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

[Bouba]

no apps, just my analysis, Tesla app or in-car screen, miles at %, multiply up to 100%, showed 214 miles at 76% yields 269 at 100%, orig 100% is 285 miles, now 269 miles is 5.4% loss/degrade

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

looks like I might have made an error...because Tesla dialed back the range for the MYP to 285 miles...so you are correct

 

[AAKEE]

looks like I might have made an error...because Tesla dialed back the range for the MYP to 285 miles...so you are correct

Dialed range back? Sounds strange.

 

[nicksp]

This is exactly right of course! But no more than needed, with ample margin. This will put many owners below 55% the vast majority of the time.

Needs are not entirely dependent on miles driven. For those owners that do not live in a house, or live in condos, it can get pretty tiring to constantly keep charging to 55% or whatever chart they're following.
There are many that charge to full or close to full and have the same degradation as the guy who adheres to these charts.

 

[AAKEE]

There are many that charge to full or close to full and have the same degradation as the guy who adheres to these charts.

It’s not really.

If you go to the bottom with it and really check the real world values there are no cars that regularly are charged to and consume time at 80-90% that has as low degradation as the cars that have the SOC at or below 55% most of the time.

We know from research that battery degradation is very predictable and they all follow the laws of nature (chemistry).
The split between differebt cells getting the same threatment (SOC, cycles and temperature) are very small.

 

[kpanda17]

Dialed range back? Sounds strange.

better said, aligned with the revised, new EPA measurement rules...sux

 

[AAKEE]

better said, aligned with the revised, new EPA measurement rules...sux

Not on ”old” cars sold with the old EPA I guess.

 

[kpanda17]

Not on ”old” cars sold with the old EPA I guess.

not sure thats true

 

[AlanSubie4Life]

not sure thats true
View attachment 1022907

It won’t change the range on cars already sold.

So use 303 miles for your vehicle I guess. Can use energy screen method too.

My parents just got a Model Y 2024. Energy screen method seems to work ok, 79.5kWh or so, but the rated miles are completely messed up. Don’t match the old or the new value for EPA (it works out considerably lower than the current published EPA value (Tesla website) of 310 miles, comes out to be just over 300). Not sure how third-party apps will deal with that. I assume it will fix itself on the first software update. But maybe I have bad data (have not seen in person). Who knows.

 

[kpanda17]

It won’t change the range on cars already sold.

So use 303 miles for your vehicle I guess. Can use energy screen method too.

My parents just got a Model Y 2024. Energy screen method seems to work ok, but the rated miles are completely messed up. Don’t match the old or the new value for EPA. Not sure how third-party apps will deal with that. I assume it will fix itself on the first software update. But maybe I have bad data (have not seen in person). Who knows.

why wont it change the range on cars already sold? remember, its just a code update and it does say yes specifically for 2023 which I have
my brother's brand new MYLR also just changed after a code UG

 

[AlanSubie4Life]

why wont it change the range on cars already sold?

Just isn’t done - would be super upsetting to owners and open up all sorts of potential warranty claim issues (which would be meritless but tough to explain that to the customers!). (Notable exception was Model 3 LR RWD several years ago but that was special. And it actually was not a change to the EPA. They just updated the car to display closer to EPA results by adjusting degradation threshold (no change to energy or the constant).)

it does say yes specifically for 2023

Only new testing of 2023, should that occur.

my brother's brand new MYLR also just changed after a code UG

Yes, brand new cars sold after the changes (so for example a Model Y LR sold with a claimed 310 miles range, per Monroney sticker, rather than the 2023 330 miles) may not display the right range initially then will be updated in the first software update. This happens occasionally and does not contradict above.

For my parents’ car they apparently seem to err on cautious side and ensure that it reads lower than EPA initially. Going to try to get some documentation on this but tough to justify having the parents take pictures of their energy screens, lol. Looks like 206 miles at 68% on 2023.44.300 (factory firmware), extrapolating to 303 miles (this was consistent for multiple Model Y vehicles they looked at, too). Energy screen gave about 79.5kWh. (Rated range for 2024 Model Y LR AWD is 310 miles.)

 

[AAKEE]

It won’t change the range on cars already sold.

The (most certainly) same EPA range as at delivery/registration might be misstaken for a lowered range and very low degradation in the future. I already see that coming

 

[David99]

I'm on my third Tesla, a 2023 Model Y performance. The car was manufactured in October and I took delivery at the end of October. This is the first 8k miles and 4 month. My range has not dropped one bit. If anything, it went up a tiny bit. They say the battery loses capacity the most in the beginning, then it slows down. So far I don't see that at all.

Here is what I did. I followed Jeff Dahn's suggestions. I do shallow charges and charge more often. I tend to stay between 65% and 25%. When I don't need the car I keep it around 30%. I drive rather gently. Very few hard accelerations. I use Superchargers 98% of the time.

I am aware that 8k miles and 4 months isn't all that much, but the green line shows the average of all the other Model Y vehicles that have the same milage. Mine has the highest range. I don't know if I'm just lucky. Time will tell. I will keep posting updates.

