What Percent is Your Tesla Charged to While at Home?

[AAKEE]

Doing all of that, what percent of degredation do you think you'd save in that battery pack over lets say, 3 years? someone charging to 90 percent in a cool climate, vs someone charging to say 60 percent? I we thinking a 5 percent savings?

Yoy would like to use 55% maximum for a new NCA-battery.
The big step where the calendar aging is situated is at about 57-58% for a new battery. Tesla use a 4.5% bottom buffer which means that the true soc is higher than the displayed. 57% true SOC is 55% displsyed.
(The step ”moves” upward with calendar aging/degradation, so after a 10% degradation the step step is at 63%, but lithium plating from fast charging move it downwards).

I have lost about 13km range during 2 1/2 years.
The other M3P 2021 at teslafi have lost in average 47 km.
I have an early 2021 so most is probably younger than mine.

In general, I’d say you cut the degradation in half.
In practical terms it can be more than cut in half.

Just compare the 25C line for 80-90% with the 40-50%

There is some further wins, like that the battery can recover from some degradation when they are cycled at low SOC. Using low SOC after for example supercharging etc can recover some of the losses tgat vame frpom supercharging.

 

[johnny_cakes]

(The step ”moves” upward with calendar aging/degradation, so after a 10% degradation the step step is at 63%, but lithium plating from fast charging move it downwards).

Very interesting. Can you share the calculation for how the step moves with degradation? My vehicle has ~14% degradation, so the step may be even higher than 63%. I don't Supercharger often.

 

[AAKEE]

Very interesting. Can you share the calculation for how the step moves with degradation? My vehicle has ~14% degradation, so the step may be even higher than 63%. I don't Supercharger often.

Basically the step (central graphite peak) is at a fixed energy level from 0% SOC.
The capacity loss is above this.

Traveling right now and I dint find the optimal picture for this, but we can use two.

Q is the stored Amphere hours.
Q1 is the charge Amphs from zero to the central graphite peak
Q2 is the charge level above the centeal graphite peak

We can se that the Q1 do not change from calendar aging only but the Q2 change.
If you have 14% calendar aging(only calendar aging, which isnt probable) you would have the step at about 66% true SOC, thats some 62% displayed.
IRL you have cyclic aging as well.
I havent bothered learning how it moves from regular cycles but I know/lesrned that fast charging moves it down. The easy way would be to think that it is safe to stay at 55% displayed SOC.
I could look into how regular cycles change this if it is important, but for my self the ”55% displayed will continue to cause low degradation” is good enough.

 

[hgmichna]

70% is the sweet spot for LFP batteries. Before long drives and occasionally at other times 100% to calibrate the BMS.

Less than 70% has no advantage in relation to calendaric degradation for LFP batteries, unless you go significantly below 40%, which is impractical.

Other Li-ion batteries I charge to 60%, if I do not immediately need more.

 

[dafish]

Deep discharges hurt the pack more than maintaining 90 percent ever will. Play it safe and charge to 90!

Total nonsense. Couldn’t be more wrong if you tried. Worse, there is plenty of data available proving it, meaning you‘re literally spouting BS without making even a tiny effort to gather actual knowledge

 

[dafish]

For non-LFP, Elon says to charge it to 90%. But what would he know..?

No, he does not. His statement was that he would use 80% accepting the mild harm for the convenience, but that he acknowledges lower, more like 70%, is better For the battery.

 

[AlanSubie4Life]

But what would he know..?

Pretty clear at this point…not much. Sadly. He’s a walking example of several non-complementary aphorisms.

But if you have some magical trick, I'd like to duplicate it on my car.

He keeps it in a freezer something like 9 months of the year.

Everything I've read said the 2018 Model 3 has a 75 kWh battery.

Not sure where this comes from. Remember to only use good sources when you read!

For example, Tesla’s EPA document produced in 2018 showed clearly the car had 79+kWh! There are many other well researched sources as well. None of these suggest 75kWh. (Some confusion may arise because usable capacity of 2018/2019 when new is about 75kWh (actually 74.3kWh).)

