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

[AAKEE]

Anybody have any insight to the Model 3/Y battery cooling logic? My Chevrolet Volt had a very aggressive battery cooling logic trying to keep battery less than 30C as soon as plugged in or driving. Of course smaller battery…

I do not have the cooling logic in numbers.
I have 50K km of logs on my M3P with teslalogger though.

My M3P ’21:
It in general do not cool the battery.
It generally (normal driving) never heat the battery, unless the battery is below 0C. When it heat the battery it heats to ”above freezing” to like 3C or so.

The battery often gets 10C or so warmer than the ambient when driving and maybe 15-17C warmer from AC charging at 11kW.
The batt temp is slowly climbing during a long drive. Higher speed means climbing faster and reaching higher temp.

When it is cold enough outside and the heat pump needs heat it takes the heat from the battery to heat the cabin.
Heating the cabin with battery heat is done until the battery reaches(drops to) 12C.
After this the heat pump use ambient air to heat the cabin (or lossy mode if too cold).
Duribg this time the battery temp increases by itself and cooling water fram the engines.
When the battery is at 17-18C, (may take about one hour) the heat pump takes the heat from the battery again, down to 12C.

In cold climate the battery is ”cooled” to take the heat to the cabin.

 

[KenC]

I don't know anything about cooling temps, but is 45c bad? That's about 113f. I'm usually concerned with whether the battery is warm enough to get full regen and full speed when charging at a supercharger. I've never thought about having it cool off.

Here's a chart from ScanMyTesla a year ago. I have no idea what it means. There's the battery chart on top and the motors chart on bottom. Just looking at the battery chart on top, it seems to show Heating target of 19F and a Cooling target of 131F. Ambient must have been 84F and the "Passive target" was 86F. Battery was 92F.

Radiator fan target of 0, must mean it's not doing any active cooling.

 

[DownshiftDre]

Interesting. So those various “targets” must be logic setpoint/thresholds and it determines when it is doing passive thermal management (without heat pump) or active thermal management (with heat pump). Thermal management is defined as heating or cooling of battery. If radiator fan is only running, I would still consider that passive thermal management as it is just relying on passive heat exchange to occur across the radiator without utilizing.

No different than a home. There are times when you can get by with open windows and ceiling and box fans, and then there comes a time that you would need to turn on the AC system because the passive way is not cutting it.

I wonder if those “targets” in your graphic change based on other parameters such as outside temperature, SOC or even plugged in or not.

For my desert summer use case I would be interested in the 131F (55C) Cooling Target number. I dont think Ive seen 55C battery temps yet. I do wish the car would run some quick active thermal management to get it back to a more modest temperature such as 86F(30C) even if the current battery is in the highlighted region between the heating (131F) and cooling (19.4F).

 

[DownshiftDre]

I don't know anything about cooling temps, but is 45c bad? That's about 113f.

Bad is relative. I think the 45C number is not the best when one looks at battery degradation curves. Hence why I wish the car did some more aggressive active cooling for example when plugged in.

 

[AAKEE]

I don't know anything about cooling temps, but is 45c bad? That's about 113f. I'm usually concerned with whether the battery is warm enough to get full regen and full speed when charging at a supercharger. I've never thought about having it cool off.

When cycling the cells 25C is good but in some cases of power demand and C-rate, higher cell temp is a little better.

This is Panasonic 18650 NCA taken out of a model S:

If I remember it right, the first aging step was lower C-rate and the second higher.
Just slightly better or slightly worse.

Remember that the annual cyclic aging is some 0.5% (to 1%) or so for most peoples cars. A slightl increase from high cell temp during driving is about negligible.

*The cycles in that chart also incorporates calendar aging from the time that went by during the test.

When not driving, the cell temp should be low to reduce calendar aging. You might remember the calendar aging charts I’ve posted hundreds of times?

 

[cyosick]

Can anyone find where they list the full and usable kWh capacity? 2023 model 3 long range

 

[MP3Mike]

Can anyone find where they list the full and usable kWh capacity? 2023 model 3 long range

They don't.

 

[Candleflame]

45C has always been target operating temperature while driving afaik. Interestingly the car struggles to reach this probably due to cooling. It only starts actively cooling the battery above 50C I think.

