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

[Phlier]

i dont think theres a 2020 stealth available.

They are a unicorn car, to be sure, but there were a few stealths made in 2020. Guy was on here last week talking about how his was totaled.

For a very short period of time (maybe a week?) you could actually order a Stealth from Tesla's car configurator, by selecting the appropriate options on the Performance configuration page.

 

[Candleflame]

I think you misunderstood me. Your reading is all legit.
I just mean that any TeslaFi plot not normalized to capacity (meaning combining model years past 2019) is not valid. For the reasons stated.
I’m actually a bit surprised TeslaFi hasn’t sorted this all out since they have everything they need to convert everything to kWh in their plots. Then they can combine the data (and normalize to starting capacity if they wish).

Pretty straightforward stuff.

In 2019 in the US the performance and the AWD both had 499km...just as I said above. And it sounds like the same value applied in Australia - just as I said. Am I missing something?

i would PRESUME so. there is no such thing as a stealth performance on teslafi, only a performance (and the stealth performance will always be a performance which has 18" tires added, no spoiler, no pedals and possibly not lowered by 1"). I think after 2019 the performance got derated by around 20km too just for the wheels. AFAIK if I go in the menu and change my 18 inch wheels the i.e. 20 inch wheels im also hit by the 20km EPA display loss but I havnt tried this as I got my own degradation issues and dont want this to infere with that.

Tbh im not sure if 2019 performance cars even got the standard 290mile rated range the 2020s have via update.
On teslafi there is no difference between the 2018 vs 2019 vs 2020 graph for degradation.

 

[Candleflame]

They are a unicorn car, to be sure, but there were a few stealths made in 2020. Guy was on here last week talking about how his was totaled.

For a very short period of time (maybe a week?) you could actually order a Stealth from Tesla's car configurator, by selecting the appropriate options on the Performance configuration page.

In Aus we didnt have a stealth or an AWD for around 2 months.
Our initial order options were either a SR+ or an AWD Performance.

The AWD performance had the same price as the AWD (!!) but was essentially a stealth performance. We could add a performance kit for i think around 5k USD which gave the usual performance gizmos. 2 months later they removed the AWD Performance and replaced it with the AWD and the.... Performance. there has been no stealth since. I always presumed our stealth performance cars were a thank you as we were the last western country in the world to get the model 3 and to get the stealth you had to order within 2 months. They also all got delivered with free premium connectivity for life. For comparison, if you buy a performance now its around 7k USD more expensive than our stealth performance in 2019.

 

[Candleflame]

Meanwhile two years later @KenC still has 310 rated miles, or very close to it. Lol.

like i wrote in numerous posts before. we are all dumb and have 0 clue what actually truly affects degradation. for the model 3 at least.
Given the new iron batteries i am highly suspcious that tesla has a semi-secret battery chemistry which doesnt behave at all like battery university wants us to believe. There has never been any proof that deep discharges, 0% storages, 100% storages, supercharging, storage temperature, exclusive AC charging ever has made any difference to the model 3s degradation. Even when following battery university advice; a discharge to 0.1% is unlikely to do any harm, if not preserve the battery. Numerous lithium ion manufacturers recommend discharging their batteries to 0.1% and freezing them for long term storage. With some others recommending 40% at cool temperatures...

Someone tweeted elon once about their long commute and the ?SR+ not being good enough. And Elon told him to just charge to 95% every day. and the reason for this arbitary number was apparently that if hed charge to 100% every day he would get no regen. Clearly cant be too bad to charge above 90% regularly then...Yes Elon talks a lot of *sugar*, but he wouldnt actively advise people to go to 95% every day if youd get signfiicant harm to the battery from going there every day. I am sure he has lots of board meetings with the engineers,

The only thing I have noticed that cars from the same batch seem to degrade in exactly the same manner. I.e. our stealth performances in Aus (easy to check as they are all August 2019 cars) all developed around 5% degradation in year 1 and 10% in year 2. regardless of whether you had 20k on the odometer or 70k.

 

[AlanSubie4Life]

On teslafi there is no difference between the 2018 vs 2019 vs 2020 graph for degradation.

So are saying you can plot them separately and they all look the same? I know, I could get a free account for two weeks but I don't want to give them my credentials and I am done with 3rd-party apps...

. I think after 2019 the performance got derated by around 20km too just for the wheels.

It was more like 37 km, since it goes from 322 miles with 18" to 299 miles with 20". (Fun fact: they actually achieved 332 miles in Tesla's test of the 2020 Performance 18".) But yes, if comparing 2019 Performance to 2020 Performance 20", yes, it is ~20km.

if I go in the menu and change my 18 inch wheels the i.e. 20 inch wheels im also hit by the 20km EPA display loss but I havnt tried this as I got my own degradation issues and dont want this to infere with that.

