Is it better for my car to spend more time at 50% or have shallower discharge cycles but spend more time at a higher state of charge.

[AAKEE]

Thank you so much for answering my questions. This really helps settle my battery anxiety.

You should not have any battery anxiety

The battery will hold up anyway.
The only reason to even care (like I do) is to reduce the degradation and keep the range.
For really long ( > 8-10 years) term it might make a difference for how lojg it takes until the battery starts to develope issues.

But in the frame of most peoples use, it is a non issue and you of course only need to follow the manufacturers (simple) advices.
(I try to write this from time to time, but its not possible to add it to every post.)

The last question I have for the health of the battery, is it better to charge fewer times and let the battery run down to a low SoC or is it better to keep the car plugged in and charge daily? I’m thinking the answer might be different for the 2 types of batteries the LG and the LFP

Thats right:
LFP’s are much less sensible to the size of the cycle, so you can do litterally thousands of 100-0% cycles. Cyclic wear is a non issue on LFP’s in the EV’s so only how calendar aging affect it is interesting in a degradation point of view.

In theory you could charge only when needed with LFP and charge when the SOC is getting low but I would charge daily to 70% and once a week to 100%.

NMC / LG likes smaller cycles better, but still cycles are nor the main thing that causes degradation. Its again calendar aging.

Use 50-60% charging level for LG NMCA as daily charging, and more when needed.
(100% is not at all dangerous as some might tell you).

To minimize degradation:
-Do not charge more than needed
-Charge often (reduces the need per above and makes the cycles smaller.
-Charge late, so the time at high SOC is reduced, specially when going above 60%.

Again thank you so much for your insight. I intend to keep this car for a long time and want to maximize its health. I’ve installed the home charger so I can do either easily.

Thanks

 

[Leftlane22]

I think it’s cool that you guys know and understand all this. I’m too dumb to worry about it so I charge my Plaid late overnight to the level I’ll need when I leave in the morning, and I do a lot of long road trips across Texas so it is to 100% at least twice a month. I also supercharge to 80% on my routes when I need to (often) and don’t think twice about it. My guess is I’ll trade this car in for something new long before I notice any degradation anyway. I have enough anxieties - no room to introduce a new one.

 

[Christopher1]

Flooring the pedal mess up your battery way more than SOC levels. Some of us got the "85pack degrading charging" two years before every 85 pack got this.

 

[AAKEE]

Flooring the pedal mess up your battery way more than SOC levels.

Well, it actually does not.

Cyclic aging is very low for the most EV owners, like 0.5% degradation each year from cyclic aging.

If you always went full throttle from 100% to 0%, there would be a significant reduction of capacity.

Higher power increase the cyclic degradation but in general batteries are good at withstanding shorter bursts like 10-15s. This is the same reason as why Teslas can do regen at much higher power at high SOC than they can supercharge.

Most cyclic tests in research is done at 1C, which is approximately = 80kW power in a 3/Y and 100kW in S/X.
This is sufficient for driving at around 200kph/125 mph.
At this rate, we still get ~1000 FCE cycles if we charge to 100 and drive down to 0%.
(1000 FCE equals ~ 400.000 km or 250.000 miles).

Hete we can se high currents on both charge and discharge. Lithium ion batteries dislikes charging at high current/power much much more than discharge at high current/power.


The same cell type, but smaller depth of discharge:

Same, but even smaller depth of discharge:


They still charge with the same C rate, which is mych worse than discharge.

This is a test of Panasonic NCA (NCR18650B) like the S/X

We can see that small cycles at low power (40-60% and C/2 so ~ 40-50kW) is good, but also that there is not a big difference between 20-80% at 1C (80-100kW) and 2C (160-200kW) between 0-100%.

Many tests show that panasonic NCA hold up as good at 2C as at 1C.

Using high power for shorter bursts as a 0-60 pull of a 1/4 mile will not affect the battery that much. Same with driving a illegaly fast drive at 125mph/200kph.
We will most probably not even see a difference in capacity between a slowly driven car and one used like above from time to time.

