What should my ideal charge percentage be?

[DayTrippin]

22 Plaid with 17k miles. I charge to 90% every night which the Tesla guy said was perfectly fine.

So 17k miles and a 14% drop in less than a year. I'd personally be pretty concerned. I have 9k miles on my 2022 S (about 9 months on it) and I have less than a 1% drop. I have very hot summers and Texas and Florida. I almost never charge over 50% except when going on a long trip and I charge up just before I leave.

So if I do the math, you've have maybe double my miles, have about 14x degradation and you live in a much cooler climate. I think I'll stick with my charging routine. For another reference point, the person who bought my Y, and lives in Texas, has a total of 38k miles. He has been following my charing protocol as much as possible but has one long commute each week of 280 miles. He charges at a higher level just for that.

His degradation is at 7% and many of the (20-25k) miles have been in pretty hot weather. He just charges up to 90% before he leaves and then keeps the charge level at 50% or lower when not on his long commute. Other than the one day, his typical commute is maybe 30-50 miles.

 

[patgilm]

So 17k miles and a 14% drop in less than a year. I'd personally be pretty concerned. I have 9k miles on my 2022 S (about 9 months on it) and I have less than a 1% drop. I have very hot summers and Texas and Florida. I almost never charge over 50% except when going on a long trip and I charge up just before I leave.

So if I do the math, you've have maybe double my miles, have about 14x degradation and you live in a much cooler climate. I think I'll stick with my charging routine. For another reference point, the person who bought my Y, and lives in Texas, has a total of 38k miles. He has been following my charing protocol as much as possible but has one long commute each week of 280 miles. He charges at a higher level just for that.

His degradation is at 7% and many of the (20-25k) miles have been in pretty hot weather. He just charges up to 90% before he leaves and then keeps the charge level at 50% or lower when not on his long commute. Other than the one day, his typical commute is maybe 30-50 miles.

Not too worried, that’s what a warranty is for. I want to enjoy my car and it’s my daily driver. If I worry too much about this stuff it will take the joy out of having this car. I’m not keeping it for 10 years. I’ll keep it until I see something better.

 

[AAKEE]

LOL no believe it or not I asked them because of this thread and was just curious. I did notice when I charged to 90% when I got the car it showed a range of 353 miles and now it shows 319 miles but the range it shows really doesn’t mean anything.

The car is calculating the range (shown at the battery symbol) by dividing the estimated battery capacity with a fixed constant. Usually there is a margin (”degradation threshold”) at top so the battery can loose a couple of percent capacity before the range start to drop.
For model 3 the margin is about 2.5% or so.

So there is a direct link between the displayed range and the estimated battery capacity.
I guess you have the 19” wheels ”mounted” in the dispaly menu?
I think it is a interesting case, might get a Plaid one day.

Maryland can get hot in July/August and today it is unseasonably cold at 32 degrees Fahrenheit.

Not that warm climate then. Asking because the temperature has a big effect on the batterys degradation from time (calendar aging).
Judged from the sum of research on NCA batteries, the first year would ”cost” about 5-6% in calendar aging if charging to 90%
Its a new battery cell, I think, so there might be differences to the latest research we can read.

What about power? Batteries degrade faster from high current (= high power) and the Plaid really has that possibility.
Did you use a lot of power very often?
I think the battery is about 100 kWh, and 1020hp is about 830kW battery power drawn from the battery (including losses).
This is 8C, a quite high power demand for a battery. The power bursts are normally short as not much time is needed to reach high speeds, and short is less ”bad” than high current during longer time.

I have a M3P and did a lot of 0-60mph runs this summer, and use the power quite often but mist often short bursts. The M3P loose power above 60mph so a longer full power run do not use high power for long.
The M3P only top out at about 5C, so about the half C-rate in total.
I did not really see a clear connection between used power and battery capacity loss in my car.

 

[AAKEE]

So 17k miles and a 14% drop in less than a year. I'd personally be pretty concerned. I have 9k miles on my 2022 S (about 9 months on it) and I have less than a 1% drop. I have very hot summers and Texas and Florida.

Because of the degradation threshold, the degradation looks much smaller initially.
The answer @patgilm got is battery degradation (without hiding the loss above the threshold). It also implies that some 3.5% is hidden above the threshold.
So if you used the displayed range for your calculations you might be a bit higher than 1%.

