JejuSoul
Posts: 1506
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Comparing BMS data on the Soul EV with the Ray EV

Tue May 02, 2017 6:38 am

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I am currently driving a 2012 Kia Ray EV with about 56,000km on the odometer.
Here are some photos taken on a recent range test.
I am using the same torque codes to read the BMS as we use on the Soul EV.

I charged to 100%, drove 100km until the battery was below 10% and then recharged to 100%.
The Ray EV does not display SOC, nor is there a reading in the BMS for SOC (display).
At 100% charge SOC (BMS) displayed 90%. At the end SOC (BMS) displayed 9.5%.

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At each of these points I took a screenshot of the BMS data.

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Energy charged = 14 kWh for 90% (roughly) => Full pack 24.5/0.9 = 15.5kWh
Energy discharged = 14 kWh for 90% (roughly) => Full pack 14/0.9 = 15.5kWh
Regenerated Energy on the trip was 5kWh.

Ah charged = 40 Ah for 90% (roughly) => Full pack 40/0.9 = 44.4Ah
Ah discharged = 41 Ah for 90% (roughly) => Full pack 41/0.9 = 45.5Ah
Regenerated Ah on the trip was 16Ah.

These numbers at first seemed reasonable but then I checked with this.

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From the external stand in 4 hours of charging I loaded 13.7kWh. There is no way I could have got 14kWh into the battery.
I was loading 16A at just under 220V. The input power was just under 3.5kW. The external c harger is correct.

The energy draw on the battery was between 2.6kW and 3.0kW depending whether the EWP was on or not. Assuming an average of 2.8kW the efficiency of the process is about 80%. I was watching this data on the screen, but didn't take a screen shot. I have the logs so will be able to get a more accurate value. Using this value suggests that in 4 hours I got 11.2kWh and thus the usable pack capacity is 12.4kWh

Update - from the logfile actual average energy draw was -2.83kW, so in 4 hours I would have charged 11.32kWh. Efficiency = 82.7%.
This reading would give a max battery capacity of about 12.6kWh.
Seems a more reasonable number given my Soul EV with 27kWh would drive 200k on a similar trip.

The main lesson here is that the Cumulative Energy Counters reported by the BMS are not to be trusted.
Last edited by JejuSoul on Fri May 12, 2017 7:36 am, edited 3 times in total.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

SoulEV2016
Posts: 572
Joined: Mon Jul 18, 2016 6:26 am

Re: Comparing BMS data on the Soul EV with the Ray EV

Tue May 02, 2017 10:18 am

Have you a Chademo plug on this car ?
Chademo kWh-meter (in DC) can be more accurate than type 1 charger (in AC) ... no ?
Kia Soul EV 2016 Ultimate 27 kWh - Mountain hard driving (fast). Drain 1/3 of Battery after 32km. - Unlimited highway speed (153km/h at regulator).

JejuSoul
Posts: 1506
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Comparing BMS data on the Soul EV with the Ray EV

Tue May 02, 2017 10:24 pm

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Yes the Ray EV has a Chademo inlet. I will test that later.
Here is a graph from the charging session yesterday.

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Am curious why does SOC (BMS) not increase in a straight line. why the change between 38% and 44% where it goes up faster?
Does the Soul EV show this behaviour too?
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

SoulEV2016
Posts: 572
Joined: Mon Jul 18, 2016 6:26 am

Re: Comparing BMS data on the Soul EV with the Ray EV

Wed May 03, 2017 4:01 am

SOC BMS is always a formula between the max voltage (at the cell ! so 4,15v for example ... or less depending of the others cells) and balancing stage (cell deviation) with a correction of Ah-meter.

so ... battery is old or car have been storage for months before you run and charge.

That's why, in industrial usage ... we use LifePO4 for long period and not Li-Ion/Li-NMC.
Kia Soul EV 2016 Ultimate 27 kWh - Mountain hard driving (fast). Drain 1/3 of Battery after 32km. - Unlimited highway speed (153km/h at regulator).

Elmil
Posts: 142
Joined: Mon Oct 26, 2015 9:46 am
Location: Sweden

Re: Comparing BMS data on the Soul EV with the Ray EV

Wed May 03, 2017 11:39 am

JejuSoul wrote:-
Am curious why does SOC (BMS) not increase in a straight line. why the change between 38% and 44% where it goes up faster?
Does the Soul EV show this behaviour too?


I saw a similar increase on the loaner Soul EV I used a year ago. That car was the dealers demo and had probably always been c harged to 84% at their 20 kW Chademo. Had all zeros on deterioration values and around 1000 km on the odometer as I recall.
When I used a Chademo FC on the road to work, the last SOC% between 81 to 84% went really quick, so I guess some adaption to new situation occured.
Kia Soul EV 2015 / 115,543 km Sold
Kia Soul EV 2019

JejuSoul
Posts: 1506
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Comparing BMS data on the Soul EV with the Ray EV

Wed May 03, 2017 9:55 pm

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Yes. I assume the BMS will adjust the SOC during charging if it figures out it is badly calibrated.
Here is what happens on my Soul EV.

