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

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So... try plugging in every day, and charging to 90 percent for a week and see if that helps you. I have read like 95% of these battery degradation threads, and one constant in almost all of them is that if someone charges less than daily, and charges to less than 90%, the car normally reports a loss in rated range at some point. They then freak out about "lost miles".

I have 13k miles on my model 3P. I plug it in every single time it hits my garage. Not "daily" but every single time it enters my garage. I charge to 90% every single day. I have an 80 ish mile round trip to work and back. I have lost 0 (zero) rated miles. My car still charges 90% to 279 and 100% to 309 (and it charged 100% to 306 when it was new with less than 300 miles on it).

Its my belief that what gets "off" is the bms, not actual rated range. If you care about the number on the screen, try charging to 90% every day, and plugging in every day... because the manual tells us specifically that there is zero benefit to "running the car down before charging up".

Try that for a week and report back.

This is exactly what I've been doing ever since I got my car little over 2 months ago. Recently I am noticing drop in miles to 275 when 90% and 259 when 85%. They used to be 279 and 263 respectively. I only have about 2500 miles on the car...
 
I have found that changing from miles/kms to percentage takes away some of the 'worry' - 90% is always 90%. As for the actual mileage, I never get as much as I imagined I was going to get,

After reading a bunch of these threads, I switched to % vs miles also. My P3D+ 100% is 294mi after 12mo and 8,200mi. Only went to 100% three times.

You don’t pick up your phone and say, oh I’ve only got 4:17 mins of use... you pick up your phone and say 82% will last me the rest of the day.

Drive & enjoy no gas stations people!
 
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State of charge VS capacity

At any moment, the car (or any appliances that uses battery) can only tell the voltage on a battery and use that voltage to extrapolate the state of charge. There's no way for the car to know "how many miles are left on the battery" just by charging a battery to full. The way to calculate capacity is to take a set amount of votage out of the battery, and calculate the energy produced. You got a long range model 3? Drainig the battery from full to empty should get you 75kw/h of energy. You getting only 65kw/h of energy? You got degradation. We can also calculate capacity based on the energy put into the battery instead, which is what the Tesla does.**

Degradation example

So for a new long range 75kw battery, one should be able to charge each battery cell from 3.3V (0%) to 4.2V (100%) after putting 75kw/h of energy in to the battery. The Tesla's software base it's mileage reading off this calculation (there are many factors which I'll ignore in this example). If 10 years later, charging from 0% to 1000% requires only 60kw/h of energy, the system can assume that 80% of battery had been degraded, and at 4.2V (100% state of charge), the battery mileage reading would be 256 miles (320miles x 80%).

How your charging habit can influence capacity reading

The car's system can accurately gauge the battery's capacity when you fully drain then charge the battery from empty to full. But of course doing so is not good for the battery's life, and we don't want to do that all the time. In reality we often drive for 30 miles, draining the battery by about 10%, and put the car back to 90 percent charge at night. This is great for battery life, but the car now only has a limiting set of statistics to calculate its capacity.

If each battery cell went from 4.0V (73%) to 4.1V (90%) with, let's say, 12.75kw/h charged (17% of 75kw/h), then the system could assume you still have 320 miles of range. But note how small a change in voltage is between 73% and 90%. With a delta of 0.1Volt, the voltage reading can only be so accurate. Then there's fluctuation in temperature and other factors that will fluctuate this reading day by day. But if you're charging from 0% to 100%, the difference in voltage would be much more signifiant, and the bigger numbers produce more accurate results.

That is why the Tesla reps recommend to discharge and charge the battery by a large margin (10% to 100%) in order to better calculate capacity, and repeat this 3 times in a row. The car calculates capacity based on the history of multiple charges, not just one.

Time will tell

Even with properly charging from empty to full, our charging at home can only be accurate up to a certain point, and when the first year of use would only result in about 5% of degradation, your personal finding will inevitably have a high margin of inaccuracy. The only way to have a truly accurate reading is to plot a set of data from 2 or 3 years of usage. My guess is that it's too early to tell.

