Best way to charge to prevent battery degradation?

[D.E.]

“In the world of batteries, the 0% SOC is defined as the stop discharge (cut off) voltage, 2.5V in many cases for lithium ion like Tesla NCA.”

You’re doing it again, now using the “0% SOC” instead of a fully discharged voltage level of zero. SOC is a calculated value based on the full charge and the battery manufacturers acceptable discharge floor. It’s still an artificial number. That floor is still your 4.5-5% residual capacity.

I say a battery discharged to zero remaining capacity, having a 0 volt output will be damaged. You say a battery discharged to a residual charge of 4.5-5% and a voltage of 2.5V won’t be damaged. I have no problem with that. The electrolytes in your 5% charged battery are not exhausted. I doubt you disagree with my point that a battery discharged to the point it produces no voltage will likely be damaged.

if OK with you, let’s agree on the above and put this dog to bed.

 

[s_roick]

2021 MYP here. I am now down to ~260 max range. I am going to try the common method of letting the battery get below 10%, letting it sit for an hour, and then charge to 100% to see what that can do. Only about 10k miles so it is quite frustrating to see max range down to this from starting at 303 miles.

 

[jcanoe]

2021 MYP here. I am now down to ~260 max range. I am going to try the common method of letting the battery get below 10%, letting it sit for an hour, and then charge to 100% to see what that can do. Only about 10k miles so it is quite frustrating to see max range down to this from starting at 303 miles.

There is no need to charge to 100%, 95% is fine (takes much longer to charge to 100%.) The objective is to enable the battery management system to be able to measure the open cell voltage (OCV) of the cells in the battery pack over a wide range of state of charge.

The Tesla Model Y must be in sleep mode, not standby mode (awake) for the OCV measurement. The OCV measurement process takes at least several hours. Sentry mode must be off so that the Tesla Model Y can enter sleep mode (Summon Standby (a FSD feature) has to be off too.)

It can take several weeks of driving and charging to different charge levels to see a difference in estimated range. You may see an increase of displayed range of 5%. It is up to you if it is worth the trouble. Afterwards, the Tesla Model Y may slowly lose any estimated range gain.

Anytime you want to increase your real world driving efficiency and range by ~10% just lower your highway speed by 5 MPH. Lowering your speed by 10 MPH can net almost a 20% gain in efficiency and range.

 

[aronth5]

Own a 2020 MY with 32k miles on it. 2 days ago charged to 90% which gave me 263 miles of range. Typical. Before departing for a trip I bumped up the charge to 100%. Since I would be leaving in an hour didn't expect the final 10% to finish with the last 10% usually taking a long time due to do tapering.
I was completely surprised when in exactly 1 hour the charge completed at 293 miles. There was no tapering timewise. Charge rate showed 30 miles of range per hour which is the max for my wall unit. Between the MY and the M3 I've done this final 10% charge many times before and never had a full charge with no tapering.
Any explanation?

 

[jcanoe]

Own a 2020 MY with 32k miles on it. 2 days ago charged to 90% which gave me 263 miles of range. Typical. Before departing for a trip I bumped up the charge to 100%. Since I would be leaving in an hour didn't expect the final 10% to finish with the last 10% usually taking a long time due to do tapering.
I was completely surprised when in exactly 1 hour the charge completed at 293 miles. There was no tapering timewise. Charge rate showed 30 miles of range per hour which is the max for my wall unit. Between the MY and the M3 I've done this final 10% charge many times before and never had a full charge with no tapering.
Any explanation?

Your Tesla Model Y's battery management system determined that cell balancing was not required after charging had completed for this charging session. There is some tapering above 95% and also cell balancing at the end of the charging session. The cell balancing is in part responsible for the additional time needed to charge to 100%, complete the charging session. (The battery state of charge can show 100% while the Tesla Model Y continues charging, cell balancing for up to an additional 40 minutes.)

 

[aronth5]

Your Tesla Model Y's battery management system determined that cell balancing was not required after charging had completed for this charging session.

Good to know and thanks. Have never had that happen after 5 years of ownership with 2 Teslas. I rarely get below 100 miles of range and typically charge to 70%. However 2 weeks ago I was down to 25 miles the lowest for this car ever. I wonder if that attributed to this? First 100% full charge since then allhough I did do a 95% charge last week.

