Supercharging Degradation?

[rush6410]

Here is some interesting anecdotal evidence of Super charger usage and the impact on my battery. Every major decline in my 100% charge range coincided with a long distance trip with super charging only. The times where the graph flat lines is at home 240v 40a charges at 90% only. So, can I conclude that super charging causes degradation? Thoughts.

 

[Harvey Danger]

A couple other things that would be helpful to see annotated on that graph would be calendar dates (so you could see if there is maybe some warm-weather / cold-weather seasonality) and also the timing of any firmware updates that may have tweaked the charge estimation algorithms over the years.

But yeah, overall, this is definitely not the same logarithmic shape you see in curves fit to fleet wide data plots..

 

[ngng]

Here is some interesting anecdotal evidence of Super charger usage and the impact on my battery. Every major decline in my 100% charge range coincided with a long distance trip with super charging only. The times where the graph flat lines is at home 240v 40a charges at 90% only. So, can I conclude that super charging causes degradation? Thoughts.

View attachment 658170

i don't think you have enough info (nor do I). 100% range is really just a calculation, i think it could be a factor of things, including but not limited to firmware updates, cell rebalancing (when/how often did you charge to 100% and drain as low as possible)? maybe the inverse is true, that your range has been lying to you and has been "recalibrated" correctly when you do long trips

 

[rush6410]

A couple other things that would be helpful to see annotated on that graph would be calendar dates (so you could see if there is maybe some warm-weather / cold-weather seasonality) and also the timing of any firmware updates that may have tweaked the charge estimation algorithms over the years.

But yeah, overall, this is definitely not the same logarithmic shape you see in curves fit to fleet wide data plots..

I actually have all that data. I will add it on the graph.

 

[ngng]

do you have any data on when you did full charges, and what the range looked like after?

 

[rush6410]

i don't think you have enough info (nor do I). 100% range is really just a calculation, i think it could be a factor of things, including but not limited to firmware updates, cell rebalancing (when/how often did you charge to 100% and drain as low as possible)? maybe the inverse is true, that your range has been lying to you and has been "recalibrated" correctly when you do long trips

Another thought or possibility is how the BMS calculates range. I know that the X battery I have is not supposed to have the same issue that the model 3s were having in regards to miscalculations where multiple different levels of charges and sleep needed to balance. So, it seems we can rule out the BMS miscalculating the range. And, is resetting the range because of the long trip with multiple SOCs during the trip. Or, can we?

What I do know is the drops with sustained reduction always occurred with a trip with multiple SC charges. Since trips are the only time I use SCs, it provides a constant. All other non trip related charges where all level 2. The other constants are I always charge to 90% at home which is at least 95% of the overall charges. I rarely charge to 100%. And if I do it is for long drives only where I am getting in the car and driving as soon as it hits 100%. I have never let it sit at 100%. Since I have all the data as it relates to the mileage/charge chart, I'll layer some of the data points you suggested.

 

[rush6410]

do you have any data on when you did full charges, and what the range looked like after?

I do and I'll post it later.

 

[ngng]

Another thought or possibility is how the BMS calculates range. I know that the X battery I have is not supposed to have the same issue that the model 3s were having in regards to miscalculations where multiple different levels of charges and sleep needed to balance. So, it seems we can rule out the BMS miscalculating the range. And, is resetting the range because of the long trip with multiple SOCs during the trip. Or, can we?

What I do know is the drops with sustained reduction always occurred with a trip with multiple SC charges. Since trips are the only time I use SCs, it provides a constant. All other non trip related charges where all level 2. The other constants are I always charge to 90% at home which is at least 95% of the overall charges. I rarely charge to 100%. And if I do it is for long drives only where I am getting in the car and driving as soon as it hits 100%. I have never let it sit at 100%. Since I have all the data as it relates to the mileage/charge chart, I'll layer some of the data points you suggested.

would be interested in seeing all your data.

another question: what is the interval between your long trips? just thinking out loud here...if, when you do a full charge before departing on a trip and the your range is recalculated, maybe the range fluctuations you are seeing are actually normal and the supercharging is a red herring.

a handful of supercharging should not make any noticeable difference, when compared to say overall mileage or charging cycles

 

[rush6410]

Ok...here it is. I added as much layered data as I could. Green Star is 100% charges level 2. Red Star is Superchargers. Red Block are multiple Supercharges on extended trip. As you can see, it started out pretty smooth at the beginning with smooth alternating level 2 and Supercharger charges. Then it starts to go south only when I supercharged with an extended trip. The blue line 90% charges level 2.

