Hi
@AAKEE I discovered your posts since a couple of months and your tips are fresh air in an ocean of fake myths.
I bought model 3 on September 2020 and my use case is a little bit strange: I use my car on weekends only.
I changed job last year. Before I commuted weekdays, a 60 miles roundtrip.
Now I work 160 miles away, but one week at the time and about one week of three or four. So the car stands at home (or is driven very short by my wife to her job) but I have kept the 55% SOC charging target to have freedom of action.
This slightly rises my average SOC from some 30-35%, to 46 or so at the moment. In the end it might be over 50% as I often only do short drives when being home and free.
In the balance between easy ownership I think 55% is the sweet spot for me. Its possible to lower to 50% but what the heck, it will not be no noticable difference in the long run.
If the extreme lowest degradation was the goal, I could have the car at 20-30% and time the charging so it was stopped at 30%. But then I couldnt unplanned drive to the bigger city 45km away, at least not in wintertime and still have SOC to have the freedom of movement.
Also, I wouldnt have done 45 supercharging sessions and about 25-30 full charges.
If you only drive it at weekends you could either charge it “always” to 50% or so or not charge it in the end of the weekend. Leaving it at 10-30% is not bad.
If the lowest degradation is more important to you than the freedom to be able to go away at any point, leave it low in the end of the weekend and charge just before the first drive on the next weekend. Do not charge more than needed and charge often.
Before you set yourself into a habit that makes it hard to own the tesla, remember that the battery would hold up anyway, and that the keeping low-principle with charging to 50-55% instead of 80% and use low soc cycles with “charge often” will cut the usual degradation in half. I can not decide it for you, but i can say that my approach is “without making it awkward”.
So I tried to study so many publications, websites, service tickets and so on, to try to keep my battery sound and safe.
Because I can't "regularly charge it" like every commuters like you!
(Maybe I should have worried more about the paint on the car instead..)
There is something that confuses me since day one: this sentence in the user manual
View attachment 901022Expecially during COVID lockdown (I'm from Italy) I leaved my car plugged, target SoC to 50%.. for weeks.
If I had read your posts some years ago I would have kept it unplugged! Or at least I would stop the charge.
I always connect the cable when arriving at home (I have the WC in the garage slot for my Tesla).
I have it set to scheduled charging. It does not start the charging when the cable is connected. The charging starts on the set time only.
In your opinion, why the Tesla wrote this paragraph?
First: Teslas recommendations is not always for giving the absolute lowest degradation.
They of course have a combination of giving acceptable degradation with as few “rules” as possible. It is supposed to be easy to own a EV, otherwise Teslas vision wont be fulfilled.
In my opinion that sentence is misleading and DANGEROUS!
Nope, it is not.
Always connected is one easy “rule” that helps with a lot:
- All consumption when the car is parked will be drawn from the net. This means less cycles for the battery. Reduces cyclic aging.
- It will ensure “charge often” which gives smaller cycles, that reduce the cyclic wear
- You will not forget to charge the car, comming out the next morning, stressed to go to work and find the car nor connected or charged would not make you happy.
The main basics for Tesla is to ensure that not too many cars (more or less none need a battery change within warranty).
You can not sell a EV, advertise 300 miles range and in the same time recommend to keep it at 10% with almost no practical range.
So Tesla calculates that you charge to up to 90% daily. 80% is probably as “bad” or even slightly worse.
If you do 80% every day and live in a hot climate you might loose 7% the first year. After 8 year in total you will be about 20%.
But each year then you only have 1% calendar aging each year, and it is slightly reducing so the car will be worn out before the battery is dead.
If you did charge often, you did have small cycles so the cyclic aging was very small.
There still is a good margin to the 30%.
I think Teslas advice is very good. In general, to conquer the world with electrical vehicles, they need to prove easy to use, and the owner need not to feel constrainted by rules and “donts” or range anxiety etc.
Remember, the battery will survive by only following Teslas simple advices.
There is only one wrong thing with Teslas advices: The rumors that says “Tesla says” when Tesla doesn’t.
My posts is
not needed to save your battery from the death.
My posts has two purposes:
-Help with killing the myths so people doesn’t do contraproducing things like wonder “why the degradation is high despite always babying it at 80%”.
- For the ones that like to minimize the degradation for other reasons, help with tips how to keep the degradation low.
Also I was afraid to go down to 20%.. another stupid tip I got from manual!
I think one of the myth’s did get you
Please read the manual and enlighten me where to find that dont go below 20% (Actually one of the first things i did after getting my Tesla and reading here at TMC, a swedish forum and participating in some facebook groups was skimming the manual, and teslas online pages to find what they really did write and recommend. I did this as the most common forum line was “tesla says”, but I could not find these.)
For example, Tesla writes about leaving the car for an extended time, at an airport or so. They say that we should count with 1% SOC loss per day and that two weeks = 14%. There is no information about having 20% as the lower limit. (I was to lazy to find the english version but this is my manual in swedish stating this).
On the contrary to “20%” the manual actually states that there can be damages of the HV battery get dsicharged below 0%. They even give the example of the LV battery (12V) that is a lead acid battery and these do not like to get discharged at all. A drained lead acid battery will loose capacity.
If 20% was as bad as the forum myth, first of all, Tesla would write about it. Secondly, my battery would be gone (instead of showing very low degradation, as it does. 495-497km range out of 507km after 2 years and 57K km).
I have not ever seen Tesla write about the 20%, ever. I would call it a fat myth, not founded by Tesla.
This is a picture from a old aerticle, 2006 or so. Tesla was probablyt quite new at this, and the batteries of today do not have that 2% limit. Anyway, as our Teslas still has 4.5% true SOC when 0% is displayed, and the battery cell voltage is not below 3.00Volts, we can not reach that state without driving below 0%. I have driven down to -2% that is about 2.5% true SOC twice.
The recent research tell us that it is quite safe down to 0% true SOC, but in our case we doesnt need to think about it as We are above that 2% true SOC if we only drive down to 0% displayed.
I can't understand if leaving it plugged and "charge stopped" is the same to leave it unplugged.
As I did write above, it reduces the charging cycles by using any needed power directly from the net and therefore less charging and discharging cycles. Does not do very much for my car that is using very little energy parked….like 1% a week or so.
But the advice is for everyone, and some people use sentry all year.Sentry over one year would be > 20 FCE cycles (20 cycles of 100%-0%).
During winter, preheating and battery conditioning etc use much energy if used each day. Same as with sentry.
teslamotorsclub.com
