What should my ideal charge percentage be?

[AAKEE]

One factor that determines degradation is how long this charge rate is sustained. Quick bursts of energy, such as when you decelerate and regenerate, don't really stress the battery,

Was just about to make the same comment.
Also, regen reduces the cycle depth which is good for NCA and NMC, and at least nit bad for LFP.

Tesla changed the regen settings about one year ago and then reduced the regen at cold battery and high SOC. Probably a change to counter found degradation from high regen.

I wouldnt worry at all, but we have the possibillity to not take the foot completely from the accelerator pedal and instead use the foot to regulate the decceleration ( = regen power).
I can see the regen power on my SMT setup behind the steeribg wheel and I sometimes linut the regen by purpose.

 

[geordi]

Latest Model S degradation looks encouraging. About 12% after 200k miles.

Tesla gives update on battery degradation: only 12% after 200,000 miles

Tesla has released a rare update on the battery degradation in its electric cars. The automaker claims its batteries only...

electrek.co

My X has the original battery and at 104k miles, was at 11.7% degradation from an owner who avoided supercharging. This would seem to be age related more than anything else. Since I bought it, I have now put 16k miles on it and the battery is showing 12% (so a loss of .3 more percent) with some HARD cycles of 100% on a road trip to under 5%, because of the distances between chargers and environmental conditions (30mph headwind!) on the trip.

Supercharging is unlikely to have been the cause of the increased wear on the battery. In my S which started my ownership last year with a brand-new battery and has now earned in just under a year, 50k miles on that battery and already 900 cycles and 88% supercharging.... It is showing 1% degradation. DRIVE them.

Interesting to think about. Of course, A supercharger starts out at 150 or 300 kW, so 60 isn't so much of a hit. But I am sure that you are right, and those little charge cycles probably do a miniscule amount of damage. Certainly worth the cost, in my mind.

If you don't use it, what's the point?

One factor that determines degradation is how long this charge rate is sustained. Quick bursts of energy, such as when you decelerate and regenerate, don't really stress the battery, because remember you have just been moving ions and electrons in the opposite direction to get the car up to speed in the first place and there's plenty of "room" for the reverse chemical reaction to occur. And in the case of the battery in a Tesla, 60 kW isn't much, especially below 50-60% SoC, and is less than 1C.

Superchargers start out at zero kWh, and ramp up to what the BMS in the car says it is allowed to reach based on the conditions, battery temp, SoC, and capacity of the pedestal. ALL of this is being managed by the BMS which is very good at what it does. The X has shown peak charging rates of 172kWh, BUT it only is at that level for a few seconds, and tapers downward slowly and continuously through the charge cycle. It's not like it is holding a high rate for minutes at a time. Far from it, that peak rate was so quick that I couldn't even get my phone open to get the picture of the dash!

With 14k cells in the pack, at 172kWh that works out to 12 watts into each battery for a few seconds. I can see why they would taper down quickly with that much going in, that's 4 amps at normal cell voltages and higher with depleted cell voltage. Into cells that are around C-cell size. (ish).

But the BMS is managing it, so rock it out. Someone mentioned that you "have to" charge to 80-90%.... No you don't! You can Supercharge as much or as little as you'd like - as you get close to full, BOTH a 6kw slow-home-charger and a Supercharger will taper off to LESS than 4kWh - I watched a supercharger sending 2kWh as it was searching for the finish point, and yes it took a looooooooooooong time. But I was also at that point running an experiment to see where it would actually stop, and making sure that the BMS DID know where the top was - and I was on a road trip so it wasn't going to sit at that full mark at all. I needed that power right away!

 

[AAKEE]

My X has the original battery and at 104k miles, was at 11.7% degradation from an owner who avoided supercharging.

One thing that is interresting is how you determined the degradation.
A 100% range value and/or the energy app calculation would be good.

With 14k cells in the pack, at 172kWh that works out to 12 watts into each battery for a few seconds. I can see why they would taper down quickly with that much going in, that's 4 amps at normal cell voltages and higher with depleted cell voltage. Into cells that are around C-cell size. (ish).