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The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

JejuSoul
Posts: 1506
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Comparing BMS data on the Soul EV with the Ray EV

Fri May 12, 2017 7:35 am

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Done another range test on my Ray EV. This time drove 91km over 3 days and got down to 4.5% SOC (BMS). It shows turtle!
Does anyone know for sure what SOC (BMS) shows when the pack is empty with the Soul EV. I have never been below 10%.

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The stats based on the Cumulative Energy Counters are -

Energy charged = 14.6 kWh for 95% (roughly) => Full pack 14.6/0.95 = 15.4 kWh
Energy discharged = 9 kWh for 95% (roughly) => Full pack 9/0.95 = 9.4 kWh
Regenerated Energy on the trip was 4 kWh.

Ah charged = 42 Ah for 95% (roughly) => Full pack 42/0.95 = 44.0 Ah
Ah discharged = 42 Ah for 95% (roughly) => Full pack 42/0.95 = 44.0 Ah
Regenerated Ah on the trip was 12 Ah. (This time there was no mountain driving.)

The Ah numbers are consistent with the test done two weeks ago.
I am struggling to make sense of the kWh figures. I don't know what such a huge discrepancy means.

Update - from the logfile actual average energy draw was -2.742kW, so in 4 hours and 8 minutes I would have charged 11.33 kWh.
This reading would give a max battery capacity of about 11.9 kWh.
It is very similar to the previous value. It seems the actual energy capacity now in the pack is about 12 kWh
Last edited by JejuSoul on Fri May 12, 2017 11:01 pm, edited 2 times in total.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

SoulEV2016
Posts: 572
Joined: Mon Jul 18, 2016 6:26 am

Re: Comparing BMS data on the Soul EV with the Ray EV

Fri May 12, 2017 7:58 am

kWh are based on the voltage measure.
When you charge the pack and it is old, the voltage is always high than rise.
At contrary, when you discharge the pack, the voltage SAG really HUGE when you use to drive.

at cell level, it's like that :
- cell can evolve from 3,00v to 4,20v
- builder allow only 3,20v and 4,15v
- when you charge and the pack is old, the voltage evolve from 3,90v to 4,10v (and BMS strategic change to balance the cell from 4,00v to 4,15v for example)
- when you discharge, the cell voltage evolve (when it is old) from 3,85v to 3,30v (4,15v~4,10v is a hollow point)

and then, the kWh is different than the Ah.
on Bike, we only measure the Ah because is more like the fuel liter in a tank.

kWh is good to see ageing effect on a pack.
Usually, on bike, the cells are deviate before the SAG voltage of the pack.

On this Kia Ray EV, it's a good product so all cells aging together.

What is your cell deviation at drive and at 7kW charger and at Chademo 43kW charger ?
It's a good indicator, too ... especially when the pack are below 10%.
Kia Soul EV 2016 Ultimate 27 kWh - Mountain hard driving (fast). Drain 1/3 of Battery after 32km. - Unlimited highway speed (153km/h at regulator).

JejuSoul
Posts: 1506
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Comparing BMS data on the Soul EV with the Ray EV

Fri May 12, 2017 5:48 pm

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Just like in my previous test SOC (BMS) did not increase in a straight line. Why the change between 38% and 44% where it goes up faster?
This time I do not believe it is badly calibrated, given that I have already done a calibration test a week before.

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Also the Cumulative Energy counter shows the same anomaly. This explains why the Energy Counter cannot be used to measure the capacity of the battery

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The Cumulative Current is the same.

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To show this is not real. The Energy Draw does not show this effect.

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Last edited by JejuSoul on Fri May 19, 2017 2:38 am, edited 1 time in total.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.

Elmil
Posts: 142
Joined: Mon Oct 26, 2015 9:46 am
Location: Sweden

Re: Comparing BMS data on the Soul EV with the Ray EV

Sat May 13, 2017 12:34 am

JejuSoul wrote:-
Done another range test on my Ray EV. This time drove 91km over 3 days and got down to 4.5% SOC (BMS). It shows turtle!
Does anyone know for sure what SOC (BMS) shows when the pack is empty with the Soul EV. I have never been below 10%.

Yes, when I did a 100% to 0% range check last summer, the battery turned off at 297.2V while the SOC (displ) went from 1.0% to 0.0%.
The SOC (BMS) showed 2.5% and went to 2.0% a couple of seconds later and stayed so for two minutes until I connected the charg er.
Kia Soul EV 2015 / 115,543 km Sold
Kia Soul EV 2019

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