Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[AAKEE]

The current capacity that it shows is the current "nominal" capacity, while by default the original capacity that it compares against may be the original "usable" capacity (or in my case what it thought was the original "usable" capacity calculated from an incorrect original "nominal" capacity).

It was never really a ”usable” in any of the original capacity or current capacity.

It was a mix up of what value Tessie actually calculated. In real, Tessies calc always was the total / ”gross” capacity.

Tessie has fixed one part of it by removing the term ”usable” which will be good.

The original capacity inside the meter (which can be adjusted as you say) is more often wrong than correct.
In EU its very common that cars with the Panasonic 82 kWh battery is wrongly identified as the LG with 78.8kWh.
In some cases the 78.8 kWh LG is wrongly identified as the 77.8 kWh panasonic.
In the Facebook groups I take part in, post showing Tessie degradation page is more often wrong than right.

 

[user8]

Wow, amazingly low degradation. Congrats!

Your car would certainly benefit from being in a garage, but cooling it to prevent battery degradation may not be the best use of resources. While I'm open to adopting a low SoC strategy, I've accepted that ambient temperature and time are two factors beyond my control.

TMC lurker/ first time poster so apologies in advance if this question has been covered or is just plain ignorant on its face.

Would it make sense to have the ability to manually set an active cooling threshold (say 25 deg. C/ 77 deg. F) while plugged in post charging cycle—ideally to 50-55% with a eye toward reduced calendar degradation of course—if one lived in a very hot climate?

 

[DownshiftDre]

TMC lurker/ first time poster so apologies in advance if this question has been covered or is just plain ignorant on its face.

Would it make sense to have the ability to manually set an active cooling threshold (say 25 deg. C/ 77 deg. F) while plugged in post charging cycle—ideally to 50-55% with a eye toward reduced calendar degradation of course—if one lived in a very hot climate?

It would make sense. I live in Vegas and wish the active cooling thresholds were more aggressive. It is currently set at 133F and way out of the way. There should be an option to lower as I would take the range hit or pay the shore power to get the better cooling thresholds.

 

[AAKEE]

TMC lurker/ first time poster so apologies in advance if this question has been covered or is just plain ignorant on its face.

Would it make sense to have the ability to manually set an active cooling threshold (say 25 deg. C/ 77 deg. F) while plugged in post charging cycle—ideally to 50-55% with a eye toward reduced calendar degradation of course—if one lived in a very hot climate?

The heat pump would need to run 24/7 for several months or more, very quickly we would have thousands of running hour on the heat pump which might cause trouble in the long term. It is probably not made to run as many hours as a heat pump in a building.
One year driving might give us 300hours heat pump working time.

 

[AAKEE]

Looks like the BMS is about spot on.

60 km might be a little on the low side, I guess. I would prefer to see 150km or 100 miles driven. Just using the SOC/range we probably need a longer drive.
It probably also is better to drive at a decent speed and not too fast.
I have done all my checks on drives to the work, 240km.
But even with only 60km driven, if we see a change in range after the drive it is a indication as from the describtion below.

If the BMS was way off, it would probably be enough to show if it was over- or underestimating.
In your case, as you ”only” lost 1% after two days, your BMS is probably showing about right.

The basics for this is:
We expect the BMS to be spot on = no change of SOC/displayed range after the sleep.
Range decrease after the sleep = overestimation of the capacity.
Range increases sfyer the sleep = underestimation.

This version is a simplification from doing the same with Scan My Tesla which will give a more precise result. I did a few double checks from the displayed range and they basically show the same result as with Scan My Tesla, but as the resolution is lower, so a longer drive would compensate for this.
——————————————————————
Before the drive, let the car sleep (after the charge etc) to make it record the correct ”true” SOC. This is important as we need a BMS starting the estimation from a correct SOC.
After the drive you should record these numbers after the drive:
-SOC and range (in km) at end of the drive. Take this value asap, before any readjustment happens.
-Used energy for the last drive. The total kWh might be fine but [distance x average consumption] gives a more exact result.