The only unit to calculate a battery's capacity and degradation is kilo watt per hour. Not any units in miles or kilometers. What we are seeing is just an algorithm making a best guess.

I must claim that this is all based on my personal finding and is prone to mistakes. There are also a lot more stuff like how the maximum voltage also degrades over time which I'm omitting to keep this short. Please correct me if anything here is incorrect.

** In a lab environment, calculating drain is more accurate than calculating charge because you can simulate the speed of discharge with the application. But when you're driving an EV, it's impossible to have this perfect discharge environment to calculate drain as current varies like crazy and regen braking happens every few minutes.
 
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The car's system can accurately gauge the battery's capacity when you fully drain then charge the battery from empty to full.
As I explained in a previous post that is not necessary if you have the battery's charge/discharge characteristic. The capacity can be estimated from a partial charge but as I also indicated in that post the estimate is better if the charge is substantial (so that the voltage change is appreciable). The algorithm can determine the quality of a partial charge's estimate and partial charge estimates can be used to assess battery state if the quality is accounted for. There is math that makes this doable and I'm pretty sure Tesla knows that math.
 
As I explained in a previous post that is not necessary if you have the battery's charge/discharge characteristic. The capacity can be estimated from a partial charge but as I also indicated in that post the estimate is better if the charge is substantial (so that the voltage change is appreciable). The algorithm can determine the quality of a partial charge's estimate and partial charge estimates can be used to assess battery state if the quality is accounted for. There is math that makes this doable and I'm pretty sure Tesla knows that math.

Agreed. My intention was to say "The car can MOST accurately gauge", not to imply that charging from empty to full is the only way. These calculations are never all or nothing. The more data, the merrier. The next 2 paragraphs went on to talk about just that. I hope my point wasn't too confusing.
 
After reading a bunch of these threads, I switched to % vs miles also. My P3D+ 100% is 294mi after 12mo and 8,200mi. Only went to 100% three times.

You don’t pick up your phone and say, oh I’ve only got 4:17 mins of use... you pick up your phone and say 82% will last me the rest of the day.

Drive & enjoy no gas stations people!
If 100% is only 10 miles, I’m not going to pickup the phone and call my wife and say I’ve got 100% so I’ll be home no problem. I personally look to a mileage estimate to figure out how often I need to charge especially when we have two cars sharing one charger.
 
You don’t pick up your phone and say, oh I’ve only got 4:17 mins of use... you pick up your phone and say 82% will last me the rest of the day.

It’s much more apropos to compare to a gasoline car.

I wouldn’t expect a fuel vehicle to say: “Range to empty: 3.6 gallons” ... instead, it lists an approximate distance, which is exactly how I treat the battery gauge in my Model 3. I want the approximate distance I can go, keeping in mind it’s not an exact science. I try not to let that meter go below 50 miles in either a gas or battery car. Really simple.
 
I have the exact same problem as others are describing here (2019 M3 LR AWD). I'm located in the Netherlands, Europe so I have my car set up to use metric for kilometres. I am now at 13K kilometres. Since my summer holiday early August where I did a 1400km roadtrip I have seen a 10km range drop at 90% SoC (which is what I tend to charge up to every so many days). I'm on the road a lot at customers (Consultant) so I charge here and there up to whatever point I can reach (many customer based chargers are meant for Hybrids and only supply single phase 16amps so 3,7Kw).

Next week my car is going in to the Amsterdam SeC as I have owned the car since March and have a MASSIVE list of complaints which Tesla has refused to address (or fix) before. The range loss is the latest addition but I also notice that the range is much further from realistic than it initially was. For example; I charge the car to 90% (now getting 440kilometres instead of 449km I got originally). I then unplug the car and get in - by which time the range indicates 438km (poof - what happened to the 2 km's since unplugging?). I then drove 2,2 kilometers to a different building at 50Km/h max speed (in Chill mode, no HVAC and very gentle acceleration) and I have lost another 5 kilometres.