100 kWh pack has 8256 cells.

172 kW (not kWh) on a 100 kWh pack is 1.72 C. C-rate is good to relate for charging power.

100 kWh / 8256 cells gives about 12.2Wh per cell, 3300mAh each.

The amps would be at least 1.72 x 3 = 5 (probably closer to 6A) to reach 172kW.

This is from this research report cycling panasonic 18650 NCA Cells (NCR18650PD)

Lithium plating is the main thing that cause the degradation. The cell capacity is 2.9Ah, so 3A is about 1C.

These tests did not preheat the cells so it causes more damage than a heated cell as preheating above 40 deg Celcius minimize the lithium plating.

Recently we had a Swedish 2019 Model 3 Performance where the battery totally died with several cells (not only one) that stopped working, internal short cuts wich is the end state of severe lithium plating.
That car had 230K km, and about 70% supercharging.
My own conclusion is that that was directly related to supercharging.
The car did not show extreme degradation shortly before the break down of the battery.
I would be carefull with huge numbers of supercharging sessions.

 

[DayTrippin]

I'll provide a few anecdotal data points from my own cars. I've used recurrentauto.com and their free service for consistent battery degradation measurement as well as the Tessie app and all my cars are plugged into TeslaFi.com to track usage.

All my cars are kept at as low of SoC as possible. So I never charge above 50% except when I absolutely need more range and can get it by charging more at home and avoiding an SC stop. I minimize my discharge cycles and charge up just before leaving to help keep my average SoC low.

2022 - M3 LR w/acceleration boost
It lives in a very hot climate for about 7 months of the year. Only supercharger use was when Tesla charged it up to bring it to me. It has about 6k on it and is 14 months old. According to almost every service/app I've used the battery is at 101%. Based on the measurements, it has a higher predicted range than a typical M3 would have when brand new.

2022 - MS LR - just sold
It lived in a very hot climate for about 7 months of the year. About 2k miles supercharger for a long road trip. Never ran SC above 65%. It had about 8k+ on it and was 14 months old. I must have made at least 150+ full power 0-60 passes, often in sets of 10 back to back with no break. A lot of those turned into 1/4 passes if conditions allowed. According to almost every service/app I've used the battery is at 99-100%. So basically minimal to no degradation.

2022 - MS Plaid - just bought
It apparently lived in a very hot climate as well based on the CarFax. From what I could tell, a lot more supercharger use than my MS LR. It had less than 6k on it and was 12 months old (so newer than my car). Using the same tools to measure the battery degradation it is at 97%. So basically minimally 3 times the degradation of my MS LR, with fewer miles and calendar aging.

2021 - MY LR w/acceleration boost - sold but with my data and data from current owner
It lives in a very hot climate for about 9 months of the year. It had about 8k, 2k or SC use, and 1% degradation when I sold it. The person who bought it from me has put almost 50k miles since then in the last year. It has seen lots of SC use, probably about 70% of its charging is while on his long commute of 170 miles each way. The MS LR can't make it on a round trip even starting on a full charge. Battery degradation is currently sitting at 7% It was aging more quickly but I helped with a strategy to minimize SC use and to keep his average SoC lower when not on his commute which can be 2-3 times a week.

You can draw whatever inferences you want from the data. I have my own hypothesis. The tale of the two S's encourages me to believe that my approach results in less degradation. So I minimize SC use, keep my average SoC low, charge just before going, and don't charge more than I need to. Fortunately the MS LR or Plaid are hella quick even at a 40% SoC so I am not really giving up much in performance. Given the S's better range to begin with, I can have a lower SoC and have a decent range.

 

[AAKEE]

I'll provide a few anecdotal data points from my own cars. I've used recurrentauto.com and their free service for consistent battery degradation measurement as well as the Tessie app and all my cars are plugged into TeslaFi.com to track usage.

Good data.

Tessie have a little bit of issues with both the original capacity as well as the "usable capacity so I do not thrust them, (just for you to know so best is to use another source to find a more correct number. Not that I think you have that much degradation as you do it very well.

We had a swedish model S owner that was very happy with only "4 % degradation" after 170K km and a battery capacity of 74.5kWh.

