better to charge to 90% or allow run down to 10%?

[SabrToothSqrl]

My previous Standard Range X - I'd have to 100% charge it for my use case.
With my new 2023 X - much bigger battery, but it wants to charge to 80% (Vs. the 90% of my old X).

SO... for my use case, is it better to leave it at 80% and get home with about 13%.
OR Charge to 90% and get home with 23%?

I'm sure it's meaningless overall, but curious if it's better to go up 10%, to save it from the bottom end.

Just thinking about battery life/wear, and that it would be better to hit 90% vs running lower.
My record, on my old X, was making it home with 2%!

 

[shahryaran]

Is battery calibration pointless?!

Let's say your car has some amount of battery degradation and you can't get the range you want. You were told to calibrate battery and you may get some range back. Here is the thing... It doesn't matter and don't worry about it. The fact is that the actual amount of battery capacity is there...

teslamotorsclub.com

 

[John in LB]

I would charge to 85%, ending up at 18%. I try to keep the battery in the middle of its range. Not sure how great of a benefit it is, we are just talking about small changes...

 

[Tam]

My previous Standard Range X - I'd have to 100% charge it for my use case.
With my new 2023 X - much bigger battery, but it wants to charge to 80% (Vs. the 90% of my old X).

SO... for my use case, is it better to leave it at 80% and get home with about 13%.
OR Charge to 90% and get home with 23%?

I'm sure it's meaningless overall, but curious if it's better to go up 10%, to save it from the bottom end.

Just thinking about battery life/wear, and that it would be better to hit 90% vs running lower.
My record, on my old X, was making it home with 2%!

Some like to keep their battery low.

I subscribe to the practice from the very old article below: It’s better to be high than low if you have to make a choice:

The Rules of Model S Road Tripping

Driving a Tesla is a bit different from driving a gas car, or even most electric cars. On a daily basis, there is no concern about “range anxiety.” Owners expect their car to have a full “tank” every morning, and have enough range to do whatever they want. After a while they never look at the...

teslamotorsclub.com

 

[dafish]

Search for some posts from @AAKEE, likely the most informed of us on this topic. in the interim for best battery longevity:

1. charge to know more you must have for your trip.
2. charge as close to departure time possible.
3. Running to very low charge level is a non-issue, unless DC fast charging- then it’s preferable.

Personally I ABC to 54%, bring it higher for trips using “departure charge”, and plan to arrive at 10% using 3.1 miles per KW.

 

[AAKEE]

My previous Standard Range X - I'd have to 100% charge it for my use case.
With my new 2023 X - much bigger battery, but it wants to charge to 80% (Vs. the 90% of my old X).

It doesnt want to charge to 80%. It is the upper daily limit. Going below 81% removes the information line about 80% daily.

Before the manual said ”below 90%”, which was valid for ages.

Nor the manual or the app does aim to get minimal degradation. Tesla wabt the car to have as little restrictions as possible, and want the use to be easy.

SO... for my use case, is it better to leave it at 80% and get home with about 13%.
OR Charge to 90% and get home with 23%?

I'm sure it's meaningless overall, but curious if it's better to go up 10%, to save it from the bottom end.

Bottom end is not dangerous fpr the battery.

Just thinking about battery life/wear, and that it would be better to hit 90% vs running lower.
My record, on my old X, was making it home with 2%!

Cycles is not causing very much degradation for the most people.

High SOC causes more calendar aging but it is the time at high SOC that is the driving factor (and also temperature which you often can not change) so charging late (finished shortly before the drive) reduce the most of the calendar aging.

There wont be a big difference between 90-23 or 80-11%.

The big difference will be made by charging late in your case, if you need 67% SOC for the daily drives.

At weekends it could be a good idea to not charge at all if you do not need the car, or charge to 50-55% if that covers the weekend daily need.

 

[SabrToothSqrl]

thanks!

 

[Rocky_H]

This difference you're talking about is of the small impact variety, where you may have some observable amount of degradation difference in 25 years. But for your own sanity and stress level, when you need to consume that much of the battery, I just wouldn't intentionally run such lean margins on it, and I wouldn't hesitate to use 90% just so you don't get yourself in a range bind.

 

[Joer293]

On Tesla 0 range is really ~5% or so. I’ve driven 20 miles past 0. In all the charts I’ve seen, it’s more about how long does the battery sit at a low or high charge. it’s chemical reactions, which take time, they aren’t instant. If you charge right after the drive, when you get home, no worries. On the top end is the same, charging to 100 isn’t bad by itself if you drive right away, letting it sit above 98% is what wears the battery. luckily vampire draw, sentry and cabin overheat means you’ll never have to worry about wearing a battery out for being too charged For a month in airport parking.

 

[AAKEE]

On Tesla 0 range is really ~5% or so. I’ve driven 20 miles past 0.

For all newer cars 4.5%.

Older S/X used a fixed kWh buffer like 4kWh for the larger batteries.

In all the charts I’ve seen, it’s more about how long does the battery sit at a low or high charge.

Did you really ever see a chart based on science/research showing increased calendar aging at low SOC? I didn’t.

I did read, at least 200-250 research reports about lithium batteries…and I did not see one.

it’s chemical reactions, which take time, they aren’t instant. If you charge right after the drive, when you get home, no worries.

As charging right after the drive supposedly refers to low SOC, it is actually the other way around.
Low SOC (down to 0%) causes less degradation from time than higher SOC.
No need to charge right after the drive for that reason.

On the top end is the same, charging to 100 isn’t bad by itself if you drive right away, letting it sit above 98% is what wears the battery.

That is a myth.

