Maximum charge level for daily use

[slmitchell737]

Good articles. I appreciate the info.
I have a 230 mile minimum round trip commute once or twice a week to an airport where I’d like sentry mode and cabin overheat protection on. Model Y dual LR -

Tradeoffs.....there’s a balance somewhere for me. Do I charge to 100% and mitigate the number of times and amount that I supercharge? (Knowing SCings negative effect on long term battery health) If I drive slow enough I can make the round trip depending on how many times Sentry mode is activated in the lot
Or....do i leave my house with 70% knowing I’ll be doing that much more supercharging on the commute?

which is more detrimental? Supercharging often or operating the battery to its limits?

 

[Stuck4ger]

This thread reminds me of the back and forth arguments people would have on the VW forums as to when they should change their brake fluid.

I sometimes have the sun in my eyes and it seems to move up or down while I drive. Is it better to put the sun visor down all the way or just partially, as required? I find that sometimes I can just move the seat up all the way but I’m tall and then I can’t see as far forward. I’m working on a spreadsheet to compute life lifecycle cost of the visor hinge vs the seat motor. Hopefully I’ll get good data before my lease runs out and I trade it in for a Rivian.

 

[PhantomY]

I charged my model 3 for the last two years to 90% every day or two - did quite a few road trips where got down to 10/15 percent from 100% just when about to leave. After 53K km, battery range indicated at 499km - no change from delivery 2 years before. Expect that my new model y will perform as well if treated the same.

 

[laservet]

You have a really bad attitude about this and seem to want to be angry and insulting. I am telling you what the scientific data says about this. If you disagree or don't like what the information says, you are welcome to read up on it.


No--I already told you. This is not my opinion.

Interestingly enough, Elon Musk and Jeff Dahn, the world renowned expert in lithium ion batteries who works for Tesla now DO recommend lower than 90%! Citation:
Tesla battery expert recommends daily charging limit to optimize durability - Electrek
Tesla Battery Expert's Recommendation For Maximum Battery Life - Video
Quote from Musk when asked about recommended charging range: "80% to 30%"
Quote from Jeff Dahn: "I would recommend charging to 70% normally. When you need a long trip, charge to 100%."

And other sources:
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Here's the truth behind the biggest (and dumbest) battery myths | WIRED UK
Fast charging of lithium-ion batteries at all temperatures
Lithium-ion degradation at varying discharge rates - ScienceDirect
http://css.umich.edu/sites/default/files/publication/CSS20-08.pdf



Pardon for not posting links to citations before. I didn't make any such assumptions. Stop being insulting and putting words in my mouth that I did not say.


They already have all of this information, as shown by Musk recommending lower than 90%. It is very common knowledge; not "my knowledge".


1. I am not worried about degradation. It is a fact of life, and I have found a pretty comfortable balance for me around 70-80%.
2. I don't feel a need to argue with people on the internet. I don't appreciate seeing people spreading misinformation, though. You just flat out said Tesla recommends 90%. I filled in more detail of why that was a partial answer that is used by sales people, but if the experts within Tesla are asked for more details, they will readily tell people that it is not ideal. It was then you who got mad and started arguing.

I'm just giving detailed and accurate answers for people who are asking questions and want to know how this works. This is why Tesla has the charging screen interface set up with the "Daily" section available from 50% to 90%, with letting people choose where is a good fit for them.

That last article from the U of Michigan gives a great description of what’s involved. Thanks!

 

[Pilot1226]

I don’t own a Tesla but am hoping for a Model Y once my lease is up on my current ICE.

I’m stuck with 120V charging here but I am exploring either the 5-20 or TT-30 options and using the MC with the EVSE third party adapter used with the MC exclusively.

So, if I can swing the TT-30, I would just charge to 70%. If I have to do 5-20, I’ll probably do 80 during the week to avoid a supercharger stop. I can see my wife eyerolling me already when we have to do a charging stop.

90 on weekends regardless, as we drive to and from the shore areas for the weekend - that usually us around 120 miles round trip plus incidental driving while we are there - so figure 150ish. Then I need it to be ready for work the next day, which probably would be okay regardless, even if I pulled into the driveway with low charge, I’d still get enough for work (20 miles round trip with Superchargers within 5 miles of work)

@mechrock has an excellent Reddit article and thread about the law of diminishing returns and exponential
decay on the batteries with higher charge states. Ideally I would like to run with 60% SOC unless I needed it but that would make me want 240V to be less nervous.

 

[Rocky_H]

Good articles. I appreciate the info.
I have a 230 mile minimum round trip commute once or twice a week to an airport where I’d like sentry mode and cabin overheat protection on. Model Y dual LR -

Tradeoffs.....there’s a balance somewhere for me. Do I charge to 100% and mitigate the number of times and amount that I supercharge? (Knowing SCings negative effect on long term battery health) If I drive slow enough I can make the round trip depending on how many times Sentry mode is activated in the lot
Or....do i leave my house with 70% knowing I’ll be doing that much more supercharging on the commute?

which is more detrimental? Supercharging often or operating the battery to its limits?