Tessie did show 6.7% degradation at the same time, same car.

It didnt sound correct with 4% ( time only would...) so after a check he used ABRP as the source. That calc was very off, the war had 407km original range and showed 452km on a full charge.
The battery capacity is about 72.4kWh, out of 81.5kWh, so 11.2% degradation if we use the real numbers for original kcapacity and the BMS actual.

I'm starting to think that the low numbers seen on various sites for model S and X might come from things like this.


We also had another guy in a swedish forum, when talking about low SOC strategy that always charged "high and still had 2.9% degradation <-- According to Tessie, that say. Owner ="No need to use low SOC as the degradation is minor anyway"

A reality check showed 7%.

 

[DayTrippin]

Good insight. It is also why I use recurrentauto.com mostly since it was available. My thought is I'll use several sources and if they all pretty much agree, then at least there is maybe some validity in the numbers. At least I hope the trend is accurate.

 

[geordi]

My numbers are coming from the Tessie app, and I have ensured that the original capacity is based on numbers from Jason at 057, who I believe was the first to report on these capacity numbers.

For comparisons in range / supercharging use, you should also ensure that you are comparing the same battery chemistry as well - older S and X have Li-ion, newer 3 and Y (and possibly refresh S/X) have Lithium Iron Phosphate (LFP) batteries. The profiles and degradations will be different.

I travel for work and the two cars that I have used for that were specifically purchased for that usage, especially after the articles about the Tesloop cars used *exclusively* on supercharger. The length of time that the peak rate is maintained will definitely affect the battery - BUT I still contend that the BMS is communicating with the charger and controlling this to protect the battery. Here's two charges as examples, the 163kw peak was a total of 56 minutes on the charger, the other was 19 minutes. As you can see, it ramps up, and then just as quickly comes right back down again.
The 163kw peak was from 7% to 86%, the Greenville was from 19% to 57%.

This is on the aged battery in the X. 400V Lithium Ion, 90kw rating (so 81.8 original usable)

 

[AAKEE]

For comparisons in range / supercharging use, you should also ensure that you are comparing the same battery chemistry as well - older S and X have Li-ion, newer 3 and Y (and possibly refresh S/X) have Lithium Iron Phosphate (LFP) batteries. The profiles and degradations will be different.

Model S and X has Panasonic 18650 format lithium ion of the NCA chemistry, Model 3 LR/P and Y LR /P in USA use Panasonic 21700 still NCA.
In Europe it was the same for model 3 until about 2022.

Model 3 SR did use Pansonic NCA earlier but changed over about 2021 to LFP.
The only cars using LFP is standard range cars (now "SR" is removed), this is because LFP cannot provide tha range of a LR car (to little space, and they would be heavy).
Of course the chemistry is taken in account when discussing degradation for either calendar aging or cyclic aging.

This is on the aged battery in the X. 400V Lithium Ion, 90kw rating (so 81.8 original usable)

I dont have the Xnumbers, but for reference:

When using the Tessie App (or service), the term "usable" should not be taken any notice of, as Tessie calculate the whole battery capacity.

The value inside the "meter" should be the total capacity (not "Net", not "usable" but the complete whole capacity). This is because Tessie calculates the "usable capacity" as the total capacity including the buffer. I doesnt sound like they should, if we think of the term used, but the vendors confirmed this in the vendors thread and when checking with Scan My Tesla on the same vehicle, nominal full oack is the closest value, In some cases the calculation even match, so Tessie have some bright occations also. But they should stop calling it "usable" as it really isnt according to the common accepted interpretation of the term [usable] in combination with EV batteries and buffers.

So in the end, in the meter the whole original capacity need tpo be used (including the buffer) as the degradation calc is built on the "usable capacity" using the total capacity including the buffer.

If not doing this correct, and using the tessie like tessie does imly, my car has 78.9 kWh usable capacity (which would be 82.6 including the 4.5% buffer) out of a initial capacity of 78.8 kWh (as tessie thinks my model* has. So, today after 2yrs 4 months and 61K km, Im at 3.8kWh plus (increased capacity) from the start.
Thats good, Ill will pass 100kWh usable in a few years.

