Charging Question

[flixden]

With the Tesla App, is it possible to charge the car to say 50% (or another set percentage) right after plugging it in, and then top off to say 80 or 90% right before a set departure time the next morning, or even a few days down the road?
Seems like that would be the best for the battery, right?

 

[E90alex]

No you can’t.

Best for the battery is to keep it as low as possible for as long as possible.

 

[flixden]

No you can’t.

Best for the battery is to keep it as low as possible for as long as possible.

Really?
I was always under the impression that the battery will be the happiest sitting at right around 50%, and that you wouldn't want it to be at 30% or below for extended periods of time.
I guess it could be done if you set the charge limit to 50%, and then later, when that charge is done, change it to the departure setting, and 80 or 90%, correct? But that seems a little tedious.

I also would not want it to be sitting there at only 20%, just in case something comes up, and you need to run an errand or go somewhere that wasn't expected.

 

[jjrandorin]

Really?
I was always under the impression that the battery will be the happiest sitting at right around 50%, and that you wouldn't want it to be at 30% or below for extended periods of time.
I guess it could be done if you set the charge limit to 50%, and then later, when that charge is done, change it to the departure setting, and 80 or 90%, correct? But that seems a little tedious.

I also would not want it to be sitting there at only 20%, just in case something comes up, and you need to run an errand or go somewhere that wasn't expected.

Im going to suggest reviewing this specific thread in the model 3 subforum which has a good discussion on battery charging percentage and is not (yet) 100s or thousands of posts on this topic as some of these threads go.

(edit, I guess the thread below IS "100s" of posts but not "1000s", yet... lol)

What Percent is Your Tesla Charged to While at Home?

Here’s a chart from the overdischarge test: This was performed with cells that had 2.7V min Voltage if I remember it right. Discharged to 1.5V/cell, they have almost the same cycke life. The exact 0% level is not extremely important, you should aim for not going below but if it happens, its a...

teslamotorsclub.com

To answer your original question, no you cant do what you want in an automated nature with just the tesla app. You might be able to do it if you subscribe to a third party app that interacts with your car. I dont do that, as I dont want anything interacting with my car other than the official Tesla app. Thats a personal choice I have made and I am not implying its correct, or others are incorrect by using third pary apps.

Pay particular attention to posts in the thread I linked to by member @AAKEE , who has put a lot of effort into understanding the topic of battery degradation, and includes lots of data driven information and not just "forum rumors".

 

[jcanoe]

Not with the Tesla app but you can use a 3rd party app to program a custom charging schedule.

You may want to sign up for a time of use (TOU) rate plan with the local power utility. The plan would provide cost incentives for you to charge during the off-peak window. In general you want to charge as late as possible before your planned departure time and only charge as much as you need for your daily driving.

 

[E90alex]

There is no problem with the leaving battery at lower SOC. ~55% is the biggest tipping point for battery degradation but below 50% is still (marginally) better.

You can manually change the charge level each time if you want. There are third party apps you can buy that can automate things like that but I don’t use them so I can’t give any recommendations.

How much are you driving per day? Do you have superchargers nearby?

 

[ATPMSD]

I would not, and do not, waste time worrying about this. Set the car to 90% and forget about it. If you do not have a TOU plan plug in the car when you get home. If you do, set Scheduled Charge or Scheduled Departure, and then plug in the car.

There is a lot of very well intentioned advice but there is no hard data to support it. The advice is based on general characteristics of lIthium batteries and some lab tests, but none are based on the Tesla HV pack. Based on my readings, my opinion is battery degradation is mostly related to age.

 

[Grabthar]

You can also set your charge level with a departure time. Say you set your charge level to 80% with a departure time of 7:00 am. It will just sit there all night long and figure out when to start charging such that it will be at 80% when 7:00 am rolls around.