If you have a 2019, I do not think it will. It behaves the same as the 2018 in this regard. Only the 2020 model changes in response to selecting a different wheel diameter. Because that is according to the EPA test results...which they actually did for 2020 for each of the Performance trims - thus far, they have not repeated this feat.

im not sure if 2019 performance cars even got the standard 290mile rated range the 2020s have via update.

It's 299 miles for 20" wheels (see the EPA website), and no, they didn't.

Our initial order options were either a SR+ or an AWD Performance.

Right, and in 2019, I would expect AWD, AWD Performance, and Performance to all have 310 rated miles (~499km) - just as I said originally. I think that you have confirmed this?

there is no such thing as a stealth performance on teslafi, only a performance

And therein lies the problem IF you are plotting multiple model years on the same graph, for the aforementioned reasons. I have no idea what options they provide for filtering. It's totally fine to combine 2018 and 2019 (you can even combine AWD and Performance, there's no difference, as I've said). But 2020 has to be plotted independently, and 2021 has to have a separate graph too. If you want to have good data, anyway.

If the constants are different, then you need separate graphs. Unless you convert to kWh and plot that, or you normalize to initial capacity (which has its own caveats for 2018 and 2019 due to the 76kWh vs. 77.8kWh discrepancy that has been discussed ad nauseam).

 

[KenC]

i remember you posting this age ago. i would have refused delivery. However as we all sort of know these days SOC or DC vs AC charging and storage SOC dont seem to matter much with the 3 anyway and its essentially just 5% in year 1, 10% in year 2 and then maybe another 5% over the next 10 years.

Yeah, it crossed my mind, but after waiting for it for 4 months, and with the $7500 tax credit expiring in 2 weeks; I decided to keep it, though I had the driver note the ZERO SOC. And, as AlanSubie has noted, I lucked out, as I still have 310 miles of estimated range. Seems like cold weather is much gentler on battery aging than hot weather. It would be interesting to compile a list of deg by geography, since anecdotally, it seems that owners in hot weather locales have suffered more deg. I know there's that chart at BatteryU where it shows storage at 40C vs 25C or something along those lines, but real world data would be fascinating.

 

[Phlier]

Seems like cold weather is much gentler on battery aging than hot weather. It would be interesting to compile a list of deg by geography, since anecdotally, it seems that owners in hot weather locales have suffered more deg.

As a desert rat, you have me officially intrigued. Almost to the point of actually looking at my battery degradation for the first time.... ever. But I'm afraid to start going down that rather slippery slope; I really don't need yet another thing to trigger my CDO, which is similar to OCD, but in the correct alphabetical order.

 

[AlanSubie4Life]

as I still have 310 miles of estimated range

Rock solid. Amazing.

Almost to the point of actually looking at my battery degradation for the first time.... ever

Don’t do it! Leave it on %.

 

[Candleflame]

So are saying you can plot them separately and they all look the same? I know, I could get a free account for two weeks but I don't want to give them my credentials and I am done with 3rd-party apps...



It was more like 37 km, since it goes from 322 miles with 18" to 299 miles with 20". (Fun fact: they actually achieved 332 miles in Tesla's test of the 2020 Performance 18".) But yes, if comparing 2019 Performance to 2020 Performance 20", yes, it is ~20km.



If you have a 2019, I do not think it will. It behaves the same as the 2018 in this regard. Only the 2020 model changes in response to selecting a different wheel diameter. Because that is according to the EPA test results...which they actually did for 2020 for each of the Performance trims - thus far, they have not repeated this feat.


It's 299 miles for 20" wheels (see the EPA website), and no, they didn't.



Right, and in 2019, I would expect AWD, AWD Performance, and Performance to all have 310 rated miles (~499km) - just as I said originally. I think that you have confirmed this?



And therein lies the problem IF you are plotting multiple model years on the same graph, for the aforementioned reasons. I have no idea what options they provide for filtering. It's totally fine to combine 2018 and 2019 (you can even combine AWD and Performance, there's no difference, as I've said). But 2020 has to be plotted independently, and 2021 has to have a separate graph too. If you want to have good data, anyway.

If the constants are different, then you need separate graphs. Unless you convert to kWh and plot that, or you normalize to initial capacity (which has its own caveats for 2018 and 2019 due to the 76kWh vs. 77.8kWh discrepancy that has been discussed ad nauseam).

probably is 37km, i couldnt remember the exact deratement of the performance!

teslafi isnt that good for filtering the options are very basic but it does show you what category your car has been put into and you can change the fleet degradation curve based on the model year since a few weeks too. So of course if you mix a 20" performance with a 18" stealth performance thats not gonna work. i have no idea how teslafi accounts for that. But my fleet start is 493km (i got teslafi at 3k km) so i presume it somehow takes that into account.

you dont have to give you credentials to teslafi, you can just generate a token and manually give access rights via that.