 

[AlanSubie4Life]

View attachment 1022935

I'm on my third Tesla, a 2023 Model Y performance. The car was manufactured in October and I took delivery at the end of October. This is the first 8k miles and 4 month. My range has not dropped one bit. If anything, it went up a tiny bit. They say the battery loses capacity the most in the beginning, then it slows down. So far I don't see that at all.

Here is what I did. I followed Jeff Dahn's suggestions. I do shallow charges and charge more often. I tend to stay between 65% and 25%. When I don't need the car I keep it around 30%. I drive rather gently. Very few hard accelerations. I use Superchargers 98% of the time.

I am aware that 8k miles and 4 months isn't all that much, but the green line shows the average of all the other Model Y vehicles that have the same milage. Mine has the highest range. I don't know if I'm just lucky. Time will tell. I will keep posting updates.

Since the degradation threshold for the Model Y Performance is around 79kWh (AFAIK...maybe it is as high as 79.5kWh - you could probably tell us since you haven't lost range), and these packs often start as high as 80-81kWh (EPA extracted nearly 82kWh I think on some tests), it's not surprising that you don't show loss of range in four months, in winter, with good charging habits.

You likely have lost a little, but not much. It's just not showing because you're above the threshold. (Note for Model 3 Performance...Model 3 thread...this is not the case since the threshold on that vehicle is around 80.6kWh, so will show mileage loss earlier, even with no differences in capacity loss curves.)

Comparing with miles as the x-axis, as TeslaFi seems to do, is not really useful, since time (and charging habits of course) is the biggest determinant.

But anyway definitely keep updating the thread!

 

[AAKEE]

Here is what I did. I followed Jeff Dahn's suggestions. I do shallow charges and charge more often. I tend to stay between 65% and

In addition to @AlanSubie4Life very good post:

You might wanna read some of the posts here on TMC written by me or others about research data for calendar aging and keeping the SOC below 55% most of the time.

I had the same pack but a higher degradation threshold, I did’nt loose any range until 39K km and ~ 1.5 years.

Some of the things Jeff says doesnt match the other research in detail. I do not question if he knows. He should know but he might be locked in for what to tell us from the earlier work togehter with Tesla or just is protecting himself from possible missunderstandings cousing people to sue him or something like that?
(Also, he seldom seems to make advices aimed for a certain chemistry)

You would like to stay below 55% most of the time.

- Do not charge more than needed until next charge.
-Charge often (reduces the need per above point)
-Charge late - reduces time at high SOC.

I am aware that 8k miles and 4 months isn't all that much, but the green line shows the average of all the other Model Y vehicles that have the same milage. Mine has the highest range. I don't know if I'm just lucky. Time will tell. I will keep posting updates.

Earlier there was a lot of talk about ”battery lottery” here on TMC.
I do not really believe that. Battery degradation is very predictable.

Your strategy makes a difference.

 

[RSpanner]

It’s not really.

If you go to the bottom with it and really check the real world values there are no cars that regularly are charged to and consume time at 80-90% that has as low degradation as the cars that have the SOC at or below 55% most of the time.

We know from research that battery degradation is very predictable and they all follow the laws of nature (chemistry).
The split between differebt cells getting the same threatment (SOC, cycles and temperature) are very small.

Damn...I have been trying to keep it at %60...

 

[David99]

You would like to stay below 55% most of the time.

- Do not charge more than needed until next charge.
-Charge often (reduces the need per above point)
-Charge late - reduces time at high SOC.

This all makes sense. One new thing I learned in a recent video interview with J Dahn was the study that showed it is worse to cycle in the lower end. I always assumed lower SoC is better and drove close to zero on road trips (also to maximize charge speed). But apparently it isn't good to go very low. Which brings up a new question:

On a road trip I need 60% to reach my next charger. Is it better to charge to 80% and arrive with 20% left, or is it better to charge to 65% and arrive at 5%.

 

[3sr+buyer]

Which brings up a new question:

On a road trip I need 60% to reach my next charger. Is it better to charge to 80% and arrive with 20% left, or is it better to charge to 65% and arrive at 5%.

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.

 

[Owner4523]

This all makes sense. One new thing I learned in a recent video interview with J Dahn was the study that showed it is worse to cycle in the lower end. I always assumed lower SoC is better and drove close to zero on road trips (also to maximize charge speed). But apparently it isn't good to go very low. Which brings up a new question:

On a road trip I need 60% to reach my next charger. Is it better to charge to 80% and arrive with 20% left, or is it better to charge to 65% and arrive at 5%.

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

 

[AAKEE]

This all makes sense. One new thing I learned in a recent video interview with J Dahn was the study that showed it is worse to cycle in the lower end. I always assumed lower SoC is better and drove close to zero on road trips (also to maximize charge speed). But apparently it isn't good to go very low. Which brings up a new question:

On a road trip I need 60% to reach my next charger. Is it better to charge to 80% and arrive with 20% left, or is it better to charge to 65% and arrive at 5%.

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.

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.

 

[AAKEE]

Damn...I have been trying to keep it at %60...

Not a crisis.

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.

If you have a LG NMCA-batt, 60% is on the right side.