SoH vs Charging to 100% and what I found.

Dee

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I always charge to 85% and this was my SoH in augustus when I first monitored my battery.

Screenshot_20220806-190832~2.png


That was after 23.000km
I know that degradation is the most in the first 10%, after that it'll slow down but still 90,3% isn't what I expected...

So, I changed my charging habbit and set it to 100% to see if that would change anything.

Screenshot_20220923-150616~2.png


Well, I was quite surprised to see I gained 1,14%!
This is after 25.000km.
I thought this was worth sharing!
I'll continue to charge to 100% and see if it gets even higher.
Nice huh?

 
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Dee

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I would guess the increase of SoH is related to the "recalibration". Lithnium battery capacity is hard to measure, and a 0-100% charging cycle may help the measurement.

Ref: https://insideevs.com/news/516137/recalibrate-tesla-battery-range/
Exactly.
I don't expect the battery would get any better, only the calculation.
I'm hoping to see the true SoH one day, that means: if it doesn't go any higher.

As we all know, that 100% SoC isn't really 100% and that 0% isn't really 0% either.
100% means that all the cells have reached the value of the worst cell in that particular battery (it's how BMS works).
If one or more cells don't reach that value any more (due to usage), all the other cells will be charged accordingly (to that lower value) to prevent the lowest cells to be overcharged and overheating (=even more degradation).
That means the total SoH value of the whole battery pack is lower.
That doesn't mean that the entire battery is degrading.
In fact, if you would change one or two of the lowest cells, the capacity would be 100% again, theoretically.

You can measure, quite accurately, the condition of an Li-ion cell by measuring it's voltage.
I think it's 3,76V something.
Anyway, it shows the way of charging does change the SoH calculation.
 
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whitex

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I always charge to 85% and this was my SoH in augustus when I first monitored my battery.

Screenshot_20220806-190832~2.png


That was after 23.000km
I know that degradation is the most in the first 10%, after that it'll slow down but still 90,3% isn't what I expected...

So, I changed my charging habbit and set it to 100% to see if that would change anything.

Screenshot_20220923-150616~2.png


Well, I was quite surprised to see I gained 1,14%!
This is after 25.000km.
I thought this was worth sharing!
I'll continue to charge to 100% and see if it gets even higher.
Nice huh?
What tool do you use to get these numbers?
 


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Dee

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I also found this:

Screenshot_20220729-163140~2.png


Apparently I did 18 launches.
Maybe it's possible with VCDS to reset that too.
 
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babaloo

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if you lease the car for 3 years, you may not care about the long term battery longevity.

so, based on this analysis, charging to 100% gives you the extra range when needed with little downside..
 


daveo4EV

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I always charge to 85% and this was my SoH in augustus when I first monitored my battery.

Screenshot_20220806-190832~2.png


That was after 23.000km
I know that degradation is the most in the first 10%, after that it'll slow down but still 90,3% isn't what I expected...

So, I changed my charging habbit and set it to 100% to see if that would change anything.

Screenshot_20220923-150616~2.png


Well, I was quite surprised to see I gained 1,14%!
This is after 25.000km.
I thought this was worth sharing!
I'll continue to charge to 100% and see if it gets even higher.
Nice huh?
this is great data - thanks for posting and please keep us updated with your findings.
 

B61

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this is great data - thanks for posting and please keep us updated with your findings.
It would be interesting to see measurements from someone who charged mostly at 100%…like @feye .
I charged to 100% several times as well, probably more than only up to 80-85%.
 
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Dee

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if you lease the car for 3 years, you may not care about the long term battery longevity.

so, based on this analysis, charging to 100% gives you the extra range when needed with little downside..
I highly doubt that.
I never charge at rates higher than 10kW.
I have mechanical sympathy.
Besides, I don't care about range.
I just find 90,3% was a bit of a disappointing value.
I don't lease, I don't like renting cars.
It's also a sales plus cuz you can actually show how good your battery still is.
 
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Dee

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this is great data - thanks for posting and please keep us updated with your findings.
Maybe that 85% is just a precaution of Porsche, they do offer a warranty of 100.000miles/8years so....

But the industry already show that batteries are far better than expected, especially the latest ones but we will see in a few years.
I just find it interesting that you can actually raise the value/have a better SoH calculation.
It's also just an easy way to monitor your own property.
 
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ciaranob

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@Dee

Hmmm - just did a scan of my car and my SoH is reported as 92.7% which after just over 4000 miles (6500 km) seems way too low - or not? Re mileage, yes I know :), but have been out of the country for essentially half the year to date!

I'm using the vLinker OBDII MC+ with the Car Scanner app - have no calibration as to whether this is an 'accurate' or meaningful reading etc but interested to hear from more knowledgable folk here!

The 'Car Scanner' app is iOS compatible and has a pre-configured Taycan profile - super simple to connect too. I'm using the free (with ads) vers - there is a Pro vers. w/o ads.

Once the parts for the latest 2 updates are in and I revisit to have them installed, I'll ask the dealership to provide a SoH to have on record with them.

PS: In my ignorance I never asked about SoH on delivery i.e. no reason of course to assume it would be 100% but would have been GTK as a baseline - does anyone here know what their SoH was when delivered?

PPS: For ref I have a total of 303 kWh of Direct Charging at EA stations to date - rest has been at home with only a handful of times to 100% the norm being up to 85% charging from ca 20-30%. Car has never being lower than 15% charged, 90+% over 20% before recharging.

IMG_6906.PNG


Here is the Dashboard view with SoH:

IMG_6904.PNG
 
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ciaranob

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Just remembered this thread which touches on some of my questions above - still curious though as to SoH on delivery etc. for those you know.

#1
 

ElectricSoul

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I believe that an increase of capacity could also be the result to doing a measurement closer to optimal battery temperature.
 

 
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