Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[AlanSubie4Life]

Then why don't they have 82 kWh like the other Panasonic NCA packs? That's the question. Particularly with the less efficient Y they would want to have a higher energy if they could.

We have no SMT reads from these packs though, do we?

All I know for sure is it is not uncommon for Model Y LR 2024 to have at least 79.5kWh which is very comparable to prior years. (Around 80kWh was common.)

The weird thing is the EPA result being 79kWh rather than 81kWh-82kWh. (These >81kWh levels could be seen in vehicles with SMT when brand new, but it was pretty unusual I think - 80.5kWh-81kWh was more common, briefly.)

So is there an actual difference? Seems to me most likely no, but SMT data would be good to get (at least get the full pack when new hard-coded value)…

 

[Geir]

Picture below is from cycle tests of real model 3 cells.
5-15% might look ”worse” but to begin with, as Tesla has a 4.5% buffer below zero on the display the 5-15% here is virtually like doing 0-10% on a tesla display.

The battery lost ~ 17.5% for 3000FCE (thats actually 30.000 such cycles 10-0%.

3000FCE is about 3000 x 400 km, so 1.200.000 km.
This is about 0.3% degradation per 20K km which might be a normal annual driving distance.
So if 0.3% is deemed ”worse” for one year we meed to compare it to ~ 5% calendar aging for the most common ”charge to 80% daily” for the first year, and ~ 10% calendar aging after 4 years.
View attachment 1023019

No, low SOC is not bad. We need to understand that cyclic aging means choosing between very very low cyclic degradation and very very very low cyclic degradation and if we hunt for this we probably will shoot ourself in the foot.

The sweet spot might be like i mostly use my car, between 55 to 30-35% but still, the calendar aging is so much higher the first five years if you try to avoid low SOC and end up at staying above 55% for a considerable part of the time.

First: Thanks for your efforts to guide us in charging-habbits, AAKEE!

My M3RWD LR 2019 say that I have 71 kW in the battery today after 76 000 km and close to 5 year. Calculation done like this: 192 x 296/80 = 71kWh > (77,8-71)/77,8 = 8,7% degradation. Is this normal?

The first 3 years I normally charged to 70%, and the 2 last year to 50%. (And also SC 9% of total charging, without precndition)

 

[AAKEE]

First: Thanks for your efforts to guide us in charging-habbits, AAKEE!

My M3RWD LR 2019 say that I have 71 kW in the battery today after 76 000 km and close to 5 year. Calculation done like this: 192 x 296/80 = 71kWh > (77,8-71)/77,8 = 8,7% degradation. Is this normal?

The first 3 years I normally charged to 70%, and the 2 last year to 50%. (And also SC 9% of total charging, without precndition)

Its lower than average degradation, but about as expected counting your lower SOC after three years and the climate.

The average cell temp is setting the degradation pace in the same way as SOC does. (But it is often not so easy to decide the ambient temp).

I would guess - southern Norway would have a rather low annual average temp.

I would guess the first three years would have degraded the battery about 7.7%, and the last two about 1%.

 

[Geir]

Ok.
I think the temperature is about + 5 degree median, from -15 to + 25.
I got from 70 to 50% charging too late.

Then if I follow the 50-55% rule forward, when will i need to change the battery? I would like to keep the car as long as possible. (I know that this is a difficult question…..)

 

[AAKEE]

Ok.
I think the temperature is about + 5 degree median, from -15 to + 25.
I got from 70 to 50% charging too late.

Then if I follow the 50-55% rule forward, when will i need to change the battery? I would like to keep the car as long as possible. (I know that this is a difficult question…..)

With 55% or less you can be sure that you will not wear out the battery. Most probably not with normal charging habits either.
The batteri can develope other issues from the electronic parts etc, but i guess ypu will not wear it out.

Melsomvik seems to have aroubd 9C average annual temperature. I used that as the base, so ~14-15C cell temp in average or so. (Cells heat from both driving and charging).

I have anly a annual temp a few degrees above freezing and had 13.5C average temp on my M3P. (Normally Parked in a garage with around 10C during the cold part of the year.)