If it were me, I would definitely do a short Supercharge on the way of a 230 mile drive. Mainly just because it's a pain to white-knuckle a drive to try to conserve energy when you really don't have to. A short 15 minute Supercharge session on this kind of drive that you say is once every week or two is just not that big a deal and isn't an excessive amount of Supercharging.

 

[TomServo]

This is kind of funny for us. We have owned a 2017 Volt for 4 years, it was purchased as my work vehicle (22 miles r/t for work) and as our DD running errands. It's performed brilliantly as you can see.

Here's how it performed with an EPA rating of 53 miles:

So with our new MY I guess I can set it to 30% or maybe I splurge to 40%.

 

[Pilot1226]

What were your oil change intervals on that thing? Curious.

 

[psuKinger]

Lotta great information in this thread. I'm charging to 90% until I get an electrician out to install my Gen 3 wall charger, at which point I plan to charge to only 80% to improve overall lifetime battery health (and bumping that value up only as-needed for longer trips).

One question though, that was mentioned but not debated in the kind of detail as Charge (%) was - what's everyone's take on smaller (let's say 20%-ish, for example) charging daily vs letting it run down a little more than than that (~40% or ~60%) and then charging every 2nd or 3rd day in terms of longterm battery health? Are the deeper discharges unhealthier for the battery as well? Or are you gaining anything by putting the battery through fewer "cycles," even if the per-cycle degradation is worse?

 

[artnalex]

What were your oil change intervals on that thing? Curious.

Every 25K miles. I have the same ‘17 Volt, but in grey. Great little car.

 

[TomServo]

Currently the battery life is rated at 500,000 miles, that’s way more miles then I ever put on any Ice car I have owned, on average 300,000 miles if that and it’s time to replace the car. I understand that at 300,000 miles on an Ice Engine and it’s time to replace the engine.

I charge to 90% every night. I’m in California which is home of Earthquake city. You need the 90% charge just Incase we lose power due to a schedule power outage or an Earthquake which could shutdown power plants as before. Note that Gas Stations are also out of commission during a power outage.

It’s been known that charging at 80% or lower will cause a mis-balancing of the battery and will start to show a lower range on the screen.

The car has been happy at 90% nightly. That’s my take.

Fred

What were your oil change intervals on that thing? Curious.

Per GM every 24 months. So I’ve done ONE so far and need to get it in for the second one soon. But as you can see I have less than 650 miles on the ICE. Oh and I have ZERO battery degradation, I still get the 14 kw’s I did when new. GM over engineered the Volt.

 

[Pilot1226]

That’s great. Shame they discontinued it. I’m not really a sedan driver. I prefer the hatch for cargo.

@psuKinger - In terms of absolutely best battery life, @mechrock had an article about the batteries generally liking to stay as close to 50% SOC as possible. So if you drive 10% range every day, 55% to 45%. If you drive 40%, that’s from 70 to 30. The median number is 50%.

Again law of diminishing returns here. The “extra” degradation is much less from 50 to 60 than it is from 60 to 70, and the most appears to happen from 90/95 to 100.

 

[Rocky_H]

One question though, that was mentioned but not debated in the kind of detail as Charge (%) was - what's everyone's take on smaller (let's say 20%-ish, for example) charging daily vs letting it run down a little more than than that (~40% or ~60%) and then charging every 2nd or 3rd day in terms of longterm battery health? Are the deeper discharges unhealthier for the battery as well? Or are you gaining anything by putting the battery through fewer "cycles," even if the per-cycle degradation is worse?

The is a very good question, but I need to explain what battery "cycles" are, because you're misusing it. You are referring to a charge event as a "cycle". But in articles and battery studies, a cycle is actually one complete content of the battery being depleted and refilled. So if you run down the whole thing--100% and then fill it all the way back up, or if you fun half and refill that twice, or one tenth and refill that ten times, those are all still just one battery cycle. Now of course not all cycles are created equal, as you are getting at with your question. Some of those charging methods are much harder on the life of it, depending on where that cycle is done and what temperature, etc.

OK, sorry for boring you, but now on to your question. You have it right that there is some difference, and the studies do show that smaller amounts being refilled more frequently is less damaging over time than running it down farther and then doing a much bigger recharge. But I'm not exactly doing the most ideal on that myself. We go two or three days at a time usually because we don't drive much, so even then, it's still barely getting down to about 50 or 60% before I refill back to 80%, so it's just not worth bothering with every single day for a little 5 or 10% top-up to me. And I figure I'm saving a little bit of wear on the charge port locking pin mechanism by using that half as many times. Meh.

