BMS software update

[Elmil]

The odometer was at 48978 km, previous SOH reading was at 45267. Between these readings I had several deterioration changes too, ups and downs.

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Date  Odo (km)    SOH (KDS)    MaxDet   MinDet
27/9  45267        99.2%         11.5%   10.0%
3/11  48978        99.5%         11.2%    9.7%

I will certainly ask to get the SOH-report every time I have the car to the workshop, next service will be around March if nothing else calls for it.

[JejuSoul]

Thanks Elmil, Your car is at number 2 in the deterioration race with 187,476km
The numbers I have always used in this race were a simple average of the deterioration numbers, and then follow a linear descent to 40% loss.
This was never intended to be an accurate assessment of the SOH.
Even if it turns out that this formula is the exact one that Kia is using, I don't want to put any faith in its predictions.

[Elmil]

The numbers I have always used in this race were a simple average of the deterioration numbers, and then follow a linear descent to 40% loss.
...
Even if it turns out that this formula is the exact one that Kia is using, I don't want to put any faith in its predictions.

So you already predicted this? Really nice! Well, it's most often the simple explanation that is the correct one..
And of course, what is important is whether or not this curve will be linear. Future will tell.

[ZuinigeRijder]

I had my car in for service (40.000 km) and the SOH was measured as 96.4%.



Torque Pro showed Min Det 12.1% and Max Det 14.1%, which gives an average of 13.1% just after the measurement.



I bought my car with 10.000 km on the clock and the first measurement was at 24454 km, Min Det 9.6%, Max Det 11.1%, average 10.4%.
From the CED value, the consumption was 0.20 kWh/km at 24454 km. I assume the CED value is including regen?
From 24454 km till 39901 the consumption was 0.16 kWh/km. So the demo car has been driven much faster/less economic. Unfortunately I do not know the figures at 10.000 km. If you look at the average deterioration, you see a rise in deterioration lately.



So would be the formula for deterioration: 109.5 % - 13.1 % = 96.4%.
Or another algorithm indirectly related to battery deterioration.

[SoulEV2016]

i really think that i can build the 004_CALC in this way now (with 110% from the first measure).

[Elmil]

I had my car in for service (40.000 km) and the SOH was measured as 96.4%.
..
Torque Pro showed Min Det 12.1% and Max Det 14.1%, which gives an average of 13.1% just after the measurement.
..
So would be the formula for deterioration: 109.5 % - 13.1 % = 96.4%.
Or another algorithm indirectly related to battery deterioration.

Thanks for the data, ZuinigeRijder!

So, this shows it's not just the average of the extremes, but probably the average of all 96 cells. This in turn means that a big PID structure (like the cell voltage structure) should be present somewhere from the BMS, but we still don't know how to find it. Until it's found, I think the average of the min/max values is good enough as long as they don't diff too much.

[SoulEV2016]

Yes, the BMS manage all cells individually ... and use discharge stage to manage the unbalanced cells.

viewtopic.php?f=6&t=471&start=50#p3240

and

viewtopic.php?f=6&t=471&start=140#p4570

balance stage is not very powerful, so a strategy is used to "mark" the cell ... the DET is based on this and the experience of the SK-Innovation (of destruction of cycled cells on benchmark).

if the cell rise not the 4,15-4,16v max voltage ... the DET indicator evolves with it.

[ZuinigeRijder]

Not the whole 30.5 kWh capacity is used, otherwise the total theoretical capacity would be 30.5/27 = approx 113%.
I think that it is around 110%, because there is a lower limit capacity never used, to protect the battery.
If the SOC % is 0%, the BMS % is around 2% and there is always a 1% left?

[Elmil]

.
My SOH has changed. But in the same time, it has NOT!

60,000 km service today. Went to the same KIA-authorized workshop as last time, and expected to find an SOH value of around 99.3% (matching Det 11.4/9.9) on the battery report.

When the car was ready, the battery report from KDS showed this:

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SOH (State of Health):            100.0 %
Accumulative Charge Current:      0.1 Ah
Accumulative Discharge Current:   0.6 Ah
Accumulative Charge Power:        0.0 kWh
Accumulative Discharge Power:     0.2 kWh
Accumulative Operating Time:      675 Sec


It seems that they have managed in some way to reset the BMS and clear all the history counters, probably not knowing what would happen (and still did it..)

My deterioration data is also cleared: MaxDet: 0.0, MaxCell: 0, MinDet: 0.0, MinCell 0
The BMS is in a virgin state, as if it was brand new... but the battery is the same, with 61000 km in it.

Seeing that this actually is possible, one should be careful when buying a used Soul EV from a dealer (or anyone). And what about warranty claims? Would an actual battery test be done, or just reading the SOH value.. A complete reset like this should be quite easy to discover though: There must be reasonable values on the energy and time counters compared with the odometer.

I expect my deterioration numbers to start showing values again soon - maybe tomorrow, as the c harger goes from 16% to 90%+ tonight.

[SoulEV2016]

probably BMS firmware update to correct :
- kWh/Ah counting deviation
- and operating time deviation.