# How to determine if my Model 3 LR battery degradation is as should be expected or is at an accelerated rate?



## NYer

I have a 2018 Model 3 w/ a long range battery that has 31,574 miles. I almost always charge at home using a Tesla wall charger at 48 amps. My car has only touched a Tesla supercharger once, and that was for 10 minutes to add some miles during a trip.

Through all of of the software updates, I have not seen any increase in my estimated range. Right now, a new Model 3 LR is expected to have a range of 322 miles. My normal day charge level gets me to 259 miles, and full charging for a trip gets to 288 miles. Using the 288 mile estimate, that's a 11% degradation from the 322 range for a new car. 

How should I determine if my battery is fine and my degradation is within expectations, or if I have an accelerated degradation issue?

During my last mobile service visit, the tech mentioned that Tesla has replaced batteries before for issues (Mostly S and X models, few 3's) but we didn't get into the details of the issues that those owners had experienced or the indicators of their issues.

Pictures of the charge results as of yesterday are attached.


----------



## shareef777

Unfortunately, if you're less than the warranty covered 30% degradation limit, this is something you'll have to live with. Which is very frustrating, as it shouldn't be "acceptable" for a 310mi vehicle to degrade down to 220mi and still be considered "OK". Every other sealed battery device considers 20% degradation a failure. I'm at 13k mi (after 1.5 yrs) and am seeing 6.5% degradation.

Note that even home charging to 90% will causes extended degradation. Once I changed my charging habits to 80% I saw the degradation slow down.


----------



## garsh

Your car was rated for 310 miles, so don't go by what the new ones are rated for. Given that, your 288 miles is only a 7% degradation. Most Teslas degrade less than 10% in the first year or two, then the degradation slows down tremendously. So this would be pretty much normal.

But if you'd like, you could try recalibrating the BMS. It could just be that your personal charging habits are making it difficult for the BMS to accurately guess the battery capacity.

@MelindaV, @JWardell , what's the latest info on how to correctly recalibrate the BMS?
I'm having trouble locating some of the latest posts on the topic - it's been discussed a lot.


----------



## NYer

garsh said:


> Your car was rated for 310 miles, so don't go by what the new ones are rated for. Given that, your 288 miles is only a 7% degradation. Most Teslas degrade less than 10% in the first year or two, then the degradation slows down tremendously. So this would be pretty much normal.
> 
> But if you'd like, you could try recalibrating the BMS. It could just be that your personal charging habits are making it difficult for the BMS to accurately guess the battery capacity.
> 
> @MelindaV, @JWardell , what's the latest info on how to correctly recalibrate the BMS?
> I'm having trouble locating some of the latest posts on the topic - it's been discussed a lot.


Thank you. I would welcome learning about recalibrating the BMS. Haven't seen anything on that.


----------



## shareef777

garsh said:


> Your car was rated for 310 miles, so don't go by what the new ones are rated for. Given that, your 288 miles is only a 7% degradation. Most Teslas degrade less than 10% in the first year or two, then the degradation slows down tremendously. So this would be pretty much normal.
> 
> But if you'd like, you could try recalibrating the BMS. It could just be that your personal charging habits are making it difficult for the BMS to accurately guess the battery capacity.
> 
> @MelindaV, @JWardell , what's the latest info on how to correctly recalibrate the BMS?
> I'm having trouble locating some of the latest posts on the topic - it's been discussed a lot.


Interestingly, a new perf is rated for 299mi. So based off that I only lost 3%


----------



## NYer

shareef777 said:


> Unfortunately, if you're less than the warranty covered 30% degradation limit, this is something you'll have to live with. Which is very frustrating, as it shouldn't be "acceptable" for a 310mi vehicle to degrade down to 220mi and still be considered "OK". Every other sealed battery device considers 20% degradation a failure. I'm at 13k mi (after 1.5 yrs) and am seeing 6.5% degradation.
> 
> Note that even home charging to 90% will causes extended degradation. Once I changed my charging habits to 80% I saw the degradation slow down.


Agreed. Wasn't aware of the 70% minimum level for the warranty period, which would mean my capacity would have to drop to 217 miles for them to consider it a failure. I would consider that a downgrade to a normal model 3 (non-long range...)


----------



## SoFlaModel3

My LR gets 299 on 100% now and I also never saw the bumps from software updates. Have you ever done a battery recalibration? Take it down to 10-20% then charge to 100% (steady without interruption) then take it down to 10-20% again and back to 100%. See where you’re at. 

Of course don’t leave it at 100% longer than is necessarily as the max you should sit at is 90% for a period of time.


----------



## NYer

SoFlaModel3 said:


> My LR gets 299 on 100% now and I also never saw the bumps from software updates. Have you ever done a battery recalibration? Take it down to 10-20% then charge to 100% (steady without interruption) then take it down to 10-20% again and back to 100%. See where you're at.
> 
> Of course don't leave it at 100% longer than is necessarily as the max you should sit at is 90% for a period of time.