 

[Candleflame]

Can anyone find where they list the full and usable kWh capacity? 2023 model 3 long range

probably 82kwh full and then useable like 4.5% less of that.

 

[Dymondk]

our M3P that is at around 12K and 6 months old shows 2.3% battery degradation already ( Tessie APP)

Is this what people are experiencing ?
Not really complaining, just curious and maybe a bit worried

I have m3 rwd 2023. 9 months old now. At total 8200km. Tessie shows 1.6% degradation.

 

[DownshiftDre]

When cycling the cells 25C is good but in some cases of power demand and C-rate, higher cell temp is a little better.

This is Panasonic 18650 NCA taken out of a model S:

View attachment 955320
If I remember it right, the first aging step was lower C-rate and the second higher.
Just slightly better or slightly worse.

Remember that the annual cyclic aging is some 0.5% (to 1%) or so for most peoples cars. A slightl increase from high cell temp during driving is about negligible.

*The cycles in that chart also incorporates calendar aging from the time that went by during the test.

When not driving, the cell temp should be low to reduce calendar aging. You might remember the calendar aging charts I’ve posted hundreds of times?

Ive been running some Track Mode experiments when driving around town. Battery cooling is definitely engaged as I can see the valve to the Chiller is open and refrigerant flowing through while the drivetrain coolant loop and battery coolant loop are in parallel mode. Without Track Mode, the chiller never has refridgerant flowing through it unless you are at that ridiculous 133F active battery cooling target.

Engaged Track Mode on 20 min drive each way to and from Best Buy. Battery temp started around 43C and by the time I reached the Best Buy it was 32C and dropping. Engaged it again on drive home and battery reached a steady state of 27C with heat pump running at its min speed of 500RPM. Energy graph says I took a 1.6% hit due to battery conditioning on that leg.

The only thing I disliked was I had to have AC off to force this battery cooling mode otherwise it would prioritize cabin cooling and not open the valve to Chiller. Its was 100F out and I managed ok. Ceramic tints help. “Its a dry heat”

I could also run track mode at the end of the day while plugged in and get the battery down in temp so it starts at a lower temperature through the night. That is next to try out. Ordered OBD dongle to step it up a notch.

 

[AlanSubie4Life]

Can anyone find where they list the full and usable kWh capacity? 2023 model 3 long range

Basic Search | Document Index System | US EPA

dis.epa.gov

https://dis.epa.gov/otaqpub/display_file.jsp?docid=56729&flag=1

https://dis.epa.gov/otaqpub/display_file.jsp?docid=56623&flag=1

Depends on the test temp, but it’s between something like 80.8kWh and 82kWh for the test article (clearly listed in the documents in any case).

And usable is 95.5% of that.

Your degradation threshold is about 79kWh; you won’t show obvious range loss (even though you are losing range) until your full capacity drops below that (usable drops below 75.5kWh). So once you start showing something less than 358 rated miles @ 100%, then you can multiply 79kWh by the ratio of (displayed miles @100%/ 358 rated miles) to give you your full pack capacity BMS estimate (not usable, which is again 95.5% of that value).

Usable energy is defined as 100% to 0% displayed in the car.

In the EPA documents listed, they drive until the wheels stop moving, so that is all the energy (not just the usable energy). It goes for an indeterminate time after hitting 0%.

 

[Candleflame]

Basic Search | Document Index System | US EPA

dis.epa.gov

https://dis.epa.gov/otaqpub/display_file.jsp?docid=56729&flag=1

https://dis.epa.gov/otaqpub/display_file.jsp?docid=56623&flag=1

Depends on the test temp, but it’s between something like 80.8kWh and 82kWh for the test article (clearly listed in the documents in any case).

And usable is 95.5% of that.

Your degradation threshold is about 79kWh; you won’t show obvious range loss (even though you are losing range) until your full capacity drops below that (usable drops below 75.5kWh). So once you start showing something less than 358 rated miles @ 100%, then you can multiply 79kWh by the ratio of (displayed miles @100%/ 358 rated miles) to give you your full pack capacity BMS estimate (not usable, which is again 95.5% of that value).

Usable energy is defined as 100% to 0% displayed in the car.