IRL, I'm at 78.9kWh of 82.1 kWh total capacity.

 

[AAKEE]

Model S and X has Panasonic 18650 format lithium ion of the NCA chemistry, Model 3 LR/P and Y LR /P in USA use Panasonic 21700 still NCA.
In Europe it was the same for model 3 until about 2022.

Too late to edit*.

In Europe, Tesla use LG NMC since about 2022 for Model 3 / Y built in Germany and China.

*) So no one thinks its LFP for LR/P.

 

[Dave EV]

Recently we had a Swedish 2019 Model 3 Performance where the battery totally died with several cells (not only one) that stopped working, internal short cuts wich is the end state of severe lithium plating.
That car had 230K km, and about 70% supercharging.
My own conclusion is that that was directly related to supercharging.
The car did not show extreme degradation shortly before the break down of the battery.
I would be carefull with huge numbers of supercharging sessions.

I wonder if the cold temperatures of Sweden combined with a lot of Supercharging contributed to this.

I don't recall exactly when Tesla introduced pre-heating for Supercharging, but I suspect it was partially to help reduce early failures like this, especially since otherwise, the cool average temps of Sweden to produce low rates of capacity loss.

I don't recall, but I also wonder if Tesla has also reduced Supercharger max rates at cooler temps as well.

 

[AAKEE]

I wonder if the cold temperatures of Sweden combined with a lot of Supercharging contributed to this.

I don't recall exactly when Tesla introduced pre-heating for Supercharging, but I suspect it was partially to help reduce early failures like this, especially since otherwise, the cool average temps of Sweden to produce low rates of capacity loss.

I don't recall, but I also wonder if Tesla has also reduced Supercharger max rates at cooler temps as well.

The broken M3P battery was preheated from new, as I understand it.
I wouldnt think not preconditioning was the issue in this case.

It was 85% DC-charging according to the thread, just checked.

 

[ATL67]

You guys are all overthinking this. If you don't need or want the control, set it to 90% or whatever and don't fiddle with it. We're talking about a relatively small difference over the life of the pack.

Excellent point. On the other hand, I come to this forum for the overthinking.

 

[AAKEE]

Excellent point. On the other hand, I come to this forum for the overthinking.

And, the ones that like to reduce degradation actually will have cut the degradation in half, and also doubled the life time of the pack.

 

[aerodyne]

And, the ones that like to reduce degradation actually will have cut the degradation in half, and also doubled the life time of the pack.

Aha, timely post. '22 MSLR, One year after build and 4600 miles, 70-30%, store at 55%, including long term storage at 55% for three weeks, my degradation is:


Drum roll...


0.85%

Compared to the fleet. I don't mind over thinking this, a Tesla is a thinking person's car, so someone said, I think.

 

[lwrider]

%70

 

[AAKEE]

I wonder if the cold temperatures of Sweden combined with a lot of Supercharging contributed to this.

I don't recall exactly when Tesla introduced pre-heating for Supercharging, but I suspect it was partially to help reduce early failures like this, especially since otherwise, the cool average temps of Sweden to produce low rates of capacity loss.

I don't recall, but I also wonder if Tesla has also reduced Supercharger max rates at cooler temps as well.

On old post, but some info:

I sold my car “outside” Tesla as they offered me a shameless low price, and I got whats compares to 10 grand more from another company (Carla.se).
They have my car for sale now, they also had at least 4 other swedish M3P refresh (I made a post in another thread another day).

These had according to the test protocol made by Carla 9, 10, 12 and 13% degradation. As my M3P is a very early refresh for being in sweden(built november 2020). The other cars is both 2021 and 2022 and no of the other car is even close to my M3Ps 66K km.

My car was calculated to 5% degradation (they calculate from the Full Pack When new which we know newer is reached), so to make an easy statement from comparing with other cars with the same battery, they have degraded at least twice my car despite about the same climate.
I did not use the registration to find build date, but that would probably increase the difference between these cars and mine, as most of them are younger and have less on the ODO than my car.