From the user manual:
Use Scheduled Departure to set a daily time when you want Model 3 to be ready to drive. Model 3 automatically calculates when it needs to start preconditioning and/or charging. This ensures that charging is complete and/or the cabin climate and Battery are preconditioned by your departure time.

When Scheduled Departure is displayed, touch Schedule to set a daily time when you want Model 3 to be ready to drive. Specify a time, then touch Settings to enable one or both of the following departure features. When plugging in with Off-Peak Charging enabled, the vehicle briefly draws power (you may hear clicking) to calculate the necessary charging start time.

 

[AAKEE]

I would not, and do not, waste time worrying about this. Set the car to 90% and forget about it. If you do not have a TOU plan plug in the car when you get home. If you do, set Scheduled Charge or Scheduled Departure, and then plug in the car.

There is a lot of very well intentioned advice but there is no hard data to support it. The advice is based on general characteristics of lIthium batteries and some lab tests, but none are based on the Tesla HV pack. Based on my readings, my opinion is battery degradation is mostly related to age.

I will start with saying two things:
1) -90% is OK. Your battery will survive, so no problems. But it won’t have the lowest degradation.
2) -You will struggle really,really hard to find *any* evidence that 80 or 90% is the best SOC for the longevity of the battery. I have tried this myself, to try to shoot the things I learned down from a lot of research by trying to find something that shows that its wrong. Just to be sure. The only thing on that side of the coin is myths with no data to back it up.


I do not base my statements on a opinion.
I read the research and I follow and learn the sum of all research that builds the case.

There is no single test data that show something very important. They do this together. And the data is so solid that I could calculate your cars degradation/displayed range if I get some numbers.

This is Tesla model S cells ripped lut of a 6 months old car (2017, I think):
If we take this data and put it in the other calendar aging charts, it matches very well.

20% and 50% SOC show even less degradation than the regular calendar aging charts does. There is s very probable explanation. If cells have been used at higher SOC, after lowering the SOC and leaving them there, or cycling them at low SOC they show a recovery effect where lithium restorts from lithium plating to cycleble lithium.
We should not think that 20% SOC will give exactly zero, it would have been just like any other chart if the car had’nt been used with 70-90% SOC or so.

Note that 100% show lower degradation than 80%. About 2/3 of the research reports show that 80% is about the worst SOC for calendar aging and that 100% might be less bad. Note that not all research show this, in some its about the same 70-100% and in some 100% is slightly worse, specially att higher temperatures.


Heres the two step cyclic degradation test:

Data from this research report

 

[flixden]

I will start with saying two things:
1) -90% is OK. Your battery will survive, so no problems. But it won’t have the lowest degradation.
2) -You will struggle really,really hard to find *any* evidence that 80 or 90% is the best SOC for the longevity of the battery. I have tried this myself, to try to shoot the things I learned down from a lot of research by trying to find something that shows that its wrong. Just to be sure. The only thing on that side of the coin is myths with no data to back it up.


I do not base my statements on a opinion.
I read the research and I follow and learn the sum of all research that builds the case.

There is no single test data that show something very important. They do this together. And the data is so solid that I could calculate your cars degradation/displayed range if I get some numbers.

This is Tesla model S cells ripped lut of a 6 months old car (2017, I think):
If we take this data and put it in the other calendar aging charts, it matches very well.

20% and 50% SOC show even less degradation than the regular calendar aging charts does. There is s very probable explanation. If cells have been used at higher SOC, after lowering the SOC and leaving them there, or cycling them at low SOC they show a recovery effect where lithium restorts from lithium plating to cycleble lithium.
We should not think that 20% SOC will give exactly zero, it would have been just like any other chart if the car had’nt been used with 70-90% SOC or so.

View attachment 939317
Note that 100% show lower degradation than 80%. About 2/3 of the research reports show that 80% is about the worst SOC for calendar aging and that 100% might be less bad. Note that not all research show this, in some its about the same 70-100% and in some 100% is slightly worse, specially att higher temperatures.