-After the car has been parked/locked/sleeping for 30 minutes or more: -SOC and range (in km).

The change in range (or SOC) after the sleep indicates the BMS capacity estimation error.

Each change in range/km = about 0.15kWh, or the actual constant for your car.

(Used energy +/- delta energy)/(Used energy) = the correction factor for the BMS estimated capacity / range.

For example:
Used energy = 50 kWh
Range decreased from 100 to 93km after the sleep = 7 km delta = 1kWh.

(50-1)/50 = 0.98.
The true capacity is 98% of the BMS estimated capacity.
The BMS is overestimating the capacity if this number is below 1, and underestimating if it’s above 1.
Displayed maximum range or calculated capacity from the energy app can be adjusted by multiplication by the correction factor.
——————————————————————
We expect the change in range to be very low. No change means the BMS is estimating the capacity correct.

I’ll be back later with the use of Scan My Tesla to calculate the capacity.

I have a follow up on this.

I did a 249 km drive today. Not 100% perfect for this but I already has my numbers from doing this before, this calc is to show how it is done.
I had to eat and shop after leaving home so the car was at the city with sentry on for 35 minutes, which use 290W so ~150Wh to add to the drive. The car was charged and slept 1 hour after the charge but before the drive.

This first part is the calculation by having exact values from SMT:

SOC leaving home 78.9 displayed = 79.85% true SOC*.


( SOC2 at arrival = 25.4 = 28.76% true SOC) this SOC is not needed for this, but the slight decrease after the sleep tell us the BMS has a slight overestimation of the capacity.

SOC after 1h sleep = 25.2= 28.57% true SOC.

Its better to multiply the average consumption with the driven miles, gives a more exact number that the total energy which is rounded.

Energy= 50.05 (+ 0.15 for sentry) 50.2kWh
Used true SOC = 79.85% - 28.57% = 51.28% ( = 0.5128 in absolute value)
We did use 50.2 kWh which was 51.28% SOC
TOTAL CAPACITY is 50.2/0.5128 = 97.9 kWh.


Km-calc (without SMT).
The car displayed 142km when arriving and 141km after one hour.


The change in energy for 1 km displayed = 165Wh ( = 0.165kWh) for my MSP.

The used energy is as in the SMT example still 50.2 kWh.

Correction factor: 50.2 / 50.365 = 0.9967.

The cars estimated capacity (from SMT, but can be from displayed max range or energy graph calc): 98.3kWh

98.3 x 0.9967 = 98.0kWh.

After the car had its one hour sleep the BMS nominal full pack was adjusted to 98.1 kWh, so the BMS is on track and also follows my calculation. Last time i did the same drive, the calculation predicted the BMS adjustment to the exact decimal.
At that time the drive was a single drive with no stops etc.

True SOC is calculated by [ (100- displayed SOC) x 0.045 + displayed SOC]

I have done this several times, and with the BMS severely off I predicted that the capacity really was close to 98kWh and that the car would readjust from 95.3 to 98 kWh.
For my M3P, it was severely off about one year ago, showing about 75.7 kWh, and I calculated the capacity to be about 79.0 kWh. I also made a 100-0% drive which showed close to 79.0 kWh capacity, and eventually the BMS readjusted to —> 79.0 kWh.

I’m positive this is a good way to test the capacity of there is any doubt about the capacity, or about the BMS being severely off. It might indicate if it is any idea to perform a BMS calib. or not.

 

[hey kupo]

Jeff Dahn discusses battery health last week in this video:

Takeaways:

• Degradation is higher at higher SoC. "If you go away in the summer, store at a low state of charge (30%)"
  • He chose 30% because you'll still have range when you come back from your trip.
• He said "Lower the state of charge, the better" during the Q&A. He didn't say how low you can go and still be safe.
• Stick to low depth-of-discharge. "Charging frequently to ensure lots of low DoD cycles is better than charging infrequently, leading to high DoD cycles"
  • After 2.5 years of continuous testing (equivalent of 1.5 M km travelled), cells that did 25% DoD only lost 8% capacity, while 100% DoD lost 27% capacity
• Higher the temperature, higher the degradation. "The colder it is, the longer your battery will last, as long as it's not doing anything"
• If you have a Ni-rich battery (most common with long range EV), only charge to 75% if you can
• For the following types of Li-on batteries, impact of these optimization strategies is minimal so they can be ignored:
  • LFP
  • Single crystal positives with Ni content < 70% (e.g. NMC532, NMC622)

Last but not least: even if you ignore all of these recommendations, your battery will be fine.

