Battery Ageing Model

[ksoul2084]

I have another update on my car's battery.

For ease of reading here are my previous posts in this thread...

Hi all, I recently bought a used 2016 Soul EV+ out of Quebec that was a used as a taxi for all of its life until now. My understanding is that it was likely DC Fast charged most of the time as well.

Car has 140k on the odometer. Currently a full 100% charge will report 83km range on the screen. Driving conservatively I'd say I am able to get 100km or so.

Some readings from SoulEVSpy:

Min Cell Det %: 19.1
Max Cell Det %: 36.3
SOH: 82.3%

SOH was 93.4% (Min Det: 0, Max Det: 33.2) 4 days ago before I started to drive it to work each day this week. I assume the min cell % was wrong at that point for some reason.

When I check the battery cell heat map after arriving home from my 35km commute I see:
7 cells @ 3.64v
36 cells @ 3.66v
51 cells @ 3.68v
3 cells @ 3.62v
1 cell @ 3.60
and 1 cell @ 3.58v

Thoughts?

Another update on my 2016 Soul EV+ with 141K mileage.

So this morning for the first time my GOM read over 100km estimated range with 100% charge (101km). Outside temp. is 9c.

I've been adjusting my driving habits to better suit the car and this has been consistently increasing my range over time. My commutes to/from work are generally 15.1 - 15.5 kWh/100km now which seems pretty low to me.

This mornings readings from SoulEVSpy:
Max cell det.: 38.9%
Min cell det.: 18.9%
SOH: 81.01% (this has been dropping slightly each time I check it).

Mileage is now 145138km.

GOM range has been dropping a bit and now getting 90-100km with similar temps and conditions as last post.

Max cell det. is now: 42.6%
Min cell det. is now: 0.8%
SOH: 66% (using latest SoulSpy app with improved SOH formula).

Question is should I file for a warranty replacement now or wait another month or so to see if gets even worse (which I expect it will with colder temps approaching)?

 

[notfred]

Start the warranty process now, there's no benefit to waiting.

 

[Oinq]

1 month I wouldn't wait; you gain 1 month life on the new battery.
Now if you tell me that in 1 year you are still under the mileage and age to file a claim and your actual range is enough; I personally would wait more to the end of warranty.

 

[JeroenE]

Question is should I file for a warranty replacement now or wait another month or so to see if gets even worse (which I expect it will with colder temps approaching)?

What do you think to gain by waiting?

Depending on your location you might need to wait several weeks for the arrival of replacement battery, anyway.

 

[JejuSoul]

-
I would start the replacement process now. Your battery won't last another year, so why wait another month.
I wrote on June 9th when you first posted here. 3 months later we can see the battery getting worse.

These are strange readings, and taken together with the voltage deviation of one cell that is behaving differently from the rest leads me to assume that one cell - in this case #95 - is failing. But I don't think it has 'failed' enough for you to get a replacement battery yet. Although it would be worth phoning Kia to ask what criteria they will use to judge whether the replacement is necessary. Maybe they will accept the request based on the low GOM. My guess though is that you will have to wait a few months for the SOH to come down.

Here are the stats you have posted over the last few months. I have corrected the SOH numbers so that they all use the 'Elmil' formula that is now used by SoulEVSpy. A battery with a failed cell depends purely on how badly the failed cell is doing.

Jun 06 2019,  Min 19.1%, Max 36.3%, SOH 72.8%
Jun 20 2019,  Min 18.9%, Max 38.9%, SOH 70.0%
Jul 06 2019,  Min 16.9%, Max 42.3%, SOH 66.4%
Jul 07 2019,  Min 0.6%,  Max 37.3%, SOH 71.7%
Aug 10 2019,  Min 0.1%,  Max 38.8%, SOH 70.1%
Sep 12 2019,  Min 0.8%,  Max 42.6%, SOH 66.0%

 

[ksoul2084]

The reason I was considering waiting a bit longer is to see that it continues to decline to avoid a "borderline" situation with KIA.

The range now is just enough for my daily commute. If necessary I can also 120v charge during the day at work but it's a bit of a PIA to take the charger back and forth each day.

As I am not in a province with any KIA EV certified dealers I will open a case via their website and see what happens. This is apparently the approach taken by someone else in the US successfully.

 

[Popescuiulian26]

Hello I live in central of France where is not too hot like in the south , I have a soul ev 2015 , with about 102000 km on board, in the last few months I was achieving a consumption of 14,5 kWh / 100 km . But my car charged 100% shows me only 123 km of range . Since I have this car I only made a max of 145 km with about 15kwh/ 100km . I only do slow charging with the charger provided , since I have it i have done very few fast charging chademo .
I had her checked last time when I had 85000 km , but there In the shop they had made an upgrade to the battery and drive train , and checked the Soh at 100% . The chief from the shop told they only measure the voltage of the battery. Does Kia France try to scam owners ?!
Should i start the complaint for the battery guarantee?!

