Battery Ageing Model

[SoulEV2016]

No news because, 1 month without use (charge every 15 days for 12h, no problem with 12v ACID battery).

 

[ZuinigeRijder]

3 years and 3 months old the Kia Soul EV reached 70.000 km.
Bought 1 year old with 10.000 km on the ODO meter. No idea what was the deterioration at that time, but I suspect already 8% or so.

Latest readout:
km: 70239
Avg Det: 13.8
Max Det: 15.4
Min Det: 12.1
Cumulative CED: 12473 kW

However, looking at the past data, it looks the deterioration is about 15%.
Note that after 1 year the deterioration was already 10%, so I do not know how the car was driven before, but the consumption was much higher (around 20kWh/100km) than I drive (around 15 kWh/100 km).

Here are the gory details:

Date	km	Avg Det	Max Det	Min Det	Max Cell	Min Cell	BMS	SOC	CEC	CED	kWh/km	Comments
2014-08-28	0	0.0	0.0	0.0								Assume start with 0 date of start of use
2015-09-17	10060	8.0	8.0	8.0								Bought the car, do not know the deterioration. Just a guess.
2016-01-17	18709	10.8	11.6	10.0	3	15	55.00	57.00				First readout with Torque
2016-01-27	19421	10.4	11.1	9.6								
2016-01-28	19493	12.3	13.4	11.1	43	51						
2016-02-01	19777	9.2	10.2	8.2								
2016-02-10	20419	9.2	10.0	8.4								
2016-02-20	21131	9.4	10.4	8.4								
2016-03-04	22057	11.0	11.6	10.4	3	8	32.00	32.50				
2016-03-07	22271	11.0	11.6	10.4	3	8	18.00	17.50				
2016-03-07	22271	10.4	11.1	9.6	3	83	95.00	100.00				
2016-03-11	22555	11.1	11.8	10.3	9	15	46.50	48.00				
2016-03-14	22769	10.4	11.1	9.6	9	8	95.00	100.00				
2016-03-21	23268	10.1	11.0	9.1	43	49	95.00	100.00				
2016-03-25	23553	11.6	12.6	10.6	42	59	95.00	100.00				
2016-04-01	24051	12.9	13.7	12.1	42	15	95.00	100.00				
2016-04-08	24454	10.4	11.1	9.6	9	1	95.00	100.00	5062	4951	0.202461765	start measure CEC and CED
2016-04-12	24620	10.4	11.1	9.6	9	1	95.00	100.00	5088	4977		
2016-04-13	24722	10.4	11.1	9.6	9	1	95.00	100.00	5105	4994		
2016-04-14	24876	10.4	11.1	9.6	9	1	14.00	13.50	5108	5020		
2016-04-15	24876	9.5	10.2	8.7	43	15	95.00	100.00	5132	5020		
2016-04-26	25745	9.5	10.2	8.7	43	15			5284.2	5166.5		
2016-05-04	26310	9.5	10.2	8.7	43	15	95.00	100.00	5377.4	5256.6		
2016-05-06	26478	9.5	10.2	8.7	43	15	5.00	3.50	5382.1	5286.2		
2016-05-06	26478	8.1	8.8	7.3	2	8	95.00	100.00	5408.2	5286.5		
2016-05-25	27802	8.1	8.8	7.3	2	8	95.00	100.00	5620.1	5494.5		
2016-05-26	27969	8.1	8.8	7.3	2	8	15.00	14.50	5623.5	5519.8		
2016-05-26	27969	9.2	10.1	8.2	48	83	95.00	100.00	5646.8	5520.3		
2016-05-30	28191	9.8	10.8	8.8	9	59	95.00	100.00	5682.9	5556.5		
