Model Y LR Range Reduced?

[Stevo75]

I have 2021 Model Y LR that I purchased last December. It now has about 14,000 miles on it. The published range for this car is 326 miles. I noticed recently that when I charge the battery to 100%, the range is shown as 305 miles (94% of the advertised range). I know the car never really gets the full rated range due to weather, weight, hills, and even tricks Tesla does with the EPA estimates, but I recall that when the car was new the gauge would say my range was 326 miles at 100% charge. A Better Route Planner says that my battery has no degradation and has a 75.3 kWh capacity. The calibrated reference consumption is 282 Wh/mi.

We regularly drive to my parent's house, which is a hilly 200 mile drive through NH & VT that we could do without a problem last winter when the car was new. Now this summer if the battery is anywhere less than 90% when we leave, the car will tell us that we will need to stop to charge along the way.

Does anyone know if Tesla has changed the way it calculates range? Is it possible that the car is limiting the min/max charge to improve the battery's lifetime? Or is it possible the battery has degraded and ABRP hasn't detected it yet?

 

[jcanoe]

There is nothing wrong with your Tesla Model Y's battery. An EV battery will gradually lose some capacity and range over time. You did not state when you purchased your Model Y vehicle. 110% of 270 miles is 297 miles. (326-297)/326 is ~9% loss, nothing to be concerned about.

 

[mikepatel3596]

There is nothing wrong with your Tesla Model Y's battery. An EV battery will gradually lose some capacity and range over time. You did not state when you purchased your Model Y vehicle. 110% of 270 miles is 297 miles. (326-297)/326 is ~9% loss, nothing to be concerned about.

I purchase mine in Dec 29th 2020

 

[jcanoe]

I purchase mine in Dec 29th 2020

I purchased my LRMY in June 2020. The stated EPA estimated range of the LRMY at that time was 316 miles. I estimate ~66kWh current usable battery (total battery capacity was 74kWh when new.)

The Tesla phone app currently displays 270 miles on a full charge. Based on my lifetime Wh/mi of 267Wh/mi I estimate the range to be ~250 miles. With the colder temperatures I have been averaging 300Wh/mi. I estimate my current range to be ~220 miles. (At 18 months and 5k miles I have yet to take a road trip. I have never driven more than 50 miles in a day.)

See this thread: 8% degradation after 9k miles, wtf?

 

[Krobbler]

Attached is my 100% full pack estimated range after every charge over 50% for the past 15k miles. This data is based off the BMS estimate. Your charge habits will change this peak estimated range drastically.

Currently I am showing a 5.2% loss after 33k miles but 2 months ago I was showing 11% loss. Change your charge habits and your estimated range will increase. The 3 and Y BMS needs the car to be asleep for 1.5 to as much as 3 hours to make a load balance measurement of the pack and this needs to happen at low % and high % SOC. Otherwise the BMS is just guessing low and high SOC voltages.

Please stop freaking out that your pack is bad.

 

[rjpjnk]

I think the whole idea of representing battery reserve by range is flawed, and this is why there is so much confusion and concern.

The battery does not store range, it stores energy. This is typically measured as kWh. This is the only real indicator of capacity for your car to do work. Strangely, I can’t find and basic energy meter on the Tesla. It needs one. Percentage charge is the closest we’ve got.

This capacity in kWh is a property of the size and health of the battery and does not change with driving habits.

Range, on the other hand, refers to what we DO with this energy reserve, and this strongly depends on driving habits.

The BMS attempts to estimate the expected range you will get from the remaining capacity by observing how you drive (how fast you accelerate/breaking, elevation change, etc). But this is just a guess and can change up or down any day causing you displayed max range to fluctuate even if nothing has changed with your battery’s capacity to hold energy (kWh).

By contrast, battery capacity pretty much only decreases. Each day you have a little less. Sometime this is called battery health. This is the metric that really matters - the current capacity of our battery in kWh. Maybe there is no meter for this because we might worry too much? I don’t know. We can estimate it from the energy screen of course.

 

[Johnny Vector]

...

By contrast, battery capacity pretty much only decreases. Each day you have a little less. Sometime this is called battery health. This is the metric that really matters - the current capacity of our battery in kWh. Maybe there is no meter for this because we might worry too much? I don’t know. We can estimate it from the energy screen of course.

There is no meter for this because it's very difficult to estimate in most use cases. (Note that the Leaf, or at least early ones, does have such a meter, but it's only got one digit of precision and I've never seen any test of its accuracy.) Unless you regularly leave the battery "asleep" at a wide range of charge levels, it's not possible to maintain an accurate calibration. Look at the post by Krobbler just above.

Lithium batteries have a very flat curve of voltage vs charge level, so to estimate charge level you have to do some combination of very accurate voltage measurement and dead reckoning (counting the number of amp-hours removed or added to the battery). The problem with dead reckoning is that any errors in current measurement or battery efficiency add up so you have a continuously growing error. Thus you need to occasionally reset your "current charge level" based on the voltage curve. And getting a useful reading of the voltage requires sitting without charging or discharging for hours, and then measuring the voltage to a fraction of a percent. Unless you do this at a wide range of points along the curve, you have to extrapolate from the values you have, which can give you errors at the many percent level.

This is an inherent "problem" with lithium batteries. The good part of it is that the same flat discharge curve means you have almost as much power when the battery is nearly empty as you do with it fully charged. And in reality the vagaries of temperature, headwind, and driving conditions have a much larger (and actually real) effect on range.

 

[rjpjnk]

There is no meter for this because it's very difficult to estimate in most use cases.

I agree it is difficult to estimate, but isn't it required to do so in order to display miles remaining as the car does currently?

It is an essential input to that calculation, right?