I almost never charge over 50% except when going on a long trip and I charge up just before I leave.

I would do the same! (Actually I do, but I use 55% as the standard charge. 50% is better if only looking at degradation)

So if I do the math, you've have maybe double my miles, have about 14x degradation and you live in a much cooler climate. I think I'll stick with my charging routine.

The math from the display set @patgilm at about 10% (10.5%). But as there is degradation hidden, its not a straight comparison to use that calculation.

I would guess, from research data that you have lost somewhere between 3-5% looking at the research calendar aging graphs. Estimating between 25C and 40C for 10 months so 4% is a fair guess?
[Edit] My data from >1 year logging (model 3) implies that the battery cells will be about 5C /10F or so above ambient when the car is standing in the sun. Or slightly more then 5C. A very cloudy day or night or inside the garage the cells end up at ambient temp [end edit]

If you did loose 1% displayed range and the hidden part is 3.5%, this might point in the same direction.

Is there a on screen energy app available in model S to calculate the battery capacity?
Would be interresting to compare with the energy app values…

 

[AAKEE]

Maybe @patgilm and @DayTrippin can try this to see the energy app: (if it isnt updsted and the button is present)

https://twitter.com/x/status/1518979653813161984

(Use voice command to view the energy graph)

 

[AAKEE]

His degradation is at 7% and many of the (20-25k) miles have been in pretty hot weather.

During cycling ”hot” is good. The best temperature for cycling is quite high.
This can be seen here, the calenad aging line is due to the time needed to perform these cycles, so the interresting part is the difference between the total degradation and the calendar aging line.

So a battery temp between 25-40C is good when driving.
(We also can see that 500FCE cycles which is in the ball park of 200-250K km or 130-150k mi or so, so cyclic aging is quite small and almost negligable for one year.)

He just charges up to 90% before he leaves and then keeps the charge level at 50% or lower when not on his long commute. Other than the one day, his typical commute is maybe 30-50 miles.

 

[DayTrippin]

I am not sure what active cooling measures the car does for the pack when plugged in and not charging, but our garages are not heated or cooled. In my garage at my house in Texas, I often see temps in excess of 100F (38C) in it during the summer. My garage in Florida isn't much cooler typically. If the car is left outside in Texas, the ambient temps sometimes hit 108F (42C) as well.

I used to use the "old" energy app until they removed it. Now it is back but to get it, I will have to upgrade and lose radar. I have had basically no phantom braking issues with my S and I can use AP up to 90 mph and have the following distance that works in my traffic. I may never upgrade versions of SW again on my S. My 3 was delivered without radar so I am following the normal upgrade cycle there.

As for high power usage and the effects on the battery, I have the LR. My thought when I bought the LR is if the pack is made for the Plaid, and the LR can't draw as much power from it, it should be easier on the batteries. Having owned the LR for a while, 99.99% of the time I can't use the power it has so the Plaid would be even more of a waste in most of driving. I can rarely even get to open up the 3 much since we moved. Traffic is just so dense and slow moving. Really kills the joy of having a fast car.

 

[ucmndd]

I am not sure what active cooling measures the car does for the pack when plugged in and not charging

Basically none until you get to real extreme temperatures (~100f isn’t enough).

 

[patgilm]

Maybe @patgilm and @DayTrippin can try this to see the energy app: (if it isnt updsted and the button is present)

https://twitter.com/x/status/1518979653813161984

(Use voice command to view the energy graph)

I will do that when I can. In the meantime, here is the message I received from the Tesla service guy.

"I have completed the range analysis on your vehicle and fount it to be in good working order at this time. You may see reduced range displayed on your vehicle due to two factors at this time. The first is that cooler temps will reduce range and the algorithm will compensate, the second is that you have kept the vehicle between 60% and 90% for its lifetime so far. Energy in a battery cannot be measured, it has to be estimated, the algorithm will complete these estimates with an abundance of caution. This is also causing the calculated capacity to read a little low on your vehicle. I have also sent a range analysis to your email to give you an idea of where the energy is going. Please let me know if you would like a call to discuss this further or if I am ok to close this request at this time."