2016-06-20	30535	9.5	10.5	8.5	9	49	78.00	82.00	6073.7	5941.4		
2016-07-01	31340	9.5	10.5	8.5	9	49	95.00	100.00	6207.2	6064.6	0.161719431	
2016-07-12	31846	9.5	10.5	8.5	9	49	95.00	100.00	6287.1	6143.1	0.161268939	
2016-07-15	32010	9.5	10.5	8.5	9	49	12.00	11.00	6291.1	6171.4		
2016-07-15	32010	10.3	11.3	9.3	9	15	95.00	100.00	6315.4	6171.7	0.161553732	
2016-07-25	32662	9.6	10.2	9.0	2	1	95.00	100.00	6416.9	6269.8	0.160672515	
2016-09-08	35992	10.5	11.2	9.8	43	84	95.00	100.00	6882.3	6714.5	0.15284278	
2016-09-16	36165	10.5	11.2	9.8	3	15	81.50	85.00	6971.9	6804.8	0.15829562	
2016-09-19	36361	11.5	12.2	10.7	9	15	95.00	100.00	7012.8	6841.1	0.158738557	
2016-09-21	36525	11.5	12.2	10.7	9	15	17.00	16.50	7018	6868.6	0.158860078	
2016-09-21	36525	11.1	12.0	10.1	32	15	95.00	100.00	7041.1	6868.9	0.158884931	
2016-09-26	36525	11.2	12.0	10.4	3	15	95.00	100.00	7086.7	6912.5	0.162496893	
2016-10-03	37364	11.2	12.0	10.4	3	15	14.50	14.00	7165.8	7013.3	0.159744384	
2016-10-03	37364	11.2	12.0	10.4	2	49	95.00	100.00	7189.5	7013.6	0.159767622	
2016-10-21	38705	14.2	15.2	13.2	43	59	12.00	11.50	7413.2	7244.1	0.160908006	
2016-10-21	38705	13.0	13.8	12.2	2	59	95.00	100.00	7437.6	7255.4	0.161700933	
2016-10-27	39000	13.0	13.8	12.2	2	59	13.00	12.50	7467.4	7308	0.162037674	
2016-10-27	39000	11.8	12.7	10.8	9	59	95.00	100.00	7491.3	7308.4	0.162065173	
2016-11-08	39844	13.1	14.1	12.1	9	61	95.00	100.00	7647.5	7457.9	0.162891488	
2016-11-09	39901	13.1	14.1	12.1	9	61	63.50	66.00	7648.7	7468.3	0.162963682	
2017-01-09	43944	12.9	13.6	12.2	2	59	95.00	100.00	8441.6	8239.8	0.168742945	
2017-01-31	45483	12.6	13.4	11.8			95.00	100.00	8657.3	8457.4	0.166741167	
2017-02-08	46158	14.1	15.0	13.1	42	62	53.00	55.00	8873	8675	0.171581275	
2017-02-20	47103	13.4	14.2	12.6	2	15	95.00	100.00	9065.3	8851.6	0.172219524	
2017-03-10	48319	15.1	16.0	14.1	42	59	16.00	15.50	9266.6	9068.8	0.172545569	
2017-03-11	48319	13.8	14.8	12.8	9	59	95.00	100.00	9289.7	9069.1	0.17255814	
2017-04-06	49992	13.8	14.8	12.8	9	59	15.00	15.50	9559.5	9342	0.171939854	
2017-04-06	49992	12.5	13.3	11.7	9	15	95.00	100.00	9582.7	9342.3	0.171951602	
2017-04-24	51326	13.7	14.6	12.7	9	59	30.00	30.50	9793.5	9558.3	0.171453558	
2017-05-01	51691	12.7	13.7	11.7	9	59	95.00	100.00	9882.4	9623.9	0.171564416	
2017-05-30	53593	12.7	13.7	11.7	9	59	16.00	15.50	10172.3	9929	0.170836336	
2017-05-30	53593	11.7	12.7	10.7	9	59	95.00	100.00	10195.4	9929.4	0.170850063	
2017-06-07	54172	11.7	12.7	10.7	9	59	16.50	16.00	10273	10028.1	0.170842587	
2017-06-07	54172	12.5	13.3	11.7	3	49	95.00	100.00	10296.1	10028.4	0.170852682	
