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

[Candleflame]

No, thats a myth.

Some third part apps seem to use data that is influenced by temperature.

The BMS data is not. The Nominal Full Pack number is not in general affected by temperature.

This change is quite high and must mean the BMS either was of before and adjusted back now, or the other way around.

It would be possible to calculate the approximate capacity from average SOC and sverag temperature.

A quick calculation says that in a warm climate like AUS the battery would have 6% calendar aging the first year if charged to 80% and not driven down below 55-60% each day.

If the car is about four years, we are looking at square root (4) x 6 = 12% calendar aging.
Cyclic aging is probably not that much so around 12% in total.

77.8 kWh x 0.88 = 68.5 kWh capacity today.
(The precise “hit” of the earlier NFP is a coincidence, I just grabbed a number for car age that seemed probable).

I could do a more precise calc with my excel formulas, taking more data into account.
For this I need:
-How many km/miles on the ODO
-Car age, manufacturing date or delivery date
-Daily charge, and end of day SOC (before next charge)
- When the charge is done each day (at arrival after work, like 6pm or middle of the night or in the morning)
- average annual temp, or city/country for me to find out.
-Is the car parke in a garage?
-Garage: temp ? ( insulated or not).

Temperature definetly affects the BMS/estimated capacity. Especially when people drive short journeys. Temperature affects resting voltage which the BMS uses to compare the voltage to the internal range table....

when I used to live in the tropics I never really had range fluctuations but once I moved to somewhere a bit cooler I started getting mild fluctuations....

 

[AAKEE]

Temperature definetly affects the BMS/estimated capacity. Especially when people drive short journeys. Temperature affects resting voltage which the BMS uses to compare the voltage to the internal range table....

Nope.

Thats a misubderstanding.

Resting voltage for Lithium ion batteries is very little affected by the temperature.
Also, colder temps do not always change cause reduced voltage. For many batteries the voltage increases in some SOC regions and reduces in some, but only very very little. Between +25 and -25C it might be only a few millivolts (up or down). Each millivolt is ~ 0.1% SOC.

I cam show you a lot of research showing this. I also can show logged data from SMT about SOC vs cell voltage vs cell temp.

I took my 2170 cells from the usual 24C storage and put a few of them outside in -20C or so for a couple of hours.
My voltage meeter showed the same viltage down to the hundred of voltage it could show.

The car (BMS) actually measures the real SOC independent of the cell temp.
The BMS SOC value do not change even when the cell temperature is -15C (I have checked this multiple times.

But the displayed SOC is reduced. It is not a matter of the BMS Measuring a lower value, but it is a matter of Tesla deliberately reducing the displayed SOC to show a more representative range (if using the range shown at the battery). The need for battery warming and the reduced efficiency in the battery at low SOC reduces the practical range.

The app that used the wronh values probably did take the “real SOC” but the reduced range, the result of that full range calculation is reduced range. But that is not a true thing for the battery capacity or the range shown with the battery not cold.

 

[dmurphy]

Do you use Scan My Tesla? Refers to Nomimal full pack?

If anything i have seen the opposite.
Stable numbers in the winter and the BMS has only been off during warm periods.

Cold temperatures are also reducing the “stress” on the battery with reduced calendar aging. We should not actually see a dip in winter from that perspective.

I know it was some app that used the wrong numbers, but they changed that later to the right ones. That caused the range to show a ”faulty” annual variation.


Below my 2.5 yrs data on my M3P.

The first “dip” shown was in july-august 2022, the second shown was in may-june 2023.

There was a slight dip in the summer of 2021 also (july) where the BMS showed slightly below 80kWh, but during the winter/spring before 81+ kWh and after the summer ~ 81kWh for the rest of that year.

View attachment 998572

I do and have been watching it for years. I don’t use TeslFi but Stats has been maintaining my battery history since the beginning. (I bungled the data at one point so records from
0-18k miles or so are lost.)

Every one of those dips is wintertime. I each one around 25k, 35k and then about 48k.

I bought a Model S in January so Timon (this car) has been on secondary duty. If it’s had 4k miles this year, that’s a lot.

Rated range dips a little when outdoor temps approach consistent freezing, and rises in the spring when we’re north of about 45F. Can count on it like a clock.

Edited to add: all this said, I admit I don’t do a damn thing to condition or be “gentle” on my battery. I drive it, plug it back in, charge to 90%. Set it and forget it.

Many in town short drives - really don’t stretch it all that often, and especially now that it’s in a secondary role, it’s mostly to and from the high school.

So I’m a walking nightmare for a NMC battery. ;-)

 

[AAKEE]

I do and have been watching it for years. I don’t use TeslFi but Stats has been maintaining my battery history since the beginning. (I bungled the data at one point so records from
0-18k miles or so are lost.)

Every one of those dips is wintertime. I each one around 25k, 35k and then about 48k.

I bought a Model S in January so Timon (this car) has been on secondary duty. If it’s had 4k miles this year, that’s a lot.

Rated range dips a little when outdoor temps approach consistent freezing, and rises in the spring when we’re north of about 45F. Can count on it like a clock.

