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Simple Question. Better to Charge to 80% or 90%

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I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity? I plan on keeping my Model 3 for a long time and I have a lot of flexibility at what level I charge to. When I picked up my car it was set at 90% and the person that gave us the orientation said to keep it at 90%. I could not find any recommendation on the best level to keep the battery in the manual. I know the batteries are different in the Model 3. Could they have different charging recommendations? Come on Tesla provide us with the facts. It would seem to be in their best interest to keep the batteries in good working order.
 
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I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity? I plan on keeping my Model 3 for a long time and I have a lot of flexibility at what level I charge to. When I picked up my car it was set at 90% and the person that gave us the orientation said to keep it at 90%. I could not find any recommendation on the best level to keep the battery in the manual. I know the batteries are different in the Model 3. Could they have different charging recommendations? Come on Tesla provide us with the facts. It would seem to be in their best interest to keep the batteries in good working order.

I think that the reality of the situation is that you can fuss around with the battery percentage (besides the 90% recommendation) and maybe preserve five miles of range over 100k miles of driving.

It’s just not really a big deal on a car with such advanced batteries, charging, and temperature management. Tesla batteries have for the most part (early 90 packs aside) proven to be very robust.
 
This site has good resource on this:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

And advise are consistent with Tesla.

Run the battery around the mid point to max life. Avoid deep discharge <20% or near full charges >80% to max life. Especially avoid having it sit full >90% for long periods when hot. Frequent shallow cycle around mid point is better than less frequent deep cycles

That being said, the diff between 70 or 80% is likely very small so I just charge to 80% and stop worrying about it. If I need to charge to 90-100%, which is very infrequent, then I try to time the charge so I drive soon after it is full.
 
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My S is just shy of 2 years old. Only 15K miles, but 0% degradation. I have never had the charge level set lower than 90%. I have sometimes stopped charging short of 90%, but it's always set to 90% or higher (only occasionally when I need the extra range).
 
I posted this on a different forum but here it is again....

For some, they say set to 80% or even 90% and never worry about it again. That mentality probably works for leasers or people that upgrade cars often. I'm neither of those AND I happen to have a long daily commute (110 miles round-trip) . Therefore I worry about this more than the average owner. For starters, calculate your daily commute as a percentage of the 100% SOC battery range. For me, that's 35% (110 mi / 310 mi). Divide this in half, 17.5% (35% / 2). Add this to 50%. For me, 50% + 17.5% = 67.5%. So, for my daily commute, charging to 67.5% is ideal for battery longevity. Next, you apply the common sense and convenience factors. This math leaves me with 32.5% at the end of my commute for "pop ups". Everyone's lifestyle is different, some may have unpredictable things constantly. For me, having 32.5% is perfectly adequate for most pop ups and a supercharger fixes it if I'm wrong. I will round up to 70% SOC. If I know I need more mileage any particular day, I can up the SOC. Don't forget climate can significantly impact these calculations, so winter might easily drive up your SOC target. Good luck and happy charging

FWIW, I am not following my own advice yet. I am set at 80% now. I new consideration I have noticed (but not experienced yet) is what happens if you forget to charge your car one night? Does that impact you? Does picking a number to accommodate your needs for this mistake make sense? Food for thought ...
I'll be getting my car on Thursday so I don't have experience yet. Having said that, I've obsessed over this topic for the past few months and I came to exactly the same conclusion. If you want to obsess about it too, do what insaneoctane recommend.

Lithium batteries seem to degrade mostly based on the amount of time spent at the extremes of charge (full/empty). This is especially true at high temperatures. Low temperatures don't seem to contribute to long-term degradation as far as I can tell. But the batteries don't work as well when they're cold so you might need to adjust your charge level accordingly. Don't worry about changing to 100% the night before a road trip because the amount of time is small presuming that this only happens once in a while.

You might save a few miles of range in a few years by being disciplined about it. There's not enough data yet (on the Model 3) to say exactly how much. But, because of the high quality batteries & good thermal management in the 3, it appears that the benefit is likely to be small. So it's not something to loose sleep over.
 
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I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity? I plan on keeping my Model 3 for a long time and I have a lot of flexibility at what level I charge to. When I picked up my car it was set at 90% and the person that gave us the orientation said to keep it at 90%. I could not find any recommendation on the best level to keep the battery in the manual. I know the batteries are different in the Model 3. Could they have different charging recommendations? Come on Tesla provide us with the facts. It would seem to be in their best interest to keep the batteries in good working order.

My S had a placard in it somewhere when I bought it recommending keeping the battery charged to 90%. People tend to obsess about keeping the batteries in good shape. Most people have experiences with laptops and cell phones losing battery life as they get older and are paranoid about it happening to their car. Tesla's battery management firmware is right up there with the best in the world for any rechargeable device. Even abused Tesla batteries rarely lose more than 10% of their original capacity over 5 years.

Some battery packs go bad. It's an odds game, some of any manufactured product is going to fail. My SO had the motherboard on her MacBook fail when it was less than a year old. The tech at the Apple store said he had worked on a lot of them and that was the first complete motherboard failure he'd seen.