 

[AAKEE]

Good to know and thanks. Have never had that happen after 5 years of ownership with 2 Teslas. I rarely get below 100 miles of range and typically charge to 70%. However 2 weeks ago I was down to 25 miles the lowest for this car ever. I wonder if that attributed to this? First 100% full charge since then allhough I did do a 95% charge last week.

No, as you did charge to 90% before the 100% charge and the car was able to sleep between it also performed a balancing at 90%. So most of the balancing was already done when you charge to 100%.

 

[adiecidue]

Its actually the other way around.

The urban legends is like:

”Charging to 80 (or 90%) is the best for longevity because Tesla says that”
—> IRL Tesla say ”less than 90%

”If you charge to 100% you need to drive asap, otherwise the battery get hurt”
—> IRL there is no data suggesting 100% is much worse than 80-90%. In extreme temperatures the rate is higher but not by far. (This doesnt mean I recommend leaving it there for long periods)

“Going below 20% is bad for the battery.”
—> IRL there is no data that support this myth. Actually, the lower the better down to 0%.

We do see differences.

First, I started to use the low SOC strategy more or less directly after delivery. I have about 18-20% Supercharging energy wise (~50 sessions) and about 30 charges to 100%.
2 yrs 4 months (61K km) and the difference is clear.
There is quite a few cars here and at a swedish forum that adopted the low SOC stategy, the low range drop is seen by virtually all of the one I know of.
View attachment 932605

I started to learn about lithium batteries about 2006-2007, because tgere was myths already then. After reading research I adopted the low SOC during storage.
I still have lithium polymer batteries from 2009 that works fine today but most of my friends have to throw their batteries after a few years.
The science /research is agreeing very much on how lithium ion batteries work and what cause them to degrade.

There really is not much to be uncertain about if lokking into the sum of all research results.



Tesla off course want to give the owner as few restrictions as possible. It should be easy to own and use an EV.

If Tesla on one hand said EPA range = 358 miles, and on the other hand said “please do mot charge more than 55%, they probably would be sued for non true advertisement.

Teslas advise will not be the ones maximizing battery longevity. They will ensure that the batteries in general will not need warranty replacements (100.000 miles and eight years is the law mininum warranty in US).

Its quite safe to say that you can reduce the degradation to half (or better) by staying low in SOC (as much time as possible below 55%).

If you tell me:
-What tesla you have (for knowing original capacity and range).
- how old it is, down to months ( X yrs Y months) since delivery or build date.
- To what SOC you charged most times.
-End of day SOC (before next charge)
- when /time on the day you start the charge
- The climate where you live, average temp.
- if you park it in a garage or outside.

Then I’ll tell you your expected degradation, expected range today.
(This assumes you owned it since new or know this data for the previous owner as well).
You do not even need to tell me the miles driven.
Tested on quite a few cars so far and it mostly hit quite close.
(This is because calendar aging is predictable and also the main degrading factor for the first 5-8 years.)

Try me!

-What tesla you have (for knowing original capacity and range).
*2022 Model Y
- how old it is, down to months ( X yrs Y months) since delivery or build date.
*Exactly 18 months
- To what SOC you charged most times.
*Normally charge to 85%
-End of day SOC (before next charge)
*Approx. 185
- when /time on the day you start the charge
*6 pm
- The climate where you live, average temp.
*Avg. Temp 80-90 degrees
- if you park it in a garage or outside.
*Garage

 

[AAKEE]

-What tesla you have (for knowing original capacity and range).
*2022 Model Y
- how old it is, down to months ( X yrs Y months) since delivery or build date.
*Exactly 18 months
- To what SOC you charged most times.
*Normally charge to 85%
-End of day SOC (before next charge)
*Approx. 185
- when /time on the day you start the charge
*6 pm
- The climate where you live, average temp.
*Avg. Temp 80-90 degrees
- if you park it in a garage or outside.
*Garage

I guess end of day SOC isnt 185

I used 32C (90F) as cell temp average, was different in different parts of Florida so.
I used 65% SOC as end of the day, before the new charge.
I used 81kWh as the original capacity, guessed LR/P 82.1kWh batt? ( '22 model Y, LR or Performance or RWD? )

Is the garage insulated?