2017-06-14	55116	12.5	13.3	11.7	3	49	18.00	17.50	10430.7	10181.9	0.170598787	
2017-06-14	55116	12.5	13.4	11.5	9	59	95.00	100.00	10453.2	10182.2	0.170608571	
2017-06-27	55955	0.0	0.0	0.0	0	0	50.00	52.00	0.5	4.3	-0.15703311	OBC reset
2017-06-28	55993	14.0	15.0	13.0	2	35	95.00	100.00	19.2	10.1	0.152631579	
2017-06-29	56158	14.0	15.0	13.0	2	35	15.00	14.50	22.6	36	0.156157635	
2017-06-29	56158	12.2	13.0	11.4	2	15	95.00	100.00	45.9	36.6	0.1591133	
2017-07-10	57163	12.2	13.0	11.4	2	15	16.50	16.00	179.1	184.4	0.149089404	
2017-07-10	57163	11.4	12.6	10.2	9	49	95.00	100.00	202.2	184.7	0.149337748	
2017-07-22	58337	12.1	12.8	11.3	1	59	15.50	15.00	364.1	363	0.150587741	
2017-07-23	58337	10.8	11.7	9.8	9	59	95.00	100.00	387.2	363.3	0.150713686	
2017-07-24	58495	11.7	12.7	10.7	9	59	95.00	100.00	411.9	388.5	0.151259843	
2017-07-29	58995	11.0	12.1	9.8	9	59	95.00	100.00	488.1	463.9	0.151184211	
2017-08-09	60091	14.1	14.7	13.4	9	68	17.50	17.00	633.1	628.5	0.150918762	
2017-08-10	60091	11.8	12.5	11.0	2	25	95.00	100.00	655.8	628.9	0.151015474	
2017-08-31	61743	12.0	12.9	11.1	3	8	18.50	18.00	890	873.7	0.150207326	
2017-08-31	61743	12.6	13.3	11.8	2	61	95.00	100.00	912.5	874	0.150259157	
2017-09-09	62760	14.4	15.6	13.1	3	8	18.00	17.50	1054.6	1034	0.151315209	5 days in a row below 19%
2017-09-10	62760	12.9	13.9	11.8	9	59	95.00	100.00	1077.1	1034.3	0.151359295	
2017-09-11	62898	15.2	15.6	14.7	1	15	95.00	100.00	1098.3	1055.8	0.151447501	
2017-09-13	63010	13.9	15.3	12.5	3	8	95.00	100.00	1117.2	1074.1	0.151637137	
2017-09-14	63170	13.2	14.2	12.1	3	59	95.00	100.00	1139.2	1096.4	0.151365211	
2017-10-09	65211	12.6	14.4	10.8	7	15	45.00	46.50	1455.1	1417.8	0.152711755	
2017-10-16	65730	12.6	14.4	10.8	7	15	16.00	15.50	1528.6	1499.1	0.152920716	
2017-10-16	65730	12.9	14.0	11.7	9	59	95.00	100.00	1551.6	1499.4	0.152951407	
2017-11-03	67047	14.7	15.3	14.0	2	8	95.00	100.00	1783.3	1722.1	0.154868374	
2017-11-14	67824	14.0	15.2	12.8	21	8	95.00	100.00	1921.4	1853.7	0.155817676	
2017-11-15	67943	15.8	16.3	15.3	2	59	95.00	100.00	1940.3	1873.5	0.155922589	
2017-11-22	68430	15.8	16.3	15.3	2	59	15.50	14.50	2007	1960.1	0.156777555	
2017-11-22	68430	14.3	15.2	13.4	9	59	95.00	100.00	2030.3	1960.5	0.156809619	
2017-12-02	69151	15.6	16.6	14.6	5	62	94.00	98.50	2166.3	2091.2	0.158146408	
2017-12-08	69529	15.6	16.6	14.6	5	62	95.00	100.00	2236.7	2159.7	0.158788861	
2017-12-15	69774	15.6	16.6	14.6	5	62	95.00	100.00	2283.9	2205.6	0.159295173	
2017-12-21	70239	13.8	15.4	12.1	7	12	50.00	52.00	2355.5	2290.5	0.160053206	70.000 km

