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

[KenC]

Source please?

Okay, made me look for it, but it's in this thread, which is well worth reading the whole thing:
Battery Degradation Scientifically Explained

 

[MarcG]

Okay, made me look for it, but it's in this thread, which is well worth reading the whole thing:
Battery Degradation Scientifically Explained

Thanks for the link. I watched the entire video and there was no mention of voltages or SoC beyond which degradation occurs. Where did you get the 3.92V / 63% SoC from?

 

[KenC]

Thanks for the link. I watched the entire video and there was no mention of voltages or SoC beyond which degradation occurs. Where did you get the 3.92V / 63% SoC from?

Ha, you've got to skim thru the whole thread! There are some pics of cracked cathodes, and I vaguely recall 3.92V was the threshold, and someone else said that was 63% SOC.

It's well worth reading.

 

[yhap2003]

I know this is an old thread but just want to report that I’m having the same exact issue as OP since the delivery of my car. I should have “returned it”. When I took the car off the lot in 2019 I was basically getting SR range and not SR+.

SC and support is of no use telling me the same story. I’m just hoping my battery capacity craps out quicker so I can make a warranty claim.

 

[Candleflame]

That may be what the car shows. But then you see all new owners complaining about barely being able to go over 300km.

While I can easily do 430km in my model 3.
So you have to take with a grain of salt whichever value the car is showing.

Tesla was being optimistic with the LR before, they took it to another dimension with the MIC Sr+

completely irrelevant. we are not talking about how efficcient you drive your 3 or how efficient your AWD 3 is compared a 20" 3 or other EVs.
we are purely talking about battery degradation which gets measured in % or kwh or rated km.

 

[Candleflame]

Just look at it in the summer time.

i live in north australia. we dont have a winter. we just have summer, hell, summer, summer here.


On that note im now down another 4km. So well into the 450s now. And no, my range does not fluctuate. it just goes down. and i dont supercharge often.

 

[diamond.g]

i live in north australia. we dont have a winter. we just have summer, hell, summer, summer here.


On that note im now down another 4km. So well into the 450s now. And no, my range does not fluctuate. it just goes down. and i dont supercharge often.

This is kind of why I think Tesla should stop using rated range and base it off of how folk are actually driving (ie use the energy screen number).

 

[Candleflame]

This is kind of why I think Tesla should stop using rated range and base it off of how folk are actually driving (ie use the energy screen number).

that has nothing to do with what we are talking about. noone has any issue with rated range. mine could be 800km for all i know and it wouldnt matter as it is just a constant applied to the pack. The point is DEGRADATION or RANGE loss not how far you can drive with that range.
I can essentially drive 10% less distance after just 30k km and I do need the range as the distances in australia are vast and charging stations (especially fast ones) are very far apart. nevermind that it slows down your effective charging rate even on ultrafast dc chargers.

 

[diamond.g]

that has nothing to do with what we are talking about. noone has any issue with rated range. mine could be 800km for all i know and it wouldnt matter as it is just a constant applied to the pack. The point is DEGRADATION or RANGE loss not how far you can drive with that range.
I can essentially drive 10% less distance after just 30k km and I do need the range as the distances in australia are vast and charging stations (especially fast ones) are very far apart. nevermind that it slows down your effective charging rate even on ultrafast dc chargers.

I thought they were kind of one and the same. Tesla isn’t selling pack sizes anymore they are selling a particular range and performance level. By sticking with a rated range, be it EPA or WLTP, they are inadvertently giving away what the pack size is, and thus allowing folks to track how much degradation has happened. Basically what I am saying is the battery range indicator is really only showing you how much energy your pack has based on with EPA rating or WLTP rating. It has nothing to do with how you are driving.

Switching to a GoM, or at minimum showling an efficiency rating like TeslaFi would help folk figure out how to get rated range, ignoring degradation for the moment. From there they could add a Battery Health status under the service menu so folks can see how their battery is doing otherwise. Or maybe a menu to show module health since the worse performing module brings the whole pack capacity down.

 

[diamond.g]

To others point Tesla doesn’t say anything about degradation of the pack outside of the 30% in 8 years warranty. According to SMT I have lost 11% of my pack in the 36k miles I have had the car so far. So I get the concern. I am just not sure how Tesla could advertise pack aging or even if they should, seems like no one else does.