My commute home shortly thereafter was 60km in fairly gentle traffic and I have consumer over 80km according to the range indicator. This always used to be the case but not by such a large margin.

I have also been viewing the 'since last charge' measurement which tells us the distance traveled and kWh consumed. This is almost always 300km and 51 to 52 kWh's consumed. That's from 90% down to less than 20km's left (for capacity testing purposes - I don't usually allow the battery to run down that far). Also made certain that no Sentry mode was used or other consumers like Keep Climate On or so. Also within 2 or 3 days max. Surely the phantom drain can't account for such a large loss? 90% down to just a few percent should be more than 52kWh's right?

I am an Android phone user (no iPhone, just an iPad) so I guess there's no way I can get all the stats people are posting here on their battery degradation right?

off topic:
So - SOO little faith left in Tesla here in the Netherlands but desperately hoping they can fix all my issues this time. I'm tired of dealing with it all. Never had the 'fun' one expects along with Tesla ownership and driving...
 
I have also been viewing the 'since last charge' measurement which tells us the distance traveled and kWh consumed. This is almost always 300km and 51 to 52 kWh's consumed. That's from 90% down to less than 20km's left (for capacity testing purposes - I don't usually allow the battery to run down that far). Also made certain that no Sentry mode was used or other consumers like Keep Climate On or so. Also within 2 or 3 days max. Surely the phantom drain can't account for such a large loss? 90% down to just a few percent should be more than 52kWh's right?
.

What's the outside temperature vs cabin temperature? A lot of energy is used to heat the cabin. My 3LR charges to 88% at 444km and 90% at 455km. It's been 1year and 3 months and 41,000kms. One Canadian winter (horrible range in winter), Spring/summer/fall has been close to the rated 100% efficiency of ~137Wh/km.
 
I have the exact same problem as others are describing here (2019 M3 LR AWD). I'm located in the Netherlands, Europe so I have my car set up to use metric for kilometres. I am now at 13K kilometres. Since my summer holiday early August where I did a 1400km roadtrip I have seen a 10km range drop at 90% SoC (which is what I tend to charge up to every so many days). I'm on the road a lot at customers (Consultant) so I charge here and there up to whatever point I can reach (many customer based chargers are meant for Hybrids and only supply single phase 16amps so 3,7Kw).

Next week my car is going in to the Amsterdam SeC as I have owned the car since March and have a MASSIVE list of complaints which Tesla has refused to address (or fix) before. The range loss is the latest addition but I also notice that the range is much further from realistic than it initially was. For example; I charge the car to 90% (now getting 440kilometres instead of 449km I got originally). I then unplug the car and get in - by which time the range indicates 438km (poof - what happened to the 2 km's since unplugging?). I then drove 2,2 kilometers to a different building at 50Km/h max speed (in Chill mode, no HVAC and very gentle acceleration) and I have lost another 5 kilometres.

My commute home shortly thereafter was 60km in fairly gentle traffic and I have consumer over 80km according to the range indicator. This always used to be the case but not by such a large margin.

I have also been viewing the 'since last charge' measurement which tells us the distance traveled and kWh consumed. This is almost always 300km and 51 to 52 kWh's consumed. That's from 90% down to less than 20km's left (for capacity testing purposes - I don't usually allow the battery to run down that far). Also made certain that no Sentry mode was used or other consumers like Keep Climate On or so. Also within 2 or 3 days max. Surely the phantom drain can't account for such a large loss? 90% down to just a few percent should be more than 52kWh's right?