Result, not that far from 10% loss.
306 miles range, if it is an LR

 

[gt2690b]

I guess end of day SOC isnt 185

I used 32C (90F) as cell temp average, was different in different parts of Florida so.
I used 65% SOC as end of the day, before the new charge.
I used 81kWh as the original capacity, guessed LR/P 82.1kWh batt? ( '22 model Y, LR or Performance or RWD? )

Is the garage insulated?

Result, not that far from 10% loss.
306 miles range, if it is an LR

View attachment 945085

Nov 2021 LR AWD delivery average temp 23C in Colorado average SOC 45% kept in garage

Charge to 70 end the day at 40 charge 2 hours before leaving

You should make the calculator public

 

[AAKEE]

Nov 2021 LR AWD delivery average temp 23C in Colorado average SOC 45% kept in garage

Charge to 70 end the day at 40 charge 2 hours before leaving

What I need for the formulas is:
-Manufacturing month or purchase month.
-The Regular set charging level you use.
-End of the day SOC, before charging.
-When you start the charging a regular day
-Is the car in a garage or outside?
-The climate, warm or cold?
-Current odometer.
-Average consumption since new

I calculated an approximate ODO for your car from the 30% cycles, about 36000km/ 22K miles ? (not that important as normal driven miles does'nt wear that much).
Do you know what battery you have, its either the old Panasonic, or the new one (77.8 or 82kWh) ?
The degradation numbers below is the same regardless, but I did use the Remaining capacity from the 77.8 kWh battery


326 miles EPA ? In that case it looks like the 77.8kWh battery I guess.
Im not too familiar with the model y and degradation tresholds etc but your cars full range should be somewhere aorund 309 miles today.
(you might be able to perform a energy graph calculation of the battery capacity to check? )

You should make the calculator public

I'm planning for this. I use the actual range or capacity I get in response from these posts to evaluate the data that drives the formulas.
Not tomorrow, but maybe later this year I will have the time to set a homepage up with this.

 

[gt2690b]

What I need for the formulas is:
-Manufacturing month or purchase month.
-The Regular set charging level you use.
-End of the day SOC, before charging.
-When you start the charging a regular day
-Is the car in a garage or outside?
-The climate, warm or cold?
-Current odometer.
-Average consumption since new

I calculated an approximate ODO for your car from the 30% cycles, about 36000km/ 22K miles ? (not that important as normal driven miles does'nt wear that much).
Do you know what battery you have, its either the old Panasonic, or the new one (77.8 or 82kWh) ?
The degradation numbers below is the same regardless, but I did use the Remaining capacity from the 77.8 kWh battery


326 miles EPA ? In that case it looks like the 77.8kWh battery I guess.
Im not too familiar with the model y and degradation tresholds etc but your cars full range should be somewhere aorund 309 miles today.
(you might be able to perform a energy graph calculation of the battery capacity to check? )

View attachment 945256


I'm planning for this. I use the actual range or capacity I get in response from these posts to evaluate the data that drives the formulas.
Not tomorrow, but maybe later this year I will have the time to set a homepage up with this.

i have a 7 seater so i think the EPA was 316 new... i thought i had the 82kwh but most of my calcs indicate 77.8.. ordered late july 2021 delivered early nov 2021

heres a sheet wehre i calculated capacity from some longer drives (looks like it was about 77.8 when new but sometimes calculated higher.. i thought software locked to 77.8):

modely-battery.xlsx

Sheet1 Capacity Calc <a href="http://192.168.1.41:3000/d/zm7wN6Zgz?from=1684482157000&to=1684484297000&var-car_id=1&var-drive_id=4897">5/19/23 1:42</a>,<a href="http://192.168.1.41:4000/geo-fences/new?lat=39.835131&lng=-104.766810">DIA Salt Shed, Denver</a>,<a href="http://192.168.1.41:4000/geo...

docs.google.com

 

[AAKEE]

i have a 7 seater so i think the EPA was 316 new... i thought i had the 82kwh but most of my calcs indicate 77.8.. ordered late july 2021 delivered early nov 2021

Just checked at epa.gov:
For model year 2021 it was the 77.8 kWh battery for the LR (but the 82 kWh pack for the performance).
For 2022 it was the 82 kWh pack on both.