And here some graphs:

 

[SiLiZiUMM]

On my side, here is the graph for my car so far (we just passed the 40 000km mark yesterday). We are now just under the 100% under SOH mark.

We are also "stuck" on the same SOH and deterioration values since the beginning of November....

Second graph shows min and max deterioration values, and trendline for both.

 

[Kish]

First off, I want to say thanks JeJu for putting together the Torque PIDs, they have been incredibly useful in getting more technical info out of the car!

I recently purchased a 2015 Soul EV, roughly 37k miles. I'm the second owner and live in SoCal. The car is a lease return and the original owner lived in Northern Cali and drove the 37k miles. When I initially bought the car, the GOM read around 70 miles, but as I drove it more, it dropped 70-> 65->60->55->50 miles. There seemed to be some serious battery degredation. I decided to do a range test to see how far I can drive on a full charge (and how much kwh can be pulled out). Here are my results.

Here are Torque readings from before the range test:

The test was done at 80mph on flat highway with no wind, cruise control on. Low battery warning came on at ~45mi (when range went to ---). Ultimately I was able to drive ~51 miles until I hit 1% (last few miles @ city speeds). Consumption was around 2.5mi/kwh on the dash.

Here are Torque readings from after the test:

Torque reading from full charge to 100% the next day:

Please only look at the 1st row (other rows is from charging a dffferent EV). Note that EVSE kwh reading is from the wall. It is a very constant 6.6-6.8 kW charging speed, until the last 20-30 mins, then it tapers off. Example from a more typical charge after commute:

Looks like I did both things I shouldn't do with the Soul EV battery: drive at fast speeds and drive down to low %, ha! Did I really mess up my car by doing this? 20.4 / 27 kwh usable means 75.5% SOH, not 79.4% SOH? (20.4 kwh * 2.5mi/kwh = 50mi on GOM seems correct.)

 

[JejuSoul]

-
Hi Kish, welcome to the forum.
I think you will soon be getting a free replacement battery, so it doesn't matter what you do to this already heavily degraded one.

But when you do get the new battery and want it to last a long time, avoid regularly driving fast for long distances.
It's fine once in a while when you're in a hurry to get to the airport for instance. But the stress put on the battery by daily commuting 55 miles on the freeway at 75mph is going to age the battery fast.

I don't know if this is your actual car, but there is a thread that describes this exact experience and the problems caused.
27,000 miles 86-mile range; my Soul EV commute is over

Edit
The link above was originally wrong. I fixed it above.
It had been pointing here - Soul EV capacity warranty
The capacity referred to is the usable 27kWh not the total 30.5kWh

 

[Kish]

Thanks for the warm welcome!

Looks like you're correct on the battery pack replacement (or repair), I'm well under the 10 yr/100k limit for the warranty. However it does clearly state that the SOH must be under 70% for Kia to take action. I'm currently at 20.4 / 27 kWh usable means 75.5% SOH, so do you think Kia will bother to take any action? Or is SOH calculated on total capacity (30 kWh) in this case it would be 20.4 / 30 kwh = 68% SOH.

I was just concerned about further degradation as the one-time simple drain test caused SOH loss from 83.1% -> 79.4% (3.7% loss). If I keep doing this, I'll just make it worse? . Once (or if) I get a new battery pack replacement, I'll be very careful not to drain the battery to low % as well as cruise at high speeds for extended period of time.

 

[JejuSoul]

-
You didn't damage the battery doing a range test. It just calibrated. The BMS algorithm adjusts when you fully charge to 100%, because it can get out of alignment when you haven't done so for a while. Am guessing it had been sitting on a lot somewhere degrading in the summer heat before you bought it.
There is a thread about calibration here - Battery Calibration

The battery capacity warranty is based on usable capacity not total.

 

[Kish]

Ah gotcha. Thanks for that link about the BMS calibration, the article on Battery University was insightful. I assumed Li-Ion batteries were exempt from the "memory effect", unlike older battery chemistries that need to be deep cycled for best performance. In this case we're talking about the BMS calibration, not the physical Li-Ion battery. Yep, my car was sitting at the dealer's lot for 2 months before I bought it (it wasn't driven a single mile!), so the BMS being out of alignment makes sense.

UVO app itself says to charge to 100% at least once a month:

Since I'm sitting at 75.5% SOH, Kia is probably not going to replace the battery...yet, I'll have better luck after the battery pack has degraded 5.5% more. In the meantime, I might as well bring the car into a Kia dealership to see what their SOH measurement is, and see how it compares to the Torque values. I also may end up doing a few more range tests "just for fun"

 

[notfred]

There is a BMS update that fixes a problem with preheating at very cold (-25C) temperatures. If you take it in to a dealer and they apply the update then that resets the BMS counters and your battery will show 100% SOH until it actually learns the battery condition again.