 

[Candleflame]

I thought they were kind of one and the same. Tesla isn’t selling pack sizes anymore they are selling a particular range and performance level. By sticking with a rated range, be it EPA or WLTP, they are inadvertently giving away what the pack size is, and thus allowing folks to track how much degradation has happened. Basically what I am saying is the battery range indicator is really only showing you how much energy your pack has based on with EPA rating or WLTP rating. It has nothing to do with how you are driving.

Switching to a GoM, or at minimum showling an efficiency rating like TeslaFi would help folk figure out how to get rated range, ignoring degradation for the moment. From there they could add a Battery Health status under the service menu so folks can see how their battery is doing otherwise. Or maybe a menu to show module health since the worse performing module brings the whole pack capacity down.

not really and i dont care about the pack size per se. What matters is the distance you can travel. and that is now 10% less as advertised or 10% less of what i could achieve when the car was delivered. we all expect some degradation. but not above 10% when the car has <50k km. Hansjoerg gemmingens Model S with 1 million km (well 750k km for the battery) only has 12.5% degradation.

it makes you wonder whether tesla is artifically clamping down the battery to reduce long term risks with the battery. like a sneaking battery gate to prevent fires.

 

[diamond.g]

not really and i dont care about the pack size per se. What matters is the distance you can travel. and that is now 10% less as advertised or 10% less of what i could achieve when the car was delivered. we all expect some degradation. but not above 10% when the car has <50k km. Hansjoerg gemmingens Model S with 1 million km (well 750k km for the battery) only has 12.5% degradation.

it makes you wonder whether tesla is artifically clamping down the battery to reduce long term risks with the battery. like a sneaking battery gate to prevent fires.

The battery warranty for the 3 and Y is worse (mileage cap) than the (old) one for the S and X, though they did add a degradation clause (that didn’t exist for the S and X). So there is that.

 

[AlanSubie4Life]

Switching to a GoM, or at minimum showling an efficiency rating like TeslaFi would help folk figure out how to get rated range, ignoring degradation for the moment.

This wouldn't help. It's not like people wouldn't notice that their GoM doesn't read what it used to read! And the Tesla does have a GoM on the Energy Screen.

For example, the GoM in my Spark EV registered (usually) 80+ miles when it was new. It now (usually) reads 63 miles. I noticed!

It's not really THAT different than an energy meter, except that that number in the Spark does roughly indicate how far I can go, and it bounces around a bit (goes way up or way down) especially if I just did a 50-mile downhill drive, or I was blasting the heat (this behavior is silly). However, in the Tesla, I've never had an issue predicting how far I can go. It's just a scalar applied to the number, smaller value for colder temps, larger value for warm optimal temps.

But it will still reflect energy loss and it's not going to stop people noticing their capacity loss (which is what people actually care about, for good reason - because it affects their projected range (the GoM on the Energy Screen)).

 

[AlanSubie4Life]

Hansjoerg gemmingens Model S with 1 million km (well 750k km for the battery) only has 12.5% degradation.

What kWh did he start with, and how many kWh does he have now (not rated miles)? I've wondered about this because on the Model S they have changed how it works over time (so you can't just look at the rated miles difference and use that for the degradation, necessarily - there used to be a hard limit on displayed miles and it wouldn't change for a while when you started driving...apparently. This is hearsay - I don't know for sure - that's why I wanted to know what the kWh difference is...)

 

[diamond.g]

This wouldn't help. It's not like people wouldn't notice that their GoM doesn't read what it used to read! And the Tesla does have a GoM on the Energy Screen.

For example, the GoM in my Spark EV registered (usually) 80+ miles when it was new. It now (usually) reads 63 miles. I noticed!

It's not really THAT different than an energy meter, except that that number in the Spark does roughly indicate how far I can go, and it bounces around a bit (goes way up or way down) especially if I just did a 50-mile downhill drive, or I was blasting the heat (this behavior is silly). However, in the Tesla, I've never had an issue predicting how far I can go. It's just a scalar applied to the number, smaller value for colder temps, larger value for warm optimal temps.

But it will still reflect energy loss and it's not going to stop people noticing their capacity loss (which is what people actually care about, for good reason - because it affects their projected range (the GoM on the Energy Screen)).

I get what you are saying, but again even if there is degradation as long as it is under the 30% lost in 8 years, Tesla isn’t likely to do anything about it. So it kind of is a moot point in that regard.
I think folks think the 3’s pack would have similar characteristics to the S, but fail to realize the S had/has 16 modules to spread poor performing modules across instead of the 4 we have with the 3 (and soooo many more cells as well).

