[FRC]

Actually waking up and thinking better, I was incorrect. Ignore me.

I guess that's why I didn't understand it. I was stupidly paying attention to the words you used...

 

[JimKilby]

I have a Tesla 3 with less than 6k miles. I top off daily to 80% as directed in the manual. Until about 3 weeks ago, an 80% charge showed 213 available. Doing the math (213/.8 = 265), that equals what the promised 265 miles. However, now when I charge to 80%, it lists 197 miles available (doing the math equals 246 maximum). That's a 7.6% reduction in less than 6k miles. I call Tesla and they say that is 2% less than the average loss in range at 6k. I find that hard to believe. Also, I just reset my BMS by discharging to 6% the charging to 100% but I see no difference in the readings. Can anyone shed any light as to whether I should be concerned? There is so much conflicting advise on the internet.

 

[JasonF]

Set the battery indicator to percentage instead of miles (on the Display settings) by default, and then see if you're using a higher percentage than normal doing your regular daily/weekly trips.

The mileage is always a rough estimate. The battery seems to always know what percentage is available, though, so drastic changes reflected in that are probably a better indicator.

An example of what I mean would be if you normally make a drive of x number of miles, and the battery used to go from 80% to 77% for the trip, but now it's consistently going to 73% instead (accounting for weather and speed differences, aggressiveness of driving, etc).

 

[garsh]

I have a Tesla 3 with less than 6k miles. I top off daily to 80% as directed in the manual. Until about 3 weeks ago, an 80% charge showed 213 available. Doing the math (213/.8 = 265), that equals what the promised 265 miles. However, now when I charge to 80%, it lists 197 miles available (doing the math equals 246 maximum). That's a 7.6% reduction in less than 6k miles. I call Tesla and they say that is 2% less than the average loss in range at 6k. I find that hard to believe. Also, I just reset my BMS by discharging to 6% the charging to 100% but I see no difference in the readings. Can anyone shed any light as to whether I should be concerned? There is so much conflicting advise on the internet.

I've moved your post to a previous thread on this topic.

Please read through the earlier threads here. Some degradation is normal. But also, if you don't often run your battery low, then the BMS' estimate of battery remaining can become less accurate, and it tends to report a conservatively lower range to make sure you don't accidentally run out. It's probably a combination of the two.

 

[bwilson4web]

I should be concerned?

You might consider getting TezLab, a yearly fee based App to track battery history..

The battery will lose capacity but not uniformly. Your rate seems high but mine seems low, 5.7% after 2.5 years and +54k miles. We have a temperate climate and in the Spring low loss but in the Fall somewhat higher.

Good luck!

Bob Wilson

 

[Resist]

So what does everyone leave their cars charged at while at home? Thankfully I stopped using the mileage screen a long time ago and only use the percentage screen. I used to keep it charged at 80% and lately I've kept it at 70%. But now I'm hearing 90% might be better. I don't drive my 2018 LR Model 3 every day. Obviously I want the battery to last a long time but also want the BMS to show the correct range and right now it doesn't give my the full 310 miles, it's more like 290 miles with less than 16k miles on it. I don't think I have battery degradation, I think the BMS just needs to be re-calibrated, something I've never done.

But I would like to know what to keep it charged at while at home. I've watched a lot of videos about it and they all makes sense but are also conflicting with each other.

 

[garsh]

Obviously I want the battery to last a long time but also want the BMS to show the correct range and right now it doesn't give my the full 310 miles, it's more like 290 miles with less than 16k miles on it.

The majority of battery degradation occurs in the first 24k miles. You're unlikely to have 310 miles at this point. If you want to recalibrate the BMS, take the car on a long trip with the battery starting around 90%, until the battery is below 50%. Leave it sit there several hours or overnight. Then charge it up (level 2, not supercharging) to 90% and let it sit there several hours/overnight. That should allow the BMS to experience a large enough range of battery operating conditions to give a better estimate. I would guess that you'll see about 295 miles after doing this.

 

[JWardell]

I feel like a broken record reminding folks to not take their estimated range seriously. Leave it on percentage. The milage range is calculated on large discharges/long highway drives. Charging to 100% will not help improve that calculation. Letting your car sit for days or lots of local driving reduces it. You will see it tick up after a few long distance trips.