Accelerating the car to top speed and keeping it there until the battery is drained will probably be noticed as increased degradation if it is done several times.

Just charging daily to 80-90% and driving average annual ranfes will make the battery loose ~ 10% in calendar aging during the first four years.
It would be very hard to reach a cyclic aging of 10% for the first four years.

My M3P was charged low daily, but > 30 full charges during 2.5 years. I did a lot of 0-60 mph and 1/4 mile runs. (I used the power very often).
Still my car had very low degradation compared to other M3P with the same ODO reading.

Same with my Plaid, I have used the power quite much (which is clearly noticed on the tires threads) but my battery is way above the average Plaid capacity after 1 year from the manufacturing date.

The gain I get from having low SOC most of the time widely surpasses the small extra losses from the use of high power.

My battery topped 98.4 kWh according to the BMS, and still is at 97.2 kWh after 19K km / 12K mi and one year.

The other Plaids in Sweden I know about using Scan my tesla and about the same climate has lost much more capacity. (The are below 95kWh after one year and sbout the same ODO).
From forum discussions we can se that we have similar addiction for high power and fast acceleration
(The other guys mostly do 80% daily)

 

[Christopher1]

Aakee: passing one car increase the temperature of the pack 1°c . That's rough
Your totally wrong. That's why tesla reduced the output after a peak on our packs. And charging etc.
This is what really degrading batterys. That's why other manufacturers have time limits etc. 5sec.. 7 sec. No heat problem. Just what this do to cells.
Teslas battery guru represented Tesla in a Cort in Norway. They didn't realize what kind of damage high currant in / out did to a "cold" batteri(not winter cold).. He had Lot of good info. It's a reason tesla heating the packs more over time. forget about soc. Don't let it stay 10> <90 over a long period.
If you love your battery, touch the throttle as little as possible. It's a killer. Always was

 

[AAKEE]

Flooring the pedal mess up your battery way more than SOC levels.

Well, it actually does not.

Cyclic aging is very low for the most EV owners, like 0.5% degradation each year from cyclic aging.

If you always went full throttle from 100% to 0%, there would be a significant reduction of capacity.

Higher power increase the cyclic degradation but in general batteries are good at withstanding shorter bursts like 10-15s. This is the same reason as why Teslas can do regen at much higher power at high SOC than they can supercharge.

Most cyclic tests in research is done at 1C, which is approximately = 80kW power in a 3/Y and 100kW in S/X.
This is sufficient for driving at around 200kph/125 mph.
At this rate, we still get ~1000 FCE cycles if we charge to 100 and drive down to 0%.
(1000 FCE equals ~ 400.000 km or 250.000 miles).

Hete we can se high currents on both charge and discharge. Lithium ion batteries dislikes charging at high current/power much much more than discharge at high current/power.
View attachment 1042513

The same cell type, but smaller depth of discharge:
View attachment 1042514
Same, but even smaller depth of discharge:
View attachment 1042515

They still charge with the same C rate, which is mych worse than discharge.

This is a test of Panasonic NCA (NCR18650B) like the S/X

We can see that small cycles at low power (40-60% and C/2 so ~ 40-50kW) is good, but also that there is not a big difference between 20-80% at 1C (80-100kW) and 2C (160-200kW) between 0-100%.

Many tests show that panasonic NCA hold up as good at 2C as at 1C.
View attachment 1042517

Using high power for shorter bursts as a 0-60 pull of a 1/4 mile will not affect the battery that much. Same with driving a illegaly fast drive at 125mph/200kph.
We will most probably not even see a difference in capacity between a slowly driven car and one used like above from time to time.

Accelerating the car to top speed and keeping it there until the battery is drained will probably be noticed as increased degradation if it is done several times.

Just charging daily to 80-90% and driving average annual ranfes will make the battery loose ~ 10% in calendar aging during the first four years.
It would be very hard to reach a cyclic aging of 10% for the first four years.