 

[mechrock]

That’s great. Shame they discontinued it. I’m not really a sedan driver. I prefer the hatch for cargo.

@psuKinger - In terms of absolutely best battery life, @mechrock had an article about the batteries generally liking to stay as close to 50% SOC as possible. So if you drive 10% range every day, 55% to 45%. If you drive 40%, that’s from 70 to 30. The median number is 50%.

Again law of diminishing returns here. The “extra” degradation is much less from 50 to 60 than it is from 60 to 70, and the most appears to happen from 90/95 to 100.

I suggest reading over this post if you are interested in battery degradation and what's best for your battery.
Battery Degradation Scientifically Explained

Really is a gold mine of information and worth the read.

 

[DanDi58]

90% daily charge and this is why, I live in California which is home of the earthquakes. You should always prepare to have a good charge just Incase of a power outage. Note that even the Gas Stations are also down due to no power. But you can store a few gallons of fuel in the garage. Where as the EV don’t have that option.

Tesla also was nice enough to extend the range when we had those hurricanes on the East Coast mainly Florida and up the coast. If you’re in one of these locations whether Hurricane season or Earthquakes you should be prepared and have plenty of juice left in the tank to get the heck out of town.

Fred

Well, at least with a hurricane you get a couple days warning, so you can simply add this to the prep list... Not so with an earthquake unfortunately.

 

[ArtK]

You have a really bad attitude about this and seem to want to be angry and insulting. I am telling you what the scientific data says about this. If you disagree or don't like what the information says, you are welcome to read up on it.


No--I already told you. This is not my opinion.

Interestingly enough, Elon Musk and Jeff Dahn, the world renowned expert in lithium ion batteries who works for Tesla now DO recommend lower than 90%! Citation:
Tesla battery expert recommends daily charging limit to optimize durability - Electrek
Tesla Battery Expert's Recommendation For Maximum Battery Life - Video
Quote from Musk when asked about recommended charging range: "80% to 30%"
Quote from Jeff Dahn: "I would recommend charging to 70% normally. When you need a long trip, charge to 100%."

And other sources:
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Here's the truth behind the biggest (and dumbest) battery myths | WIRED UK
Fast charging of lithium-ion batteries at all temperatures
Lithium-ion degradation at varying discharge rates - ScienceDirect
http://css.umich.edu/sites/default/files/publication/CSS20-08.pdf



Pardon for not posting links to citations before. I didn't make any such assumptions. Stop being insulting and putting words in my mouth that I did not say.


They already have all of this information, as shown by Musk recommending lower than 90%. It is very common knowledge; not "my knowledge".


1. I am not worried about degradation. It is a fact of life, and I have found a pretty comfortable balance for me around 70-80%.
2. I don't feel a need to argue with people on the internet. I don't appreciate seeing people spreading misinformation, though. You just flat out said Tesla recommends 90%. I filled in more detail of why that was a partial answer that is used by sales people, but if the experts within Tesla are asked for more details, they will readily tell people that it is not ideal. It was then you who got mad and started arguing.

I'm just giving detailed and accurate answers for people who are asking questions and want to know how this works. This is why Tesla has the charging screen interface set up with the "Daily" section available from 50% to 90%, with letting people choose where is a good fit for them.

So, if the CEO of Anheiser-Busch said it was okay to drink a twelve-pack of beer every night, would you treat that as gospel also?

 

[Pilot1226]

I think there are technical limitations of Lithium batteries that are exacerbated by maximum charge capacity as “routine”.

80% daily or even 90% daily if you need it seems acceptable. I’m going to try 80 unless I have a trip.

 

[Rocky_H]

So, if the CEO of Anheiser-Busch said it was okay to drink a twelve-pack of beer every night, would you treat that as gospel also?

I'm not taking his word because he said it. I was pointing out that what he said also agrees with "The Science (TM)". You know--that thing that a lot of people these days think is elitist and not to be trusted.

 

[Arctic_White]

Randomly picked 80%. My average day I use 15% or so. So 65-80% is where I live.

Will report back in 10 years how it did!

I picked 90% as that's what the manual says.

Typical day would mean I'm using 15% of the battery, but some days (random) can be as much as 60% resulting in just 30% battery remaining.

I try not to go below 30% if I can help it, and my car has never gone below 20%.

I'll also report back in 10 years (if I keep my car that long) to see how the battery is doing.

 

[Rocky_H]

I picked 90% as that's what the manual says.

The manual does not say to use 90%. The car shows a range on the charge limit slider from 50% to 90% that is marked DAILY, and you get to pick where within that area works well for your balance of being nearer the middle if you want to be healthier for the battery, but being high enough that you have enough driving range to use.

That wouldn't make any sense at all, since 91% to 100% is not recommended for constant daily use and will display a warning if you do that. So 90% cannot magically be perfect if 91% is considered not recommended.