Thank you!
Again, a Tessie user with ”low degradation” and the usual ”usable capacity” discussion.
Turns out he has about 10% exactly as expected by the time.
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What Percent is Your Tesla Charged to While at Home?
- Thread starter Resist
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Again, a Tessie user with ”low degradation” and the usual ”usable capacity” discussion.
Turns out he has about 10% exactly as expected by the time.
Boy, don’t even have my MYLR yet and already have some battery anxiety. Based on everything I read so far it sounds like charging up to 55% for daily driving and not letting it drop below 20%(?) will extend life of calendar aging, which is my biggest concern since I tend to keep vehicles for the long term and don’t flip them every few years or so. I still have my 2003 F250 7.3 Diesel with only 147,000 miles on it. Just hoping to get same age expectancy from EV w/o having massive battery degradation, maybe it’s not practical?
Our Scenario is:
Work remotely now, so drive probably less than 10 miles a day, some days not at all.
May put on 100 or so miles over the weekend.
Live in PNW so our charging temperature would be less than 25 degrees Celsius 98% of the time.
Will have Wall Charger installed (60 amp)
I have heard everything from:
Just go by Tesla recommendation of 20% - 80% or 90% depending on range you need for daily driving and plug in daily.
Use the 20% - 80% for daily but only charge when you get close to the 20% charge left. (so could be once a week of maybe longer between charges)
Use 10% - 50% rule for daily, charging daily.
It’s important to take your SoC up to 100% (long trips) or at least twice a year so you’re not always charging at a low SoC.
What you be your best charging recommendation based on our scenario?
Absolutely NONE of this "needs" to be followed. Its just information. The difference between possibly having lost 20 miles from your max range vs losing 8 miles from your max range after a period of 3 years (made up numbers) is not going to change the usage of the car for the vast majority of people.
My car charges to 281 as a Max range right now (model 3 Performance, almost 5 years old). It was charged to 90% exclusively for the first 3.5 years of its existence. If I had charged to 50% instead of 90%, would it read a higher number? Probably. How much higher? I am not sure. Perhaps it would show 289-290? Will that difference change my usage of the car at all, in the slightest? No, not one...single... bit.
Do I charge it to a lower number now? Yes, but I charge to 70% cause I dont care that much about all this min maxing. Its not necessary in the slightest. I am not disputing the results, just disputing the fact that some people get all wound up about "omg I need to do this now", when they dont, if they dont want to, and its not like the car is going to spontaneously combust, nor is it like there will be 60 miles less range because you didnt only charge to 48% or something.
There is no advantage at all of running it down to charge it back up, so if you are trying to min max, then set it to 50% charge in the app, use the car and let it charge back up to 50%, if 50% also makes you comfortable that if you needed to "get in the car and go" you would be happy with the amount of range that will be, keeping in mind that you not going to get your rated range.
If your goal is to minimize degradation with an NCA battery car, and your daily use is such that 55% is plenty to avoid running out or getting range anxiety, then just charge to 55% as needed. For when you anticipate longer trips, charge to whatever higher level is needed for the longer trip.
But note that if you are a heavy user of heat or AC, or drive significantly faster than about 65mph, your actual mileage will be lower than the rated mileage.
jjrandorin, pretty much said it all.
Just follow the Tesla advice, and you’ll be fine.
Theres one big ’but’: do not read what people say that Tesla says in forums etc. Forums and people in general have a mix of 50-70% myths combined with 30-50% what Tesla actually says. One example is that the forums says that Tesla says Charge 90% daily. That is not correct, Tesla says “keep the full charge limit of the battery to under 90% for Daily use.”
If you read it as written, they recommend anything between 50-90% (or 50-89% actually, but….)
As per above or @jjrandorin just follow the Tesla guidelines, and you’ll be fine.
If you like to reduce the degradation (can be cut at about half by using the low SOC strategy). Only important if you plan to keep the car for long, or if you really like to reduce the CO2 footprint etc.
There’s mainly myths above. Again, for Teslas advice read Teslas instructions By yourself.
HenryT
Active Member
I have studied lithium battery rersearch reports sine quite long time back (I have used lithium batteries for other purposes since long time).
I think when people read statements that are completely wrong(trying to reduce the degradation and searching for information), these are myths that we should try to stop from floating around.
The less battery myths the better.