Just wanted to give you a heads up in case when you take it to the dealers they apply the update and they tell you that the issue is fixed, it isn't.

 

[Kish]

Ah, good to know! In this case, I may need to make multiple visits to the dealer :?

 

[JejuSoul]

-
Here's a comment to explain what State of Health SOH is, and how it is measured by us on the Soul EV.

The SOH is an indication of the point which has been reached in the life cycle of the battery and a measure of its condition relative to a fresh battery. A new battery has 100% SOH. This goes down as the battery ages.

The Soul EV OBD provides degradation data for the loss from the total capacity of the battery. However what we call SOH and refer to is the percentage of usable capacity remaining.

For cars prior to 2017 with an original BMS we know that there is a 10% buffer of battery capacity that is lost before any loss of usable capacity occurs. We see this when comparing our own data with the GDS reading for SOH taken by the Kia service tech. Hence on Torque you start with 110% SOH.

We do not know if the BMS algorithm for calculating SOH has changed in later cars. We do not know if the way the BMS handles the buffer has changed. For example the new 30kWh Soul EV may work the same as our cars. Hence on Torque you can start with 110% SOH. But we won't know for sure until someone compares our readout with the GDS reading for SOH taken by the Kia service tech. And that can only be done once the usable capacity has gone below 100%. We need to wait for 2 years!

An example of someone not understanding the SOH reading is here. Official Kia Soul EV thread
mtndrew1 who used to post his data on this thread states in his signature - "2015 Kia Soul EV+ Lease returned 10/14/17 45,000 miles w/ 13.8% degradation."
But we can see his data posted here, he actually only has a 3.8% loss from usable capacity.

 

[Kish]

Out of curiosity, I checked the SoH values on the Soul EV again today, and to my surprise they were up to 91.7% (up from 79.1% last month)! Hoping that it was just the BMS being un-calibrated again, I ended up doing another range/drain test:

To 1% yielded only 47.9 miles!

After a full recharge, the Soul EV pulled 18.52 kWh from the wall and still shows 90.2% SoH! This should be 68.59% of SoH, what's going on here? Likewise, the 23.1 max kWh available shown in Torque should be < 18 kWh.

I have not yet taken the car in to the dealer yet.

 

[JejuSoul]

-
Yet another car driven far and fast that seems to be suffering battery degradation. - Getting only 73 miles in the winter

The other main cause of battery problems is extreme heat - Arizona SOUL EV Heat testing

All these 'bad' cars seem to be 3 year rentals. This thread is going to be most of use for the owners who buy these second hand cars at auction, and want to know how to get the replacement battery. An example is here - 2015 Soul EV: My Battery Replacement Story

And a reminder - none of the cars being tracked on this thread have serious degradation. My car which is average for these 'good' cars still has 100% SOH after 3 years and 44,000km. Some comments and an example from Spain here - KIA EV Soul battery decay

 

[JejuSoul]

-
I was inspired to start this thread by the great work being done to analyse the battery degradation on the Nissan Leaf Forum.
In particular - Battery Aging Model and Battery Capacity Loss
It turns out that understanding the real world long term losses in battery health is much harder than originally thought.

The latest study to look at this is by the group Flip the Fleet in New Zealand. - Benchmark your Leaf before buying!

They have collected data from second hand Nissan Leafs in New Zealand purchased from both Japan and the UK.

...we present a scatter graph of the SoH versus odometer of the EVs of different year and model. You can see the wide scatter in the graph – obviously lots of other things than just age of the EV and odometer affect battery health. Flip the Fleet needs more data to test ideas about what causes this variation and to see how best to minimise battery SoH loss.

Their full study is here - Accelerated Reported Battery Capacity Loss in 30 kWh Variants of the Nissan Leaf

There's a comment by pushevs about this result - Nissan Leaf battery degradation data: 24 vs 30 kWh batteries

It’s not surprising that the 30 kWh versions suffer more from charge/discharge cycles, since they are more often charged to 100 %. Remember that the option to limit the charge to 80 % was present in the 24 kWh version, but was removed when the 30 kWh battery was introduced (to game EPA range ratings…).