 

[ngng]

Ok...here it is. I added as much layered data as I could. Green Star is 100% charges level 2. Red Star is Superchargers. Red Block are multiple Supercharges on extended trip. As you can see, it started out pretty smooth at the beginning with smooth alternating level 2 and Supercharger charges. Then it starts to go south only when I supercharged with an extended trip. The blue line 90% charges level 2.

View attachment 658554

wow, that's way more work that I would have put into it lol. thanks! do you happen to have the corresponding discharge levels as well? honestly, I don't think it's related to supercharging. this feels like a cause of correlation not equaling causation. I still think it's related to your 100% charges. I suspect when you pull up your discharge data, that you've discharged pretty low after your 100%.

also, your car is fairly low mileage. a bulk of the battery degradation is gonna happen early on (if I remember correctly). from 257 to 240 doesn't seem too unreasonable.

 

[rush6410]

You could look at this two ways. One, the Supercharging is causing the degradation. Two, The Supercharging, because of always coinciding with extended trips, gives the BMS more data to calculate range more accurately. But, there are many discussions indicating that the model X is always accurate with estimates without needing the extra data.

 

[rush6410]

wow, that's way more work that I would have put into it lol.

Luckily Teslafi did most of the work. I just cut and paste their data visualizations.

 

[rush6410]

do you happen to have the corresponding discharge levels as well?

I do not think I have that information. Can you explain how I may be able to get that.

 

[rush6410]

I still think it's related to your 100% charges

The green stars were all of my 100% charges and all level 2. Plus they didn't seem to impact the estimates. The Red stars were SC charges that never went to 100% except for the last one. At most the SC charges were anywhere from 60% to 85% charges. So, it is hard to believe it is related to the 100% charges. I am leaning more towards the BMS getting better data with more varying charge points at different charge level when I am traveling even though all discussions have said that shouldn't be a factor. Again, my second conclusion is the SC charges are impacting my battery, which has been discussed.

 

[ngng]

I do not think I have that information. Can you explain how I may be able to get that.

I'm not sure how you logged your data, but I know teslamate allows you view that data

 

[ngng]

The green stars were all of my 100% charges and all level 2. Plus they didn't seem to impact the estimates. The Red stars were SC charges that never went to 100% except for the last one. At most the SC charges were anywhere from 60% to 85% charges. So, it is hard to believe it is related to the 100% charges. I am leaning more towards the BMS getting better data with more varying charge points at different charge level when I am traveling even though all discussions have said that shouldn't be a factor. Again, my second conclusion is the SC charges are impacting my battery, which has been discussed.

the 100% charge doesn't matter if it was a L2 or SC. it's my understanding that getting your battery charged up high, then drained down low recalculates your estimated range.

 

[ngng]

You could look at this two ways. One, the Supercharging is causing the degradation. Two, The Supercharging, because of always coinciding with extended trips, gives the BMS more data to calculate range more accurately. But, there are many discussions indicating that the model X is always accurate with estimates without needing the extra data.

you and I have different battery packs (100kwh) and I have more miles (40k), but I see the opposite: a slightly increase in my range (fraction of a mile haha)

 

[Harvey Danger]

The annotated graph is fascinating. I agree, way more detail than I thought possible. Impressive. And no I can't discern a pattern. There are two sharp drops. They both occurred some time after, but not immediately after, some supercharging. But the long stable periods also contained supercharging, so to me there's not a clear enough connection. Anyway cool graph.

 

[rush6410]

The annotated graph is fascinating. I agree, way more detail than I thought possible. Impressive. And no I can't discern a pattern. There are two sharp drops. They both occurred some time after, but not immediately after, some supercharging. But the long stable periods also contained supercharging, so to me there's not a clear enough connection. Anyway cool graph.

The two circled supercharge charges resulted in a pretty major drop with a sustained post estimate. The only difference with these two charges compared to the rest is they were high percentage charges; 98 and 93% respectively. Hard to tell what actually is going on. I am leaning more towards BMS miscalculations. The two circled trips help reset the estimate.