Model 3

Best charge level to maintain life of the battery?

I have my daily charge level set to 62% and I am plugged into a standard 120v wall socket in my garage all the time.

I don’t take a lot of long trips. What is the best charge level to maintain the battery for the longest period of time?

Comments

  • Jeff Dahn has suggested 70%. However, probably much difference between 70% - 90%. I just set mine at 70% as I rarely use more than 10% of the battery capacity for daily driving.

    https://electrek.co/2017/09/01/tesla-battery-expert-recommends-daily-battery-pack-charging/
  • *not much difference
  • never going above or below 50% is best.
    However:
    - you don't go very far that way so the car is useless
    - you don't really know where 50% is
    40% to 60% will probably allow your battery to last about 2 days longer over 10 years than uselessly sitting at 50% (I made up these numbers) so don't worry about it as long as your battery spends most of its time between 20% and 80% or 10% and 90% if you regularly need to be able to drive a long way. Going to 100% and down to near zero occasionally is fine as long as the battery doesn't remain that high or low for very long and you don't do it often.
    or, in the immortal words of @stingray_don from a few minutes ago: "not much difference"
  • For storage, 50% is probably ideal.
    For usage, between 45% and 75% is probably ideal. It is better the charge again mid-cycle than to go all the way down.

    However, to echo the above, it is unlikely to make a significant difference unless you regularly store your car at a high SOC (don’t be afraid of a full charge if you need one, but when you’ve charged, get going) or regularly cycle nearly the full capacity.
  • Best? 70%

    20%-80% is good

    90% will not see significant differences.
  • Ok, I’ll keep my car plugged in and maintained at 70%. Is that ok? I hope to keep my car for twenty years.

    As an aside, I’m amazed at people who keep their Teslas outside, exposed to the elements. I would not have bought this car if I didn’t own a garage but that’s just me.
  • > @larry_98733015 said:
    > Ok, I’ll keep my car plugged in and maintained at 70%. Is that ok? I hope to keep my car for twenty years.

    Yes thats fine. If you are looking for an optimal range, 70% is what i would call optimal. Specifically though, its whatever gets you through each day and provides a buffer for potential emergencies, road closures, you know all the garbage you dont plan for which is why you never drive your gasoline car around with less than a quarter tank left.

    I do 22 miles per day so 70% is plenty for me. On days where i make a trip after work, i charge to 95%.

    Frequency is key for battery health. Charging to 100% a handful of times does not destroy your battery.
  • Larry, why 62%.. It just seems like an odd number since on the screen and the app, the markings are 50 ,60, 70, etc....
  • > @jordanrichard_629778 said:
    > Larry, why 62%.. It just seems like an odd number since on the screen and the app, the markings are 50 ,60, 70, etc....

    In the app, when you slide the bar, you can pick any number. Somebody on here mentioned 62%, if I recall correctly or maybe they said 60%, lol.
  • 50-62% was JB Straubel’s answer many years ago.
  • Just to leap off BH's point, much of what people "hear" has been passed down from the past.

    For example, "they" say that a battery pack's end of useful life is when it gets down to 70% of it's original range.... Ok, for the current Model S, that would mean the pack is toast when it's full range is down 281 miles...………

    While I still have yet to learn where is the is 70% rule came from, I do highly suspect that it was based when the Leaf first came out.
  • 70% comes from the article on the battery engineer, referenced above.
  • It also comes from comparing the percent of battery utilization, with cell voltage variance.
    +/- 20% ie. 30%-70% is an optimal range.

    You will not ruin your battery charging to what makes you more comfortable.
  • edited October 22
    Right..... from when? As my perfect example above about the current Model S illustrates, that 70% is as outdated as heating your house with coal.

    Even applying this 70% rule to my car's (2014 S85) original range, that means once my car gets down to 185, it becomes a 4800 paper weight.
  • @larry,
    "I’ll keep my car plugged in and maintained at 70%. Is that ok?"
    That will be just fine.
    About 20 years. Sure. The only question is the battery. I've got 8 more years on my 2018 Roadster for its 20 year point so I'll let you know between now and then whether you'll need to replace the battery or parts of it.
  • 2018 Roadster, huh? ;) I'll let you get away with 2008....

    I'll echo Earl and Nagin's advice, and extend it a bit.

    If you want the absolute best battery life, set your charge level to 50% and never, ever drive the car. If you insist on driving the car, set your charge level to 55%, and never let the battery drop below 45%.

    OK, let's go to the real world. In the real world, Lithium-Ion batteries don't generally "fail" - the amount of energy they can store slowly drops. This reduction occurs mainly as a result of charge/discharge cycles, although time and temperature play a part. A generally accepted industry standard is that a battery is considered worn-out when it can only store 80% (or sometimes 70%) of the energy that it could when it was new. As a rule-of-thumb, 1000 full cycles (0%-100%-0%) is generally considered a good lifetime for a Lithium-Ion cell, bringing it to that 80% point. Note that, for a 300 mile EV, 1000 cycles is 300,000 miles.

    Research also indicates that there are advantages to charging to less than 100%, and discharging to higher than 0%. Limiting your regular charging to 90%, and discharging to 10%, will give you significantly more miles out of your battery before it wears out. Limiting to 80%/20% has a much, much smaller impact, and 70%/30% has essentially zero improvement over 80/20.

    As jordanrichard points out, that "80% is worn-out" rule is absurd for a modern Tesla EV - my 310 mile rated Model 3 LR RWD would "only" have about 250 miles of range available at that point. I don't know about your world, but in my world that would be plenty for a 20 year old, 300,000 mile vehicle. A bunch of Tesla Model S owners got together at one point, and created a database of battery health vs. odometer miles - and it indicated that 300,000 miles certainly looked like a reasonable expectation for 80%.

