JejuSoul
Posts: 1419
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Battery Calibration

Mon Nov 16, 2015 9:30 pm

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A couple of users recently seemed to have gained range and improved battery performance after either an L1 slow charge to 100% , a lengthy road trip, or both.

mtndrew1 wrote:... So yesterday I pulled the 240V at 75% and let the car charge to 100% overnight on the 120V charge cable thinking that may give the car some cell balancing opportunity. I have no data to back it up, but it sure seems to have worked as I achieved my highest-ever capacity remaining estimate yesterday aside from the tightly-controlled Tony Williams test...
here : Battery Degradation and Performance Patterns

SiLiZiUMM wrote:I'm back from a 500+ trip again :lol: 3 QC stations visited on each way. On our way back, we almost pushed the limits of the battery, skipping a few QC in Québec City. We arrived there at 3%, with the turtle blinking :)

On our way back, the deterioration values changed. It was "7EC 24 00 32 2B 00 06 0D" before, I have now "7EC 24 00 2D 2D 00 01 01".
here : Soul Spy

Perhaps this is consistent with a recommendation on the Battery University site to do a battery calibration once every 3 months.
See : http://batteryuniversity.com/learn/arti ... alibration

Image
Last edited by JejuSoul on Tue May 29, 2018 9:07 am, 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.

Birkeland
Posts: 68
Joined: Fri Dec 12, 2014 12:21 pm

Re: Battery Calibration

Tue Nov 17, 2015 10:44 am

Interesting post and article from Battery University. The manual of the Kia Soul recommends to fully charge the High Voltage Battery once a month or more often. They do not say why, but it is most likely because of battery calibration.

I use a 6.6kW charger (the manual refers to this as "normal" charger, and the L1-charger that comes with the car as a "trickle-charger" which is only to be used if "normal-charger" is not available). The reason for this is probably because the battery is in a state of chemical processes when charging, and the slower the charger, the longer the battery is undergoing chemical processes which is also a factor in battery degradation.

My question is if it is possible to achieve the same effect of calibration with the 6.6kWh charger, or if I should use the 10Ah(2.3kWh) charger that came with the car.
Owner of a 2015 KIA Soul Exclusive, Titanium Silver

khaihon
Posts: 10
Joined: Fri Sep 04, 2015 2:41 pm
Location: Los Angeles, CA

Re: Battery Calibration

Tue Nov 17, 2015 2:40 pm

this is anecdotal, but i was charging my RAV4EV for about 8 months on its L1 trickle EVSE before upgrading to a 40A L2 one. when I switched to L2, I noticed a drop in my range. At first, I thought there was something to it, but I came to realize when I was on L1, I would try and maximize my range via my driving style. On L2, I was less concerned with being conservative and definitely took more advantage of the power. The actual difference between charging on L1 and L2 are probably negligible with L2 being more cost effective since it you will have a greater power efficiency.

JejuSoul
Posts: 1419
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Battery Calibration

Tue Nov 17, 2015 10:37 pm

This topic of calibration poses an interesting question - are the increases in range and performance real, or just corrections to earlier less accurate data. Battery University in the link above states that anomalies contribute to errors that are inherent to all smart batteries and in time manifest themselves in false state-of-charge estimations and other discrepancies.

We are also talking about 3 possibly different effects. Or perhaps these 3 are aspects of the same thing.
1/ Calibration.
2/ Cell Balancing.
3/ Increased energy input using L1 ch argers. (this one improves actual range not just the displayed data)

It is possible that in the first case above (mtndrew1) we are merely seeing effect 3. We have no data to show that the 96 battery cells were imbalanced beforehand nor balanced afterwards.
There is a quote about this here : Road Trip: Atlanta to NJ and back. LONG post w/ Stats
roxworld wrote:Layered charging: Just remember that 100% is usually not 100% if it wasn't reached with the slowest charging method.
Before a big road segment, I often will QC, followed by L2 and top off with a trickle charge for the maximum charge.

The second case (SiLiZiUMM ) seems to show effect 1. We do have battery cell data for this car. It shows slight improvement in cell balance on an L1 charge to 94%. But that slight improvement is similar on all L2 ch argers I have seen too. (from 6 cells varying by 0.1 V with the rest to only 1 varying). There is no change to the battery deterioration data at this point. The better values for the battery's deterioration are seen at the next stop of a lengthy trip.

To answer the question is it possible to achieve the same effect of calibration with the 6.6kWh ch arger, I assume yes. I did a road trip last week to test this. I L2 charged to 100%, drove 215km and then charged back up again. I measured my battery's health before and after. No loss, no gain. But my battery already had very low deterioration. I intend to do the same thing next month ( to test the effect of temperature on driving distance) so will let you know if any calibration occurs.
Last edited by JejuSoul on Tue May 29, 2018 9:09 am, 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.

ourmuskokalife
Posts: 17
Joined: Sat Aug 22, 2015 11:52 pm
Location: Muskoka

Re: Battery Calibration

Wed Nov 18, 2015 3:55 pm

We are in a condo and don't have a level 2 charger, so every night we charge overnight with the Level 1 charger and during the day while at work we use a level to 30a we installed at work. Last week took a long drive and took it down to a 3% charge and plugged it in for 30 hours of the level 1 charger. Still 130km at 100%.
Loving Life and living it well
in our 2016 Electric Blue & Polar White EV+

JejuSoul
Posts: 1419
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Battery Calibration

Tue Dec 22, 2015 8:27 am

JejuSoul wrote:To answer the question is it possible to achieve the same effect of calibration with the 6.6kWh ch arger, I assume yes. I did a road trip last week to test this. I L2 charged to 100%, drove 215km and then charged back up again. I measured my battery's health before and after. No loss, no gain. But my battery already had very low deterioration.
The answer to the above is, "yes". Battery Calibration does occur using a normal ch arger (L2) and not just the trickle ch arger (L1). Also the calibration effect can be either up or down.