 

[Johnny Vector]

Yes, you do need that to display miles remaining. That's why the "miles remaining" varies so much, leading to threads like this. Providing miles remaining is slightly less misleading, I think, because people realize it's an estimate. Giving a number of kWh of capacity sounds more precise, but it really isn't. That's why the Leaf only tells you to 10% precision how much degradation you have.

 

[rjpjnk]

Actually, miles remaining requires 2 estimates: (1) kWh remaining and (2) miles per kWh. The second one is also a prime contributor to the reason miles remaining varies so much, since it depends on driving habits. So miles remaining has all the uncertainty of kWh remaining further compounded by the uncertainty in estimating miles per kWh. These two are multiplied to get miles remaining right? This is one reason simply showing the kWh remaining would be more reliable- one less estimate involved.

 

[Johnny Vector]

Actually, miles remaining requires 2 estimates: (1) kWh remaining and (2) miles per kWh. The second one is also a prime contributor to the reason miles remaining varies so much, since it depends on driving habits. So miles remaining has all the uncertainty of kWh remaining further compounded by the uncertainty in estimating miles per kWh. These two are multiplied to get miles remaining right? This is one reason simply showing the kWh remaining would be more reliable- one less estimate involved.

That is a much clearer explanation of what I was trying to say. Thanks!

 

[OCDriver]

I have a model 3 dual motor delivered late Dec 2019. A few months ago, I noticed a 10% reduction in max range. I thought it might be due to some environmental factor or perhaps mileage. However, my brother has seen exactly the same reduction on his identical purchased at the same time and he has significantly fewer miles on his car. This definitely seems like a software update limiting the max battery charge. Anyone else noticed this?

 

[modlyowner]

[2021 MY owner with 21K miles and ~5% battery capacity loss after 14 months of ownership]

I have a bit of a different take on this topic. Sure, 5-10% capacity loss in the first year is "normal" if you have read the dozens of threads on these forums, of if you talk to Tesla once this issue crops up. But call me crazy - I really think that Tesla's communication on this expectation is really poor. If dozens if not hundreds of owners are confused or complaining about it, it's a big red flag that some transfer of that information has failed. In fact, I did my own "research" before purchase and the only official Tesla communication I was able to find was battery capacity loss of under 10% by the 200K mile mark (if these forums are any indication, that information is patently false - nothing official about 5-10% capacity loss within one year).

Tesla: Battery Capacity Retention Averages 90% After 200,000 Miles

In the "2020 Impact Report," Tesla reiterates high battery capacity retention (low degradation) in its electric cars.

insideevs.com

Of course, Tesla service will tell you this is normal once you contact them, but good luck getting a salesperson to breathe a word about it before your purchase is signed. I'm not sure if the other EV manufacturers are better on communicating battery capacity/battery life but it feels pretty clear to me Tesla has failed on this front, perhaps on purpose. I'm sure sales would take a hit if they were up front about the fact that the advertised EPA range is likely to degrade within the first 12 months as a result of reduced battery capacity.

 

[shannonc13]

I picked up mine early June last year and I seem to be getting the same usable capacity as you.

Wait till you get to 30k, now I’m topping off at 287. 330 was long range but it mostly showed 318 then 305 now 287. I got mine Xmas 2020

 

[chan_man]

shannonc13, this is exactly what my LR is now at 32k

 

[Pianewman]

Wait till you get to 30k, now I’m topping off at 287. 330 was long range but it mostly showed 318 then 305 now 287. I got mine Xmas 2020

Same here, same delivery date, similar numbers.

 

[Krobbler]

Your charge habits will change how the BMS calculates energy and your estimated range. Read the page on the link below before freaking out that you have extreme degradation. Following the calibration and cell balancing takes time and depending on your driving it could take weeks to complete. I try to do this every 3 to 4 months to help recalibrate the BMS and my estimated range always bounces back.

Tesla battery management system (BMS) calibration

Tesla battery management system (BMS) calibration instructions

tesla-info.com

 

[shannonc13]

Same here, same delivery date, similar numbers.

I’m told we may get an over air update at some point that may help improve our range to a higher number again at some point. Fingers crossed.

 

[rjpjnk]

Just to illustrate how little the battery capacity (range) estimates can be trusted take a look at this graph. I have logged my estimated 100% range for over a year now using TeslaFi. Note the huge dips (like the one I am in presently at the end). There are range drops of 6-7% in a matter of weeks sometimes, then it recovers for some unknown reason. At one point in the middle my range was higher than 90% of other cars, now I am lower than 99% or all other cars. Not sure what to make of such data. Surely my battery didn't "get better" in the middle then get sick again.

 

[tonyb99]

Did Tesla hire some ex-Volkswagon software engineers? (Remember Dieselgate?)

 

[Koolio46]

Just to illustrate how little the battery capacity (range) estimates can be trusted take a look at this graph. I have logged my estimated 100% range for over a year now using TeslaFi. Note the huge dips (like the one I am in presently at the end). There are range drops of 6-7% in a matter of weeks sometimes, then it recovers for some unknown reason. At one point in the middle my range was higher than 90% of other cars, now I am lower than 99% or all other cars. Not sure what to make of such data. Surely my battery didn't "get better" in the middle then get sick again.

View attachment 853701

Check out this thread, especially there Op’s post. It’ll explain why it fluctuates, it’s all about how the BMS does it’s measurements and calculations of estimated range.

How I Recovered Half of my Battery's Lost Capacity

Or am I mis-interpreting the green line? The green line is plotted by miles, AFAIK. Not time. It’s a bit confusing. But this will largely eliminate any seasonality if it existed in the data (no idea what TeslaFi does).

teslamotorsclub.com