210 range yesterday could not get me 180Km, without having to find a level 3 charger to get home. (80 kmh max , no AC used).

Another change is the efficiency rating (scale of 1 to 8). I was consistently getting 7 or 8 for 5 years. Now I see 4 to 6 all the time and only 8 for a few minutes a day. it seems the range and efficiency calculations are unstable, often I see one range on shut off, and then a few minutes later start up and it is 5 Km range different. Once I saw the range drop by 10 km instantly as I drove.

I believe after 5.5 years of ownership of this car, having a OEM company modify a car to degrade its range is against consumer protection principles. I am thinking that KIA is degrading batteries to reduce its risk of replacing batteries. This reduces the range that was sold to consumers below to what was its "stated" range. Does anyone else have the same experience and concerns? (FYI we loved the car UNTIL the updates, now it is tainted to us, all because of software).

Also the original recall was for "fire" risk, and the harness was to be inspected. Does anyone know why a degrading of the battery cell voltage was supposed to reduce the risk? I cannot find the reasoning/explanation on the BMS changes and what they were supposed to do to reduce the risk.