Lots of great info in the video - worth watching!

Great video. I don't see how there's much mystery around battery care.

His temperature slides have some practical uses. You can mitigate capacity loss in high temps, e.g 95f/35c+, by cycling the battery at the lowest SoC range that's convenient for you. The lower the better.

If you have cold temps in winter, it's OK to cycle at a higher SoC. Nice if you need a bit more of a buffer for inefficient driving, e.g. snow/slush.

 

[AAKEE]

Great video. I don't see how there's much mystery around battery care.

His temperature slides have some practical uses. You can mitigate capacity loss in high temps, e.g 95f/35c+, by cycling the battery at the lowest SoC range that's convenient for you. The lower the better.

If you have cold temps in winter, it's OK to cycle at a higher SoC. Nice if you need a bit more of a buffer for inefficient driving, e.g. snow/slush.

It is not really the cycles SOC in combination with tempersture.

The cycles themself mostly give the lowest degradation at about 25-40C. (In general, cycles cause a very little part of the degradation for the aversge Tesla owner).

It is the time at high SOC and or high temperature that causestje most degradation (calendar aging).

So we can cycle hour cells at high SOC during the hot summer still with minimal degradation, if we charge just before the drive and if we drive the battery down to low SOC (<55% prefered for Panasonic NCA).

 

[shahryaran]

Bought it used directly from Tesla two months ago. Driving to work everyday total of 10 miles on each day with AC on all the time here in Orange County and sometime little extra miles here and there. Sentry mode is also on most of the time.

But I have to charge it once or two times a week. Is it normal?

The graph shows I drive above the projected line for the most part.
I calibrated the battery from 11% to 100% showing 292 EPA miles only.

 

[UncleCreepy]

Bought it used directly from Tesla two months ago. Driving to work everyday total of 10 miles on each day with AC on all the time here in Orange County and sometime little extra miles here and there. Sentry mode is also on most of the time.

But I have to charge it once or two times a week. Is it normal?

The graph shows I drive above the projected line for the most part.
I calibrated the battery from 11% to 100% showing 292 EPA miles only.

Seems normal to me. My 2020 M3AWD is currently at 287 miles range at 100%. The car has 74,500 miles on the odometer.



Sentry mode keeps the computer running which accounts for about 250 W power usage or 1 kWh every four hours. This might be what is affecting your range.



Regardless, you should recharge at every chance you get. It won't have any effect on the Wh/mile but helps with battery longevity.

 

[jjrandorin]

But I have to charge it once or two times a week. Is it normal?

Yes

if you dont have home charging, people who tend to have some version of " Oh I only drive (insert mileage, in your case 10) miles a day to work, and this car has a 290 mile range battery. I know I dont have home charging, but I will be able to charge every (X, in your case 20) days and still have some left over. Not having home charging is not an issue at all".

And it doesnt work that way at all (not even a little).

If you do have home charging, plug it in, there is no reason not to.

 

[shahryaran]

2020 M3LRAWD AB with 40k miles on it bought directly from Tesla.

AC is on most of the time.
Sentry mode is off most of the time.

Can't seem to get even 200 miles!

Any suggestion is appreciated.

 

[804son]

Lots of threads on this topic, suggest you use the search function and do some reading.

 

[KenC]

2020 M3LRAWD AB with 40k miles on it bought directly from Tesla.

AC is on most of the time.
Sentry mode is off most of the time.

Can't seem to get even 200 miles!

Any suggestion is appreciated.