The advices given in forums should be built on facts and science.
This quiz test what myths you was caught by:
Battery quiz
Not going to make much difference on degradation for one or two days, especially as you're going to be driving after you charge it. I personally would charge up higher for more flexibility, and lower cost and no worry about a full or broken supercharger station.
I follow the science here, and thanks to the great investigators in this thread, I charge up to 50% most days. When I need to make a trip I charge up as high as I feel like I need to avoid any chance of range problems. I've done 100% a few times, so I can make a full round trip with extra range for additional unexpected side-trips, stops, AC use, sentry mode, or whatever. The few 20 days or less a year charging up higher, for part of the day, makes little difference compared to 345 days staying below 50%.
My degradation is very small (358 -> 350 in 11 months), and indistinguishable from zero in the last 6 months. I don't use any apps, just extrapolation from the displayed SOC and displayed range.
If you are charging to 50% in order to preserve your battery's range for occasional long trips, why not charge it to the higher level needed to minimize needed charging stops on the occasional long trip, since that is what your "saving" your battery for?
E90alex
Active Member
Charge it to 80-100 right before you leave and just follow what the navigation tells you to do as far as charging stops.
No need to bend over backwards and try to keep it below 50% on a road trip. That would be a waste of time and be of little to no benefit. Road trips are different than daily use because in daily use, the car spends the majority of the day sitting for hours and hours on end at a steady charge level, so a lower SOC is beneficial when it’s just sitting. On a trip you’re constantly driving and using up the battery and not just sitting at 80/90+% for hours so it’s less of an issue.
The purpose of pointing out these recommendations is so people can make small changes that may benefit the battery longevity without having to modify their routine or inconvenience themselves.
For example if you only use 20% of charge daily and plug in every night, it makes no difference whether you charge to 50% or 90%, so why not charge lower if it’s better for the battery and doesn’t require any change in your routine? But if you have a long commute and use like 60% per day then absolutely charge higher and don’t worry about keeping it under 50% and having to charge mid day in order to make it home.
These recommendations are not saying do not ever charge over 50% under any circumstance or else your battery will explode. Don’t be afraid to charge the car to whatever you need it to, especially on a trip.
Charging to 100% on AC is still probably better for the battery than charging to 50% on a Supercharger. I say don't hesitate to charge to as much as you need before the trip.
I frequently am faced with a home-to-home trip with the option of either charging to a high SOC using my L2 TWC, or else stopping briefly in route at a Supercharger. I'll always choose the higher L2 SOC. DC Fast Charging is tough on an EV.
That said, the Supercharger network is a beautiful thing. I never cease to smile when stopping for a "splash and go."
That said, the Supercharger network is a beautiful thing. I never cease to smile when stopping for a "splash and go."
Very many good advices lately!
I’m happy to see!
People mostly assume that miles kills the battery, and that high SOC is very bad.
It is the calendar aging that degrade the battery most, not the miles.
As calendar aging is = SOC x temp x time, if the time is very low the calendar aging will be this also.
70-90% is about as bad as 100%, so do not be afraid to use 100% when needed (just as Tesla says, use it for trips/travelling).
Cyclic aging might be higher at 100% but cyclic aging still is low compared to the calendar sging the forst five years or so.
I charge to 100% whenever I need, and in the end about half of my about 35 full charging sessions has been out of curiosity etc.
I also have about 45 Supercharging sessions. I use supercharging any time I need, but if not needed I charge full at home.
One example is going to IKEA, its a 150km single way trip, no fast chargers at all at IKEA and nearby. A full charge take me both ways even in cold weather.
Last time we went there, it wasnt planned so the car was at 55%. Charged on the only supercharger between to cover the whole trip.
I have about 18% supercharging which probably is normal/average.
Still, my car has very low degradation.
Why?
Because it mainly has been at a SOC at or below 55%.
If you need to leave the car for one night at 100% , it will not hurt the battery more than 80% at the same time or in hot weather like 80% at 1.5 nights. In some cases, 80% will degrade the battery nore than at 100%.
If leaving the car at high SOC was very bad, Tesla would have put a note in the manual.
Lithium batteries can be charged well above “100%”. 4.20V per cell has been chosen to better keep the life of the battery.
It is possible to charge it to 4.3 or even 4.4V, but the life will be short and they are mu h more dangerous in terms of overheat/fire etc.