 

[KenC]

Ski season is mostly over, only a couple weekends left at Killington, so I took out my skis, raised the back seats, got back there, removed the console cover and re-plugged in my OBDII reader, and opened the SMT app to see what it said, since I haven't had it plugged in since January.

So, after 5 ½ yrs, and 65k miles, apparently I'm still using the top buffer. Cell imbalance is only 4mV, which is what I typically see. I still keep it at 60% SOC, and I've run it down way lower than ever before, even into the negative back on Thanksgiving. Everything seems good still.

 

[DownshiftDre]

Ski season is mostly over, only a couple weekends left at Killington, so I took out my skis, raised the back seats, got back there, removed the console cover and re-plugged in my OBDII reader, and opened the SMT app to see what it said, since I haven't had it plugged in since January.View attachment 1047228
So, after 5 ½ yrs, and 65k miles, apparently I'm still using the top buffer. Cell imbalance is only 4mV, which is what I typically see. I still keep it at 60% SOC, and I've run it down way lower than ever before, even into the negative back on Thanksgiving. Everything seems good still.

We really need a case study with you. Your charging habits, DoD, temps, driving style, etc. Maybe you are invoking some kind of battery healing within your concept of operation and operating environment.

 

[AlanSubie4Life]

We really need a case study with you. Your charging habits, DoD, temps, driving style, etc. Maybe you are invoking some kind of battery healing within your concept of operation and operating environment.

Cold and low.

 

[KenC]

We really need a case study with you. Your charging habits, DoD, temps, driving style, etc. Maybe you are invoking some kind of battery healing within your concept of operation and operating environment.

Well, in the thousands of posts I've made, I've detailed it a few times. It's not complex. I got it in December of 2018, and set my nightly charge to 80%, within 6 months, I had changed to 60%, based upon reading that the cathode cracked at 3.92V. I estimated that was 63%, so I decided to charge up to 60%. Much later, I found out that 55% seemed to be the sweet spot, but I had been doing 60%, and it had been working, so I decided not to change things up. My car lives outside in a carport, and I don't baby it.

Now, roadtripping, I charge up to whatever level required, 80%, 90%, etc. I just don't leave it at high levels for too long. That's from the Recurrent app, and it too shows my car is an outlier:

As you can see, I set my nightly charge to 60%, but sometimes I charge at higher SOCs, and sometimes I charge at really low SOCs. The 80% line at the beginning of March was just spurious data. I charged to 80%, then went to the airport and parked. I left the car at 60%, but Recurrent thinks I was charging for 2wks at 80%, when it was sitting in an airport parking lot dropping to about 53%.

I always plug in at night. My daily trips are about 20-30miles, so 60% down to 50% and back to 60%, usually. I tend to drive a higher proportion of road surface vs highway, but I usually drive about 10-15mph above the speed limit.

In the SMT data you can see how much of my charging was AC vs DC, so I did plenty of Supercharging. My car is set for max regen, and I don't raise my SOC to balance cells or anything, they've always been in the 4 to 10mV range, but usually 4 to 6mV.

Seriously, I don't micromanage the car, I set the SOC to 60% and that's been about it.

 

[Zoomit]

Seriously, I don't micromanage the car, I set the SOC to 60% and that's been about it.

And you live in Maine, where average ambient temperatures are more favorable to battery longevity than in hotter climates.

 

[Bouba]

Ski season is mostly over, only a couple weekends left at Killington, so I took out my skis, raised the back seats, got back there, removed the console cover and re-plugged in my OBDII reader, and opened the SMT app to see what it said, since I haven't had it plugged in since January.View attachment 1047228
So, after 5 ½ yrs, and 65k miles, apparently I'm still using the top buffer. Cell imbalance is only 4mV, which is what I typically see. I still keep it at 60% SOC, and I've run it down way lower than ever before, even into the negative back on Thanksgiving. Everything seems good still.

Why don’t you admit the truth ?....your ski season never ends...it’s year round. Keeping your car parked permanently above the tree line is the only way to preserve the battery

 

[AAKEE]

And you live in Maine, where average ambient temperatures are more favorable to battery longevity than in hotter climates.

Low average cell temperature is the key, combined with low SOC.

@KenC I have forgot, but do you keep it in a garage or outside? If garage, cold one I guess?

