Ok I was at the Tesla Service Center and with my 2023 MYLR manufactured in Austin. The service rep told me it was a good idea to charge to 100% once a month to extend battery life. I have also read and seen videos this is necessary to do once in a while to balance battery. And drain battery to 10% also once in a while. I have not seen any posts here that address this. Thanks for responding. I have the 2170 batteries. I normally only charge to 70%. The manual gives no guidance about this.
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Is 100% charge on MYLR once a month good for extended battery life?
- Thread starter agmonaco
- Start date
Charging to 100% will not extend the battery life but won't damage the battery as long as you start to drive the Tesla Model Y shortly after the charging session is completed (within XX hours). Charging to a high state of charge and letting the battery remain at a high state of charge will, over time, reduce the total battery capacity. This is not the same as shortening the life of the battery, only reducing the capacity and thereby the maximum driving range on a full battery charge.
High storage temperatures and high state of charge are the worst scenario for the battery. Charge daily as needed, per the Tesla app set the daily charging limit anywhere between 50% and up to 90% (a lower average state of charge will help minimize battery degradation.) The additional battery capacity degradation, over time, when charging daily above 80% versus maintaining the battery at ~50% to 55% is in the range of -3% to -5% additional loss of battery capacity. This equates to a reduction of ~16 miles of driving range.
When the Tesla Model Y and battery are new the Tesla Model Y's battery management system (BMS) does not have much data to use when attempting to accurately estimate the state of the battery. You can help improve the accuracy of the BMS algorithms by driving and parking the Tesla Model Y over a wide range of state of charge. When parked, leave Sentry mode set to Off at the home location (also turn off Summon standby if you have purchased FSD) so that the Tesla Model Y will enter Sleep mode. This will enable the BMS to measure the open cell voltage (OCV) of the cells in the battery. The OCV measurement will happen automatically, takes several hours to complete. Cell balancing (a separate battery maintenance function from the OCV measurement) will take place automatically as needed, once charging has been completed. You could charge to ~95% periodically instead of 100% (100% takes much longer) so that the BMS could measure the OCV at this high state of charge.
High storage temperatures and high state of charge are the worst scenario for the battery. Charge daily as needed, per the Tesla app set the daily charging limit anywhere between 50% and up to 90% (a lower average state of charge will help minimize battery degradation.) The additional battery capacity degradation, over time, when charging daily above 80% versus maintaining the battery at ~50% to 55% is in the range of -3% to -5% additional loss of battery capacity. This equates to a reduction of ~16 miles of driving range.
When the Tesla Model Y and battery are new the Tesla Model Y's battery management system (BMS) does not have much data to use when attempting to accurately estimate the state of the battery. You can help improve the accuracy of the BMS algorithms by driving and parking the Tesla Model Y over a wide range of state of charge. When parked, leave Sentry mode set to Off at the home location (also turn off Summon standby if you have purchased FSD) so that the Tesla Model Y will enter Sleep mode. This will enable the BMS to measure the open cell voltage (OCV) of the cells in the battery. The OCV measurement will happen automatically, takes several hours to complete. Cell balancing (a separate battery maintenance function from the OCV measurement) will take place automatically as needed, once charging has been completed. You could charge to ~95% periodically instead of 100% (100% takes much longer) so that the BMS could measure the OCV at this high state of charge.
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E90alex
Active Member
I have had no issues charging to 50-55% over the year I’ve owned my Model 3 LR and only charged it to 100% once during that period when on a trip. Also only got down below 10% once and very rarely below 30%. No issues with BMS getting uncalibrated at all.
I have the same car as you, and generally don’t worry about charging habits. 40% of my charging is on the road with Superchargers (typically to 80%), 40% is at home (usually to 60-80%, but 90-100% before road trips), and the rest is L2/L3 public charging. Battery looking pretty good.
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Hey Starship I have seen that App b4. Seen some positive and negative reviews.
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For what it's worth, I've never charged to 100%. I've just never needed to. I only charge to 50% for my daily commute, and 80g to 90% for trips.
Charging to 100% won't extend the battery life, but it might temorarily help calibrate the range calculations.
I see no way it can help longevity, and many who know better can present a lot of data suggesting it's not beneficial. Largely harmful? No. I treat it like alcohol. Moderation, say below 55%, is fine, an occasional "Full load" isn't the end of things, while regular heavy use is bad.
I ABC to 53%, departure charge for trips as needed. Car has never seen 100% since I took delivery, 90% twice, 80% once, 75% anytime I'm taking a trip. I suppose a dozen times now. I've no reason to believe my BMS is inaccurate, but short of it stopping running how would I know? I plan trip recharges at 12-15% percent, have been as low as 2% while in the local area.
I ABC to 53%, departure charge for trips as needed. Car has never seen 100% since I took delivery, 90% twice, 80% once, 75% anytime I'm taking a trip. I suppose a dozen times now. I've no reason to believe my BMS is inaccurate, but short of it stopping running how would I know? I plan trip recharges at 12-15% percent, have been as low as 2% while in the local area.
ucmndd
Well-Known Member
There is no battery health, longevity, or “calibration” benefit to charging to 100%.