It's been a bit since I've shared my battery graph, but it continues to show this logic. The estimates are crazy. They went down drastically when I stopped commuting and rarely went further than the supermarket in 2020. And when I had some weekends driving to other states this summer, it shot back up afterwards. The only real guide to actual degradation is the fleet average graph, and as you can see it's nothing to worry about, your battery will be useful for many many many years.

 

[Resist]

The majority of battery degradation occurs in the first 24k miles. You're unlikely to have 310 miles at this point. If you want to recalibrate the BMS, take the car on a long trip with the battery starting around 90%, until the battery is below 50%. Leave it sit there several hours or overnight. Then charge it up (level 2, not supercharging) to 90% and let it sit there several hours/overnight. That should allow the BMS to experience a large enough range of battery operating conditions to give a better estimate. I would guess that you'll see about 295 miles after doing this.

See right here is some the conflicting information that's out there. Others are saying to charge it to 100% then drive it down to less than 10%, let it sit for an hour or two. Then charge it back up to 100% and drive it right away (of course) and it should be recalibrated. I personally don't think my battery has degraded because I've been very careful with it. And yes I know not to keep the display in mileage mode, but every now and then I do like to check it. It kind of bugged me to see that it dropped so much with so few miles on the car, especially since we were supposed have gotten a software range increase months after I bought my Model 3, but I it never showed over 310 miles. I think it was at that point I switched to the percentage display.

 

[garsh]

See right here is some the conflicting information that's out there. Others are saying to charge it to 100% then drive it down to less than 10%, let it sit for an hour or two. Then charge it back up to 100% and drive it right away (of course) and it should be recalibrated.

@JWardell has done a lot of investigation into how recalibration occurs. He's got data recorders connected to the CAN bus, and spends a lot of effort investigating various aspects of the car's performance. So while it's true that charging fully and running down fully will cause a recalibration, I trust his data that it's not at all necessary to put that much stress on the battery. While Tesla's cell chemistry is very resilient compared to other Lithium Ion cells, they will still see some small amount of additional degradation when SOC is too high or low.

Here's an older post from JWardell that I had bookmarked. I think he's even said that it's no longer necessary to go over 90%, but perhaps he can chime in to update us.

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

 

[JasonF]

I think he's even said that it's no longer necessary to go over 90%, but perhaps he can chime in to update us.

I don't think anyone knows for sure, not even Tesla. Last time I was in for service (a few months ago) they told me that there is no need to do anything special, and the battery will eventually calibrate itself.

Tesla also told me when I picked up the car in 2018 to plug in and charge to 90% daily - which I still do - and even Elon Musk at one point said 90% was fine. But then I keep getting advice from others who tell me I never should have charged higher than 80%, and I never should have plugged in daily, and doing both already caused damage to the battery (3 years later, so it's too late now!) - but I don't see evidence of that yet. So really, nobody truly knows.

I feel like nobody truly knows for sure, but I also feel changing charging habits every month to meet whatever the current advice is will probably do more damage to the battery than giving it a regular daily feeding of 90%.

 

[bwilson4web]

One mitigation is the continued growth of the SuperCharger network both numbers and speed. So addition of the Ozark AR and Lowell AR SuperChargers closed the gap. Then the Joplin MO SuperCharger was relocated and upgraded to V3, 250 kW peak. These changes closed the gap to my Mom's home in Coffeyville KS. A full charge in Joplin means arrival with 66% SOC and the ability to return,

It is the combination of battery health and a denser, faster SuperCharger network that keeps our cars operational.

Bob Wilson

 

[FRC]

To maximize the health and life of your car's battery, set your SOC to 50% and keep it plugged in. Never drive the car. Never.

 

[GDN]

To maximize the health and life of your car's battery, set your SOC to 50% and keep it plugged in. Never drive the car. Never.

You know what I like about you @FRC , if the Texan doesn't have a smart a** comment to make, then we know the Georgian will.

 

[JWardell]

I don't think anyone knows for sure, not even Tesla. Last time I was in for service (a few months ago) they told me that there is no need to do anything special, and the battery will eventually calibrate itself.