 

[KenC]

Low average cell temperature is the key, combined with low SOC.

@KenC I have forgot, but do you keep it in a garage or outside? If garage, cold one I guess?

Outside in my temporary carport. I jury-rigged a couple pieces of wood with white tape, and yes, it'll park, but not all that well. Yes, I'm getting a new license plate! It was approved!

 

[KenC]

Why don’t you admit the truth ?....your ski season never ends...it’s year round. Keeping your car parked permanently above the tree line is the only way to preserve the battery

Yes, it's true. I usually park it here at the free destination charger at the ski resort. I like that it's close to the primary lift! That's 2 weeks ago.

 

[KenC]

And you live in Maine, where average ambient temperatures are more favorable to battery longevity than in hotter climates.

Yes, but I keep waiting to hear from Tesla owners in Canada and Norway about how their batteries are doing. I mean, it's at least as cold as Maine, right?

 

[AAKEE]

Yes, but I keep waiting to hear from Tesla owners in Canada and Norway about how their batteries are doing. I mean, it's at least as cold as Maine, right?

I would guess colder.

Average annual ambient is below freezing in the northern Norway and Sweden. Norway has the Gulf Stream heating it nicely, so Sweden probably is colder.
But that cold that most people use heated garages.

 

[Tha_Ape]

Well, in the thousands of posts I've made, I've detailed it a few times. It's not complex. I got it in December of 2018, and set my nightly charge to 80%, within 6 months, I had changed to 60%, based upon reading that the cathode cracked at 3.92V. I estimated that was 63%, so I decided to charge up to 60%. Much later, I found out that 55% seemed to be the sweet spot, but I had been doing 60%, and it had been working, so I decided not to change things up. My car lives outside in a carport, and I don't baby it.

Now, roadtripping, I charge up to whatever level required, 80%, 90%, etc. I just don't leave it at high levels for too long. That's from the Recurrent app, and it too shows my car is an outlier:View attachment 1047279
As you can see, I set my nightly charge to 60%, but sometimes I charge at higher SOCs, and sometimes I charge at really low SOCs. The 80% line at the beginning of March was just spurious data. I charged to 80%, then went to the airport and parked. I left the car at 60%, but Recurrent thinks I was charging for 2wks at 80%, when it was sitting in an airport parking lot dropping to about 53%.

I always plug in at night. My daily trips are about 20-30miles, so 60% down to 50% and back to 60%, usually. I tend to drive a higher proportion of road surface vs highway, but I usually drive about 10-15mph above the speed limit.

In the SMT data you can see how much of my charging was AC vs DC, so I did plenty of Supercharging. My car is set for max regen, and I don't raise my SOC to balance cells or anything, they've always been in the 4 to 10mV range, but usually 4 to 6mV.

Seriously, I don't micromanage the car, I set the SOC to 60% and that's been about it.

You do exactly what I do, same daily miles and everything. I hope in a few years my car is an outlier, but realize that's likely not going to be the case

 

[DownshiftDre]

Well, in the thousands of posts I've made, I've detailed it a few times. It's not complex. I got it in December of 2018, and set my nightly charge to 80%, within 6 months, I had changed to 60%, based upon reading that the cathode cracked at 3.92V. I estimated that was 63%, so I decided to charge up to 60%. Much later, I found out that 55% seemed to be the sweet spot, but I had been doing 60%, and it had been working, so I decided not to change things up. My car lives outside in a carport, and I don't baby it.

Now, roadtripping, I charge up to whatever level required, 80%, 90%, etc. I just don't leave it at high levels for too long. That's from the Recurrent app, and it too shows my car is an outlier:View attachment 1047279
As you can see, I set my nightly charge to 60%, but sometimes I charge at higher SOCs, and sometimes I charge at really low SOCs. The 80% line at the beginning of March was just spurious data. I charged to 80%, then went to the airport and parked. I left the car at 60%, but Recurrent thinks I was charging for 2wks at 80%, when it was sitting in an airport parking lot dropping to about 53%.

I always plug in at night. My daily trips are about 20-30miles, so 60% down to 50% and back to 60%, usually. I tend to drive a higher proportion of road surface vs highway, but I usually drive about 10-15mph above the speed limit.

