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

[Quickst]

the BMS does heat the battery while parked, to ensure that the battery temp will no drop below critical and cause damage.

The multiple TeslaBjorn YT videos demonstrate this is not the case. Additionally when extremely cold the BMS displays SoC as less than actual to account for need to heat up battery with battery energy before driving

@AAKEE
Does anyone know what the nominal "operating" temperature is for the Tesla battery - for nominal driving (not supercharging)

Yesterday's temps immediately after city driving:
I am thinking operating temp is around mid 30⁰C because the battery inlet loop temp is 36⁰C. It was also the same when ambient temp was 37⁰C earlier in the afternoon.

 

[AlanSubie4Life]

EPA charge-depletion tests for Model 3 2022 pull 80.8kWh in room temp test and 77.3kWh in 20F test, just as a datapoint.
A 4.5% discrepancy.

Compare to Model 3 2020 79.2kWh/72.5kWh, 8.5%

 

[AAKEE]

@AAKEE
Does anyone know what the nominal "operating" temperature is for the Tesla battery - for nominal driving (not supercharging)

The battery temp will adopt to ambient when the car is not used or charged.

Any drive with no preconditioning will start at the battery temp the car has at the moment and the battery temp will slowly increase from internal processes and that the coolant loops from the car passes trough the battery unless:
It is cold and the cabin needs heat at the same time as the battery has spare heat then the heatpump takes the heat energy from the battery and heats the cabin. This means the battery will be cooled during the drive.

So the cell temp might reach 35C during a longer summer drive.
It also means the battery temp can be as low as 5C after a longer winter drive.
Anyting between this normal depending on ambient temp and the cell temp before the drive.

Starting the drive with a freezing cold battery without preconditioning will mean the battery will be freezing cold during the initial part of the drive and the cell temp will rise slowly.

Preconditioning only heats the battery if it is below about 5C and then it only heats to about 5C. (Probably small differences between tesla models here deoending on the battery).

 

[Steve446]

The battery temp will adopt to ambient when the car is not used or charged.

As a complement to your comments here is a graph showing ambient and battery temperatures extracted from SMT over the last 2 years for my M3 LR 2021. The values shown are monthly averages so individual temperatures will obviously be higher or lower. The car is based in W France with an Atlantic Ocean influenced climate so neither too hot or cold year round.

 

[AAKEE]

@Steve446
The quoting didnt work…

I guess you could get the average annual numbers from that?

I made a post a few pages back for the first 6 months with my MSP:
Average ambient 13.37C
Average cell temp 17.27C

I did have SMT logged data for 2.5 yesrs on the M3P, with about 5C delta between cell temp and outer temp. (But the car is often garaged so the average ambiebt around the car is not as low as the outer air ambiebt.

Average annual outer temp is about 0C here and avg cell temp was 13C during these years.

 

[Steve446]

@Steve446
The quoting didnt work…

I guess you could get the average annual numbers from that?

I made a post a few pages back for the first 6 months with my MSP:
Average ambient 13.37C
Average cell temp 17.27C

I did have SMT logged data for 2.5 yesrs on the M3P, with about 5C delta between cell temp and outer temp. (But the car is often garaged so the average ambiebt around the car is not as low as the outer air ambiebt.

Average annual outer temp is about 0C here and avg cell temp was 13C during these years.

Yes here are the averages for 2022:

17.8 24.3 6.5

Ambient Cell Difference (all in °C)

The car is parked outside under a carport.

 

[AAKEE]

Yes here are the averages for 2022:

17.8 24.3 6.5

Ambient Cell Difference (all in °C)

The car is parked outside under a carport.

The Delta is close to my findings, and also close to what I use in my calculations for degradation.

If you look closely on the summer months I guess you see a higher delta than average and lower in the winter, so about 7C delta during summer and 5C wintertime for me.
Cars without heatpump will have a higher delta during cold periods as the battery is not “cooled” by the heat pump.

The two facts above made me set 25C average for jyavenards car, despite annual average 16C in Melbourne. Probably ended up relatively close to the actual average temp for his car.

For kicks, could you @Steve446 perhaps find ands share the average ambient annual outside temp for your place?
(Edit: I think I found 13.5C annual average for Loire Antlatique?)

 

[PACEMD]

Temperature is not even a real thing. Just a number, like time and money, imaginary constructs. Feeling cold? Or in the dark? Or broke? It's all your imagination. So steep out into the light, like a hot rich person, and imagine buying a new battery.........

 

[Steve446]

The Delta is close to my findings, and also close to what I use in my calculations for degradation.

If you look closely on the summer months I guess you see a higher delta than average and lower in the winter, so about 7C delta during summer and 5C wintertime for me.
Cars without heatpump will have a higher delta during cold periods as the battery is not “cooled” by the heat pump.

The two facts above made me set 25C average for jyavenards car, despite annual average 16C in Melbourne. Probably ended up relatively close to the actual average temp for his car.

For kicks, could you @Steve446 perhaps find ands share the average ambient annual outside temp for your place?
(Edit: I think I found 13.5C annual average for Loire Antlatique?)