 

[aerodyne]

Update...'22 MSLR with 7500 miles.

Stored at 50%, unplugged, covered, indoors for 8 weeks while I was in Argentina. Did not wake the car up, monitored by Teslafi. Ending SoC 33%, used 17kw or 13w/hr average.

Recharged to 50%. Rated range is now slightly GREATER at 401 miles than when I left.

IMO, charging to 90% or above to improve range is a fools game, and any positive results are likely do to battery being warmer due to charge.

If you must obsess over the battery or rated range, then realize the smaller the charge cycles, the lower the Storage SoC, and the lower the Storage temp will all have an improvement, however slight, on degradation.

The ideal percentage (50% works for me) would be whatever you need for the day, leaving about 30% SoC for buffer and reserve, but not to exceed 90% unless you need it. I have never been below 19%or over 88%.

Degradation wise, leading top 30% in the Teslafi fleet at 1.2%

 

[AAKEE]

Update...'22 MSLR with 7500 miles.

Stored at 50%, unplugged, covered, indoors for 8 weeks while I was in Argentina. Did not wake the car up, monitored by Teslafi. Ending SoC 33%, used 17kw or 13w/hr average.

Recharged to 50%. Rated range is now slightly GREATER at 401 miles than when I left.

IMO, charging to 90% or above to improve range is a fools game, and any positive results are likely do to battery being warmer due to charge.

If you must obsess over the battery or rated range, then realize the smaller the charge cycles, the lower the Storage SoC, and the lower the Storage temp will all have an improvement, however slight, on degradation.

The ideal percentage (50% works for me) would be whatever you need for the day, leaving about 30% SoC for buffer and reserve, but not to exceed 90% unless you need it. I have never been below 19%or over 88%.

Degradation wise, leading top 30% in the Teslafi fleet at 1.2%

There is an issue with teslafi when we have two different range with two different wheels selected.
I do not know if the same is valid for MS LR but for my Plaid, selecting 19” wheels set me in top and using 21” selection put me at third from bottom.
The average line is between the normal range for 19” and 21”.

Not meaning anything in your case, using 55% or below will reduce the degradation rate with about 50%.

The lower the SOC the less calendar aging.
I charge to 55% at home (sweet spot between low degradation and good range).
When at work (one week at the time I park at 10-25% and leave it during the work week. Usually do some smaller drives to the supermarket etc. during the week.

Tested a change to 19”, and then was highest range, thats the peak.

 

[tesluv108]

Update...'22 MSLR with 7500 miles.

Stored at 50%, unplugged, covered, indoors for 8 weeks while I was in Argentina. Did not wake the car up, monitored by Teslafi. Ending SoC 33%, used 17kw or 13w/hr average.

Recharged to 50%. Rated range is now slightly GREATER at 401 miles than when I left.

IMO, charging to 90% or above to improve range is a fools game, and any positive results are likely do to battery being warmer due to charge.

If you must obsess over the battery or rated range, then realize the smaller the charge cycles, the lower the Storage SoC, and the lower the Storage temp will all have an improvement, however slight, on degradation.

The ideal percentage (50% works for me) would be whatever you need for the day, leaving about 30% SoC for buffer and reserve, but not to exceed 90% unless you need it. I have never been below 19%or over 88%.

Degradation wise, leading top 30% in the Teslafi fleet at 1.2%

I’m about to park at an airport for 4 nights wondering if I should leave cabin overheat protection off? It’s supposed to 80+ highs every day next week but I will have shield cover on. This will be a good test as I have been losing about 1.5% phantom a day

 

[AAKEE]

I’m about to park at an airport for 4 nights wondering if I should leave cabin overheat protection off? It’s supposed to 80+ highs every day next week but I will have shield cover on. This will be a good test as I have been losing about 1.5% phantom a day

The car itself is supposed to handle high ambient temps I guess?
Cabin overheat supoosed to save children firgot in the car?

If you have a cover I guess its not a issue anyway.
Do you use sentry mode? I guess any of these keep the car awake.

One week for me with both my M3P and MSP ”cost” about 1% or so.
About 0.1 kWh/day