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

[DrChaos]

Hmm, from what I understand @AAKEE would say it's better to go lower, even all the way down to 0%.

For calendar aging yes and long term use, but cyclic behavior and not needing a tow is a different consideration. Your daily charging habits matter more than long road trip behaviors, unless long road trips are every day.

Daily max charge of 50-55% seems to be great. Most people will drive 10-30% per day.

 

[Owner4523]

Dialed range back? Sounds strange.

@AAKEE - I have the 4860 battery in my 2023 MY AWD SR. Tessie reports my battery capacity is 67.4, but I can't seem to confirm that anywhere. Do you have any thoughts on this?

 

[David99]

For faster charging to minimize trip time, the latter is theoretically better. However, arriving at 5% after using 60% leaves little margin for error in estimation of use, so it may be better to charge to 70-75% to target arrival at 10-15% if there is any uncertainty about consumption.

Oh yes it is pretty risky to aim for 5% arrival. It was more a theoretical question from a battery health perspective. Looking at the graph showing the different cycles levels, it appears going below 20% is when it gets a little worse, while the higher end seems to be about the same as the all other percentages. Thge way I would interpret it is to rather charge higher than driving it lower.

 

[AlanSubie4Life]

Tessie reports my battery capacity is 67.4, but I can't seem to confirm that anywhere. Do you have any thoughts on this?

Starts around 70kWh. Capacity loss should start showing around 68kWh. How many rated miles do you have now at 100% and what did you start with? (279 miles is the undegraded value for 2023 Model Y AWD, non-LR.)

Tessie can’t display numbers above the degradation threshold so if 67.4kWh is the actual degradation threshold, then Tessie won’t display higher than that. If you have 279 miles still then Tessie is probably reasonably accurate in its 67.4kWh value (as a value for the threshold, NOT your pack capacity). If you are at 277 or so, then 68kWh is the actual threshold and you might have started higher, maybe as high as 69-70kWh.

 

[Owner4523]

Starts around 70kWh. Capacity loss should start showing around 68kWh. How many rated miles do you have now at 100% and what did you start with? (279 miles is the undegraded value for 2023 Model Y AWD, non-LR.)

Tessie can’t display numbers above the degradation threshold so if 67.4kWh is the actual degradation threshold, then Tessie won’t display higher than that. If you have 279 miles still then Tessie is probably reasonably accurate in its 67.4kWh value (as a value for the threshold, NOT your pack capacity). If you are at 277 or so, then 68kWh is the actual threshold and you might have started higher, maybe as high as 69-70kWh.

Thanks, are you sure it's 70KwH? Do you mind sharing where you saw that info? I'm not 100% sure as I don't think I've charged my car to 100%, I don't really want to do that. I've got a little under 3,000 miles. Right now Tessie says battery health is 100%, capacity is 67.4 and Max Range is 278.

 

[AlanSubie4Life]

Do you mind sharing where you saw that info

EPA document as I recall. 76.5-77.2kWh recharge value (couldn’t see the DC in these docs), but that definitively means about 68.5kWh DC. Not sure where I got the 70kWh - saw it in one prior post of mine but I gave no source. I’d go with 68-69kWh.

https://dis.epa.gov/otaqpub/display_file.jsp?docid=54970&flag=1

Anyway you can calculate the constant using energy screen, with miles displayed, then multiply by 279 to give the threshold. Capacity starts a bit above that typically. I’d expect with the EPA value that threshold is about 67.5kWh.

 

[Owner4523]

EPA document as I recall. 76.5-77.2kWh recharge value (couldn’t see the DC in these docs), but that definitively means about 68.5kWh DC. Not sure where I got the 70kWh - saw it in one prior post of mine but I gave no source. I’d go with 68-69kWh.

https://dis.epa.gov/otaqpub/display_file.jsp?docid=54970&flag=1

Anyway you can calculate the constant using energy screen, with miles displayed, then multiply by 279 to give the threshold. Capacity starts a bit above that typically. I’d expect with the EPA value that threshold is about 67.5kWh.