In the SMT data you can see how much of my charging was AC vs DC, so I did plenty of Supercharging. My car is set for max regen, and I don't raise my SOC to balance cells or anything, they've always been in the 4 to 10mV range, but usually 4 to 6mV.

Seriously, I don't micromanage the car, I set the SOC to 60% and that's been about it.

Thats awesome. And wasn’t it born (delivered) with no charge where you had to get trucked to a supercharger on your first day of ownership?

Do you start to charge as soon as you get home for the day or do you set departure charge?

If departure charge, How long does your car rest at the 60% before you actually drive off for the day?

L1 charger? L2 charger?

Do you precondition when you supercharge?

I’ve seen posts in the past where you push SoC down to 0% or even negative for some drives? How often? Do you think your cars rests at those hyper low SoC for days sometimes?

 

[KenC]

Good memory. Yes, it came home delivered to a rest stop, since I live on a narrow dirt road, with Zero SOC at the end of the day. Driver said he loaded it that way, so he wouldn't take my suggestion of just unloading at the end of my dirt road and letting me roll it downhill the 1/4mi to my house, as it was dead; I pushed it back onto the semi, and he hauled it to a supercharger where I charged for 2hrs, before going home.

I plug in and charge as soon as I get home. I've read it's best to charge when the battery is warm, less plating of the anode. I use the portable charger that came with the car with a NEMA 14-50 plug.

I don't always pre-condition, because I'm not always in a rush and sometimes I only need 5% to make it home safely, so no, I don't always pre-condition.

I generally don't like to go below 10%, but this past winter I've been below 10% quite a lot because I skied about 2x as many days, 42, than the year before. I drive around 160mi roundtrip, and since I'm starting with 60%, and typically 58% due to BMS drift, there's not much room for error in Winter! The day I got below 0% SOC was my nephew's bday when I went skiing, then drove to brother's house, and then home. I thought I had enough, but I had 3% to go 10miles, and it was cold! I ended up -1.2%.

No, I don't let it sit at low SOCs. As soon as I get home, I plug in. I don't overthink it. When I'm home, I plug in and charge.

 

[DownshiftDre]

Good memory. Yes, it came home delivered to a rest stop, since I live on a narrow dirt road, with Zero SOC at the end of the day. Driver said he loaded it that way, so he wouldn't take my suggestion of just unloading at the end of my dirt road and letting me roll it downhill the 1/4mi to my house, as it was dead; I pushed it back onto the semi, and he hauled it to a supercharger where I charged for 2hrs, before going home.View attachment 1047620
I plug in and charge as soon as I get home. I've read it's best to charge when the battery is warm, less plating of the anode. I use the portable charger that came with the car with a NEMA 14-50 plug.

I don't always pre-condition, because I'm not always in a rush and sometimes I only need 5% to make it home safely, so no, I don't always pre-condition.

I generally don't like to go below 10%, but this past winter I've been below 10% quite a lot because I skied about 2x as many days, 42, than the year before. I drive around 160mi roundtrip, and since I'm starting with 60%, and typically 58% due to BMS drift, there's not much room for error in Winter! The day I got below 0% SOC was my nephew's bday when I went skiing, then drove to brother's house, and then home. I thought I had enough, but I had 3% to go 10miles, and it was cold! I ended up -1.2%.View attachment 1047634

No, I don't let it sit at low SOCs. As soon as I get home, I plug in. I don't overthink it. When I'm home, I plug in and charge.

Thank you! Interesting that you charge immediately and then your car sits at 60% for overnight (half day?) and cycle is 60% to 50% back to 60%. Was wondering how your battery had handled lithium plating and SEI buildup through your procedures. Lot of literature on how some of these help maintain capacity. I don’t know the details, but interested if other know.

On my 2022 M3P, I have been charging only to 50% and don’t drive everyday and keep my SoC super low. Sometimes sits for days at 20-30% in enclosed garage and even lower and I am showing more degradation (was 7% but recently jumped to 8%+) than I would have thought. Yes we have a hot summer in Vegas here but I don’t do most of my driving until the evenings. Sometimes I just charge to 30-40% and don’t go to 50% because it’s enough for what I do.