 

[AlanSubie4Life]

as long as it is under the 30% lost in 8 years, Tesla isn’t likely to do anything about it.

Yeah, I didn't say they would. Just saying people will be able to figure out their capacity loss, and there's not much point in hiding it or obfuscating it. Personally, I like the energy display of the battery gauge. I've seen how a GoM works and it's bad, imo. I almost ran out of charge in the Spark one time, because it tricked me (uphill vs. downhill, it predicts higher range when you actually will have lower range, as a specific example - pretty obvious of course, but I was not dealing with an extreme elevation difference, but it still meant I cut it really close).

had/has 16 modules to spread poor performing modules across instead of the 4 we have with the 3 (and soooo many more cells as well).

I'm not sure what to make of that or whether that actually makes much difference. Certainly fewer cells potentially will make the capacity loss more strongly quantized if you actually have a cell drop out by blowing its fusible link or whatever (I'm not sure how common this is - while it certainly can happen, it's probably not the reason for most of the capacity loss, but not sure). But not sure the modules will really make much difference. It's still a similar number of cells in series, the difference is the parallel number (it looks like 96s74p vs. 96s46p) which would lead to greater quantization under some degradation scenarios.

 

[diamond.g]

Yeah, I didn't say they would. Just saying people will be able to figure out their capacity loss, and there's not much point in hiding it or obfuscating it. Personally, I like the energy display of the battery gauge. I've seen how a GoM works and it's bad, imo. I almost ran out of charge in the Spark one time, because it tricked me (uphill vs. downhill, it predicts higher range when you actually will have lower range, as a specific example - pretty obvious of course, but I was not dealing with an extreme elevation difference, but it still meant I cut it really close).


I'm not sure what to make of that or whether that actually makes much difference. Certainly fewer cells potentially will make the capacity loss more strongly quantized if you actually have a cell drop out by blowing it's fusible link or whatever (I'm not sure how common this is - while it certainly can happen, it's probably not the reason for most of the capacity loss, but not sure). But not sure the modules will really make much difference. It's still a similar number of cells in series, the difference is the parallel number (it looks like 96s74p vs. 96s46p) which would lead to greater quantization under some degradation scenarios.

Yeah a straight up battery health (or module health) screen would be nice under the service menu. Maybe even show the cell im/balance level as well (not sure how helpful that info is). Not saying we have to have it because we can infer a lot from what is shown, and gather even more info with a tool like SMT. It falls under my nice to have category.

For your second paragraph, I wonder about it too as the chemistry between the s/x and 3/y is supposed to be the same (for the same battery supplier at least), so really the only major difference would be the total capacity and cell/module arrangement.

 

[Candleflame]

What kWh did he start with, and how many kWh does he have now (not rated miles)? I've wondered about this because on the Model S they have changed how it works over time (so you can't just look at the rated miles difference and use that for the degradation, necessarily - there used to be a hard limit on displayed miles and it wouldn't change for a while when you started driving...apparently. This is hearsay - I don't know for sure - that's why I wanted to know what the kWh difference is...)

he never said, there was an interview where he said he has 12.5% degradation. im sure someone like him just uses scanmytesla to read it out.
He does say he cruises at 120km/h 99% of the time and doesnt go lower than 20% (Even though current understanding is that low SOC is probably not harmful at all to the battery, even if the car sits at 0%. Certainly cars which sat in american junkyards for months at 0% dont have any more degradation than other cars)

 

[Candleflame]

I get what you are saying, but again even if there is degradation as long as it is under the 30% lost in 8 years, Tesla isn’t likely to do anything about it. So it kind of is a moot point in that regard.
I think folks think the 3’s pack would have similar characteristics to the S, but fail to realize the S had/has 16 modules to spread poor performing modules across instead of the 4 we have with the 3 (and soooo many more cells as well).

maybe we are all lucky and in 4 years time our batteries hit that if this continues.
im down another 2km today at charging to 100%. hm.

 

[SmartElectric]

Silicone was fist added to the S&X cells when they went from the 70/85kWh packs to the 75/90kWh packs.

I was wondering how they ballooned the pack, sure seems like tits a lot of effort for a small gain. Oops, sorry for the spelling mistake. "its a lot".