Have a new Model Y LR want to charge my battery levels to preserve battery health. My commute to office is 30 miles each way, I can charge at work as well. Should I maintain charge levels at 80% or should I set it lower does a lower rate help the battery or not? Should I keep the battery state of charge time lower or keep it at 80?
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Ideal State of Charge Kevel
- Thread starter Murph21
- Start date
E90alex
Active Member
Many many many threads on this. Just search for posts by the user AAKEE for data to back it up.
But generally, charge to the lowest % that allows you to use the car without inconvenience. Below ~57% is ideal for the battery in the Y LR to minimize degradation if that works for you.
I only charge to 50% daily. I only use 10-15% a day so 50% is more than enough. Even if I forget to charge one day.
But generally, charge to the lowest % that allows you to use the car without inconvenience. Below ~57% is ideal for the battery in the Y LR to minimize degradation if that works for you.
I only charge to 50% daily. I only use 10-15% a day so 50% is more than enough. Even if I forget to charge one day.
fiehlsport
Tire Guy
When it comes to these ideal charge level discussions questions I think it only really matters if you plan to charge the car and not use it for any extended period of time (ex: weeks to months). In those cases it would better to charge it to like 60%-70%.
However if you are plugging and using the desired charge rate within a few hours it should be fine. Even if you set a departure everyday it can be roughly estimate when you leave but it can still vary. Whether it is 50% or 80% it doesn't really matter all too much if you are exercising the battery soon.
However if you are plugging and using the desired charge rate within a few hours it should be fine. Even if you set a departure everyday it can be roughly estimate when you leave but it can still vary. Whether it is 50% or 80% it doesn't really matter all too much if you are exercising the battery soon.
E90alex
Active Member
Yes and no. If you are going to be constantly driving the whole day and will be depleting the battery then it no the charge limit doesn’t matter much.
But for most people the car is “in storage” for the vast majority of the day. Eg if you charge to 80% and use 5% to drive to work where it sits for 8 hours and you use another 5% to drive home where it may sit for 12+ hours, this increases the time spent at higher average SoC. Even worse if you immediately charge back to 80% when arriving home and let it sit overnight.
It doesn’t require a certain length of time of being “unused” before degradation kicks in because it’s all cumulative and depends on the average SoC of the battery in a day/week/month/year/lifetime.
ATPMSD
Active Member
Your options:
- Get a big pot of coffee and read the thousands of posts on this subject
- Use 50% as a middle bar. If you normally consume say 20% on your daily commute, then charge to 60% and return home with 40%
- Don’t overthink this. Just keep the car in the SOC range of 20%-80% and enjoy your car!
I understand that but what im saying is if the guidelines are 50-80% is recommended for normal daily use then having it sit in 70% should be fine. It would be insane to me to think that even letting the battery sit at 70% for 12+ hours is somehow not good for the battery. Again we are not talking about letting it sit at 90%+ for 12+hours daily. If the batteries are that sensitive that you can only let them sit even overnight at 50-60% then we are screwed and as an advertisement that EVs are the future then it is not a good way to get people on board because most people don't just have 5-10 mile commutes every day.
Sure if you are only using 5% of the battery total and you have a starting point of 80% then why even charge every day. I wouldn't even bother. If you are able to charge to 50% everyday because you have a short commute...good on you. I don't charge my car every day even though I can with a home charger, I opt not to because its not really necessary. For day to day use I think as long as you are using the battery every day it shouldn't have a practical impact. I agree if you are doing long term storage that is a different story where you might not use the car for a 2-3 weeks to months.
Btw battery "degradation" happens regardless if you are charging every day to just 50-60% from day 1. There is no way to avoid battery degradation.
ucmndd
Well-Known Member
Define “not good”. The science is pretty clear - cell calendar aging is accelerated by high states of charge and temperature. Lower for both is better. The effect is cumulative over time.
If you have conveniently accessible home charging and aren’t using it daily, you’re foregoing one of the best benefits of an EV - always having a “full tank”. Free yourself from the “charge it high and run it down” ICE mentality.
Nope. But there’s sure a way to minimize it.
I don't find the need to keep myself plugged in if I am not using the maximum of the battery every day. Keeping yourself plugged in all the time when not in use is only for people that can have a home charger installed which I will argue is still the minority of folks because even folks who own a home don't all opt to install a home charger let alone people who live in apartments or rent homes which do not have access to install a home charger.
If you are relying on public charging, they are not recharging their car everyday and certainly not keeping their SOC at around 50-60%. Trust me it would get old. I did it for a bit until I got my home charger installed. I got a home charger installed not for the fact that I can always have a "full tank" but because #1 i don't have to deal with waiting to sit and wait at a DC fast charger all the time when it comes time to charge and is cheaper per kw and #2 help increase the value of the home to say that it is EV ready with a NEMA 14-50 plug installed.
I mean I understand that 50-60% is ideal if you can afford to do so but if 80% was sooo detrimental to the battery even for daily use then why is that number even thrown out there. I mean what is it? First it was not leave it at over 90% then it is 80% and now we are saying keep it at 50%. Certainly not going to convert people over to EVs if there needs to be this constant paralysis by analysis of trying to keep the car at a certain SOC for storing my car overnight.