So, when the manufacturers set 4.20V as the norm for 100%, and max voltage limit, they probably wouldnt set that at a limit that kills the batteries.
My 35 2170 panasonic nca cells has been at 100% for about three months, at 10C and also at 24C. They are fine!
I’m happy to see!
People mostly assume that miles kills the battery, and that high SOC is very bad.
It is the calendar aging that degrade the battery most, not the miles.
As calendar aging is = SOC x temp x time, if the time is very low the calendar aging will be this also.
70-90% is about as bad as 100%, so do not be afraid to use 100% when needed (just as Tesla says, use it for trips/travelling).
Cyclic aging might be higher at 100% but cyclic aging still is low compared to the calendar sging the forst five years or so.
I charge to 100% whenever I need, and in the end about half of my about 35 full charging sessions has been out of curiosity etc.
I also have about 45 Supercharging sessions. I use supercharging any time I need, but if not needed I charge full at home.
One example is going to IKEA, its a 150km single way trip, no fast chargers at all at IKEA and nearby. A full charge take me both ways even in cold weather.
Last time we went there, it wasnt planned so the car was at 55%. Charged on the only supercharger between to cover the whole trip.
I have about 18% supercharging which probably is normal/average.
Still, my car has very low degradation.
Why?
Because it mainly has been at a SOC at or below 55%.
If you need to leave the car for one night at 100% , it will not hurt the battery more than 80% at the same time or in hot weather like 80% at 1.5 nights. In some cases, 80% will degrade the battery nore than at 100%.
If leaving the car at high SOC was very bad, Tesla would have put a note in the manual.
Lithium batteries can be charged well above “100%”. 4.20V per cell has been chosen to better keep the life of the battery.
It is possible to charge it to 4.3 or even 4.4V, but the life will be short and they are mu h more dangerous in terms of overheat/fire etc.
So, when the manufacturers set 4.20V as the norm for 100%, and max voltage limit, they probably wouldnt set that at a limit that kills the batteries.
My 35 2170 panasonic nca cells has been at 100% for about three months, at 10C and also at 24C. They are fine!
Guess I will keep my car at 50% when not driving it for days, in an attempt to stop as much degradation as possible on my 4 1/2 year old Model 3. This car has to last me long enough for Elon to let us transfer FSD to a new Tesla, because I won't pay $15,000 (or more) for it. And I'd like to have it on a new car as I use Summon all the time, for getting my car out of the garage. Plus I'd like the newer hardware since it's clear Elon is making it so not all the newer hardware can be implemented into older cars.
I got 12 of 13 correct. The exception was, "What is the optimum storage SOC for a lithium ion battery to reduce the degradation from time ?", which I answered with 20%. The correct answer was given as 0%.
I would argue that 0% cannot be the correct answer, because self-discharge, albeit very slowly, would take the battery below 0%, which is not good. I propose to add a 10% choice and take that as the correct answer.
I would argue that 0% cannot be the correct answer, because self-discharge, albeit very slowly, would take the battery below 0%, which is not good. I propose to add a 10% choice and take that as the correct answer.
Down below, is examples from different research reports and actual tests of calendar aging. (I have some more, but I recon these examples will make the case
).I see your point, and if we would ask a researcher or a doctor's degree in the subject, he would say ”It depends” and then ask ”For how long?”
When he get the answer ”less then 6 months, he would say ”0% absolute”.
The self discharge of lithium ion batteries is very low at low SOC.
Also, at 0% the cell is mot completely emoty. 0% is set by the cut off voltage during discharge.
Overdischarging the battery do not kill it as long as the overdisharge id not too much.
Overdischarge from 2.5V to 1.5V doesnt make a noticable difference in cyclic wear in the research.
So, even at 0% the cell is safe and the low self discharge will keep it within safe limits for a long period. In many of the research tests, the cells had three months between the checkups.
The question is of technical art, not practical about what SOC to leave your vcar with, for a extended parking. If it was, I’m with you.
The questions is ment to brake the myth so I would prefer to follow the scientific research results and also not introduce any new myths (like that 10% would be the best SOC).
In the comment, I did put ”Its still adviced to charge an electric car son after arrival if the SOC is close to 0%”
Are you OK with this (explanation and the comment) or do you think it will need more explanation?
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