I am an Android phone user (no iPhone, just an iPad) so I guess there's no way I can get all the stats people are posting here on their battery degradation right?

off topic:
So - SOO little faith left in Tesla here in the Netherlands but desperately hoping they can fix all my issues this time. I'm tired of dealing with it all. Never had the 'fun' one expects along with Tesla ownership and driving...


If all of the issues you are talking about are the car not matching up to the estimates it has, tesla is not, and will not be able to "fix" any of that so you will continue to be disappointed in that. The battery carries energy... not "miles", and everything in this car uses energy. AC / Heat, acceleration, etc etc.

Yours is another in a long long (long) line of data points of people having an issue with the miles display when they "charge up every so many days". I also doubt that you paid this close attention to your gas cars and took it to the dealership because you got 1-2 MPG less than what the car was rated (typical gas car with 15 gallon engine, 2 MPG less would be 30 "miles lost"). I have never heard of a person taking their gas car to the dealership because they get 2MPG less than the sticker. They just accept that there are factors at work that would cause that. Why people dont do that with a tesla I dont understand.

Now, I am assuming your "so many issues" have much more than how many miles I am getting has gone down a few KMs in a year of driving", so hopefully they can address those for you... but your complaint in this thread they will not be able to address at all. If you have not gone through a winter with your car yet, be prepared to be MUCH MUCH more disappointed.
 
What's the outside temperature vs cabin temperature? A lot of energy is used to heat the cabin. My 3LR charges to 88% at 444km and 90% at 455km. It's been 1year and 3 months and 41,000kms. One Canadian winter (horrible range in winter), Spring/summer/fall has been close to the rated 100% efficiency of ~137Wh/km.

Temperature is around 20 degrees celcius - so couldn't be more battery friendly I believe. I never get efficiency about 165 wh/km (but do you have a RWD or AWD?). Charging to 90% has never exceeded 449 km in my case. But it was stable for a long time. I only charged to 100% a few times end of July and that gave me exactly 499km. I dread the upcoming winter :/

I suspect either the drivetrain or the battery. I just don't know. The sudden drop without even having driven makes me think it's the battery. But I have noticed things that make me suspect the drivetrain (also) - a couple of times on accelerating fast when the car was quite new I got sudden jerks (decreased acceleration as if I hit something). During our roadtrip this summer I noticed how noisy the (front?) drivetrain was; very audible indeed. A clear whine especially when decelerating.

What a mess..... never expected this from a 65K euro car....
 
I am an Android phone user (no iPhone, just an iPad) so I guess there's no way I can get all the stats people are posting here on their battery degradation right?
.

You can get TeslaFi on any web device and its battery report graph (several have been posted here) is very useful for checking on battery degradation. But it must be taken with a grain of salt. In yesterday's charge the data collected by TeslaFi showed that my battery capacity had gone up a little but their graph showed 100 range going down a little. The discrepancy isn't much, though, and the indicated trend tells the same story.

As an Android user you are in better shape than iPhone users as there is an Android app that lets you tap the CAN bus which gives you the real story on what is going on in the car if you know how to interpret it.
 
Temperature is around 20 degrees celcius - so couldn't be more battery friendly I believe. I never get efficiency about 165 wh/km (but do you have a RWD or AWD?).

I have an AWD and here are my wh/km from TeslaFi (car might display slightly higher or lower) since I got my car (I'm in Canada):
October 2018 177 Wh/km
November 2018 202 Wh/km
December 2018 210 Wh/km
January 2019 231 Wh/km
February 2019 218 Wh/km
March 2019 204 Wh/km
April 2019 178 Wh/km
May 2019 162 Wh/km
June 2019 151 Wh/km
July 2019 153 Wh/km
August 2019 155 Wh/km
September 2019 170 Wh/km

So only getting close to rated range in June, July and August.
 
I'll wade in on this, with some somewhat unscientific info.
My M3 LR AWD has ~ 17,000 mi.
I have been treating this car much like my new phone - neurotically keeping the battery above 40% and below 85%.
I keep it at percent - because the mileage reading is just too inaccurate, esp in cold weather.