That said, do it whenever you want/need and don’t think twice about it.
That said, do it whenever you want/need and don’t think twice about it.
Tesla battery management system (BMS) calibration
Tesla battery management system (BMS) calibration instructions
tesla-info.com
How to improve the battery management calibration
As said, the BMS needs a number of stable readings at different states of charge. To get a stable reading, the car needs to be left in it's sleep state for several hours. The following steps are fairly simple and are not required to be done that often to help the BMS achieve a good level of calibration.- Leave the car overnight and/or in the day occassionally without sentry mode enabled allowing the car to deep sleep for several hours.
- Do not charge the car every night. Leaving the car at different states of charge, across a broard range, helps provide a spread of readings. Even once a month, at a SoC below 50% can help.
- Turning off 3rd party apps that keep the car awake, and don't query the car with the Tesla app unless necessary while doing either of the above.
Over time the car should recalibrate itself using these reading and should correct any under reading of the available range plus you are giving the battery time to sort itself out and the various battery groups to stabilise between themselves.
Cell balancing
While the battery cells will sort themselves out up to a point if the car is simply left, there can still be some residual imbalance in the cells. To address this, the battery benefits from a 100% charge.- Plug the car in to charge, preferably on a AC charging point although you can also do this on a rapid chargerbut it may block it for others for some time.
- Set the charge limit to 100% and leave the car to charge.
- When the car reaches what appears to be 100% it may well say it has finished charging but it is drawing current. Leave the car charging until it indicates no energy is being added to the battery. This can take some time (an hour or so) after the car appears to have reached 100%. The charge rate may drop to under 10A which is fine. Let the car do what it needs to do.
- Eventually the battery will stop stop taking on current. Be mindful if you have the heating on, the car will still be taking current, but not for the purposes of charging the battery.
- If the car won't allow 100% to be set, this may be a calibration issue and address that aspect first.
ucmndd
Well-Known Member
I don’t find a random Tesla fan site with no obvious citation or substantiation of their recommendations to be a particularly compelling or authoritative source.Tesla battery management system (BMS) calibration
Tesla battery management system (BMS) calibration instructions
You can search this site for just about any post from @AAKEE , who has poured a lot of information into trying to dispel specific battery myths (one of which is that charging to 100% is somehow better for the battery). It isnt. It isnt necessarily worse, either, and it may make the range number on the screen read different, but it isnt going to change actual "battery health" which is what a ton of these threads tend to focus on.
ucmndd
Well-Known Member
As I said, citations help. Reference material of any kind helps. What doesn't help me believe in the veracity of an online source is serving up no less than 9 banner ads on a single page. Kinda makes you question the motivation.
Jjrandolin mentioned AAKEE, who has a plethora of great, thoroughly researched posts on this general subject. Jason Hughes of 057 Tech, who probably knows these cars better than anyone outside of Tesla, said 4+ years ago that the need to charge to 100% so the BMS can balance or calibrate hadn't been the case for some time. It does what it needs to, whenever it needs to.
Yes, it seem range display may occasionally drift if you keep the car in a narrow SoC band for a very long time. But that causes no harm whatsoever, nor does charging to 100% to correct it "extend battery life" as OP was told. Maybe it makes you feel better about any perceived degradation, but that's about it.
While I do not recommend to leave the battery often at 100%*, it is not at all that bad as the myth says.
Calendar aging is about as bad at 80% as it is at 100%. In some cases, 80% is the worst SOC to have the battery at.
Here’s a common result of calendar aging:
For 60-100% the calendar aging is virtually the same. At high cell temps, its just a little higher at 100% than at 60-80%.
This means that at 40C 9hours at 100% wears as much as 10 hours at 25C.
This is a almost new real Model S pack taken apart and the cells tested:
80% is the worst SOC among the tested SOC’s (not multipoint, but 20,50 and 100% is also tested)
This is 2170 NCA cells ”of a non disclosed brand”.
I did buy 35 pieces of Tesla model 3 2170 NCA cells, and performed calendar aging tests for 1.5 years. My numbers look the same and very very close to the model S cells, I saw ightly less calendar aging at 100% than at 80%. I used Teslas SOC numbers (Voltage vs displayed SOC) for my tests so the 80% I used was the same voltage as when we read 80% displayed.
Besides this, there is literally hundreds of research reports showing the same thing, and none showing that 100% causes rapid degradation. Tesla do not tell us to drive asap after a 100% charge.
Teslas “below 90% daily” is because it makes us use smaller cycles, reducing the cyclic aging with about 30-50%.
*)Because there is no reason to do it. Ot because it is very bad.
The Tesla community has a problem or two:
-Not reading the manual but using not correct info from forum/facebook and taking these as true facts. (For example, saying that Tesla recommends 80 or 90% as the daily charge to a LR/P. The manual on all LR/P says ”to under 90%” which per definition is *any* setting below 90%).
- Thinking that Teslas advice is solely given to reduce degradation.