That's the way to calibrate the BMS? Drain it, full charge, drain it again and back to 100%? Sounds like it would stress the battery even more. Yeah, I try to baby my 3, mostly because I have no experience with trying to extend the life of a Li ion battery...


----------



## garsh

NYer said:


> That's the way to calibrate the BMS? Drain it, full charge, drain it again and back to 100%? Sounds like it would stress the battery even more. Yeah, I try to baby my 3, mostly because I have no experience with trying to extend the life of a Li ion battery...


Yes, it does stress the battery a little bit. But that's generally how you calibrate a BMS. The BMS can make better predictions when it's able to analyze the battery over a large range of charge levels. But IIRC, you just have to get it below 20% and above 90% to allow the BMS to come to a better understanding.

Also, @Mad Hungarian ran into BMS issues on his cross-country supercharging trip. His issue was a little different though - the car died while the BMS reported that it still had 8% battery remaining. Ian, what did Tesla suggest that you do to recalibrate the BMS in your case?


----------



## NYer

garsh said:


> Yes, it does stress the battery a little bit. But that's generally how you calibrate a BMS. The BMS can make better predictions when it's able to analyze the battery over a large range of charge levels. But IIRC, you just have to get it below 20% and above 90% to allow the BMS to come to a better understanding.
> 
> Also, @Mad Hungarian ran into BMS issues on his cross-country supercharging trip. His issue was a little different though - the car died while the BMS reported that it still had 8% battery remaining. Ian, what did Tesla suggest that you do to recalibrate the BMS in your case?


Good info. Appreciated.


----------



## Ed Woodrick

SoFlaModel3 said:


> My LR gets 299 on 100% now and I also never saw the bumps from software updates. Have you ever done a battery recalibration? Take it down to 10-20% then charge to 100% (steady without interruption) then take it down to 10-20% again and back to 100%. See where you're at.
> 
> Of course don't leave it at 100% longer than is necessarily as the max you should sit at is 90% for a period of time.


That is NOT FACT!!!

Look at the testing for the impact of a battery at 100%. If left on charger for a year, that batteries loose a few percent. That's indeed for generic cells and not the Tesla battery. Many have left their car at 100% for longer periods, like a week with no impact.

To let the Battery Management System recalibrate, leave it plugged in and charging for at least a few days.

Indeed, a 2018 LR RWD was rated for about 310 miles. I am charging to 310-311 every few months when I take a road trip.

(And I don't tend to leave the car plugged in. I'll charge to 100% if I think that I may need it. I charge to 80% or 90% depending on how I feel when I set the limit. I take a long trip at least every other month and have over 40,000 miles on it. I work at home and don't commute, so most miles are long travel.) The car has done less than normal travelling now that a Model Y parks next to it.


----------



## Bigriver

@NYer, yes this is a topic discussed a lot. First and foremost be aware that battery degradation and the rated range shown for your car may be 2 totally different things. The battery degradation is a real, physical process. The rated range displayed in the car is from an algorithm that none of us fully understand.

Here are some links. First is a long description in a long thread. I quote it because it and follow up posts contain info quoted from Tesla.


PA_Ray said:


> (Long post) In the fall I posted about a significant drop in range on this thread. Eventually I got hold of tech support who looked at my records and said to schedule a service appointment. About a week before I was contacted by pre-service support and below is clips from what they said:
> ___
> 1. Good afternoon Ray. I am a service technician here with Tesla's virtual service team and have been looking into your concern. I have pulled your vehicles log data and have spent a bit of time reviewing it and running remote tests and analysis on the vehicle, especially the HV pack and related systems. Before we go as far as to bring your vehicle in to the service center here, I'd like to ask you to do a little "home work" with me on this one. I do see that you charge your vehicle very regularly, which is fantastic. However I do see that the HV pack operates within a relatively narrow window of charge (generally 55-85%). This is terrific for battery longevity, but over time it does tend to make the battery "forget" what it is fully capable of. What I would like you to do is extend this window if at all possible. Let the battery go down to @30% or even lower if you feel comfortable with that (using the heat and "dog mode" are handy for this) and let it sit for a few hours (generally 2-3) then charge it back up to 90% and let it sit (plugged in). I'd like for you to do this a few times, like 4 or 5 or even more if at all possible then I'd like to re-run my tests. What this does is allow the battery to remember where the "bottom" is and recalculate what its energy capacity is more accurately.
> I'm going to move your appointment to an "outstanding" status pending the outcome of what we see after this.
> 2. Letting it go down to around 20% is great. That's what I'd like you to do for a few charge cycles. But instead of going all the way to 100% afterwards, let it come up to 90% and just let the car rest at that point. If it's at all possible during these "rest phases" could you turn off things like sentry mode and advanced summon too? That'll let the HV system recalculate what its true capacity is again and we can go from there. Everything else on the car looks great from here. I have your vehicles information saved and will continue to monitor its progress periodically during the next few days.
> 3. I've been continuing to monitor the packs progress over the past few days and am seeing some change in its calculations. This is a very good thing indeed. Keep doing what you're doing but do try and get its charge pretty low. The more often it can do that, the faster it can recalculate what it has and can do.
> 4. 90% is the "sweet spot" for charging a Model 3. The cells and bricks are happiest at that level. It is possible to drain the battery down when the car is not in use. If you park in a garage, you can vent the windows a little and run the heat from the mobile app. Don't worry about draining it too low. The car knows to shut it off if the SOC gets down to around 20% to prevent it from getting too low.
> ___
> I did this for six weeks and here are the results:
> View attachment 31971
> View attachment 31972
> 
> 
> Clearly it worked well. I have the following questions out to the Tesla tech, I'll let you know what he says.
> ___
> I wanted to follow up on my car and battery. Over the past month I have been following the plan and recovered the estimated range. Thanks for your help. My questions now have to do with the ongoing approach to charging. Here are a series of questions in no particular order.
> 1. Should I stay at 90% as the target charge?
> 2. Is it bad to plug in every night and charge up (my preference)? If not, I now know what to do if the range slips again. Is that a problem to repeat the recovery process multiple times as needed?
> 3. Should I rest the battery for 2 hours before starting charging?
> 4. Is it better to vary the starting points of the charge. Not necessarily dropping to 20% but avoiding the daily 25% drain and recharge cycle I was in?
> There were a couple times where I needed to quickly do a little charge because of an unexpected trip (and my range anxiety) and once that we didn't take the car because I had run it so low. With it being winter here, and significant range degradation due to the cold, I want to keep the charge fuller most of the time. Again, thanks for your help. Take care.
> ___
> I wanted everyone to see this and I'd love feedback from those of you who know battery technology on my questions. I plan to continue to drain it lower before charging, charge to 90%, and always let it "rest" before charging. Thoughts?


Second link is because when JWardell speaks, people are wise to listen. He has spent more time than most of us diving into details of our how our cars work.


JWardell said:


> So many things affect the range value that your car and Teslafi uses for that plot. It is not a real gauge of your battery's physical condition and degradation. It's a software algorithm that averages tons of parameters over a long period of time, and it doesn't recalibrate all that often. The best thing you can do I switch your gauge over to percent and stop stressing over range.
> 
> Battery balancing will trigger only when over 90% -let's say charge to 92% to be sure, but no need for 95 or higher- and only if the BMS thinks things are out of whack enough to do so. No need to start from 20% or whatever.
> But the calculations and range will not update until after a balance the car then goes for a good drive and gets the battery below 50%.
> After driving below 50% and sitting, parked, not charging, it will start updating the range calibrations. You might even notice it in TeslaFi if you see the range going UP while sitting there parked.
> 
> I triggered that a week and a half ago, and had some more 90% charges due to lots of travel last weekend too, where normally I only ever charge to 80%. You can see the bump at the tail end of my TeslaFi battery graph. Otherwise, there is a big overarching effect of average temperature over the previous several WEEKS. Tesla corrects for seasonal temperature and it's very apparent in my graph.
> View attachment 32619


And the third link is because it's the most recent thread hat I immediately thought of about battery range predictions.



JasonF said:


> Because I had been furloughed for a few weeks, and I'm just now resuming work somewhat from home, my Model 3 has unfortunately been spending most of the week in my garage. When it does go out lately, it's usually not for long drives, just for short runs to the few places that have reopened so far. When it's stored, it's in a garage that during the spring/summer months is between 85 and 95 degrees, which according to Bjorn Nyland's videos should keep the battery at its happiest.
> 
> Unfortunately the lack of activity seems to have gradually reduced the capacity of the battery. I tried using the low-impact rebalance method - charge above 90% and then let the car sit for a couple of days, which was easy given the circumstances - but it actually _reduced_ the capacity further. It used to average about 285 miles at 90%, now it's averaging 280 instead. I thought perhaps it was just the estimation that changed, but it does seem to top out at 307 miles at 100% - it's supposed to be rated for 325
> 
> That means at 2 years old in July, the battery seems to have possibly permanently lost about 6% of its capacity. I believe that's supposed to be considered normal-ish for the first few years of ownership? The alarming part though is just under half of that loss occurred during the last 3 months. It could be a coincidence - perhaps just before the battery loss stabilizes is when it loses the most. And of course, I don't actually know if it will stop there.
> 
> So I guess the question is...is this in line with what other people are seeing as well, or do I have a problem to solve?


----------



## JWardell

My biggest advice is to switch your display to percent instead of range. Turn off the stress. It matters not. Think in percent, just like your phone.

The Model 3 batteries are incredibly resilient and do not suffer horrible degradation common to so many other cars and devices.

Alternately, if you're in to crazy data and graphs like me, then subscribe to TeslaFi and watch your estimated capacity change over time, they do a great job keeping track and even comparing it to average. But just treat it as a game. It's not a big deal.