I can not find any different rating for a seven seater. Did not hear about this before either.

heres a sheet wehre i calculated capacity from some longer drives (looks like it was about 77.8 when new but sometimes calculated higher.. i thought software locked to 77.8):

modely-battery.xlsx

Sheet1 Capacity Calc <a href="http://192.168.1.41:3000/d/zm7wN6Zgz?from=1684482157000&to=1684484297000&var-car_id=1&var-drive_id=4897">5/19/23 1:42</a>,<a href="http://192.168.1.41:4000/geo-fences/new?lat=39.835131&lng=-104.766810">DIA Salt Shed, Denver</a>,<a href="http://192.168.1.41:4000/geo...

docs.google.com

It’s locked!

But you can use the energy graph to calculate the total battery capacity.

*average* x ”estimated range” x 100 / SOC = Wh

( SPC should be high enough, perhaps 70% or more to eliminate the big possible faults from that SOC is a rounded number)

 

[gt2690b]

Just checked at epa.gov:
For model year 2021 it was the 77.8 kWh battery for the LR (but the 82 kWh pack for the performance).
For 2022 it was the 82 kWh pack on both.

I can not find any different rating for a seven seater. Did not hear about this before either.



It’s locked!

But you can use the energy graph to calculate the total battery capacity.

*average* x ”estimated range” x 100 / SOC = Wh

( SPC should be high enough, perhaps 70% or more to eliminate the big possible faults from that SOC is a rounded number)

oops i unlocked it now

the 7 seater used to go from 326 miles to 316 miles on the tesla website when you clicked 7 seater if i recall correctly.. it seems to stay the same now hmm...

 

[Nosna]

Read through the entire thread m…very insightful.

So the TLDR summary is this, correct? Keep SOC as close to 50-55% or below as much as possible.

 

[Nosna]

@AAKEE

After reading this thread I think I’m going to switch to the low SoC method.

However with they being said, I have had my MYLR for 2 weeks and have been keeping it at 80% SOC consistently charging almost every night to top off. How much “damage” have I done in regards to battery degradation versus if I would have went with the low SOC method.

 

[AAKEE]

@AAKEE

After reading this thread I think I’m going to switch to the low SoC method.

However with they being said, I have had my MYLR for 2 weeks and have been keeping it at 80% SOC consistently charging almost every night to top off. How much “damage” have I done in regards to battery degradation versus if I would have went with the low SOC method.

0.559%

Not kidding, or only kidding a little. But it is a very theoretical number.

Ten months of 80% at 25C would cost about 5% and 10 months at 25C at 55% or less would cost 2.5%.
2 weeks is 0.5 x ((0.5/10)^0.5)x5 = 0.559%

But as we know there is that recoverey effect that probably can reduce that number, so less than 0.6% then.
Its probable that quite much from the loss will be recovered, at least if looking at the data from a research test of Tesla model S cells that was taken out of a 6 month old Model S

 

[sulluEV]

Hello - I am new to this forum. We just got a brand new 2023 tesla model y long range awd. My tesla has less than 800 miles. It indicates it has 279 miles @ 85% battery charge. It used to indicate 280 miles but now it consistently shows 279 projected miles. (0.85*330 = 280.5 miles). How much are others getting? Also, do we have data for 80%, 90% battery charge?

Thanks so much!

 

[YW555]

Totalled.

Seriously though, I wouldn't bother thinking about degradation until your battery warranty is about to go out.

 

[zoomer0056]

Hello - I am new to this forum. We just got a brand new 2023 tesla model y long range awd. My tesla has less than 800 miles. It indicates it has 279 miles @ 85% battery charge. It used to indicate 280 miles but now it consistently shows 279 projected miles. (0.85*330 = 280.5 miles). How much are others getting? Also, do we have data for 80%, 90% battery charge?

Thanks so much!

Do some reading on TMC. Search for battery, SOC, degredation and other terms. You'll find a lot of info and answers to your questions.