Tesla also told me when I picked up the car in 2018 to plug in and charge to 90% daily - which I still do - and even Elon Musk at one point said 90% was fine. But then I keep getting advice from others who tell me I never should have charged higher than 80%, and I never should have plugged in daily, and doing both already caused damage to the battery (3 years later, so it's too late now!) - but I don't see evidence of that yet. So really, nobody truly knows.

I feel like nobody truly knows for sure, but I also feel changing charging habits every month to meet whatever the current advice is will probably do more damage to the battery than giving it a regular daily feeding of 90%.

I do know for sure, and so does Tesla, as they improved their battery balancing algorithms long ago. Only back in the first year Model 3 would not balance below about 90%. But now it keeps itself almost continuously balanced. I've been driving with the live battery balance state in front of me all year, and it is almost always a shockingly low 4-6mV. This compared to values 10x that might eat a small bit of capacity. The "charge to 100%" misinformed advice is simply to force a balancing, but it will make no difference if the pack is already balanced, as it almost always is.

Separate from balancing, is the BMS capacity estimate algorithms, which do coulomb counting on significant continuous discharges (long drives). NOT on charges. In other words, sum volts and amps over time to estimate energy used between two settled (parked) points. In other words, a highway drive of more than half the pack, and park for a bit so it has time to settle and trigger the new energy capacity estimate. If you have teslafi and pull up that park after a drive and actually look at each logged minute, you will see the remaining range work its way UP.
THAT is a recalibration, but just one. Consider the entire pack capacity estimate a rolling average of the last several recalibrations. Doing this just once helps and adds a few miles. Do it several times (go on a road trip for a few days), and you will see the range estimate climb significantly. You can see that in your teslafi battery graph.

Conversely, if your car is sitting for several days or just going for short drives, you will see the range estimates fall.

It's a very technical way to come up with a range estimate, and different than the way nontechnical people think that just want range based on their driving over the last number of miles as many other manufacturers do. But it is NOT a great way to do it (though you will feel better understanding it), because how you drove the previous miles may have nothing to do with how you drive in the future. That milage estimate doesn't know ahead of time if you will be driving much faster, uphill, etc. Instead Tesla just concerns itself with estimating the energy in your battery, and displays that energy applied to the fixed EPA range rating as its estimated range. It's using miles to show kWh.

 

[JasonF]

I do know for sure, and so does Tesla, as they improved their battery balancing algorithms long ago.

But understand that some of us spent 2-3 years getting all kinds of advice from supposed official sources. I know just enough about lithium batteries in general to know they can take plenty of abuse beyond their optimum specs (unlike NIMH where one abhorrent charge or discharge can kill it), so I'm not scared of damaging the battery. Quite a lot of people see it as alien tech that will explode if you just look at it wrong, so conflicting information is terrifying to some people.

Then again, I don't think I'm doing exactly the right thing. Especially because exactly the right thing can be circumstantial - like for example if the only way to keep the battery healthy would be to drive at least x number of miles every day. I can't really dedicate to that since I work from home, so I'd have to live with not treating it optimally.

Or like with charging it to 90% daily - I did that originally because multiple trusted sources told me either that's what I was supposed to do, or that it was at least ok. I keep doing that not because I'm stubborn, but because...have you ever heard about the "Monty Hall Problem"? As long as I know 90% is ok, I don't want to change my selection only to discover years from now that I never should have changed it. Especially because small lithium batteries don't like sudden changes in charge or discharge habits too much. Will I someday discover that 90% was really horrible for the battery? I don't know.

 

[Dr DuMont]

But understand that some of us spent 2-3 years getting all kinds of advice from supposed official sources. I know just enough about lithium batteries in general to know they can take plenty of abuse beyond their optimum specs (unlike NIMH where one abhorrent charge or discharge can kill it), so I'm not scared of damaging the battery. Quite a lot of people see it as alien tech that will explode if you just look at it wrong, so conflicting information is terrifying to some people.

Then again, I don't think I'm doing exactly the right thing. Especially because exactly the right thing can be circumstantial - like for example if the only way to keep the battery healthy would be to drive at least x number of miles every day. I can't really dedicate to that since I work from home, so I'd have to live with not treating it optimally.