I think as long as you heed to the general battery guidance of 20-80% you should be fine. I think not heeding to the guidance (constantly charging to 90%+ or draining until <10%) is more detrimental to the battery degradation in the grand scheme of things. Also even if you charge at 80% the idea is that you are doing departure charging which in theory means you are not sitting at 80% for too long vs. scheduled charging which you have more chances of the car sitting in 80% for a more extended period of time.
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E90alex
Active Member
There’s a difference between something that’s distinctly “bad” for the battery and something that’s “better” for the battery.
The only truly “bad” things for the battery (ie may lead to premature failure) are running the HV battery completely dead and letting it sit for extended periods or leaving it at 100% for extended periods. Extended periods meaning weeks/months.
Other than that, the batteries in general are pretty robust and should last past the warranty period no matter how you treat it. If your goal is to simply have the battery not fail prematurely then there is zero need to give it a second thought. Charge to whatever you want within Teslas recommendations. 50% is fine. 70% is fine. 80% is fine. Even 90-100% is fine.
However, most of the discussions about battery charge limits and degradation is to try and minimize degradation as much as possible so the battery stays healthy for as long as possible. As you said, there is no way to prevent degradation, but there’s very clear evidence on ways to minimize degradation.
So no, 70%, 80%, even 90% charge isn’t “bad” and won’t fry your battery. But 50-55% charge is better if you want to minimize degradation.
Also there’s absolutely zero reason to not plug in every day if you have a home charger, even if you had only used like 5% that day. Instead of setting higher limit and running it down before plugging it back in, it’s better to set a lower limit and just plug in daily.
Obviously this doesn’t apply to people without home charging because that would be far too inconvenient to try and charge daily and keep it under 55%. I’m of the camp that doesn’t think people should even buy an EV if they don’t have work/home charging but that’s a different topic.
ucmndd
Well-Known Member
It depends on whose daily use you are talking about. In my case it may prove very good business to charge to 80% because I can avoid SC top ups daily. That would cost more than a new battery. I would be silly to charge to 90 or 100 unless I had to for a trip. Charging to 70 makes no sense as it only increases the likelihood of needing a topup to get through the day.
The 80 number is highly interesting to me!
If I wind up getting through the 80 regularly I will have to do some more research on long term degradation from going to 90 vs cost of a middle of the day SC for ten minutes.
I am very interested in getting the absolute best out of my battery. I want it to last me to retirement in ten years time with a useful capacity remaining. It's only proper that I look into the margins for small savings that accumulate over that time frame.
In the case of someone who only sips at the battery most days they can avoid unnecessary deterioration by only charging it back to 55% daily. The 80 number is mute and not very interesting. Not irrelevant. Your battery will last longer since you have been paying attention.
If you trade your car every two or three years it's probably irrelevant to you. Not the next owner.
Never assume someone else uses the battery the same way you do.
Not quite sure what you are saying here. You might be confusing me for someone else. I didn't say avoid charging to 80% nor did I say to charge to 90% or 100% on thh daily is even ideal. In fact I think we are more aligned than you think if you re-read my entire post. Since it sounds to me like you don't have a home charging setup and have to rely on public charging it totally makes sense to charge to 80% which is what is being quoted even by Tesla for ideal daily charge usage as a tick on their charging bar. I even said it didn't make sense for people who don't have home charge to have to SC to just 50-60% every day just to preserve the ideal chart diagram that everyone here is probably quoting by AAKEE. While that might be true that is probably assuming some extended period of time sitting in that SOC.
What I was saying before was I personally schedule "departure charging" so when I do charge at home and charge to between 75-80% that I am not even sitting at 75-80% for that long since I gulp about 20-22% battery per round trip each time I go to work. By the time I get to work one way I am already down to 68-70% which is a little better for battery SOC for a few hours and by the time I get home, I am sitting around 58-60% which is a nice SOC to be sitting around anyways.
That is why even if I charge to 50% daily for use using departure charging, by the time I get to work I would be sitting at 40% for several hours and 30% by the time I get back home and then would have to wait until the wee hours in the morning for it to begin charging during off peak hours back to 50%. No matter what you do...you will not be sitting in the ideal 50-60% SOC 24/7 365 during when the car is not in use if you are truly using it right.
What I do agree with the others here is that if you are not planning to use the car for several days or even weeks (ex: vacation) then yeah charge it to only 50-60% and let the Tesla battery sit happy in that SOC while not in extended use because ideally it shouldn't really drain the battery especially if you don't wake it up during vacation. I know I was on a 2.5 week vacation and came back and it only drained maybe 1% and that is because from time to time I woke up the car from deep sleep.
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Read the bit I quoted. You were dismissing the importance of the 80% threshold number. I was correcting you.
If I was wanting to max my battery life with your usage I would be doing a daily topup to 65% in order to maximize time in the happy zone.
You are right that it is all an extrapolation of the capacity decay vs charge level results of long term steady state storage. We are assuming the integral sum of the averages applies when in use instead of steady state. It is logical but as far as I know not yet proven. It may only apply to storage conditions!
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