But the failure rate of Tesla battery packs is low and Tesla is pretty good about fixing them, though sometimes it takes some convincing if it's just one cell bad that's looking like worse than usual degradation. I would assume the Model 3 batteries and packs are at minimum equal to the quality of the Model S/X packs, though the Munro tear down indicated the Model 3's packs are probably better built than the S/X packs.

I'll be getting my car on Thursday so I don't have experience yet. Having said that, I've obsessed over this topic for the past few months and I came to exactly the same conclusion. If you want to obsess about it too, do what insaneoctane recommend.

Lithium batteries seem to degrade mostly based on the amount of time spent at the extremes of charge (full/empty). This is especially true at high temperatures. Low temperatures don't seem to contribute to long-term degradation as far as I can tell. But the batteries don't work as well when they're cold so you might need to adjust your charge level accordingly. Don't worry about changing to 100% the night before a road trip because the amount of time is small presuming that this only happens once in a while.

You might save a few miles of range in a few years by being disciplined about it. There's not enough data yet (on the Model 3) to say exactly how much. But, because of the high quality batteries & good thermal management in the 3, it appears that the benefit is likely to be small. So it's not something to loose sleep over.

Li-ion batteries work best at temps a little hot for humans, low 100s F, but cold slows down most chemical processes, so a cold pack may not be able to deliver as much energy (or take as fast a charge) as a fully warmed up pack, but it should survive OK. Heat accelerates most chemical processes, so an overly hot battery will start to break down. That's what happened to early Leaf batteries, Nissan's cooling system was poor and in hot climates the packs got too hot.

My father was a professional photographer and had a photo supply business on the side. He kept color film in the freezer to preserve it. He found film 10 years past it's expiration date was usually just fine.
 
I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity?

Because it's a trade-off; there's no one recommendation that's the best for all circumstances, especially once you factor in the fact that the more complicated the advice the less chance there is of people following it accurately and never making mistakes.

For example, if we assume that standing at 70% is better than standing at 90%, but discharging to 5% is worse than discharging to 25% (both probably true to at least some degree). So a recommendation to charge to 70% would only be definitely better if you never drive the car more than about 100 miles between charges. If you ever do, then it becomes a question of which is worse - the high SoC standing after charge or the higher stress due to driving down to low SoC, which is likely to vary with things like temperature and your driving style. You could have a more complicated instruction to base your charge level on the driving you estimate you are going to do the next day, but that depends on how accurate your forecasting is - could easily end up worse than just picking a fixed level.

Fortunately, the differences we are talking about are small.

So Tesla can safely give advice that says "charge to no more than 90% as convenience suits you" and expect few horror stories on degradation. Meantime, enthusiasts can debate strategies to wring the absolute last fraction of life out of their batteries - and since it's impossible to be completely sure, the discussion is endless.
 
I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity? I plan on keeping my Model 3 for a long time and I have a lot of flexibility at what level I charge to. When I picked up my car it was set at 90% and the person that gave us the orientation said to keep it at 90%. I could not find any recommendation on the best level to keep the battery in the manual. I know the batteries are different in the Model 3. Could they have different charging recommendations? Come on Tesla provide us with the facts. It would seem to be in their best interest to keep the batteries in good working order.
Because the best is 50%, and that would be annoying to maintain.
80% is almost as good, as much more useful. Even 90% is fine. 100% only for a few hours.
Don't forget that even kept at 50% in the freezer your batteries will still lose capacity over the years. Time is the great enemy of us all...
 
Just charge at 90% and don't worry about it. I did charge at 80% for a couple of years, but noticed that the displayed range went down. Went back up after charging to 90%, with the odd 100% charge on trips, so the loss appears to be balance (on the 85S, balancing starts at 93%). After 108K miles and over five years it's now lost between 3% and 4%. Note that driving under 50% heats the battery more than driving above 50% for the same amount of power required, so charging to 50% isn't the answer unless the car is being stored.
 
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I've only had my S100D for 6 months. In those 6 months I've only charged to 100% twice (day 1 and last weekend). My daily charge is set to 75% and my uphill weekend commute is set to 90% (185 miles with 5,000 ft elevation gain). With 14,000 miles put on the car in 6 months, my full charge rating now says 336 miles, up one mile from the 335 it said on day 1. I don't know what to make of this, but it certainly isn't degrading too quickly. :)
 
I don't understand why Tesla owners need to debate what is best for the batteries. Why can't Tesla provide us with the best charging level for battery longevity? I plan on keeping my Model 3 for a long time and I have a lot of flexibility at what level I charge to. When I picked up my car it was set at 90% and the person that gave us the orientation said to keep it at 90%. I could not find any recommendation on the best level to keep the battery in the manual. I know the batteries are different in the Model 3. Could they have different charging recommendations? Come on Tesla provide us with the facts. It would seem to be in their best interest to keep the batteries in good working order.
Because I plan to keep the car for 10+ years and I want the battery to be as good as possible in the 10th year. If I can take some simple preventative steps in the meantime to aspire to that goal, then that's what I want to do. I recognize that the engineers at Tesla have probably thought this through in excessively more detail than I ever could (unless I go back to school so that I can join them) and they have a vested interest in making sure that the batteries last as long as possible. But, to whatever amount my actions can contribute (balancing convenience, of course), that's what I want to do. I realize that I'm probably obsessing over a very small, if any benefit. But, I don't think anything anyone has suggested will increase the degradation of the battery so what does it hurt?