View attachment 998579

"Range" might be affected by factors I wrote about before, and might have nothing to do with the actual battery capacity. I do not know anything about stats, but we easy could have factors showing less range at the same time as the battery capacity is not affected.

My NFP taken directly from the BMS did not show less capacity winter time.

So I’m a walking nightmare for a NMC battery. ;-)

To good that you do not have a NMC battery. All cars listed in your personal info use NCA chemistry - You can relax and sleep with sweet dreams

 

[Steve446]

Say what you will, but I have a noticeable impact to my battery capacity annually as we swing through temperature changes. I do gain some capacity back every spring.

Been watching the same pack for 5 years and can set my watch to it.

I have two EVs, a 2017 Renault Zoé R90 41 kW and a 2021 M3 LR 75 kW. Where I live in W France by the Atlantic coast, weather systems can be a significant impact on ambient air temperature from one day to the next, particularly in winter when the air temperature can change from 4-5°C to 14-15°C in a few hours. My M3 has not shown any repeated significant or really noticeable wow impact on NFP/SoC to these changes. However, my Zoé, which has an ambient air cooling system has shown some quite noticeable differences in SoC in this case. See also the temperature impact on retrievable capacity for Zoé in this link: Renault ZOE ZE 40 full battery specs - PushEVs ("Here is how much temperature impacts the capacity of your battery")

 

[dmurphy]

To good that you do not have a NMC battery. All cars listed in your personal info use NCA chemistry - You can relax and sleep with sweet dreams

Hahaha that’s what I get for replying at o’dark thirty. Yes yes all of our cars are NCA - 2x 18650s and 1x 2170.

 

[Bouba]

I have two EVs, a 2017 Renault Zoé R90 41 kW and a 2021 M3 LR 75 kW. Where I live in W France by the Atlantic coast, weather systems can be a significant impact on ambient air temperature from one day to the next, particularly in winter when the air temperature can change from 4-5°C to 14-15°C in a few hours. My M3 has not shown any repeated significant or really noticeable wow impact on NFP/SoC to these changes. However, my Zoé, which has an ambient air cooling system has shown some quite noticeable differences in SoC in this case. See also the temperature impact on retrievable capacity for Zoé in this link: Renault ZOE ZE 40 full battery specs - PushEVs ("Here is how much temperature impacts the capacity of your battery")

I have the 2022 M3LR 75 kWh MiC...(and also in France)...I agree, the climate doesn’t affect the range that is shown in the car. My car now has about 25,000 km with approximately 3% battery loss. How is your battery holding up, is it showing any loss of range ?

 

[Steve446]

I have the 2022 M3LR 75 kWh MiC...(and also in France)...I agree, the climate doesn’t affect the range that is shown in the car. My car now has about 25,000 km with approximately 3% battery loss. How is your battery holding up, is it showing any loss of range ?

Yes just a bit less than 3% @ 19500 kM - it varies a bit depending on whether you use NFP or kM range. Actually I think my M3 is holding up better against this crazy Breton weather than the plants in my garden

 

[Bouba]

Yes just a bit less than 3% @ 19500 kM - it varies a bit depending on whether you use NFP or kM range. Actually I think my M3 is holding up better against this crazy Breton weather than the plants in my garden

My car is 2021 of course....so, same car same usage same degradation...amazing really.

 

[David99]

The whole temperature thing makes no sense when you think about it. The battery temperature is rarely the same as the ambient temperature. In winter, if the cars stands a lot and you drive very little, it will be closer to ambient temps. But as soon as you drive longer, or charge or even supercharge, the battery temperature is similar or even the same to what it is in the summer. The BMS only cares about battery temperature.

Tesla's BMS knows exactly about the effect of low temperatures on the usable battery capacity and even shows it to the user as the blue section of the battery percentage when the battery is cold. It means you can use less of the available capacity. It doesn't mean the battery lost it.

One other thing that always gets thrown into the discussion is 'weather affects range'. That has nothing to do with the capacity of the battery and thus with the rated range. It only means, bad weather conditions use more energy and as a result you can't go as far. The rated range is not adjusted to weather conditions. Just as it is not adjusted to driving speed or your driving style or elevation change. All these things affect practical range of course. But they have nothing to do with how the car shows rated range.

Rated range is a reference consumption determined by the standardized test cycle. That consumption number and the batery capaity determine what the car will show as rated range. It is not adjusted for anything.

 

[brkaus]

Here is our 2018 3 LR

Not sure what I take away from it.

And our 2017 S100D

 

[navguy12]

Here is our 2018 3 LR

Not sure what I take away from it.

View attachment 998636

And our 2017 S100D

View attachment 998641

I have no extra data except what the car SOC tells me.

I also have a (May 2018 build with 120,000 km (74,000 miles)) TM3 and I have also noticed, since getting 2023.27.X, that my range at 100% SOC has been creeping back up.

My latest top up to 100% (last month, for a long distance trip) showed 480 km (296 miles) while eight months ago the best I could get was 463 km (286 miles).