    So, my recommendation to you is:
    If you want the absolute best, longest life out of your batteries, you're doing great. In 30 years when the seats are ripped, the foam is flattened, the paint is peeling, the car makes funny noises going down the street, and you can park it in the bad areas of town with absolutely no concern, your battery will still be in great shape.

    If you're one of those people who sell their car every 10 or 15 years (or even (gasp) more often), just don't worry about it. Follow the manual (don't charge over 90% every day), and get on with life.
  • > @Frank99 said:
    > 2018 Roadster, huh? ;) I'll let you get away with 2008....
    >
    > I'll echo Earl and Nagin's advice, and extend it a bit.
    >
    > If you want the absolute best battery life, set your charge level to 50% and never, ever drive the car. If you insist on driving the car, set your charge level to 55%, and never let the battery drop below 45%.
    >
    > OK, let's go to the real world. In the real world, Lithium-Ion batteries don't generally "fail" - the amount of energy they can store slowly drops. This reduction occurs mainly as a result of charge/discharge cycles, although time and temperature play a part. A generally accepted industry standard is that a battery is considered worn-out when it can only store 80% (or sometimes 70%) of the energy that it could when it was new. As a rule-of-thumb, 1000 full cycles (0%-100%-0%) is generally considered a good lifetime for a Lithium-Ion cell, bringing it to that 80% point. Note that, for a 300 mile EV, 1000 cycles is 300,000 miles.
    >
    > Research also indicates that there are advantages to charging to less than 100%, and discharging to higher than 0%. Limiting your regular charging to 90%, and discharging to 10%, will give you significantly more miles out of your battery before it wears out. Limiting to 80%/20% has a much, much smaller impact, and 70%/30% has essentially zero improvement over 80/20.
    >
    > As jordanrichard points out, that "80% is worn-out" rule is absurd for a modern Tesla EV - my 310 mile rated Model 3 LR RWD would "only" have about 250 miles of range available at that point. I don't know about your world, but in my world that would be plenty for a 20 year old, 300,000 mile vehicle. A bunch of Tesla Model S owners got together at one point, and created a database of battery health vs. odometer miles - and it indicated that 300,000 miles certainly looked like a reasonable expectation for 80%.
    >
    > So, my recommendation to you is:
    > If you want the absolute best, longest life out of your batteries, you're doing great. In 30 years when the seats are ripped, the foam is flattened, the paint is peeling, the car makes funny noises going down the street, and you can park it in the bad areas of town with absolutely no concern, your battery will still be in great shape.
    >
    > If you're one of those people who sell their car every 10 or 15 years (or even (gasp) more often), just don't worry about it. Follow the manual (don't charge over 90% every day), and get on with life.
    >
    >

    Seats can be replaced or reupholstered. The car can be repainted. Parts can be replaced. Funny noises can be diagnosed and ameliorated.

    My parents kept their vehicles in pristine shape for decades so I guess I inherited a gene.

    Seeing as I have never bought a new car in my left, before this one, and never spent more than $5k for a used car or truck, I’m reeling from the amount I spent but I am happy.
  • in my life
  • If you’re planning on keeping the car that long, remember that batteries can be replaced also. Used model 3 packs are expensive now, but as EVs become commonplace and battery prices continue to fall, the people who are buying and repurposing then will have more and better options, and the used model 3 packs will become just another used part.

    In any case, I applaud your intention, and believe that you bought the best car for exceptionally long term ownership.
  • Due to covid, I mostly drive my car to pick up food and groceries. I charge my car to 55% and by the end of the week it goes to about 45%. I just charge it back to 55% again.

    I did do a road trip this past weekend where I charged it to 100% and reached a Supercharger at 5%. It was by choice to keep the wife happy. Passed a few other Supercharger on the way.
  • >>> I did do a road trip this past weekend where I charged it to 100% and reached a Supercharger at 5%

    and that's exactly how Tesla expects you to use your car. I've pulled into an SC with 1% charge remaining, although I don't recommend that (the last 50 miles I was sweating bullets watching the estimated battery charge at my destination; when it went negative I slowed down).
  • @larry,
    Don't forget that there is an age component to battery degradation in addition to cycle life. Originally, Tesla told us we could "expect" 500 cycles, 5 years on the original Roadster batteries within the 70% capacity lifespan. This was based on laptop computers' use of 18650 cells.
    Clearly, they over-delivered since, nearly 12 years and 65K miles later, we're still not there.
    We have probably done full range charges over 100 times. I've run down to less than 2% several times and I ran it down to where it needed a tow once. It sat overnight at 100% charge once or twice. It has never gotten below 10% without charging immediately upon arrival.
    500 cycles X 200 miles/charge = 100,000 miles was Tesla's original reliability requirement for EVs. The number of cells to give that 200 miles/charge ended up providing enough power for the amazing sub-4 second 0-60 acceleration that put it into the supercar class. At that point a business plan emerged that would lead to Tesla's "secret master plan".
    Enjoy your car. You should get several million miles out of it although you may end up replacing or refurbishing your battery pack.
  • I am at 183,000 miles on my MS 85, with a 8% loss. At that rate, by the time my car reaches this “70%” rule, it will have 686,250 miles on it. However as I mentioned above, at 70%, my full range will be 185 miles. Now, since when I go on road trips I am stopping every 2 hours, so as long as my car’s full range is say 140 miles, it will still be a road trip car. At my current loss rate, it will take 1,189,500 miles to reach that point.
  • Interesting topic.
    But guys, your thoughts about charging current. Does it make sense to reduce Amps ?
  • You can't, except on AC chargers where the current is already low to begin with. Reducing current on those will not help your battery in any significant way, but it will reduce charging efficiency.
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