Over the last month I have seen the following changes occur after a 100% L2 charge.
After a big jump up - which I assume is a calibration effect - the maximum deterioration has risen slowly.
After a similar big jump up the minimum deterioration has fallen slowly.
My car is 7 months old and has about 11,000km.

From about 8,000 to 10,000 nothing happened (max det 3.5%, min det 0.1%)
Then the following.
9,752km (max det 4.5%, min det 4.4%)
9,950km (max det 5.5%, min det 4.4%)
10,003km (max det 6.0%, min det 3.1%)
10,794km (max det 6.5%, min det 2.4%)
Last edited by JejuSoul on Tue May 29, 2018 9:10 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: Battery Calibration

Wed Dec 23, 2015 10:20 am

JejuSoul:
Last night another jump in the deterioration values occured during normal (2 kW) charging overnight.
The deterioration values jumped up from 10.3/9.2 to 11.2/10.2 and this was at 22610 km and 5 weeks since last change. All 96 battery cells showed 4.08V (0xCC) just as they did last time the deterioration values changed.
Kia Soul EV 2015 / 115,543 km Sold
Kia Soul EV 2019

ZuinigeRijder
Posts: 110
Joined: Thu Dec 31, 2015 3:59 am

Re: Battery Calibration

Mon Feb 01, 2016 9:50 am

For me the battery deterioration is going up and down since I have the OBDII dongle.

Max Deterioration % is going from 11.6 to 11.1 to 13.4 and back to 10.2 today.
Min Deterioration % is going from 10 to 9.6 to 11.1 and back to 8.2 today.

Always use a normal charger at work, I believe 3.6 kW max, and now and then my home charger @ 2 kW.

JejuSoul
Posts: 1419
Joined: Wed Jul 08, 2015 6:47 am
Location: Jeju
Contact: Website

Re: Battery Calibration

Wed Feb 03, 2016 12:20 am

ZuinigeRijder wrote:For me the battery deterioration is going up and down since I have the OBDII dongle.
As I said before I think this seems quite normal. Three of the four cars for which we have multiple data seem to do this. But we do have a very small dataset so perhaps all 3 of these cars are outliers. I doubt it but it is possible. Evidence for my view is that Battery University suggests than an accurate value for SOH is hard to get.

Had you written your post on the mynissanl eaf forum however you would have been dismissed as a Troll or an idiot.
Just look at the thread : "SOH value jumping around."
People on that thread seem to believe that SOH will always be measured accurately to 1/100 of a percent and will decline in a perfectly linear fashion. Given the data we are getting I would put an error band of +/- 5%, with all kinds of yo-yoing and stepped descent. The margin of error we are getting makes it hard to make any judgement on a particular driving or charging style. We can't even say that climate makes any difference to deterioration. Hopefully with more data we can average out some of the errors.
Last edited by JejuSoul on Tue May 29, 2018 9:11 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: Battery Calibration

Mon Feb 29, 2016 12:36 pm

So, I finally got another change in my deterioration values. And this time they took a big leap backwards!

Code: Select all

Date        Km        Max   Cell    Min    Cell   SOC
2015-11-01           9.3%   32     8.3%    1   92.5%
2015-11-05  18780    9.8%    2     8.4%    8   92.5%
2015-11-19  19751   10.3%   24     9.2%    1   91.5%
2015-12-23  22610   11.2%    3    10.2%    8   92.0%
2016-02-29  27339    9.8%    2     8,8%    8   92.0%
During winter I have been charging to 100% most of the time, and rarely drained the battery more than down to 30%. Yesterday I drained it down to 9% displayed (10% batt) and in the following nightly charge the update came. And as every time before, the update happened when all 96 cells displayed 0xCC (2.04V) and at around 92% displayed SOC.
It looks very clear that some sort of calibration is done when the BMC gets the opportunity to look at a wider range of SOC. So the fact that people observe deterioration values "jumping around" could possibly be connected to a greater variation in charging/discharging habits.

Another interesting finding from my logs is this:

Code: Select all

SOC(bat) Ah     kWh
10 - 50% 31,4   10,9
50 - 90% 31,8   12,9

The data is from last night's charging, and the table shows that charged Ah's are basically the same from 10 to 50% as they are from 50 to 90%. But the kWh's are less at the lower 40% than at the upper 40%. This is actually quite logical, as the kWh's are depending on the battery voltage, which is around 20% higher at 90% SOC than at 10% (during 2kW L2 charging). I see the same pattern in all data that I have analyzed.
The conclusion must be that the SOC numbers for at least the total battery is the percentage of Amp hours, not kW hours. The displayed SOC is a bit biased in respect to the total (display is ~51.5% at 50%bat), but even so, one SOC% is much more equal across 10-90% if it is based on Ah. Not a surprise really, but we didn't know for sure if Kia had linearized to the kWh's or not. I think they have not.
Kia Soul EV 2015 / 115,543 km Sold
Kia Soul EV 2019

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