 

[JejuSoul]

-
Popescuiulian26 - I guess that your SOH is about 75% and that you should wait a few more months. You could check for yourself by running one of the diagnostic programs like Torque or SoulEVSpy.

...In the shop they had made an upgrade to the battery and drive train , and checked the Soh at 100% . The chief from the shop told they only measure the voltage of the battery. Does Kia France try to scam owners ?!

No. Probably not. It is ignorance not malice.
Everywhere the story is the same. The mechanics think that a BMS software upgrade is a 'fix'. Doing this upgrade is what they are told to do. They do not know what it does. It actually fixes a heating issue at very low temperatures. But a side effect of the BMS software upgrade is that the counters all get reset. The battery computer now thinks the battery is brand new.
Voila! They have fixed the battery, because now the SOH shows 100%.
It takes a week or more of normal driving and charging for the BMS to re-learn what the actual state of the battery is.
Trying to speed that process up by longer drives seems to have mixed results. - see Should I return my 2016 Soul EV?

They also do this when the OBC is broken. They apply a software update which adds extra diagnostic routines.
They will then tell you that the car is fixed.
In this case you need to force them to check by charging the car. The diagnostic routines only trigger when a charging fault occurs, not when the software is added.

 

[ksoul2084]

Another data-point on my 2016.

It takes approx. 10.5 hours to charge my car from 20%-100% on my 120v Level I charger (approx. 1.4 kW).

According to this charging calculator (https://www.homechargingstations.com/ev-charging-time-calculator/), that would correspond to approx. 17kWh of battery capacity available in total, which works out to about 63% of the original 27kWh battery capacity. This also jives fairly well with my SOH of 66%.

 

[RoxyDG]

Since there's tons of posts on here I want to apologize if I'm being too redundant. My 2016 Kia Soul EV+ has 24100 miles and state of health report per the dealership is less than 50%. As I type this I'm sitting in the dealership waiting room because they are arranging my rental car. From what I understand, this issue is related to the climate here in Houston, Texas where we have miserable hot conditions about 5-6 months out of the year. Average high temp is around 92-99 degrees Fahrenheit in the summer (or something like that). The service rep told me she's had many replacements in the past two years and they are almost all with less than 30,000 miles on the odometer. The highest she's had was around 32,000 miles! Sheesh! You'd hope Kia has corrected poor performance in hot weather issue for the 2020 model. Frankly Kia should offer a big fat credit instead and I'd buy a 2020 model with it. It seems like that would be a win-win for Kia because it would spare them the time and cost of a new battery replacement while selling a new car. Oh well.

 

[Omar]

Hi everyone,

I have a Kia Soul EV+ 2015, I bought 16 months ago, my current ODO meter reading is 72,000 Km. Last year the car was consistently delivering 200 Km range. in the summer this year I noticed a small decline, it became like 190 Km, but it was consistent.

In this month I started to notice significant battery performance drop. I used to consume around 37 - 38% for my daily commute, nowadays it is around 45%. The GOM reading was like 155 Km (But the car actually reaches 190 Km), now the car reads 137 Km @ 100% charge.
it would likely drive around 150 Km.

Yesterday I bought an ODBII and below is my battery cell map @100% Charge

And this is it when I arrived to work, at 81% charge, after driving 34.4 Km.

and this is another one while charging

and some BMS screen shot while charging

Does the first cell map explain such a significant drop ? please help me understand

 

[JeroenE]

Does the first cell map explain such a significant drop ? please help me understand

I don't think it does, but as far as I know it never really does. Even when my car had a bad battery it would still show it was charged to 4.10V.

Why don't you take a look at the SOH?

 

[Omar]

I already did, it shows 69% !
But I am using the Soul Spy Lite, the free version. Is this figure reliable ?!

and how could that big drop happen in a month ?! I used for a 15 months and it was performing fine.

 

[JeroenE]

I already did, it shows 69% !
But I am using the Soul Spy Lite, the free version. Is this figure reliable ?!

Yes, it is the best that we know of right now. You're right in the edge of the warranty so it might be that Kia will read 70%. The reading we know of is not exactly the same as Kia reads it.

Nonetheless I would advise to get a battery health check with your Kia dealership. Unless that's very inconvenient because they are far away or something like that. In that case you might want to wait a few weeks until you know for certain it would go below 70%.

and how could that big drop happen in a month ?! I used for a 15 months and it was performing fine.