I would guess Ken’s car happened to be a slight outlier on initial pack capacity too. There is SOME variation of pack capacity initially (though typically quite small). But it definitely seems possible he started at 79kWh.

And remember, with the 2018/2019, it does not show rated range loss until solidly below 76kWh. This is extremely well documented (see degradation threshold discussions).

All that being said, clearly this car is an outlier. Outliers happen! Don’t be so quick to imply prevarication - especially when Ken has been posting well documented information about his car here for years. It’s an outlier, caused by temperature, storage SOC, and initial capacity, to name a few factors.

I still remember in 2019, people telling me in posts, that my range would start dropping in 12 months

Yeah, I was one of those people! I remain flabbergasted.

I predict your car will start showing range loss in the next 12 months.

 

[golferguy]

LOLView attachment 935036
Have you heard of SMT? ScanMyTesla? That's their best guess of the actual capacity of our batteries from 2018. Currently, the batteries are around 82kWh, so mine didn't start especially large.

Maybe the trick is mine came home delivered in cold December, with zero charge. Yep, zero.View attachment 935037
Anything else you'd like me to answer?

I've been posting my data, which doesn't add up, but doesn't make me a liar, here ever since I placed my order, which was in August of 2018. I still remember in 2019, people telling me in posts, that my range would start dropping in 12 months. Hasn't happened yet.

Interesting 5yr old photo, but 6 hours to SuperCharge?

Do you have a current photo of 100%/310 mile predicted range? Something recent.

 

[johnny_cakes]

Basically the step (central graphite peak) is at a fixed energy level from 0% SOC.
The capacity loss is above this.

Traveling right now and I dint find the optimal picture for this, but we can use two.

Q is the stored Amphere hours.
Q1 is the charge Amphs from zero to the central graphite peak
Q2 is the charge level above the centeal graphite peak
View attachment 935385

We can se that the Q1 do not change from calendar aging only but the Q2 change.
If you have 14% calendar aging(only calendar aging, which isnt probable) you would have the step at about 66% true SOC, thats some 62% displayed.
IRL you have cyclic aging as well.
I havent bothered learning how it moves from regular cycles but I know/lesrned that fast charging moves it down. The easy way would be to think that it is safe to stay at 55% displayed SOC.
I could look into how regular cycles change this if it is important, but for my self the ”55% displayed will continue to cause low degradation” is good enough.
View attachment 935387

Very interesting, thank you!

 

[KenC]

Interesting 5yr old photo, but 6 hours to SuperCharge?

Do you have a current photo of 100%/310 mile predicted range? Something recent.

When the car was home delivered, it had ZERO SOC. Since I live on a longish dirt road, the semi truck driver couldn't deliver it to my home, but suggested meeting me at a rest stop. Of course the rest stop he chose, he mistakenly thought had a charger. Since the driver hadn't told me anything until he had unloaded the car, I didn't know the car had zero soc, so I couldn't tell him the rest stop had no chargers.

I suggested we take it to my dirt road and let me roll it downhill to my house, but he wouldn't agree, since it was really ZERO. Apparently, it was zero when he loaded it that morning, and now it was late in the day and I was the last delivery in December. Who knows how long the car had been at zero? It had never been to a delivery center, as the interior had industrial plastic residue all over the dash, and it had been 2 months since shipping from Fremont. It probably had never been charged since leaving Fremont.

In this pic, I had just pushed the car back onto the semi, because it had so little charge. With a battery at zero, if you wait a little, you can get a tiny bit of charge out, but in this case, I had to push, it was that little.

We took my car 10miles away to a rest stop with a supercharger.

The delivery semi is right in front of the car. It's December in Maine. It's cold. The battery has to warm up before it can start to charge. I actually waited about 2hrs before driving it home.

Okay, looking at the time stamps, I got about 189mi/61% in around 1h50mins of supercharging, and the timezone is 3hrs off. So, looking at the map, it shows my car is in Vergennes, VT, though it was actually in Augusta, Maine. Perhaps, the car hit zero SOC in Vermont, and that's when it last had GPS lock.