If you really want to extend the life of your battery, stay away from the top and bottom 5% as much as possible. That's about it. This battery loves high currents, so supercharging doesn't hurt it as it does with the older S&X.

Finally, if you really want to give that computer-estimated range a boost and recalibrate the software, charge to 90% and let it sit overnight or a day or two. Then, go for a long highway drive down to at least 50%, or less. Let it sit parked for several hours and you should see a new better range estimate.

Unfortunately as many of us have not been driving much stuck at home the last 5+ months, the software hasn't had a chance to see a large continuous discharge to recalculate estimates, so the ranges all seem poor. But it's just software. Your battery is still happy!


----------



## JasonF

JWardell said:


> My biggest advice is to switch your display to percent instead of range. Turn off the stress. It matters not. Think in percent, just like your phone.


I had mine in miles until recently because I'm not good at doing the math of how far the car will go if I'm on a longer drive someday. Then I reasoned it out:

- That "longer drive" hasn't really happened it 2 years. And if it does someday, I have the choice of either looking for "refilling" as I approach 25% just as I did with the gas car.

- The navigation now will schedule charging stops designed both to minimize overall charging time during the trip, and also prevent "white knuckle" incidents where you barely make it to the charger. Unless you ignore the recommendations. So I don't really ever _have_ to try and compute remaining miles.

- Gas cars primarily use percentage, and I got used to _that_. And their miles estimates _also_ suck. So why not just keep the battery above 1/4, like I did with the gas car?

- It occurred to me that my dropping mileage estimate might have a really simple and stupid cause. More on that below.



JWardell said:


> Unfortunately as many of us have not been driving much stuck at home the last 5+ months, the software hasn't had a chance to see a large continuous discharge to recalculate estimates, so the ranges all seem poor. But it's just software. Your battery is still happy!


This is what I referred to in the last point above. I now believe it may be more than just letting the car sit for long periods of time. When you run errands, you tend to unconsciously want to just get it over with, so you drive a little more impatiently than you do just driving to work. Going to work, you're driving there to spend 8+ hours, and there's no point in getting there quickly because you're not going to get it done any faster, so you drive there more patiently and efficiently.

Depending on how impatient you are running your errands - or perhaps trying to squeeze more driving fun out of it - you could use as much battery power as your entire drive to work. Over the course of 4 months, that makes the battery state start to compute its estimates based on _much_ lower efficiency, and eventually it says "Hey, you know that 90% you charge to every day? I now don't think it's going to last more than 280 miles at the rate you burn through power." Even if it's being computed using group efficiency numbers over Tesla's network, _everyone_ doing this same change of habits at the same time is still going to skew that estimate.

I'm guessing the people to ask about this phenomenon might be those who take their Model 3 to the track once or twice a month. I bet that _really_ messes with the mileage estimate.


----------



## FRC

JWardell said:


> My biggest advice is to switch your display to percent instead of range. Turn off the stress. It matters not. Think in percent, just like your phone.
> 
> The Model 3 batteries are incredibly resilient and do not suffer horrible degradation common to so many other cars and devices.
> 
> Alternately, if you're in to crazy data and graphs like me, then subscribe to TeslaFi and watch your estimated capacity change over time, they do a great job keeping track and even comparing it to average. But just treat it as a game. It's not a big deal.
> 
> If you really want to extend the life of your battery, stay away from the top and bottom 5% as much as possible. That's about it. This battery loves high currents, so supercharging doesn't hurt it as it does with the older S&X.
> 
> Finally, if you really want to give that computer-estimated range a boost and recalibrate the software, charge to 90% and let it sit overnight or a day or two. Then, go for a long highway drive down to at least 50%, or less. Let it sit parked for several hours and you should see a new better range estimate.
> 
> Unfortunately as many of us have not been driving much stuck at home the last 5+ months, the software hasn't had a chance to see a large continuous discharge to recalculate estimates, so the ranges all seem poor. But it's just software. Your battery is still happy!


LISTEN TO @JWardell, Use percent and if you car gets you to your next charge, you are good. You'll hear lots of advice about tnis, good and bad. Drive your car, if it degrades into the warranty parameters, Tesla will handle it by law(it won't)


----------



## JWardell

JasonF said:


> I had mine in miles until recently because I'm not good at doing the math of how far the car will go if I'm on a longer drive someday. Then I reasoned it out:
> 
> - That "longer drive" hasn't really happened it 2 years. And if it does someday, I have the choice of either looking for "refilling" as I approach 25% just as I did with the gas car.
> 
> - The navigation now will schedule charging stops designed both to minimize overall charging time during the trip, and also prevent "white knuckle" incidents where you barely make it to the charger. Unless you ignore the recommendations. So I don't really ever _have_ to try and compute remaining miles.
> 
> - Gas cars primarily use percentage, and I got used to _that_. And their miles estimates _also_ suck. So why not just keep the battery above 1/4, like I did with the gas car?
> 
> - It occurred to me that my dropping mileage estimate might have a really simple and stupid cause. More on that below.
> 
> This is what I referred to in the last point above. I now believe it may be more than just letting the car sit for long periods of time. When you run errands, you tend to unconsciously want to just get it over with, so you drive a little more impatiently than you do just driving to work. Going to work, you're driving there to spend 8+ hours, and there's no point in getting there quickly because you're not going to get it done any faster, so you drive there more patiently and efficiently.
> 
> Depending on how impatient you are running your errands - or perhaps trying to squeeze more driving fun out of it - you could use as much battery power as your entire drive to work. Over the course of 4 months, that makes the battery state start to compute its estimates based on _much_ lower efficiency, and eventually it says "Hey, you know that 90% you charge to every day? I now don't think it's going to last more than 280 miles at the rate you burn through power." Even if it's being computed using group efficiency numbers over Tesla's network, _everyone_ doing this same change of habits at the same time is still going to skew that estimate.
> 
> I'm guessing the people to ask about this phenomenon might be those who take their Model 3 to the track once or twice a month. I bet that _really_ messes with the mileage estimate.


It's not just having fun driving for errands-which I absolutely done every time-but the car spends a ton of energy cooling down the cabin for each of those short trips, and other things. I also don't pay much attention to efficiency. But that is also why I ignore range, because I know it is not at all accurate, as it's counting on you driving quite slow to achieve it. The same is true with every other car you buy


----------



## WhiteDust

garsh said:


> Your car was rated for 310 miles, so don't go by what the new ones are rated for. Given that, your 288 miles is only a 7% degradation. Most Teslas degrade less than 10% in the first year or two, then the degradation slows down tremendously. So this would be pretty much normal.


Wasn't the range briefly updated to 325 on LR RWD before the dual motor started received updates? I saw that for about 2 weeks on my car, then the next update was back to 310, but now I might get 277 after 25k miles.


----------



## WhiteDust

JWardell said:


> It's not just having fun driving for errands-which I absolutely done every time-but the car spends a ton of energy cooling down the cabin for each of those short trips, and other things. I also don't pay much attention to efficiency. But that is also why I ignore range, because I know it is not at all accurate, as it's counting on you driving quite slow to achieve it. The same is true with every other car you buy


This is true, but I believe Elon stated the magic energy usage is supposed to be 250 Wh/mi to achieve the efficiency rated for the vehicles. I would (poor word choice) assume climate control usage is calculated in the energy usage. My lifetime rating is 233 Wh/mi and I mostly achieve rated range during early spring/late fall on short trips in the South.

I've also had energy usage below 250 Wh/mi at highway speeds of moderate distance, but the expected range and distance don't exactly line up.

With all that said, I just try to enjoy the car as much as I can for as long as I can. As long as I can get to the next supercharger or make it home, I'm happy. I plan to have Tesla check the battery about a year before warranty runs out to verify it's still "good".


----------



## garsh

WhiteDust said:


> Wasn't the range briefly updated to 325 on LR RWD


Yes, but it sounds like NYer has an AWD, since he references the current 322 mile range rating. But Tesla has most likely implemented a few additional efficiency tricks in the latest cars in order to obtain that additional range.

IIRC, the original AWD cars were tested at 307 miles, and Tesla asked the EPA for a variance (which was granted) in order to advertise all the vehicles as having 310 miles.


----------



## garsh

WhiteDust said:


> I believe Elon stated the magic energy usage is supposed to be 250 Wh/mi to achieve the efficiency rated for the vehicles.


<citation needed/>


> I would (poor word choice) assume climate control usage is calculated in the energy usage.


EPA testing is done at room temperature. So even if climate control is on, it won't be doing much during testing.

https://www.myev.com/research/buyers-sellers-advice/how-the-epa-rates-electric-vehicles


----------



## WhiteDust

garsh said:


> <citation needed/>
> EPA testing is done at room temperature. So even if climate control is on, it won't be doing much during testing.
> 
> https://www.myev.com/research/buyers-sellers-advice/how-the-epa-rates-electric-vehicles


Sorry, I wasn't referring to EPA testing, but rather the (vehicle's calculation) rating displayed in vehicle while driving. Current Trip/Lifetime.

I'm looking for the citation.

Edit: It wasn't Elon and range wasn't mentioned, but rather the target consumption for the HW 3 chip. I guess I'm just remembering it wrong and equating it to the range estimates. www.youtu.be/Ucp0TTmvqOE @1:42:00. This is an example of the brain putting a bunch of things together over long periods of time and not exactly remembering them correctly.


----------



## NYer

Bigriver said:


> @NYer, yes this is a topic discussed a lot. First and foremost be aware that battery degradation and the rated range shown for your car may be 2 totally different things. The battery degradation is a real, physical process. The rated range displayed in the car is from an algorithm that none of us fully understand.
> 
> Here are some links. First is a long description in a long thread. I quote it because it and follow up posts contain info quoted from Tesla.
> 
> Second link is because when JWardell speaks, people are wise to listen. He has spent more time than most of us diving into details of our how our cars work.
> 
> And the third link is because it's the most recent thread hat I immediately thought of about battery range predictions.