 

[Candleflame]

Yeah, it crossed my mind, but after waiting for it for 4 months, and with the $7500 tax credit expiring in 2 weeks; I decided to keep it, though I had the driver note the ZERO SOC. And, as AlanSubie has noted, I lucked out, as I still have 310 miles of estimated range. Seems like cold weather is much gentler on battery aging than hot weather. It would be interesting to compile a list of deg by geography, since anecdotally, it seems that owners in hot weather locales have suffered more deg. I know there's that chart at BatteryU where it shows storage at 40C vs 25C or something along those lines, but real world data would be fascinating.
View attachment 654339

I live in north Australia and in particular my tesla spent quite a bit of time in the scorching outback so I am very interested in the heat argument. Its getting autum here now but it still hits 30C at daytime and 23C at nighttime. Climate is exactly the same as Miami in Florida but with a slightly hotter winter. Outback 45C daytime 35C nighttime is normal and my car spent around 2 months there.
Im not sure what the battery temps are but I have now got SMT running so Im gonna have a look at the battery temp in the afternoon at at nighttime tonight.

However, I have asked a few people here who got the stealth performance (again, its a good baseline car coz it was only available here for 2 months and the LRAWD was not on offer) and the ones who live in the south with temperatures more similar to spain have exactly the same degradation as I have.

How do you use your battery normally? just top off to 90% every day?

 

[KenC]

I live in north Australia and in particular my tesla spent quite a bit of time in the scorching outback so I am very interested in the heat argument. Its getting autum here now but it still hits 30C at daytime and 23C at nighttime. Climate is exactly the same as Miami in Florida but with a slightly hotter winter. Outback 45C daytime 35C nighttime is normal and my car spent around 2 months there.
Im not sure what the battery temps are but I have now got SMT running so Im gonna have a look at the battery temp in the afternoon at at nighttime tonight.

However, I have asked a few people here who got the stealth performance (again, its a good baseline car coz it was only available here for 2 months and the LRAWD was not on offer) and the ones who live in the south with temperatures more similar to spain have exactly the same degradation as I have.

How do you use your battery normally? just top off to 90% every day?

I got it in Winter, so I started with 90%, but within a couple months, I switched to 80%, since I didn't drive all that far on a daily basis. Then during the first late Summer, I switched to 60%, after reading the "scientific" battery thread. I wanted to reduce the risk of cathode cracking, which seemed to occur at 3.92V or what we guessed to be about 64% SOC. Since then, I've stuck to 60%, though I charge higher if I need to.

 

[Dave EV]

Ever since I've purchased my 2019 LR AWD, I've charged it using the Tesla Wall Connector in my garage.

When charging, it says it's doing so at 48 amps. I'm never in a rush to charge. Should I set the charger to something lower than 48 amps? Would this help with battery longevity?

As others said, no, there's really not any evidence that 48A is going to be any different than something slower in terms of rate of battery capacity loss. Maybe, if it's very cold (near, below freezing), you might notice as you do have to limit charging rates to avoid lithium plating at those temps.

That said, there's another reason to reduce the charging rate a bit - the amount of heat loss in wires and connectors on the AC side can be significantly reduced by reducing the current a bit. If you have a weak point in your wiring or connectors, running just a bit lower will minimize the risk of something failing. For example, if you cut your current 50% say 24A, any heat loss in the cables will be cut by 75%. (P = I^2 * R). Going to just say 40A from 48A will slow down charging by ~17%, but reduce heat build-up by ~31%.

like i wrote in numerous posts before. we are all dumb and have 0 clue what actually truly affects degradation. for the model 3 at least.
Given the new iron batteries i am highly suspcious that tesla has a semi-secret battery chemistry which doesnt behave at all like battery university wants us to believe.

What iron batteries? Aside from the LFE batteries used in Shanghai SR+ models, I don't think there's anything that special about Model 3/Y batteries. Maybe studies have been performed on lithium batteries about what types of factors affect the rate capacity loss, and that are the following (in no particular order):

• Time (the older the battery, the more capacity loss it will have)
• Temperature (the higher the temperature, the faster it will lose capacity)
• Charge/discharge rates (the faster you charge and discharge, the faster it will lose capacity)
• Cycle depth (the deeper the discharge cycle, the faster it will lose capacity)
• State of charge (the higher the average state of charge, the faster it will lose capacity)

And all of these factors can combine to cause other issues - for example - you can't charge very fast at very low temps without causing extra damage compared to high temps. But if the car is just sitting - you want the battery nice and cold.