At the end of the day, I suspect it's just a personality difference between you and me (nothing wrong or right about either approach). I like to obsess over technical details and learn even more than what's in the manual. If possible, I want to learn (or speculate as to) how the recommendations in the manual were arrived at. Maybe I'm weird but I think it's kind of fun.
 
I drive about 60 miles a day. I can only charge at work. Is it better to charge to 80% daily? Does it more negatively effect the battery if I charge to 90%? Should I charge to 80% M-TH and then charge to 90% on Friday?

Thanks in advance!
80% is better than 90% for most weather. I'd charge higher if it's below freezing out and lower if it is hot enough to use air conditioning for any reason.

So think like this if range isn't an issue:

100% for unusual circumstances (like right before a trip, but very shortly before)
90% in the winter
80% spring and fall
70% summer
60% if its the hottest day of the summer and you can handle the range limitation
50% if you are going to leave it sitting for a day or two, charge it back up if needed later before you use it.

If you need more range tighten up the table

100% for unusual circumstances (like right before a trip, but very shortly before)
95% in the winter
85% spring and fall
75% summer
65% if its the hottest day of the summer and you can handle the range limitation
55% if you are going to leave it sitting for a day or two, charge it back up if needed later before you use it.

If you are lazy or don't want to hassle pick a number from the above that fits an average and lit it use that most of the time. Doesn't terribly matter if you pick 70% or 75% or 80%.

But me I change my charging behavior based on use and temperature.
 
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Hey, I know I am driving a computer on wheels, but now you're telling me it is a smart phone? I refuse to set it to %! :p

A bit off-topic, but I wish you could display both % and mileage. Navigation displays destination charge in %, but I like to see mileage so I can do quick math of adding actual miles to remaining miles to have a decent idea of just how efficient the vehicle is being - just lazy enough to not want to calculate my own %.
 
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A bit off-topic, but I wish you could display both % and mileage. Navigation displays destination charge in %, but I like to see mileage so I can do quick math of adding actual miles to remaining miles to have a decent idea of just how efficient the vehicle is being - just lazy enough to not want to calculate my own %.

Same here. The best compromise is to show miles on the dash and use your energy chart to show current percent.

EDIT: Oops, didn't notice you're in a Model 3. So this may not apply.
 
Much wisdom in this thread!

To add one more kernel: If you live somewhere prone to natural disasters which arrive without notice (earthquakes, rather than hurricanes), you may want to sacrifice degradation risk (slightly) by charging to a slightly higher percentage and doing so earlier in the evening (as soon as rates drop). Here in shaky SoCal, even though our weekday drives are short, we begin charging our cars at 8 PM and charge them to 80%.

Now, if only Tesla would allow vehicle --> home use. We have two Powerwalls coming this summer, but each stores only a zippy 14 kWh.
 
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Great thread.
Sort of off the original topic, (sorry) but still in line with what’s best for the battery; I have a follow up question. ?

I live in a less than ideal climate for Lithium Ion life.
Summers are often above 30 degrees celcius / 86 degrees Fahrenheit for a few months.
And
Often below -25 degrees celcius / -13 Fahrenheit for a few months in the winter.
Welcome to Ontario Canada. :)

My question is:
If I leave the car plugged in every night (which I plan to do when I get one), will the car (Model 3), automatically keep the battery warm all night to preserve its life, or similarity, automatically cool in the summer.?

If not, I guess heating the garage, for those nasty two months, may be ideal I suspect.

Thanks !
 
Great thread.
Sort of off the original topic, (sorry) but still in line with what’s best for the battery; I have a follow up question. ?

I live in a less than ideal climate for Lithium Ion life.
Summers are often above 30 degrees celcius / 86 degrees Fahrenheit for a few months.
And
Often below -25 degrees celcius / -13 Fahrenheit for a few months in the winter.
Welcome to Ontario Canada. :)

My question is:
If I leave the car plugged in every night (which I plan to do when I get one), will the car (Model 3), automatically keep the battery warm all night to preserve its life, or similarity, automatically cool in the summer.?

If not, I guess heating the garage, for those nasty two months, may be ideal I suspect.

Thanks !
Assuming the Model 3 is the same as the Model S, you are not supposed to leave it in -30 C or below for more than 24 hours (The ambient temperature is -30 or lower for 24 hours continually). It will keep warm if plugged into a 240 V line above -30. A 120 V line will use all it's energy to keep the battery warm and won't actually charge.