The combination of these, thinking that Tesla says ”you should charge to 90%” and believe that this comes from the ”keep degradation at a minimum” casuses a few issues. Charging to 80-90% and thinking that this i “babying” the battery. Its not.
If we combine the sum of the research /test results we can see that Teslas advices is easy to understand. They are not mainly based only on keeping the degradation low, in fact this is a minor part. The advises is mainly made to be very few, and to be applicable in any situation and to give you the most use of the car without needing to have any knowledge of batteries.
I recommend everyone to read Teslas advices for their own cars, reading what actually is written and not trying to assume anything else. Its not much, and it is easy to understand.
There’s no advice not to leave the car at 100%.
Theres no advice not to drive down to low SOC numbers.
Theres no advice about best charging level between 50-90%.
There is a lot of rumors/myths though:
-“If charging to 100%, you need to drive asap, otherwise the battery degrades fast.” This is not true.
- “Tesla say we should charge to 80%”(90% is as common myth).
This is not true. “AWD vehicles: keep the full charge limit of the battery to under 90% for Daily use.”
-“Its not healthy to go below 20% SOC”
This is not true.
I can say this and be very sure that I am not wrong. The research that is very massive is in 99% of the cases very agreeing on how and what degrades the batteries. The last 1% of research either has the wrong conclusions or have a test setup that hides sone facts. In some cases thY have made wrong assumptions leading to wrong conclusions. In 95% of these 1% the actual test results are in line with all the other results, but only the conclusions is wrong.
All research together, there is no research showing even the smallest sign of that 100% SOC is very bad or that 80-90% causes low calendar aging or that low SOC like below 20% is bad.
All the statements I call myths, are things which you can not find any qualitative facts that support those myths.
Its not good to try to find battery facts on sites that report on EV cars and news. In many many cases, the reporters are lured by the myths as well.
Saidly enough, battery university has some clearly debatable “facts” and clearly was fooled in some case by using a not that good research report. They have good information as well but if trying to find facts its not really easy to distinguish the good facts from the myths.
I plan to make a internet site with facts only built on the research. When I get the time to do that I do not know. The plan is to refer to a lot of research to build the case.
I do not think there is one solid place to learn the correct fact about batteries at this time.
The best thing is to read research reports, and as there is very many I could recommend one that is massive but covers very many aspects, and is from authors that have a solid pack of reports that do not have any clear flaws.
Good Research report (Yes, it is written in english, just skip two pages of german foreword).
Had you left off "calibration" from your first comment above, I would not have posted the link I did. I do not believe charging to 100% occasionally leads to better battery health. The site I posted, spoke on calibration and cell balancing. The benefit to that, is knowing where you stand and even better, the car knowing where it stands. That way someone won't get left on the side of the road, thinking they had 5 or even 10% battery life left or someone may like knowing exactly where they stand with true SOC or miles left, etc. So yes, keeping narrow band SOC may cause calibration to drift, as you've conceded. Charging to 100% once in a blue (I suggest) may help to bring it back in line.
Aakee:
Two questions:
1) Am I to take away from this that battery temperature is also important? I see a battery at 25C has significant less calendar aging than one at 50% (other things being equal).
2) Looking at the charts you post, they seem contradictory. The first shows quite a bit of aging over 80%, a notable increase over ~95%. The second contradicts this, showing a marked dip at 80% and improveing again as SoC increases. Which are we to use as "bottom line"?
Two questions:
1) Am I to take away from this that battery temperature is also important? I see a battery at 25C has significant less calendar aging than one at 50% (other things being equal).
2) Looking at the charts you post, they seem contradictory. The first shows quite a bit of aging over 80%, a notable increase over ~95%. The second contradicts this, showing a marked dip at 80% and improveing again as SoC increases. Which are we to use as "bottom line"?
Just briefly charging to 100% will probably not help the BMS with the capacity calculation.
I have found that, as I often have done it, charging to 100% and drive of asap or possibly before the charging is totally completed (by planning the charge to be finished when I need to drive away) do not cause a change to the Nomimal full pack.
As it seems, letting the car fall asleep after the charge, and read the OVC etc do let the car change the NFP.
The BMS calibration probably do not need a 100% charge, nor do it need to see the absolute end point 0% either.
But seeing more of the ends, like somewhere between 0-20% and 80-100% is enough to estimerate the capacity better.
But the BMS need to see the OCV, so time to fall asleep plus some descent time at rest for the battery, at least one hour or two is good.
I have found that, as I often have done it, charging to 100% and drive of asap or possibly before the charging is totally completed (by planning the charge to be finished when I need to drive away) do not cause a change to the Nomimal full pack.
As it seems, letting the car fall asleep after the charge, and read the OVC etc do let the car change the NFP.
The BMS calibration probably do not need a 100% charge, nor do it need to see the absolute end point 0% either.
But seeing more of the ends, like somewhere between 0-20% and 80-100% is enough to estimerate the capacity better.
But the BMS need to see the OCV, so time to fall asleep plus some descent time at rest for the battery, at least one hour or two is good.
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