This is extremely helpful. Thank you for providing this information.

I'm a bit disappointed that I need to deep drain and recharge my battery in the hope that the BMS recalibrates itself as it strains the battery in the process. Good info nonetheless.


----------



## JasonF

NYer said:


> I'm a bit disappointed that I need to deep drain and recharge my battery in the hope that the BMS recalibrates itself as it strains the battery in the process. Good info nonetheless.


I was told that wasn't necessary, and just charging slightly above 90% a couple of times would do it.


----------



## MelindaV

garsh said:


> @MelindaV, @JWardell , what's the latest info on how to correctly recalibrate the BMS?
> I'm having trouble locating some of the latest posts on the topic - it's been discussed a lot.


sorry - not sure how I missed this, it just came up in my alerts today! (weird)...
for me, after spending a year trying all sorts of different combinations (charging daily to 90% - only charge when the battery gets down to sub 20%, then charge to more than 90% - only charging on reduced power instead of the full WC 50A capacity - etc, etc.. ). for me, what seems to have made a difference was stop driving to the office daily, and let the car sit for days at a time without being driven (not a very fun way to change something). or it was just a coincidence









for timeline reference, that flat section was March 12-19 when I was at a rental house and plugged into a 110v outlet, followed by the drive home and a few months of maybe taking the car out once a week for a short drive.


----------



## Thorongil

I've got to wonder what impact phantom drain/AC/Sentry has on the algorithm as well. I was worried about range loss, given that I've got pretty high efficiency overall when I noticed that total range seemed to creep down as phantom drain crept up. Does the total range take into account loss of actual range due to phantom drain? If so, this would make a lot of sense...


----------



## Ed Woodrick

MelindaV said:


> sorry - not sure how I missed this, it just came up in my alerts today! (weird)...
> for me, after spending a year trying all sorts of different combinations (charging daily to 90% - only charge when the battery gets down to sub 20%, then charge to more than 90% - only charging on reduced power instead of the full WC 50A capacity - etc, etc.. ). for me, what seems to have made a difference was stop driving to the office daily, and let the car sit for days at a time without being driven (not a very fun way to change something). or it was just a coincidence
> View attachment 34988
> 
> 
> for timeline reference, that flat section was March 12-19 when I was at a rental house and plugged into a 110v outlet, followed by the drive home and a few months of maybe taking the car out once a week for a short drive.


I don't see you mention anything about charging to 100% (at least 95) and letting it sit for a few days. 
40,000+ miles and still 311 for me.


----------



## eyedrop0

Best method for revealing capacity loss Ive found is:

Drain car as low as possible, then charge to 100% full at the slowest rate possible (110v) Let it settle/balance for a day then try charging again. Once your sure its at 100%. This makes sure your balanced before starting the test.

Next, run it down again to as low as possible then charge to 100% using a third party charge counter (such as a DC fast charging station or app connected wall charger.) It will show you how many kWH you put into the battery. Compare this to reference new pack usable kWH, account for the few miles left in the battery, and there is your answer.

And BTW, tracking the range number/GOM could be useless as the car updates driving history, changes firmwares, etc... Better to think in terms of sheer battery capacity loss.


----------



## Bigriver

Ed Woodrick said:


> I don't see you mention anything about charging to 100% (at least 95) and letting it sit for a few days.





eyedrop0 said:


> then charge to 100% full at the slowest rate possible (110v) Let it settle/balance for a day


Where is this suggestion to let it sit at 100% for day(s) coming from? I don't recall hearing anyone ever suggest that. Although I consider myself pretty willing to exercise my battery, I can't imagine being willing to let it sit at that high SOC for any length of time.



eyedrop0 said:


> Next, run it down again to as low as possible then charge to 100% using a third party charge counter (such as a DC fast charging station or app connected wall charger.) It will show you how many kWH you put into the battery. Compare this to reference new pack usable kWH, account for the few miles left in the battery, and there is your answer.
> 
> And BTW, tracking the range number/GOM could be useless as the car updates driving history, changes firmwares, etc... Better to think in terms of sheer battery capacity loss.


In my early Tesla days, I thought this would all be simple math and I had done several calculations focused more on the kWh used and/or added, such as you suggest. KWh just seems a better unit than rated miles. But I never found those calcs to be very satisfying as they didn't cleanly square away. After reading your post, tho, I decided to revisit current battery capacity from this vantage point, using my vast data collected by Teslafi for both my model 3 and my model X. I chose charges in which I had added at least 50% of the battery capacity, which was plentiful for the model X and I judged to be adequate for the model 3. I extrapolated the full battery value from the "kWh added" (Teslafi value that is pulled directly from Tesla API) based on SOC that was added (e.g., 10% to 90% is 80% added.) I did not do any intentional battery balancing routines (except last model 3 data point), but my cars' batteries are not typically cycled through narrow ranges, which is apparently a root concern for accuracy of BMS calcs.