Do you not have access to charging?
• The rec is to always be charging, as shallow discharges are better than deep discharges for battery longevity.
• Also, it's rec'd not to charge up to 100% unless road-tripping. 80% or less is rec'd for daily use. This isn't an LFP battery right?

Little short trips will require initial cabin cooling which uses more battery than steady-state cooling. No different than ICE, so based upon your driving needs, you may not do as well as others.

 

[shahryaran]

Do you not have access to charging?
• The rec is to always be charging, as shallow discharges are better than deep discharges for battery longevity.
• Also, it's rec'd not to charge up to 100% unless road-tripping. 80% or less is rec'd for daily use. This isn't an LFP battery right?

Little short trips will require initial cabin cooling which uses more battery than steady-state cooling. No different than ICE, so based upon your driving needs, you may not do as well as others.

All my tires were 2 psi low.
Fixed that,
Changed to chill mode
Turned off sentry
With minimum AC
and now i'm getting very good range to consumption ratio

 

[honor_the_driv]

I’ve never had an EV before and I’m trying to get a better sense of realistic expectations for the “standard” 2023 Model Y, the one with an estimated 279 mile range and AWD. I’ve been searching for real world range figures but most reviews are for the long-range or performance versions of the Model Y.

Can anyone point me towards real range figures for the 279 mile range Model Y, ideally in warm and hot weather?

In this post from @HMHM (Knowing the Real World Driving Range of Your Tesla — No More ‘Range Anxiety’) has the long range Model Y and said he can realistically expect 175-200 miles based on 90% to 20% SoC (70% of the energy capacity). 70% of the EPA estimated 326 miles would be 228.2 miles so 175-200 mile range realistic expectation would mean 76.6% to 87.6% real world range compared to the EPA estimated range. Is this consistent with what people are generally getting?

I also checked Tesla’s Online trip planner and oddly, the 279 mile range Model Y is not on there. The RWD Model 3 is the option with the closest range, at 272 mile range. I entered a trip of 248 miles and the suggested trip would include two stops for charging. I get that it would be a bad idea to drive the car until you are in the low single digits of charge percentage, but I would have expected that a single stop add something like 25% battery charge would have been enough to finish the trip would a reasonable margin- Go Anywhere | Tesla. Is it expected that this is how you’d want to do this trip?

 

[AlanSubie4Life]

Can't seem to get even 200 miles!

You used 55% of your battery (not 65%) to go 133 miles. Seems fine, projects to 240 miles, let’s call it 230. You should expect about 200 miles on a full charge on a road trip at high speed in ideal conditions. Sometimes a little further but it depends on elevation change, etc.

get that it would be a bad idea to drive the car until you are in the low single digits of charge percentage

No this is not a problem at all. Feel free to do so. Don’t plan to arrive at a place at 5% if you’re currently at 100%, but if you are at 30-40% and that’s the projection it will usually be just fine.

has the long range Model Y and said he can realistically expect 175-200 miles based on 90% to 20% SoC (70% of the energy capacity). 70% of the EPA estimated 326 miles would be 228.2 miles so 175-200 mile range realistic expectation would mean 76.6% to 87.6% real world range compared to the EPA estimated range. Is this consistent with what people are generally getting?

Seems about right. Depends on many factors even in ideal conditions (most notably elevation change and headwinds/tailwinds which often accompany hot “ideal” conditions).

Can anyone point me towards real range figures for the 279 mile range Model Y, ideally in warm and hot weather?

I think what you have found is probably pretty reasonable. Good rule of thumb is about 200 miles. It’s a bit lower for the Y than for the 3, of course (with identical batteries).

Try ABRP for route planning, though even that is not ideal. The Tesla planner doesn’t always plan to minimize the number of stops. It nearly never provides the optimal plan. That’s an optimization problem best left to the driver.

 

[honor_the_driv]

Try ABRP for route planning, though even that is not ideal.

Does that stand for A Better Routeplanner? If so is there any way to get ABRP natively on the Tesla display? I'm not sure if Tesla has anything like an app store.