In my own experience once the battery gets bad it can go quite quickly, especially if it's warm/hot and you use a lot of rapid charging. Even though I live in a moderate climate it was quite noticeable in the summer that the battery got worse and worse each week.

 

[Oinq]

Force a calibration.
You can force it by charging to 100%, then let it go under 19% (It can take several days), then back to 100% in one time.
After this read again the SOH.

 

[ksoul2084]

Mileage is now 145138km.

GOM range has been dropping a bit and now getting 90-100km with similar temps and conditions as last post.

Max cell det. is now: 42.6%
Min cell det. is now: 0.8%
SOH: 66% (using latest SoulSpy app with improved SOH formula).

With the first coldish weather of the year upon us I've taken some updated SoulSpy readings.

Mileage 145949.8km
SOH 58.5%
Max cell det 49.7%
Min cell det 25.2%

So yeah, it's time to file a warranty claim.

(I can post pics of all the SoulSpy data if you'd like)

 

[Oinq]

It would be nice if you read the data just before deliver the car, and try to get the report from them for compare.

 

[JejuSoul]

...(SOH =) 69% !
Is this figure reliable ?! and how could that big drop happen in a month ?!

Hi Omar,
Yes the number reported by SoulSpy is probably close to accurate.
We have seen a lot of cars suffer sudden rapid deterioration in the last few months.
Some have had a single cell failure, which causes the entire pack to fail. This seems easy to understand.
Some, like yours do not have a single cell failure. They also suffer sudden rapid deterioration.

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

I have two 2015 Soul EVs.
The first I bought new. It has done 61,500km. The SOH is 98%. It doesn't show any loss of range since new.
The second I bought in late July this year. It has done 80,500km.
It started at 85% SOH. Then 5 weeks later 80%. Now 5 weeks after that 75%.
The first 5 weeks were hot summer days, maybe 32C. The next five weeks were autumn, maybe 22C.
The decline is happening at the same steady rate.
There is no single cell that has failed. The worst cell number varies sometimes 2 sometimes 96.
But the cell voltage deviation is fairly small.

The original Soul EV is used for short, slow drives, about 15km each way. The new one for a longer, faster drive, about 40km each way.
I tested the 'good' car on the longer route. It uses 25% of the battery to do 40km. The bad car uses 35% to do the same.

The 'bad' car now takes 3 hours 50 minutes to charge to 100% on my home ch arger. (It was 4 hours a few weeks ago.)
When new my 'good car' took 5 hours.

The GOM at 100% SOC on the 'bad' car was 155km when I bought it, then 135km 5 weeks ago, now 120km.

While none of these figures are totally accurate, all are suggesting that the current SOH of the 'bad' car really is around 75%.
If I continue driving the same way this car will soon be able to claim a replacement battery.
Or I could decide to drive much slower, and see if that will slow the rapid decline.
-

 

[Omar]

Thanks for your explanation,

Now my SOH dropped to 64.7%. I do not know if the warranty covers my KIA, the car is imported from USA-California, I do not think that KIA middle east will accept a warranty claim.

The max and min deterioration are 43.8% and 4.4% respectively (big gap !!). I monitored the SoulSpy readings very closely, and I have good knowledge in battery systems. I also consulted an expert who dismantles electric car batteries then reassemble them to be used in PV Solar Systems. The issue is clear.
When you charge the car, the voltage of max deterioration cell (#14) jumps higher than the rest, the jump amount depends on the charging power, the more power the more the jump is. When the car is near to full, if any cell voltage reaches 4.18/4.20 V, the charging stops. The charge percentage shows 100%. But in fact, other cells are not fully charged, most of them are at 4.10/4.8 V.
The charge percentage is directly related to the max cell voltage. If you want to charge the car more, then just use less current!, then the jump is lower, and the other cells can reach 4.10/4.12 V.
All the cells in the battery are connected in series, which means the bad cell will make the battery lose capacity at the bottom and the top of the battery charge cycle. I consulted the expert guy, and asked him if I could just bypass the worst cell !. He confirmed that would enhance the charging/discharging performance, thus the range!. Or of course I can replace it, along with another weak cell (#78). But the Soul cells are rare, not easy to find.
In Jordan, we have several repair shops who can repair or replace batteries with acceptable prices. They have good experience in doing so. Most of them are electrical or electronics engineers.

 

[Oinq]

Hello Omar

Thank you for your comprehensive explanation, I learned something today
It seems the fact I always charge my car at 6A, turns to be a good habit

I would try to file a claim with Kia, the answer no you already have; it won't get worse.