St Nazaire / Loire Atlantique / Pays de Loire seems to be around 12-13°C yearly average based on historical meterological data. Similar to that which you found.
The data I have for the last couple of years (as recorded by my M3 and extracted by SMT) seems to be a bit higher than that - I suppose because the data is an aggregate of parking and driving/road trips. The latter nearly always happen in the warmer months and use supercharging. These would likely skew the average recorded battery temperature a little bit higher than the parked/stored value.

I also averaged the 2023 data (or 11.5 months of it) which gives average 15.8°C and battery average of 22.7°C.

 

[Vol16]

My data clearly shows a correlation between temperature (winter months) and range. Especially from 2021 to present. Ignore early 2020 that jump is from where I switched from a mid-range to a long range.

 

[AlanSubie4Life]

My data clearly shows a correlation between temperature (winter months) and range. Especially from 2021 to present. Ignore early 2020 that jump is from where I switched from a mid-range to a long range.
View attachment 999273

If that is TeslaFi that is normal because they are doing it wrong.

 

[Quickst]

40C today. Immediately after driving home battery temp 43C

If charging plug is plugged in and SoC 40% but I manually stopped the charging so the charging does not bring the SoC to 50% minimum charge limit, will the vehicle use power from the charging plug for anything?

 

[Bouba]

will the vehicle use power from the charging plug for anything?

The implication from this article is that it does

Tesla updates Supercharger billing to add cost of electricity use for other than charging

Tesla has updated its Supercharger billing policy to add the cost of electricity use for things other than charging, like...

electrek.co

 

[Quickst]

The implication from this article is that it doe

Sorry, I'm not talking about supercharging, but rather AC charging

 

[AAKEE]

40C today. Immediately after driving home battery temp 43C

If charging plug is plugged in and SoC 40% but I manually stopped the charging so the charging does not bring the SoC to 50% minimum charge limit, will the vehicle use power from the charging plug for anything?

Yes, all energy needed will be drawn from ”the wall”.
When the car sleeps, the sleep current is still frawn from the LV-battery, but other than that the car use the supply from the wall.

Of course, it only is allowed to use power according to the Amphs setting, so whenever the car needs more power than the it is allowed to use from the wall, the rest is drawn from the battery.

For example connected with the UMC at 10A 230 V ( = 2.3 kW) and the preconditioning of the car use 6kW, the 3.7 kW overshoot is taken from the battery.

 

[derotam]

I regularly leave the car for one week at the time outside at work. I live in a bery cold climate so the battery temp soon reaches -10 to -20C or so. If I leave the car for one week, about 1-2% less SOC is left, thats just about the same number as the 1% during summer.

So you have never seen the car do an active heat cycle to maintain some minimum temperature while parked? I know in the past at least SMT showed a -7C trigger point for Active Battery Heating "ActiveBatHeat" maybe it was called... So you have seen the battery get to pretty far below freezing and not try to heat itself?

I always wanted to see what would happen when the battery got to below -7 but it hasn't gotten cold enough where I am to look at this.

 

[AAKEE]

So you have never seen the car do an active heat cycle to maintain some minimum temperature while parked? I know in the past at least SMT showed a -7C trigger point for Active Battery Heating "ActiveBatHeat" maybe it was called... So you have seen the battery get to pretty far below freezing and not try to heat itself?

I always wanted to see what would happen when the battery got to below -7 but it hasn't gotten cold enough where I am to look at this.

I have regularly seen the car sleep one week except for the short moments of charging the LV-bat once or twice a day).
(And, of course one extra awake period or two when I when inside the var and checked the cell temp.)

It should be clear to everybody that a Tesla can not heat the battery when it is sleeping, at the HV Batt is disconnected and there is no power source available for heating.

I have several pictures from these days.
The battery temp slowly decreased and the car was mostly sleeping.

The day before the picture.

The day the picture above was taken.
The four short awakenings during the day was me entering the car checking the cell temp.

I also have (or had) all the teslafi logs, I think I posted a few pict from that about the time this picture was taken.
When I changed car I lost the possibillity to see the logs of the M3P. It might still be om the raspberry, but i only see the MSP.

Lowest cell temp I saw was -16.5C, at that time I connected the car and started the charging to heat the battery.

I also tested a few days with the car connected. There was no change, still no battery heating.

The reason Tesla says to leave the car max 1 day at -30C or below is of course thst there is no battery heating and the battery can get colder than what id good for it (electrolyte freezes around -30C according to some sources, I havent dug into that.)

 

[OldPro]

We live in San Diego, Ca. and have only used a Supercharger twice in 5 years. When we have we charge to 100% because we were on the road.
Other than that, we charge at home (Tesla Solar Panels) and then to 80%. Battery loss has been minimal.

 

[jyavenard]

If that is TeslaFi that is normal because they are doing it wrong.

what could they be doing wrong?
They read a range value at a given percentage, correlate to 100%

No more, no less.

 

[AlanSubie4Life]

what could they be doing wrong?
They read a range value at a given percentage, correlate to 100%

No more, no less.

Two different API range values AFAIK. Also visible in app I suppose.