 

[AlanSubie4Life]

Does that stand for A Better Routeplanner? If so is there any way to get ABRP natively on the Tesla display? I'm not sure if Tesla has anything like an app store.

Yes. Probably is a way to get ABRP up on the display but not while driving. It's kind of better for planning and not for actively using (though you can use it with live data from the car, it's kind of a pain (I've done it with my phone), and better to get used to just using the car's trip planner). Since you're researching the car, ABRP is appropriate...but I wouldn't anticipate using it much after you own the car.

The whole point is to keep everything as simple as possible, and adding an extra app to fiddle with does not accomplish that. Just drive the car, use the in-car trip planner, figure out its shortcomings, and figure out how to optimize the trip for your purposes. Usually rather than just plotting the trip all the way to the destination (the car will tell you which superchargers to stop at), I use the trip planner to go to the next Supercharging stop of my choice. But sometimes I do differently (depends on how familiar I am with the route). There are always going to be situations where you wish you had a bit more charge, of course. Usually it's worth the extra minute or two at the charger to avoid the large overhead of an extra charging stop. (Even though technically it's best (fastest charge rates) to just use the lowest average SOC possible on a trip, this does not account for the overhead.)

The biggest thing to be sure of is to always give yourself some extra margin from Supercharger stops (and always always make sure the projection is to arrive with greater than 5% - 10-15% is better then you can drive really fast and bring it down), so you don't have to slow down or get stressed. Headwinds can be really annoying and make that estimate be WAY off (even with the improved trip planner which is supposed to account for this, but does not). Below 5% for arrival charge and the car will make the assumption that you'll be slowing down in order to make it.


For your range question, I think it's best to just think of it in simple terms, for a road trip (doesn't apply in cities nor does anyone care about range there in most cases).

So for my car I have 68kWh available (95.5% of 78kWh battery degraded by 9%), and I know I get about 320Wh/mi when traveling at 80mph which is normally the speed of travel. So my best case range is 212 miles (68000Wh/320Wh/mi). Since I'll only go to 5% most likely, that means 200 miles. Really simple math, and gets very close. Does not account for elevation, of course (about 1.7kWh per thousand feet for my car).

The Model Y probably is higher consumption than 320Wh/mi at 80mph, but really have to get that info from owners. There are many factors (RWD vs. AWD, tires installed, etc.).

 

[skierrob]

Is there anyone here that has ever been able to replicate the Tesla quoted range for their Tesla or even gotten close to it?

IE - replicating the government test criteria, drive at about 50 MPH on mostly flat roads with no climate control with properly inflated tires, and actually be able to drive 2023 330 miles in a Long Range AWD? Etc.

I know if I take almost any ICE and drive at 50 MPH, I will exceed the EPA range. So is the EPA and Tesla "exaggerating" range even at best real-world opportunity? I don't think I have ever seen anyone be able to come close to the EPA range. In which case, in my humble opinion, the range should be lowered by the EPA and Tesla. And before you type it - "just switch to percentage and enjoy" doesn't solve the problem of not being able to drive from Los Angeles to Las Vegas (280 mile distance) without charging -- as Tesla "claimed" we could do based off estimated range of 330 miles per charge.

 

[AlanSubie4Life]

replicating the government test criteria, drive at about 50 MPH on mostly flat roads with no climate control with properly inflated tires

This is way too fast for the government test, which is conducted (on average) at lower speeds. It’s 19.6mph for city and 49mph or so for highway.

But more complicated than that because there are steady state cycles driven for extrapolation to determine capacity, and they take the weighted highway/city (0.45/0.55) results and multiply by 0.7 to 0.75, which of course extrapolates to a somewhat higher average speed.

But definitely not 50mph! That is super fast driving.

In general I think we should blame the EPA for creating a test which does not capture actual highway EV range (primary consideration at this point for many owners) as a separate metric which cannot easily be disconnected from reality.

Is there anyone here that has ever been able to replicate the Tesla quoted range for their Tesla or even gotten close to it?

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