I found that the kWh calc has even more chatter in it than the rated mile calculation. I'm not sure that focusing on kWh separates one from the BMS algorithm, since this still relies on the BMS definition of what % charge the kWh corresponds to. Obviously if I would get close to 100% added, that component would go away. The closest I got was 93% added for the model 3 and 84% for the model X.

The largest thing I learned from this exercise: I was very puzzled by the recent apparent significant increase in kWh for the model X. Those correspond to charges starting in 2020. They were at superchargers. In all cases, I had the heater or a/c on while charging. According to https://insideevs.com/news/392775/tesla-adjusts-supercharger-billing/, Tesla changed their kWh added data for superchargers to include these other energy uses. Although the energy is not going to the battery, the change was made to capture the extra kWh for billing. As a side note, tho, that change doesn't seem to have been applied to superchargers at Ft Wayne, IN. That is the location of the 2 lowest recent data points at 96 and 98 kWh.

Plots are below, should anyone care to look at them. Blue points are the kWh calcs (for >50% battery capacity added) on the left axis and reddish points on the right axis are from Teslafi (all charges), normalized to the initial rated miles (310 for model 3 and 295 for model X). Also plotted the starting and ending SOC for each of the charging sessions included in the blue kWh calculation.


----------



## garsh

Bigriver said:


> Where is this suggestion to let it sit at 100% for day(s) coming from?


+1
Ed has a good point that many people worry too much about how to protect a battery. Most of the things we talk about end up making very small differences. Tesla has designed their batteries very well, and they usually won't degrade any more than 10% over their lifetime.

But charging to 100% is one of the things that Tesla has ALWAYS said to avoid unless required for a trip. When you do so, the car will even pop up a message on the screen telling you that you should only do so for long trips. Charging to 100% and leaving it sit there is not good advice.

https://www.tesla.com/support/home-charging-installation/faq


> *What percentage should I charge the battery to?*
> Adjust how full the battery charges from the charge settings menu. For regular use, we recommend keeping your car set within the 'Daily' range bracket, up to approximately 90%. Charging up to 100% is best saved for when you are preparing for a longer trip.


----------



## eyedrop0

I agree about letting it sit at 100%, not a good idea for battery health. 

I never charge to 100% unless I have to. But for the sake of getting the best possible balance/accurate predicted range, giving the cells as much time as possible to charge/ as much voltage as possible will always give the most accurate BMS numbers. 

Its also my theory that charging fast or charging to very high SOC can help "shake" those dendrites loose and actually can do some good to the battery. 

But on the daily, of course I dont recommend charging to 100%.


----------



## iChris93

eyedrop0 said:


> Its also my theory that charging fast or charging to very high SOC can help "shake" those dendrites loose and actually can do some good to the battery.


Anything that backs up this theory?


----------



## eyedrop0

Nothing other than personal anecdotal expierence messing around with old 18650's that dipped below the 2v threshold. Sometimes shocking them with high currents can bring them back to life if a trickle charge wont bring it above your desired threshold. 

I guess its like the old "Italian tuneup" for ICE where you run it hard to "clear the cobwebs". Probably nothing to back this theory either...


----------



## mcmoyer

I swear that 285 - 290 is where I see most people saying their 100% charge is nowadays. At least the 2018-2019 model 3's. Unironically, that's where mine is as well. I switched to % battery about a year ago and quit stressing about it. That said, I just got back from a round trip from DFW to Denver and I did miss that extra few kilowatts from the long dry run from Amarillo to Trinidad, CO. If I go by my charging calculations, my battery capacity is around 69.6 kWh. Has anyone established what the official capacity is supposed to be? I know 75 is floated a lot, but do they hold off a few kWh is reserve?

The extra power would have been helpful, because it was quite embarrassing to be going 60mph in a 75mph zone and being passed by gravel haulers.

Oh, and I really hate when you're driving and it says, 

"stay below 80mph to get to your destination"

then a few minutes later, "stay below 75mph..."

then a few minutes later, "stay below 70mph..."

then a few minutes later, "stay below 65mph..."

you start to think at some point you're going to be traveling around 25mph to limp into a charging station.


----------



## Hdez

I wonder whether software updates have something to do with this loss in battery range. I've lost 2% of estimated battery range since 2020.28.5 a little over 3 weeks (7/26/20). My estimated range with 2020.24.6 was 316.25 and I'm now down to 309.51 with 28.6 according to Teslafi. I'm not complaining though. Basically my LR RWD M3 is back to the original estimated range of 310 miles after 16 mos. and 17,217 miles. Down only 5.38% from the range boost of 326.17.