Thanks. Can you walk me through the energy screen stuff you suggested? When you say ' with miles displayed' where am I to be looking?

 

[AlanSubie4Life]

Thanks. Can you walk me through the energy screen stuff you suggested? When you say ' with miles displayed' where am I to be looking?

Use the energy screen method in the sticky, but instead of using percentage for the calculation, switch to rated miles (tap on battery icon).

Make sure three digits for all numbers. Should give you the Wh per rated mile, the charge constant. Instead of pack capacity (what you get if you divide by percentage instead).

 

[Owner4523]

Use the energy screen method in the sticky, but instead of using percentage for the calculation, switch to rated miles (tap on battery icon).

Make sure three digits for all numbers. Should give you the Wh per rated mile, the charge constant. Instead of pack capacity (what you get if you divide by percentage instead).

I don't really understand what you saying.

Use the energy screen method in the sticky, but instead of using percentage for the calculation, switch to rated miles (tap on battery icon).

Make sure three digits for all numbers. Should give you the Wh per rated mile, the charge constant. Instead of pack capacity (what you get if you divide by percentage instead).

i don't see the sticky you are referring to.

 

[tm3lrawd]

I don't really understand what you saying.

i don't see the sticky you are referring to.

Here is the post on using the energy screen

 

[Owner4523]

Here is the post on using the energy screen

Thanks. That gives me 68. My car has a little under 3,000 miles, I assume that 68 is what my battery capacity is today, not when it was new, so that doesn't give me the actually battery capacity, does it? It sounds like that includes the buffer below 0. So in the Tessie app under capacity I wonder what I should put there. It defaults to 67.4.

 

[AlanSubie4Life]

Thanks. That gives me 68. My car has a little under 3,000 miles, I assume that 68 is what my battery capacity is today, not when it was new, so that doesn't give me the actually battery capacity, does it? It sounds like that includes the buffer below 0. So in the Tessie app under capacity I wonder what I should put there. It defaults to 67.4.

This 68 could be your capacity or it could be the degradation threshold. It is whichever is lower.

You can switch to % and then get the constant in Wh/mi with the same process (divide by miles rather than %). If you have three digits in each element of the formula the result will have three sig figs.

Multiply by 279 to get the actual degradation threshold. Can post the numbers used in the calculation here if you want.

I would use 68.5kWh for the starting point in Tessie. 67.4kWh is certainly too low. (67.4kWh may be the degradation threshold, not sure how it arrived at it - it is described elsewhere there is a default used, but it can also use the starting point for your car, you can see the active thread elsewhere discussing this.) As we know, Tessie cannot start any higher than the degradation threshold (just not possible with their method), so tends to assign too low a starting value. Unless you set it manually to the actual starting point.

Unless you have SMT or you meter it very carefully when the car is brand new, you can’t see your actual starting point.

All relatively straightforward.

 

[tb.dxb]

Today I want to add a few data points.

M3LR, China built, new in July 2023.

I am using the energy screen to monitor consumption and battery capacity.
- Long-time average consumption (0 to now) = 136 Wh/km
- Battery capacity (nominal 78.8 kWh) = -5%
- Range delta (stated: 625 km) = -9%

In 7 months driven close to 21,000 km. Approx 75% highway, rest city traffic. Ambient temp. 20 C (winter) - 45 C (summer).
Usual SoC = 50 - 55% , however on a few busy days each month SoC = 70 - 75% just before driving.

From what I read this seems pretty much average. I hope that battery degradation eventually settles and does not continue on the current downward path.....

 

[AAKEE]

Today I want to add a few data points.

M3LR, China built, new in July 2023.

I am using the energy screen to monitor consumption and battery capacity.
- Long-time average consumption (0 to now) = 136 Wh/km
- Battery capacity (nominal 78.8 kWh) = -5%

I did not get it, what capacity do you see now?