Of course, since installing that same software version, my car will mysteriously “use” about 4% for some sort of battery conditioning while parked overnight (according to the excuse on the energy use page) if I don’t leave the car plugged in the next evening.

 

[bkp_duke]

The whole temperature thing makes no sense when you think about it. The battery temperature is rarely the same as the ambient temperature. In winter, if the cars stands a lot and you drive very little, it will be closer to ambient temps. But as soon as you drive longer, or charge or even supercharge, the battery temperature is similar or even the same to what it is in the summer. The BMS only cares about battery temperature.

Tesla's BMS knows exactly about the effect of low temperatures on the usable battery capacity and even shows it to the user as the blue section of the battery percentage when the battery is cold. It means you can use less of the available capacity. It doesn't mean the battery lost it.

One other thing that always gets thrown into the discussion is 'weather affects range'. That has nothing to do with the capacity of the battery and thus with the rated range. It only means, bad weather conditions use more energy and as a result you can't go as far. The rated range is not adjusted to weather conditions. Just as it is not adjusted to driving speed or your driving style or elevation change. All these things affect practical range of course. But they have nothing to do with how the car shows rated range.

Rated range is a reference consumption determined by the standardized test cycle. That consumption number and the batery capaity determine what the car will show as rated range. It is not adjusted for anything.

No, the whole temperature thing makes PERFECT sense. The battery is a 1300lbs block, and as ambient temps drop, that block releases energy to the surroundings. The BMS will always work to keep the battery block within an optimal temp range, and to do that, it uses energy from the batteries.

Additionally, there is an optimal temperature range for the chemical reactions that the battery undertakes, and the colder it is, the less efficient those reactions are (they have to overcome entropy).

So, yes, the actual "battery capacity" does change with temperature. Both through changes in the chemical reactions, and changes due to the BMS expending more energy.

 

[AAKEE]

The whole temperature thing makes no sense when you think about it. The battery temperature is rarely the same as the ambient temperature. In winter, if the cars stands a lot and you drive very little, it will be closer to ambient temps. But as soon as you drive longer, or charge or even supercharge, the battery temperature is similar or even the same to what it is in the summer. The BMS only cares about battery temperature.

No.

Teslas with heat pump use the battery heat to warm the cabin, so the battery temperature will not be high as in the summer. The heat pump (model 3P 21 values) sucks the heat down to ~11-12C abd then let it rise to ~17-18C before it draws it down to 11-12C again.

The average cell temp will be higher than the cars average ambient with about 5C or so, for a car that is used to normal extent. At least it was so for my M3P.

My former M3P had 13.4C average cell temp over ~ 2 years. The average annual is sbout 0C where I live but the car is always parked in the garage, keeping about 10C during the winter time.

 

[AAKEE]

No, the whole temperature thing makes PERFECT sense. The battery is a 1300lbs block, and as ambient temps drop, that block releases energy to the surroundings. The BMS will always work to keep the battery block within an optimal temp range, and to do that, it uses energy from the batteries.

The BMS do not heat the battery when the car is parked.
The BMS do not heat the battery active when driving, but the coolant from the motors heat the battery.

The scheduled departure (and to just start the cabin heating in the app) only heat the battery if it is below ~ 5C and when heating it it heats to about 5C.

 

[AAKEE]

First 6 months on my MSP: Theres some bug, as we did have much colder than -9.5C (I have driven down to -25C this winter.)
Anyway, the difference between average ambient and average cell temp seems about the same as during the two yrs with the old car.

 

[David99]

So, yes, the actual "battery capacity" does change with temperature. Both through changes in the chemical reactions, and changes due to the BMS expending more energy.

So you see the range go up and down as the battery changes temperature by the hour? No? I didn't think so.

 

[Steve446]

My car is 2021 of course....so, same car same usage same degradation...amazing really.

It certainly is. My interest now is to see what happens to the average of M3 cars like ours using data as seen in the TeslaFi battery report. I'm fasinated to see if there's any difference but it will take some time...

 

[Steve446]

So you see the range go up and down as the battery changes temperature by the hour? No? I didn't think so.

Maybe not by the hour (!) but; averaged out a bit, shouldn't we see that the real world range of the car will change as a function of the battery capability to provide energy at any given temperature? However, the fact that we generally don't see this effect so much in Teslas is maybe a reflection of the system design and operating capability. To further my argument refer to my example - I will come back to my comments made in post #6025 earlier in this thread, about my Renault Zoé. For that car, the battery conditioning is much less sophisticated and if it gets cold (not as severe as à l'AAKEE!) I really do see an impact of colder temperatures on total available range displayed at a given SoC (consistently 2 to 5% less range!). If that same thing happened to my M3 I would be looking at a range decrease of 22 kM for a 5% downwards change in real world range!

 

[David99]

We are talking about two different things. OF COURSE does temperature affect the performance of the battery and thus the range. The rated range display of the car does not adjust to battery temperature changes. The only exception is the mentioned blue section of the battery percentage when the battery is cold. But again, the BMS knows the difference and shows it as such. The car doesn't consider that range loss.

I have had Teslafi monitor my last two Teslas over many years. There is no correlation of seasons (temperature) and rated range.