People say - charge it up immediately if you discharge it very low - but it seems that by then, you've already done most of the damage, so you might as well leave it as lower states of charge (even all the way down to 0%) put the battery in a fairly benign state. 90% is pretty high voltage wise on Teslas - that's over 4.1V - many other EVs 100% voltage. Obviously, Tesla's batteries tolerate higher voltages better than most.

Seems like cold weather is much gentler on battery aging than hot weather.

Yep. The Arrhenious equation plays a large role in terms of rate of capacity loss, all else being equal.

Anyway, Tesla's batteries seem to be pretty durable in general, so you don't really have to think about it all that much. That said, it does seem that the Model 3 loses capacity at a faster rate than the Model S and X (especially the 85 / 100 kWh packs - 90 kWh, might be similar).

 

[Candleflame]

I got it in Winter, so I started with 90%, but within a couple months, I switched to 80%, since I didn't drive all that far on a daily basis. Then during the first late Summer, I switched to 60%, after reading the "scientific" battery thread. I wanted to reduce the risk of cathode cracking, which seemed to occur at 3.92V or what we guessed to be about 64% SOC. Since then, I've stuck to 60%, though I charge higher if I need to.

funny coz thats pretty much what i do. my car sits most of the time around 60%... But I have 10% degradation haha.

 

[Candleflame]

What iron batteries? Aside from the LFE batteries used in Shanghai SR+ models, I don't think there's anything that special about Model 3/Y batteries. Maybe studies have been performed on lithium batteries about what types of factors affect the rate capacity loss, and that are the following (in no particular order):

• Time (the older the battery, the more capacity loss it will have)
• Temperature (the higher the temperature, the faster it will lose capacity)
• Charge/discharge rates (the faster you charge and discharge, the faster it will lose capacity)
• Cycle depth (the deeper the discharge cycle, the faster it will lose capacity)
• State of charge (the higher the average state of charge, the faster it will lose capacity)

the issue is that none of this is backed up by any evidence.
Iron batteries are a bit different, they like being kept hot and being charged to 100% frequently.

 

[Dave EV]

Iron batteries are a bit different, they like being kept hot and being charged to 100% frequently.

Neither of those things are true or backed up by facts for LFE batteries, either, if you are trying for maximum battery life. Same as NCA cells used for most Teslas.

 

[Rothgarr]

As others said, no, there's really not any evidence that 48A is going to be any different than something slower in terms of rate of battery capacity loss. Maybe, if it's very cold (near, below freezing), you might notice as you do have to limit charging rates to avoid lithium plating at those temps.

That said, there's another reason to reduce the charging rate a bit - the amount of heat loss in wires and connectors on the AC side can be significantly reduced by reducing the current a bit. If you have a weak point in your wiring or connectors, running just a bit lower will minimize the risk of something failing. For example, if you cut your current 50% say 24A, any heat loss in the cables will be cut by 75%. (P = I^2 * R). Going to just say 40A from 48A will slow down charging by ~17%, but reduce heat build-up by ~31%.

I was thinking I'll reduce to something below 48A anyway, just to ensure that I'll always be below what our solar panels produce. In the summer on sunny days, we definitely produce more power at any given moment while charging my Model 3 at 48A. But on partially cloudy days and winter days, we pull more from the grid while charging than the panels provide. (for reference, our solar panels provide over 100% of our yearly electric needs, including charging my car, so I'm just talking about power production while the car itself is charging)

 

[jyavenard]

i seem to have hit some sort of range recalibration event a few days ago. i woke my car after the usual 3h sleep for an OVC reading but rather than the usual +1 or 2% i quite often see i actually lost 5% of range suggesting the BMS might have realized the battery is actually more empty than it really is.

My 2019 performance Stealth went down just like yours, now range is 450km at 100%, battery nominal capacity showing 68.9kWh only.

It was showing 463km a few days early at 70.6kWh after that charge to 100%

 

[jyavenard]

Neither of those things are true or backed up by facts for LFE batteries, either, if you are trying for maximum battery life. Same as NCA cells used for most Teslas.

It's what Tesla is now documenting. Charge the MIC 2021 SR+ car with a LFP battery to 100% at least once a week.

 

[Candleflame]

My 2019 performance Stealth went down just like yours, now range is 450km at 100%, battery nominal capacity showing 68.9kWh only.

It was showing 463km a few days early at 70.6kWh after that charge to 100%

you also saying you hit some weird calibration event few days ago? did it happen just after a software update?
Or just, that over the last month you also lost 10-15km like me?

 

[jyavenard]

you also saying you hit some weird calibration event few days ago? did it happen just after a software update?
Or just, that over the last month you also lost 10-15km like me?

It happened before the 2021.4.15 software update.

Car went from 463 to 453 on March 31st, and gradually went down to 450 over the next few days