My M3P was charged low daily, but > 30 full charges during 2.5 years. I did a lot of 0-60 mph and 1/4 mile runs. (I used the power very often).
Still my car had very low degradation compared to other M3P with the same ODO reading.

Same with my Plaid, I have used the power quite much (which is clearly noticed on the tires threads) but my battery is way above the average Plaid capacity after 1 year from the manufacturing date.

The gain I get from having low SOC most of the time widely surpasses the small extra losses from the use of high power.

My battery topped 98.4 kWh according to the BMS, and still is at 97.2 kWh after 19K km / 12K mi and one year.

The other Plaids in Sweden I know about using Scan my tesla and about the same climate has lost much more capacity. (The are below 95kWh after one year and sbout the same ODO).
From forum discussions we can se that we have similar addiction for high power and fast acceleration
(The other guys mostly do 80% daily)

Aakee: passing one car increase the temperature of the pack 1°c . That's rough
Your totally wrong. That's why tesla reduced the output after a peak on our packs. And charging etc.
This is what really degrading batterys. That's why other manufacturers have time limits etc. 5sec.. 7 sec. No heat problem. Just what this do to cells.
Teslas battery guru represented Tesla in a Cort in Norway. They didn't realize what kind of damage high currant in / out did to a "cold" batteri(not winter cold)..

the early Panasonic NCA seem to have been more sensitive to cold cycling. Nit very bad but at least they did wear more from cold cycles.

The newer Panasonic NCA does not struggle with this.

Tesla only heats these actively to a few degrees above freezing, like ~ 3.5-4C (valid for both my former M3P 2021 and my current MSP).

During drives my MSP use the heat pump to suck the heat energy out of the pack down to 5C, then it is allowed to warm to ~ 8C before the heat pump draw it down to 5C again.

I live in a cold climate and had a two year logged average of cell temp of 13.5C in my M3P. Much of the 66K km driving has been done with fairly cold pack. Still the degradation was very low, I do not know of a M3P with such low degradation after 2.5 years/66K km.

My MSP is only 1 year and 20K km, so not that long time but I havent heard of another Plaid with such low degradation after 1 year.
My pack is at 97.2 kWh, which is about where many other tops and newer reaches higher.
(> 10 full charges, I do not have the number of supercharges but ~ 15-20 I guess).

If cold was killing the new batteries, Tesla wouldnt let the heatpump suck the heat out of the pack.

He had Lot of good info. It's a reason tesla heating the packs more over time. forget about soc. Don't let it stay 10> <90 over a long period.

Below 10% is not bad for the battery.

100% is not as bad as the rumor. While I do not recommend leaving the car at 100% for long time, 80% is about as bad. See picture above.

Same but actual model S cells

If you love your battery, touch the throttle as little as possible. It's a killer. Always was

But still, having the car above 60% will wear harder on the battery. At least for the panasonic lithium ion cells of today.

 

[EdCBC]

Except that isn’t correct. Did you not read posts 15 and 17. To be precise, if you have a NCA battery, it’s best to be below 55% SOC as long as possible. Please look at the charts in post 15 and note the plateau at 55%.

I have driven my 2018 LR RWD Model 3 for 63000 km. When I picked it up the charge limit was set at 88% and I left it there except for long trips. The nav system runs it down to about 10% between supercharges on the long trips, and I have set the limit as high as 96%. For the last year or so daily driving I now set the limit at 80%, per Tesla advice. I usually run it down to between 50 and 60% before charging, once in a while down to 30%. None of that seems to have hurt the battery.

 

[AAKEE]

I have driven my 2018 LR RWD Model 3 for 63000 km. When I picked it up the charge limit was set at 88% and I left it there except for long trips. The nav system runs it down to about 10% between supercharges on the long trips, and I have set the limit as high as 96%. For the last year or so daily driving I now set the limit at 80%, per Tesla advice. I usually run it down to between 50 and 60% before charging, once in a while down to 30%. None of that seems to have hurt the battery.