I ended up having him call me to discuss and that is where he explained things to me about the 14% loss and that it is nothing to worry about and to just keep doing what I'm doing.

 

[DayTrippin]

Keep in mind Tesla's best interests and yours are often at competing ends of the spectrum. All they need is for your car to make it to the end of the warranty period within their specs. Sort of what I'd call just above a worst case scenario. The sooner or more your car degrades/fails after the warrant period, the sooner you will be in the market for another car. Additionally your degradation might be "in spec" per Tesla but at the same time, the increased degradation can also impact resale value.

There are mounds of data out there that all pretty much say the same thing. For a good example of how high charge levels impact lithium batteries, just look at your cell phone and laptop batteries. Apple for example now tries to keep your charge state lower other than when you might need the capacity. Keeping your cell phone on the charger all night long at max charge definitely degrades the battery more quickly.

My wife and I both bought the same iPhone 3 years ago. I use mine a lot more than she does. Every night she place her phone on the charge and it was at 80- 100% all night long. I basically kept mine between 50-70%. We just traded our phones in. According to Apple battery app before we got rid, her phone had lost almost 20% of its capacity. My phone had lost 4%. I definitely used my phone a lot more and had a lot more charge cycle.

I'll take what Tesla always says with a grain of salt. My front hood panel gaps were "in spec" and it was no issue even though they let in water. Same for my driver's door gap. It was so tight my door hit the fender and removing paint and that was ok too.

 

[patgilm]

Fair enough, but to enjoy something like this car I don’t want to have to “monitor” it all the time and keep it within a certain percentage all the time. It’s just not worth the hassle. I drive a lot and I like to use sentry all the time so my charge goes down a lot on a daily basis and I don’t want to have to worry about how much range I have left if I don’t have to.

Also, isn’t the battery warranty 10 years? If so I’m not too worried about them telling me what I want to hear because 10 years is a long time.

As for resale value, what percentage of car buyers are obsessed about the battery that they are monitoring this to make sure it is operating at max capacity? Probably a very small population when most people have a hard time monitoring the basic maintenance on an ice car.

 

[Fiver]

Fair enough, but to enjoy something like this car I don’t want to have to “monitor” it all the time and keep it within a certain percentage all the time. It’s just not worth the hassle.

Then this is not the thread for you.

 

[patgilm]

Then this is not the thread for you.

Very true, I just happened to stumble upon it and it piqued my curiosity, didn’t mean to offend. I will politely exit from here on out.

 

[AAKEE]

Then this is not the thread for you.

It sure is, or at least was.

Very true, I just happened to stumble upon it and it piqued my curiosity, didn’t mean to offend. I will politely exit from here on out.

You have made an active choice of what SOC to use and you know that it might cost a little more degradation.
There is nothing wrong with choosing 90%

 

[Dave EV]

Fair enough, but to enjoy something like this car I don’t want to have to “monitor” it all the time and keep it within a certain percentage all the time. It’s just not worth the hassle. I drive a lot and I like to use sentry all the time so my charge goes down a lot on a daily basis and I don’t want to have to worry about how much range I have left if I don’t have to.

Also, isn’t the battery warranty 10 years? If so I’m not too worried about them telling me what I want to hear because 10 years is a long time.

As for resale value, what percentage of car buyers are obsessed about the battery that they are monitoring this to make sure it is operating at max capacity? Probably a very small population when most people have a hard time monitoring the basic maintenance on an ice car.

What I would recommend is find the lowest max charge that works for you without having to think about it.

Just know that you will have to slowly raise this over time as the battery degrades.

 

[DayTrippin]

Fair enough, but to enjoy something like this car I don’t want to have to “monitor” it all the time and keep it within a certain percentage all the time. It’s just not worth the hassle. I drive a lot and I like to use sentry all the time so my charge goes down a lot on a daily basis and I don’t want to have to worry about how much range I have left if I don’t have to.

Also, isn’t the battery warranty 10 years? If so I’m not too worried about them telling me what I want to hear because 10 years is a long time.

As for resale value, what percentage of car buyers are obsessed about the battery that they are monitoring this to make sure it is operating at max capacity? Probably a very small population when most people have a hard time monitoring the basic maintenance on an ice car.

I understand where you are coming from. At the same time, I find charge to 50% covers 99% of my driving, at least on my S, which has better real world range then the 3 or Y.