Anyway, a rather long strange trip for my car.

As for anything that shows I've got 310 miles of range? I think I showed several images already that show I've got 310miles of original EPA rated range. Here's a month ago, SMT is showing 310:

SMT is pulling the raw data from the car, and "rated range" is the EPA rating. Ideal range is the current range. 160miles is because I got home with 52% SOC:

I'm not sure people want to keep hearing my sob story!

 

[AAKEE]

When the car was home delivered, it had ZERO SOC. Since I live on a longish dirt road, the semi truck driver couldn't deliver it to my home, but suggested meeting me at a rest stop. Of course the rest stop he chose, he mistakenly thought had a charger. Since the driver hadn't told me anything until he had unloaded the car, I didn't know the car had zero soc, so I couldn't tell him the rest stop had no chargers.

I suggested we take it to my dirt road and let me roll it downhill to my house, but he wouldn't agree, since it was really ZERO. Apparently, it was zero when he loaded it that morning, and now it was late in the day and I was the last delivery in December. Who knows how long the car had been at zero? It had never been to a delivery center, as the interior had industrial plastic residue all over the dash, and it had been 2 months since shipping from Fremont. It probably had never been charged since leaving Fremont.

In this pic, I had just pushed the car back onto the semi, because it had so little charge. With a battery at zero, if you wait a little, you can get a tiny bit of charge out, but in this case, I had to push, it was that little.
View attachment 935450
We took my car 10miles away to a rest stop with a supercharger.

The delivery semi is right in front of the car. It's December in Maine. It's cold. The battery has to warm up before it can start to charge. I actually waited about 2hrs before driving it home.

Okay, looking at the time stamps, I got about 189mi/61% in around 1h50mins of supercharging, and the timezone is 3hrs off. So, looking at the map, it shows my car is in Vergennes, VT, though it was actually in Augusta, Maine. Perhaps, the car hit zero SOC in Vermont, and that's when it last had GPS lock.
View attachment 935464
Anyway, a rather long strange trip for my car.

As for anything that shows I've got 310 miles of range? I think I showed several images already that show I've got 310miles of original EPA rated range. Here's a month ago, SMT is showing 310:View attachment 935467
SMT is pulling the raw data from the car, and "rated range" is the EPA rating. Ideal range is the current range. 160miles is because I got home with 52% SOC:View attachment 935471
I'm not sure people want to keep hearing my sob story!

Do you have any SMT numbers from when it was new? Like nominal full pack etc?

 

[KenC]

Do you have any SMT numbers from when it was new? Like nominal full pack etc?

No, since I only got it 11 months ago. I was already past 36k miles. It showed 77.0kWh NFP:

That's the first SMT data I got last June.

 

[Spinkick]

Total nonsense. Couldn’t be more wrong if you tried. Worse, there is plenty of data available proving it, meaning you‘re literally spouting BS without making even a tiny effort to gather actual knowledge

Someone else showed us some data that suggests its not so simple. They did it a polite way also, which is appreciated among adults. You dont even add data of your own which could also be viewed as pure conjecture.

TLDR: buzz off

Here is a good current video too:

Around 11 minutes in. its basically keep the heat down, keep the supercharging to a minimum. charge to 80 / 90 percent. Watch depth of charge. Sounds a lot like a cell phone battery.

 

[AAKEE]

Someone else showed us some data that suggests its not so simple. They did it a polite way also, which is appreciated among adults. You dont even add data of your own which could also be viewed as pure conjecture.

Here is a good current video too:

Around 11 minutes in. its basically keep the heat down, keep the supercharging to a minimum. charge to 80 / 90 percent.

In the video: The thing about charging to 80 or 90% is simply not true.
Tesla doesnt recommend charging to 80 or 90%, they say below 90%, which include all levels below.

Try to find Teslas advice for your car. Start with the manual and see what it really says.

Watch depth of charge. Sounds a lot like a cell phone battery.