Kia played the same game as Nissan. The option to limit the charge to 80 % was removed for the 30kWh. Should we expect the same result? My own opinion is that the NZ sample size is too small, and the number of factors too great for us to make any conclusions based on this Leaf data.

----------------------------------------------------------

One effect however we can now state confidently. EVs without a liquid-cooled TMS fail in very hot climates. All the Kia Soul EV have failed in Phoenix Arizona. see - Arizona SOUL EV Heat testing

Here's the latest data for my car compared with 4 cars at the AVTA Intertek facilty in Phoenix Arizona.

 

[edzee3]

Thx for the charts of Batt Deterioration vs. distance and time. I assume the time scale is for days; correct ?
And you are now out to about 3 years.

 

[JejuSoul]

-
Yes. my car is now 3 years old, and has driven 45,000km.
I measure the battery data on my car every 250km. The blue data is all from my car.

The x-axis scales used in the charts above are days for the time chart, and km for the distance.
The y-axis shows the SOH of usable capacity. A 10% buffer is lost from the battery before any usable loss hence this axis starts at 110%.

The warranty line assumes a 7 year, 160,000km limit to 70% SOH.
I think this is the norm for most countries.
The exception is the United States where the warranty is 10 years 100,000 miles.

I am trying to make these charts as simple as possible because there is so much confusion about this topic.
And to reiterate none of the 20+ drivers who are posting their battery data on this thread are likely to get a replacement battery under warranty if the current linear trend continues.

 

[Elmil]

-
The warranty line assumes a 7 year, 160,000km limit to 70% SOH.
I think this is the norm for most countries.
The exception is the United States where the warranty is 10 years 100,000 miles.

In most European countries the limit is 150,000km, so the warranty of my car will end sometimes late next year...

We have had an unusual winter with longer periods of cold weather and lots of snow in my area. My deterioration numbers have not changed during november to march, and I think it is because of the constantly low temperatures we had (not as bad as Canada though). The day temperatures are starting to reach above 0°C lately, and so I got updates.

Current data: Odometer= 91500km Max det= 12.5% Min det= 10.0%

 

[JejuSoul]

-
Elmil - thanks for the info. Your stats are amazing. 3 years, 90,000km and you still have near 100% SOH. I am still wondering though whether the BMS reset changed the algorithm used to determine the deterioration values. It seems your values are much lower than they would have been if you had not had the BMS reset. This may also explain why some people continue to argue that they get more range after a BMS reset.
I don't get that BMS update because it is for cold weather countries only. My stats have continued a linear decline ( once I average out the spikes).

Would be nice to see more data from people who have had the BMS reset.

 

[JejuSoul]

-
Firstly a correction to my earlier statement about the battery warranty.

The Korean warranty is 10 years, 160,000km to 70% SOH.
The United States is 10 years, 100,000 miles to 70% SOH.
Europe is 7 years, 150,000km to 70% SOH.

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And some new data from my car



There was a spike up in my readings a month ago. It occurred immediately after driving fast 100km/h over a mountain.
The Min and Max reading initially reversed. This is the second time I have seen this in 3 years.
Both times were driving fast over the mountain.
It is something I rarely do, so I doubt this is coincidental.



A month later and my car is back down to a level with no loss in usable capacity.



My conclusion is that driving very fast, or just fast up a steep hill causes high battery stress which can degrade the battery much faster than normal. Perhaps this is not a problem if you only do it occasionally, but if your daily commute is 55 miles at 75 mph then it seems the battery will degrade to 70% in less than 3 years.

 

[JejuSoul]

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Here's a car in the area Seattle : see - https://www.facebook.com/groups/SoulEV/permalink/1670217449725528/

...my Soul EV has 35,000 miles and had 99.2% SOH (State of Health, ie: 99.2% of usable capacity vs new from factory) ...

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And one in Korea at 93.9% -


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Another in Germany - 95% at 75,000km
https://www.goingelectric.de/forum/...anscheinend-stark-nach-t31139-30.html#p736505