Here is Tesla's warranty info. For batteries it is 8 years. Keep in mind, they don't do anything until it is over 30% degradation. So if you get to 29% in the first year, they won't do anything until it is over 30% according to the service adviser I spoke with. A 30% hit is pretty significant to range.

Battery and Drive Unit Limited Warranty​

The Battery and Drive Unit in your vehicle are covered for a period of:

Model S Model X	8 years or 150,000 miles, whichever comes first, with minimum 70% retention of Battery capacity over the warranty period.
Model 3 Rear-Wheel Drive	8 years or 100,000 miles, whichever comes first, with minimum 70% retention of Battery capacity over the warranty period.
Model 3 Long Range Model 3 Performance Model Y Long Range Model Y Performance	8 years or 120,000 miles, whichever comes first, with minimum 70% retention of Battery capacity over the warranty period.

On another vehicle I had, it was a self-defeating cycle with respect to degradation. I didn't need to charge to a high level at first to have enough range to cover my trips. Then as it declined, I had to charge more and more until ultimately I had to charge to 100% to have any usable range. One of the reasons I bought the S is it had the longest range of any Tesla and I could keep my SoC at a lower level and still have a large buffer for my range.

I think the key to all of this is to keep your AVERAGE SoC as low as comfortable. So if you charge to 90% and quickly are down to 50% it will be less harmful than charging to a high SoC and leaving it there for a long time in high temps. So I keep my SoC as low as makes sense and charge to a higher level just before I leave. Working great for me and even more important since I operate our Teslas in such a hot environment.

As for impact on resale value, I'd say less of an issue earlier but there is a lot more info out there about BEVs in general. So more info published about the topics elevates it in the mind of the consumer. I've actually had people ask me how my batteries are holding up when then approach me about one of the cars. I know when I sell our BEVs I also mention if the degradation is very low.

At the end of the day, it is everyone's money and car and use it how they want. I plan to keep mine pretty long term so it matters to me. I wasn't sure how long I would keep it because of the abysmal yoke but since I swapped that out, I am pretty happy with the car other than the remaining idiot design choice of removing the stalks.

 

[tesluv108]

Is there anyone here with a 90kwh battery that has had the Tessie app a while? I’m curious if you would post your battery degradation as measured by the Tessie app. I’ve only had the app a month and haven’t had enough charge cycles to really get a feel for the true degradation as I think the app doesn’t adjust until several charge cycles. For example when I first installed the app and measured the degradation it was saying 0% which is impossible. Now it’s up to .4% which is still too low for a 7 year old battery. Wondering what others who have a 90kwh battery around my age show for “usable capacity”. The car is a 11/2015 build with 6550 miles on it so I expect minimal degradation but not this low.

 

[zoomer0056]

Is there anyone here with a 90kwh battery that has had the Tessie app a while? I’m curious if you would post your battery degradation as measured by the Tessie app. I’ve only had the app a month and haven’t had enough charge cycles to really get a feel for the true degradation as I think the app doesn’t adjust until several charge cycles. For example when I first installed the app and measured the degradation it was saying 0% which is impossible. Now it’s up to .4% which is still too low for a 7 year old battery. Wondering what others who have a 90kwh battery around my age show for “usable capacity”. The car is a 11/2015 build with 6550 miles on it so I expect minimal degradation but not this low.
View attachment 877128

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[Fiver]

Ha, the thread title is "what should my ideal charge level be?" The thread is currently 53 pages long, and the VAST majority of posts are about the long known facts regarding Li-Ion batteries: "Keep it charged around the middle of the pack, don't let it sit at 100%, try to keep it to shallow charge/discharge cycles when possible, & avoid extreme heat/cold."

"Naw Ima charge to 90% and not worry about it."

Well yea, then this thread clearly isn't for you. You do you.

 

[David29]

After reading this thread I put in a service request to check the health of the battery and got a call from the service guy yesterday and he said my battery is at about 86% and he looked at my charging history and said I’m doing nothing wrong, keep doing what I’m doing. Health of my battery is fine and within spec. If it gets below 70% then it could be replaced under warranty.

Did you have Tesla do that health check? What did they charge for that task? Is your car in or out of warranty?