The battery capacity is 78.8 kWh new, usually tops 79.0-79.2kWh.

- Range delta (stated: 625 km) = -9%

The max range it shows is about 576 km at 79-79.2kWh.

In 7 months driven close to 21,000 km. Approx 75% highway, rest city traffic. Ambient temp. 20 C (winter) - 45 C (summer).
Usual SoC = 50 - 55% , however on a few busy days each month SoC = 70 - 75% just before driving.

From what I read this seems pretty much average. I hope that battery degradation eventually settles and does not continue on the current downward path.....

You should have quite low degradation as the SOC had been low.

Collegues with the same car/battery did loose about 0.8-1kWh the first year using low SOC. We have much colder up here though.

 

[kpanda17]

That’s probably only a little high for just 20 months old (my Long Range, using the same method of calculations shows about a 3.6% loss over 29 months)....I have never tried a rebalancing campaign, I was saving it for a dramatic loss but you should think about it. Also 285 miles at 100% seems quite low for a new car

It’s due to the new epa reset in the newest code

 

[AlanSubie4Life]

It’s due to the new epa reset in the newest code

Does not affect cars sold prior to the adjustment (if they were sold with the prior range per the window sticker, the change will not apply). Of course, cars sold after the adjustment may receive a software update in future which aligns them with the published EPA range (Tesla will make sure this is an upwards adjustment - historically this has happened a few times for vehicles refreshed for a model year, and it has always (? - certainly all the ones I know of) been an upwards adjustment).

 

[Owner4523]

This 68 could be your capacity or it could be the degradation threshold. It is whichever is lower.

You can switch to % and then get the constant in Wh/mi with the same process (divide by miles rather than %). If you have three digits in each element of the formula the result will have three sig figs.

Multiply by 279 to get the actual degradation threshold. Can post the numbers used in the calculation here if you want.

I would use 68.5kWh for the starting point in Tessie. 67.4kWh is certainly too low. (67.4kWh may be the degradation threshold, not sure how it arrived at it - it is described elsewhere there is a default used, but it can also use the starting point for your car, you can see the active thread elsewhere discussing this.) As we know, Tessie cannot start any higher than the degradation threshold (just not possible with their method), so tends to assign too low a starting value. Unless you set it manually to the actual starting point.

Unless you have SMT or you meter it very carefully when the car is brand new, you can’t see your actual starting point.

All relatively straightforward.

This article puts it at 67.6. Thoughts? (@AAKEE )

 

[johnny_cakes]

If you have a NCA battery, 55% would been better but the calendar aging eats capacity above 55% so when you have lost about 5-8% capacity 60% will be like 55.

Does that theory continue linearly with more degradation? I have 14% degradation, so assuming 10% of that is from calendar aging, does that mean that the central graphite peak moved up to 65%?

 

[AAKEE]

Does that theory continue linearly with more degradation? I have 14% degradation, so assuming 10% of that is from calendar aging, does that mean that the central graphite peak moved up to 65%?

Calendar aging takes capacity above the ”step” but faat charging/lithium plating takes it below.
I think regular cyclic aging is mostly SEI growth so that probably eats mostly above as well.
I can not really say where the step/centeal grsphite peak is located at your pack today, but it might be around 51%.
55/90= 0.61.

If the rest of the degradation is below the central graphite peak, its ~ 59%.
(51/86)

 

[kpanda17]

Hello, my support chat with Tesla service questioning range stated:

Model Y performance fall 2022, model year 2023 to now, meaning Jan/Feb/Mar 2024, orig range is 285 miles

Model Y LR fall 2022, model year 2023 to now, orig range is 310 miles

Model year 2022, 2021 are not affected
Does not make sense as the only range significant difference is the heat pump between years 2021 to now.

My range loss after 15 month, 13K miles is 1.4% with 80% charged nightly, 95% for long road trips, 100% monthly/bimonthly rebalancing