Heres the two step cyclic degradation test:
View attachment 939318

Data from this research report

Thanks a lot, much appreciate it.
I also read through the "what-percent-is-your-tesla-charged-to-while-at-home" thread, well half of it at this point, and saw many of your posts.
Excellent data!
So ... to sum up my takeaway: it's best to keep the SOC as low as possible, for as long as possible. Of course, it will have to be within a practical range, and that will be different for different people.
But: there is no harm in running the battery down to a very low SOC on a regular basis, as long as you don't run out.

Basically, I will start charging then only before departure, and not worry about getting the SOC to 50% right after getting home.
Also, when away on vacation for 3 weeks, I should aim for a low SOC, say 20%, and leave it there if possible.

Did I get this all correct?

 

[AAKEE]

Basically, I will start charging then only before departure, and not worry about getting the SOC to 50% right after getting home.
Also, when away on vacation for 3 weeks, I should aim for a low SOC, say 20%, and leave it there if possible.

Did I get this all correct?

Yes, you did.

Remember to have a margin for range anxiety, then you are good.

If you have an LR/P in USA, then 55% is the magic number.

I use 55% as a daily SOC as it gives more range than 50% at almost no increase in degradation. Charging on schedule 03:30 AM, rendring it done some time before the normal ”go to work time”.

The Tesla is very safe battery wise down to 0% displayed, but dont leave it at 0% for extended periods.

I often park at my work with 15-20%, and the the car will be parked for a week or sometimes short trips to the store during the week. The 15-20% covers that need.
Then I charge to 70-80% directly before driving 240 km home.

For long time away, learn how the car normally use the SOC. My looses about 1% each week so 15-20% would be enough for 2-3 weeks with a good margin.
For the vacation, anything at 55% or below already cut the calendar aging in half so thats also quite good.

 

[E90alex]

Also, when away on vacation for 3 weeks, I should aim for a low SOC, say 20%, and leave it there if possible.

Did I get this all correct?

If leaving for a long trip I would personally leave it plugged in set to 50% (as that’s the lowest possible setting).

In theory it should be fine unplugged at 20% with sentry mode etc off and don’t touch the app on your phone. But sometimes random phantom drains occur and could drain the battery dead which will also drain the 12V dead since it can’t recharge itself.

Leaving it plugged in also let’s you initiate charging on your way home if needed so it’s ready to go.

 

[flixden]

Thanks to both of you!!

 

[AAKEE]

If leaving for a long trip I would personally leave it plugged in set to 50% (as that’s the lowest possible setting).

In theory it should be fine unplugged at 20% with sentry mode etc off and don’t touch the app on your phone. But sometimes random phantom drains occur and could drain the battery dead which will also drain the 12V dead since it can’t recharge itself.

Leaving it plugged in also let’s you initiate charging on your way home if needed so it’s ready to go.

Its a good Idea.

We was in US on holidays last year for about three weeks. The season back home was thunderstorm season and all neighbours had their robot lawnmoiver and tv-systems etc broken dure to a thunderstorm/lightning taking iAll equipment out.
I left the car non-hooked and would have used a friend for this if it would have been needed. (But I also new my car, knowing it doesnt draw any noticable amounts during one week. It lost below 2% during these weeks.

 

[USMCO3]

You can do that. You can adjust the charge limit right from the app. Regarding if it’s best for the battery everybody has their own opinion. I Simon follow the owners manual and charge to 90% every time I plug it in.

 

[AAKEE]

You can do that. You can adjust the charge limit right from the app. Regarding if it’s best for the battery everybody has their own opinion. I Simon follow the owners manual and charge to 90% every time I plug it in.

90% is good, but it is not per the Tesla manuals I have seen.

There might not be a noticable difference between charging to 90% and to follow the manual, but it says ”to under 90%”, at leadt for the model 3 and Y.

Following the manual word by word ”Under 90%” would mean any setting below 90, thats 50-89%.