Following Teslas advice (of course) doesn’t hurt the battery. But mostly using SOC above 55% in your case causes more degradation than using 55% or below.

Your car* probably has lost ~ 11-12% capacity or so.
If your car had been mostly at low SOC, you would be at around half the degradation.
I guess many persons are happy with the standard degradation that comes with using 70-90%, nothing strange with that

*)From a brief look at the Vancouver climate.

 

[AAKEE]

I have driven my 2018 LR RWD Model 3 for 63000 km.

I did throw your values in my formulas.
I do not have all the data but this is the result:

You could take a photo of the energy screen like this:
State of charge(%), average and calculated range on the same picture.
Down right we need the selection to be ”normal range”. From that we can calculate the BMS estimate of the battery capacity.

 

[!igs]

is it better for the battery to spend most of its time around 50%

50% is too high. You want to stay closer to 30%.

 

[AAKEE]

50% is too high. You want to stay closer to 30%.

Per principle the lowest calendar aging happens at 0% SOC.

The calendar aging is relatively flat between 30-55% for NCA cells, so there is not much gain to leave it at 30% compared to 50-55%*

So, to minimize the calendar aging we would like to leave the car for longer periods even lover than 30%.

I aim for 10-20% when leaving the car at work for one week at the time. Would aim lower but need a little margin on the long drive (~250km) to be able to circumnavigate an accident etxc.

*) There are several research tests showing the same thing (read = all tests that covers this shows that).

 

[gottagofast]

Going by this it wouldn’t be wise to take the cars battery below 25% very often would it? Like maybe a few times a year is fine but not every day?

 

[AAKEE]

View attachment 1060884
Going by this it wouldn’t be wise to take the cars battery below 25% very often would it? Like maybe a few times a year is fine but not every day?

You need to understand what you are looking at, in a practical sense.

Look at the 5-15%. As Tesla use 4.5% buffer the 5-15% represent driving ~0-10% on the Tesla.

You can see that after 3000FCE you have lost 17.5%, yes?

3000FCE equals 3000 x 400km (or 3000 x 250mi), so 1.2 million km or 750K miles.
The average driver here might do 20K km in a year or 12.5K miles a year, ok?

So the degradation from cycles would be 0.29% degradation each year from the cycles.
If you instead did 55-45% cycles, it would be 0.15%.

The difference between 0-10% on the display and the ”best regime” is 0.14% degradation each year.

If you look close below 20% on the calendar aging charts, you will find that the calendar aging will reduce more than 0.14%, from 55-45% to 0-10%.

The net would be a reduction of the degradation if you used the lowest SOC.

The chart might make it look bad, but in reality the cyclic aging for these low parts are negligible.

 

[gottagofast]

You need to understand what you are looking at, in a practical sense.

Look at the 5-15%. As Tesla use 4.5% buffer the 5-15% represent driving ~0-10% on the Tesla.

You can see that after 3000FCE you have lost 17.5%, yes?

3000FCE equals 3000 x 400km (or 3000 x 250mi), so 1.2 million km or 750K miles.
The average driver here might do 20K km in a year or 12.5K miles a year, ok?

So the degradation from cycles would be 0.29% degradation each year from the cycles.
If you instead did 55-45% cycles, it would be 0.15%.

The difference between 0-10% on the display and the ”best regime” is 0.14% degradation each year.

If you look close below 20% on the calendar aging charts, you will find that the calendar aging will reduce more than 0.14%, from 55-45% to 0-10%.
View attachment 1060886


The net would be a reduction of the degradation if you used the lowest SOC.

The chart might make it look bad, but in reality the cyclic aging for these low parts are negligible.

The 5% - 15% cycle loses a good bit of range even after 1,000 cycles though, it’s like 10% more loss compared to the others after 1,000 cycles

30% - 55% seems to be the sweet spot in both cycles and calendar aging