You are not on the correct path if you like to keep the degradation to a minimum. Your battery will stay alive at 80 or 90% as well but it will not have the lowest possible degradation.

The thing is, there is a lot of battery myths floating around and a very high part of the people got caught by these myths.

I do not know how to get you to listen to what science has to say about this.
They have a lot of real data from real tests.

DoD - its called depth of discharge. The smaller the DoD the better. But also, in general the lower down in the SOC region the better.

The cyclic aging for the normal cycles (DoD wise) we use on an EV causes very small degradation.

This is a test report of actual model S 18650 cells: Tesla cells tested
They took cells from a model S that was driven for 6 months since new.

We can see that 250 full cycles causes 8% degradation.
That is about 8% per 100.000km or about 1-2% each year, if the full 100-0% cycles is used. We know that smaller cycles cause much less wear so we are down to less than 1% per year for normal EV cycles.

Calendar aging on the other hand, causes about 5-5.5% degradation the first year if the average temp is around 25C That will be around 10% after four years. At that time the cyclic aging has not caused more degradation than maximum 4%, most probably much less (I have data about that also).

Same test, the Tesla model S cells was also tested for calendar aging:

It should be obvious that 80-90% is not the best SOC for avoiding degradation.
Note: this is not the only source for this statements. There is very many research reports finding the same thing.
In fact; there is no research data at all that find anything deviant from this. There might be only small differences like that some reports find the calendar aging slightly higher at 100% than at 70-90% (but not much), and sone find 80% to be the worst.
This is a good average for all these test reports:

You probably heard these:
- Leaving the car at 100% is very bad for the batteries. Not realy true, its a myth.
- Driving below 20% is bad for the batteries, not true, its a myth

You might wanna try the battery myth quiz.
Finds the myths you got caught by
Battery myths quiz

 

[golferguy]

No, since I only got it 11 months ago. I was already past 36k miles. It showed 77.0kWh NFP:
View attachment 935503
That's the first SMT data I got last June.

Sorry confused. Those photos of the truck and first charging where not from Dec. 2018? You just got it 11 months ago?

 

[AAKEE]

Sorry confused. Those photos of the truck and first charging where not from Dec. 2018? You just got it 11 months ago?

He is answering me if he had Scan my tesla from the beginning, which he did not.
Read my question then hes answer, then you’ll get it.

 

[jjrandorin]

Anyone interested in in depth discussion on this topic, and not an influencer youtube video which may or may not be accurate, should likely search TMC for posts that @AAKEE has made on the topic.

They are dispassionate, and filled with data, not conjecture.

There is no world in which charging to 90% on a regular basis provides similar degradation to charging to 50% on a regular basis. Now, whether one cares if they have 20 miles lost after 3-4 years or 8 miles lost (in miles terms) is another story, and how comfortable someone is in keeping an EV at 50% charge verses some higher number "if I have to go somewhere" matters as well.

I charge to 70% daily currently, because this is the number that makes me comfortable. Im not trying to tell anyone else what number to charge to, either, but I ALSO am not going to tell people that charging to 90% is "best".

 

[jjrandorin]

Sorry confused. Those photos of the truck and first charging where not from Dec. 2018? You just got it 11 months ago?

No, ken did not get the car 11 months ago. The pictures and posts are from when his car was delivered to him. "11 months ago" was scan my tesla data". I am not quite sure what you are looking for, but @KenC has posted several pictures / feedback on his particular battery so there is no questions about the results for his car.

 

[KenC]

Sorry confused. Those photos of the truck and first charging where not from Dec. 2018? You just got it 11 months ago?

SMT is an app and an OBDII reader/dongle with adapter cord. I finally caved in, trying to understand why my car's battery seemed to never age, so I got the SMT OBDII reader back in June of last year, because most people consider that info to be definitive, or at least what Tesla is also using to make warranty decisions, etc.

 

[m3p-ev]

For a brand new NCA, I see 55% being the most optimal based on data from @AAKEE . How about the lowest it can go before charging? Should we try to stay between 20-55?