Or like with charging it to 90% daily - I did that originally because multiple trusted sources told me either that's what I was supposed to do, or that it was at least ok. I keep doing that not because I'm stubborn, but because...have you ever heard about the "Monty Hall Problem"? As long as I know 90% is ok, I don't want to change my selection only to discover years from now that I never should have changed it. Especially because small lithium batteries don't like sudden changes in charge or discharge habits too much. Will I someday discover that 90% was really horrible for the battery? I don't know.

Two Model 3s exactly like save color. Built 3 weeks apart. Both cars predicted about 230 or so at 100% charge.

I drove about 75 miles/day aboard the Good Ship Venus. Charge at home at 110V, set for 90% stayed plugged in while at home. Every once in a while I got behind the curve and Supercharged to 80 or 90. Four 1200 mile round trips supercharging according to the car's wishes. After 20 months, 90% charge had dropped from 211 to 192 or so. Predicted mileage at 100% now 209. That's kinda worrisome.

The Blue Bunny drives about 10 miles a day max. Occasionally 100 miles on a weekend. (Local). Made two 1200 mile round trips to same destination as TGSV. Stays plugged in at home set to 90%. Only Supercharged on the two trips. Today it indicates 206 miles at 90% charge, predicts 229 miles at 100%.

So what's the diff? I am guessing the fact that the car only goes to retrieve the Granddaughter 5 days a week, and the occasional trip to Plano every couple of weeks, so the BMS is getting complacent. Or The Blue Bunny got a "better" battery pack.

More of a curiosity, as the Blue Bunny will have a very peaceful life as a local driver. The new Good Ship Venus, on the other hand is looking forward to lotsa long drives delivering exotic birds to their forever homes, wherever that may be.

The Red one has been sold into TURO slavery. I'm awaiting my LR AWD now, The Good Ship Venus II predicted not before 4 Nov instead of 15 Oct. <sniffle> <whine>.

As a final note, I decided some time ago just to let the cars handle the details, to do what it says (OK, sometimes on a trip I put a little more in as I am a belt and suspenders kind of guy), just relax and enjoy the drive. Seems to work out better that way. A SR+ just about met my needs, but the additional mileage as a buffer will be nice to have. Besides, at my age, more than a couple of hours sitting still and my high water warning systems go off, if you know what I mean.

 

[Madmolecule]

I am in the bottom 25%. the degradation is real but it is a battery so that should be expected. What frustrates me is Tesla is focused on their losing battle of the 9s with FSD and has not focused on the long term rapid deprecation of battery + computer. I wish Tesla would be stating that we can purchase replacement battery packs in the 10k range or they will license the bms to 3rd party companies to provide cheap upgrades. computer upgrades would also be nice if nothing else for infotainment and navigation as I have given up on FSD. I just hope I won't have trade in my 3 to get waypoints or album art in the future.

 

[JasonF]

I am in the bottom 25%. the degradation is real but it is a battery so that should be expected. What frustrates me is Tesla is focused on their losing battle of the 9s with FSD and has not focused on the long term rapid deprecation of battery + computer. I wish Tesla would be stating that we can purchase replacement battery packs in the 10k range or they will license the bms to 3rd party companies to provide cheap upgrades. computer upgrades would also be nice if nothing else for infotainment and navigation as I have given up on FSD. I just hope I won't have trade in my 3 to get waypoints or album art in the future.

This is one of the ongoing battles on Tesla's board. There still seems to be some infighting among them over whether Tesla should go full mainstream or cling to the luxury segment. This is why we see conflicting announcements from them, some making Teslas more accessible, and some making them less accessible. A portion of that fight includes that people who buy higher-end cars tend not to keep them for more than a few years, so longevity is not a big concern (take the higher-end BMW's for instance, and their tendency to disintegrate past 5 years). So right now, there is this confused attitude out of them that they want to build a car that lasts 300,000 miles, but at the same time, they're also not so concerned about it actually lasting that long.

 

[garsh]

This is the battery degradation thread.

Please discuss FSD in one of the many FSD threads. Thank you!

UPDATE: posts moved