100% only causes slightly more degradation than 80% in very high ambient temperatures, and in normal temperatures 100% causes about the same degradation as 80-90%. Actually, in some cases 80% causes worse degradation than 100%.

Theres really no need to leave the car at 100% but also not directly dangerous as the myth tell us.

Look at the blue line, relative capacity at 0.95 means that 5% capacity was lost to calendar aging during 10 months.
It is virtually the same between 70-100%

 

[dafish]

One thing to consider: Not all studies show such a sharp drop around 60% going flatter around 70%. However, all I’ve seen do show loss as we increase SOC and that in general getting steeper around 60%.

Point: there may be mild debate about exactly where degradation gets significant, but there is no doubt higher SoC accelerates it, nor that how long one sits at such a point accerbates same. Personally I use Aakee’s recommendations and move on.

 

[AAKEE]

One thing to consider: Not all studies show such a sharp drop around 60% going flatter around 70%.

Well, many researchers use few testpoints for different SOC and then combine the testpoints with straight lines which effectively hides details in between.

I have not seen any high resolution test showing any noticeable difference about the “sharp drop”

The research seems to agree that calendar aging is dependent on the anode and cathode potential, and that when these are high = low degradation and vice versa.
The central graphite peak marks a position where there is a step change in potential with a small change in SOC, causing the sharp drop.
Different chemistries have the central graphite peak at different locations, and differences in the amount of materials for the same chemistry could cause (slight) shifts of the central graphite peak position.
There is indications of a few percent differences.

However, all I’ve seen do show loss as we increase SOC and that in general getting steeper around 60%.

Point: there may be mild debate about exactly where degradation gets significant, but there is no doubt higher SoC

If we are looking to find the exact spot, we need to remember that displayed SOC differs from the actual state of charge (due to the bottom buffer Tesla use).
The difference is about 2% at 55% displayed SOC. So finding the central graphite peak at 57% means we are at 57% when the car shows 55%.

One report shows 60% on the “safe side” for a unknown brand of NCA cell.
Except for slight differences in chemistry we also need to take into account that the way to establish SOC in percent might differ between researchers. There is a huge difference between the charged Amp-hours and SOC energy wise, as each milliamphere has a higher energy content high in SOC due to the higher voltage.
SOC should be relating to energy (Watt hours etc), so 80% should mean there is 80% energy still left in the cell.
It is often possible to find a reason for a report to differ slightly from others. It is not uncommon that “mistakes” or the test setup hides or affects the test. The test report writers seldom finds this for them self, but the information often is there deep down.

The short sum up from the above is that a single report with a different finding is not enough to make a case.
We as interested EV users should look at a broad spectrum of research.

 

[DCGOO]

For all newer cars 4.5%.
Older S/X used a fixed kWh buffer like 4kWh for the larger batteries.
Did you really ever see a chart based on science/research showing increased calendar aging at low SOC? I didn’t.
I did read, at least 200-250 research reports about lithium batteries…and I did not see one.
As charging right after the drive supposedly refers to low SOC, it is actually the other way around.
Low SOC (down to 0%) causes less degradation from time than higher SOC.
No need to charge right after the drive for that reason.
That is a myth.
100% only causes slightly more degradation than 80% in very high ambient temperatures, and in normal temperatures 100% causes about the same degradation as 80-90%. Actually, in some cases 80% causes worse degradation than 100%.
Theres really no need to leave the car at 100% but also not directly dangerous as the myth tell us.
Look at the blue line, relative capacity at 0.95 means that 5% capacity was lost to calendar aging during 10 months.
It is virtually the same between 70-100%
View attachment 998563

Except that Tesla does not use NCA cells. Look up NMC (Nickel-Maganese-Cobalt. Some model 3 and Y use LFP Lithium-Iron-Phospate. LFPs love being held at 100%, and should be fully charged overnight. NMC not so much.

 

[AAKEE]

Except that Tesla does not use NCA cells. Look up NMC (Nickel-Maganese-Cobalt. Some model 3 and Y use LFP Lithium-Iron-Phospate.

No, you are wrong.

All model S and X use Panasonic NCA (NCR18650). From from first car and Still does
All Model 3 and Y Used Panasonic NCA until about end of 2020. Then USA built continued to use NCA for LR/P.
Both model 3 and Y in USA did get NCA until very recently when 3 LR only started to get LG NMCA (M50 cell), the rest still use NCA.

MIC cars did get LG NMC initially (except M3P which got NCA untill the spring of 2022.) from about the new year 2021-2022.
German built Y get the LG M50 (NMCA).

Panasonic only used/delivered NCA cells to Tesla, but the 4680 in Y seem to be the first NMC.

LFPs love being held at 100%, and should be fully charged overnight.

Thats not really true.

The reason to charge to 100% on LFP cars is the flat voltage curve, that causes the BMS to have a hard time measuribg the SOC in the battery.

The LFP’s themselfs have about the same degradation from high SOC as NCA and NMC.

We clearly can see in logs of degradation that the LFP’s loose about 5% in ~40K km and that this is not better than the NCA LR/P cars. As LFP has very low degradation per cycle, its clear that modt of this is calendar aging.

 

[ATPMSD]

SO... for my use case, is it better to leave it at 80% and get home with about 13%.
OR Charge to 90% and get home with 23%?

You could spend a month reading the forum about battery charging. Generally, I think people agree the best thing to do to optimize battery health is to keep it around 50%. That said, in your case the best range will be 83% charge returning at 16%.

But, I suggest you are overthinking this. Pick a top SOC that allows you to drive the car without being concerned about running the SOC too low and just enjoy the car. BTW, if you plan to get rid of the car before the HV battery warranty expires, than all the discussion and options really are just academic and moot.

Enjoy your new X!