----------



## tencate

I know, I know, we all love to talk about displayed range and I generally ignore all the discussion about battery degradation with the latest software update, etc.. But lately I've noticed mine APPEARS to have dropped too. Didn't bother me, mine's a 2017 car with nearly 70k miles on it. So I'd expect to see some degradation. Today I made a nice round trip to Albuquerque, did some errands, and got back home seeing yellow on the battery. I'd charged up to 80% the night before, didn't do anything special, sorta stayed near the speed limit (75 mph) and used A/C most of the way (it was 100F in ABQ today). Used up that 80% charge nicely. Tonight I plugged in and for grins ran the charging limit up to 100% to see what range would be displayed. 307 miles. I paid for 310 miles of range back in 2017  I can't honestly tell you what my battery degradation is because Tesla keeps tweaking everything about the car so they can squeeze out more and more range from a battery pack. Gotta love over-the-air software updates and big batteries too.  Seeing 307 miles made me smile.


----------



## Hdez

I know that this is supposed to level off at some point, but it keeps going down. I'm getting anxious . It's been down hill since 2020.12.6 Just installed '20.36.10 this evening. I'll keep watching and worrying.


----------



## GDN

Hdez said:


> I know that this is supposed to level off at some point, but it keeps going down. I'm getting anxious . It's been down hill since 2020.12.6 Just installed '20.36.10 this evening. I'll keep watching and worrying.
> 
> View attachment 35527


You're still in great shape compared to many others including me. I'll start by saying this, if it is SW related, just know Tesla will get ahold of that and fix it. They are really bad at breaking things and then fixing them. So if SW, it'll be back.

Here is my thread - https://teslaownersonline.com/threads/how-do-i-charge-next-to-regain-range.16703/post-290589. and to be honest, I'm not as worried now that JWardell has weighed in. He really understands this stuff and after I took some longer drives, I saw upticks on my range both times as he noted it would to help get the BMS back on track. Read the thread and then likely take some longer consistent speed drives, especially if you have just taken a lot of short drives close to home recently.


----------



## ddatta

i am seeing a 7% capacity degradation (Measured by rated miles) at a SOC

Rated Nov '18Actual May '21SOCMilesCapacityDisplay MCalc CapLoss %100​310​75​288​69.6774​7%​90​279​67.5​260​62.9032​7%​81​251.1​60.75​234​56.6129​7%​56​173.6​42​163​39.4355​6%​30​93​22.5​88​21.2903​5%​12​37.2​9​35​8.46774​6%​

Service calls to Tesla were to no vail - got a standard response - "Hardware behaving as expected"
I have about 28K miles on the car - 2018 M3, dual motor, LR, FSD
Anyone else seeing similar degradation?


----------



## FRC

Very normal. I tell prospective buyers to expect 5% in year 1, and 1% per following year. This is what I have experienced and your's seems similar. There are various threads here about rebalancing your BMS; you might try that. I would be shocked for Tesla to take any action; Why would they, you're well within any warranty limits.


----------



## mcmoyer

I think it's pretty common. Most people I see posting their range for their 2018s are around the 280~295 mark. I started using TeslaMate at roughly 25k on mine. My range was already down into the high 280's at that point. Right now it's in the mid 270s. Unless it gets down under 220 (70%), there's really nothing to do. I'm not really worried about it at this point because it's still plenty of range.


----------



## Bigriver

ddatta said:


> Anyone else seeing similar degradation?


You are spot on. I also have a dual motor picked up in November 2018. 21k miles and current full rated miles is 289. And it's right in line with Teslafi's user base.








Just curious, on what basis are you concerned that this degradation is not normal?


----------



## ddatta

Bigriver said:


> You are spot on. I also have a dual motor picked up in November 2018. 21k miles and current full rated miles is 289. And it's right in line with Teslafi's user base.
> View attachment 39558
> 
> Just curious, on what basis are you concerned that this degradation is not normal?


i did not expect a 7% degradation in just 21K miles .


----------



## Ed Woodrick

ddatta said:


> i did not expect a 7% degradation in just 21K miles .


Have you taken the car for a long drive lately? It can help the estimates.


----------



## garsh

ddatta said:


> i did not expect a 7% degradation in just 21K miles .


The majority of lifetime degradation happens within the first 20k miles (30k km).
Here's an old graph showing the degradation that Tesla Model S owners experienced, graphed against mileage (in km).
Notice that the degradation curve is pretty steep to start, then flattens out around 30k km (20k miles)

https://www.teslarati.com/wp-content/uploads/2017/09/tesla-battery-degradation-data-points-chart.jpg


Ed Woodrick said:


> Have you taken the car for a long drive lately? It can help the estimates.


As Ed alludes, some of this "degradation" may not be real. The Battery Monitoring System (BMS) is what estimates battery capacity. If you've only been taking short trips and haven't been running the battery down below 50%, then those estimates can become a little off. When that happens, it will usually assume a little less capacity than you might actually have.

The best way to recalibrate the BMS is to charge up to about 90%, then go on a long trip that takes the battery below 50%. I wouldn't bother making a special trip just to recalibrate the battery - just take the battery capacity estimate with a grain of salt until you've taken one or two longer trips.


----------