One every 1-2 weeks, I have to drive out of town - and it seems like my trip (Philly to Dover DE) generally uses a nice 35-38% discharge.
Other than that - it's just around town driving in the leafy suburbs for daily use.
So I'm lucky to have it almost always stay in that "sweet spot" of not going too low, or needing to charge past 85%.
I have noticed once or twice that it either charged past my setting a few percentage points, or that my trip used 40-42%.
But (thankfully) it hasn't stayed that way, and it seems to correct itself.
I never let the car go below 38% (only went down to 23miles on my first road trip), and have never charged more than 85%.
I'm more concerned with preserving the cells than what the car's software (which recommends calibration that can slightly degrade the cells). I'm also not thrilled with supercharging, but have been very, very thankful that it exists when I need it for long trips.
 
If all of the issues you are talking about are the car not matching up to the estimates it has, tesla is not, and will not be able to "fix" any of that so you will continue to be disappointed in that. The battery carries energy... not "miles", and everything in this car uses energy. AC / Heat, acceleration, etc etc.

Quite true - but my focus here is a strong degradation. Range that just disappears. Besides that I also have 10+ cars to compare it to (exact same specs but later batch) and my car is CLEARLY doing much less well. The other cars charge further (455km at 90% as mentioned in this thread somewhere - mine never went above 449, so different at least) and don't have magically disappearing kilometers. They are also much closer to the actual consumption in range albeit I can't mention the wh/km off the top of my head. I will compare those soon.

Yours is another in a long long (long) line of data points of people having an issue with the miles display when they "charge up every so many days". I also doubt that you paid this close attention to your gas cars and took it to the dealership because you got 1-2 MPG less than what the car was rated (typical gas car with 15 gallon engine, 2 MPG less would be 30 "miles lost"). I have never heard of a person taking their gas car to the dealership because they get 2MPG less than the sticker. They just accept that there are factors at work that would cause that. Why people dont do that with a tesla I dont understand.

I understand your point however I have always found it fascinating and interesting to monitor the consumption of my cars. Especially my previous car (a 2014 Volkswagen Jetta Hybrid) as it 'gamified' the whole driving experience. However - I must say that that car and my previous cars (mostly VW, Seat. All german anyway) were very consistent and the weather had a very predictable effect on mpg. Would they have suddenly changed I CERTAINLY would have visited the dealership... I understand that I don't expect to always reach the rated range (the rated range also rarely being achieved in my ICE cars) - but this is a different proportion all together. Also - I don't understand how close to 90% of used battery equates to 51 or 52kWh's of consumed energy. I would expect that to be much closer to 65kWh.

Now, I am assuming your "so many issues" have much more than how many miles I am getting has gone down a few KMs in a year of driving", so hopefully they can address those for you... but your complaint in this thread they will not be able to address at all. If you have not gone through a winter with your car yet, be prepared to be MUCH MUCH more disappointed.

Oh trust me; my car is a total lemon. I just never feared Tesla would leave me out in the cold like this. SO many phonecalls and promises without ANY result what so ever. From terrible paintwork (and delivery with damage) to a faulty indicator stalk, erratic camera and safety feature behaviour, creaks and cracking sounds in the interior, audio 'popping' in and out, Driver side powered window that sometimes drops down when trying to close it, a hard-to-close trunk sometimes, crunching sounds when autopilot brakes (as in traffic jam stopping), autopilot that fails to change lane without any traffic being remotely near, the list just goes on and on..... (oh and as a bonus 1,5 weeks without any FSD features because Tesla suddenly decided 'I hadn't bought them' #facepalm). Nope - it's really quite pathetic and how ever much I loved Tesla and all Elon's ventures and (still do) want them to succeed - I am now outspoken to all and anyone when it comes down to my Tesla experience..... "it's a gamble man - just be prepared for sh*t"....
 
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