In the EPA documents listed, they drive until the wheels stop moving, so that is all the energy (not just the usable energy). It goes for an indeterminate time after hitting 0%.

do the NMC batteries have a buffer? Thought that was only a thing on the NCAs (and not on the original LR RWD and certain LR AWD models)

 

[AAKEE]

Can anyone find where they list the full and usable kWh capacity? 2023 model 3 long range

I have seen reports that Canada get Made in China M3 LR.

If the VIN is ”Made in China”, you most probably has the 78.8 kWh LG with M50 NMC cells.

If you have a US built car, you most probably has the Panasonic 82.1kWh NCA.

The usable capacity is always 95.5% of the nomimal full pack, and the buffer is always 4.5% of the nomimal full pack.

The Panna 82kWh mostly show about 80.5 kWh as new, giving you 76.9 ”usable”.
The LG 78.8 mostly reach 79kWh after a couple of months, giving about 75.5 ”usable”.

I do not like the use of ”usable” as for example Tessie shows the wrong label (usable capacity) where as they actually show the number for the total capacity.

In most forums, this adds to the constant missunderstandings and myths around Teslas batteries, so for that reason its better of always using the total capacity when discussing what battery a specific car has.
For calculating the practical range, calculate with total capacity ( capacity / consumption) and then just reduce the answer by 4.5%.

 

[AAKEE]

do the NMC batteries have a buffer? Thought that was only a thing on the NCAs (and not on the original LR RWD and certain LR AWD models)

All teslas use the same buffer in basic terms, 4.5% of the total capacity.

Modern model S
All LR/P model 3/Y

RWD with LFP also seem to have 4.5% as the basic buffer but it is dynamic and can increase (seen 12%) when the BMS hasnt got the full charges that reset the energy counting.

So, yes. Teslas with NMC also use 4.5% Buffer as far as I have seen.

 

[Candleflame]

All teslas use the same buffer in basic terms, 4.5% of the total capacity.

Modern model S
All LR/P model 3/Y

RWD with LFP also seem to have 4.5% as the basic buffer but it is dynamic and can increase (seen 12%) when the BMS hasnt got the full charges that reset the energy counting.

So, yes. Teslas with NMC also use 4.5% Buffer as far as I have seen.

no im talking about the hidden buffer (in the displayed range not the battery)! the RWD and certain AWD NCA models had a patch later which removed the hidden display buffer and increased range to 522km from 499.

 

[AlanSubie4Life]

no im talking about the hidden buffer (in the displayed range not the battery)! the RWD and certain AWD NCA models had a patch later which removed the hidden display buffer and increased range to 522km from 499.

For the original RWD, even after the patch, it still has the degradation threshold of 76kWh (325rmi*234Wh/rmi). And we know those packs started around 78kWh (from SMT and EPA data).

So the display “buffer” (difference between new pack capacity and degradation threshold) was not removed, just reduced.

I don’t know what other NCA AWD models you are referring to, so not sure on that. There were some very early 2020 Model 3 Performance that showed 310 rather than 299 for example before software update, but that was transitory and a bit different.

 

[AAKEE]

no im talking about the hidden buffer (in the displayed range not the battery)! the RWD and certain AWD NCA models had a patch later which removed the hidden display buffer and increased range to 522km from 499.

We maybe could call that ”degradation threshold”, as it is not a buffer per definition.

For the model 3 LR the degradation threshold has ben 79kWh since the LG NMC was introduced in Europa.

This means that the smaller LG (M48) or 5C that was marked 74.5kWh and could reach 75 kWh, not was affected of the degradation threshold. Any change in estimated capacity redulted in a change in range.
For the larger LG, (M50) or 5L that was marked 78.8kWh, it didn’t reach the treshold either. In some cases they topped 79-79.1kWh after a few months. I’ve heard of one example of 79.4kWh nominal full pack and that one must have just precise come over that degradation treshold.

 

[Quickst]

Which is best for overall ageing:

MYLR 2023
Charge to X% is almost always followed by driving. So storage charge no more than X-3%

Charge limit 55% (as displayed by BMS)
1) 45-55% every day
2) 35-55% every second day
3) 25-55% every third day

Charge limit 45%
4) 35-45% every day
5) 25-45% every 2nd day

I don't want to go below 20% because I use Sentry but no problems if sometimes less than 20%

Easy to go to 100%, as I have lots of charging options too.

 

[AAKEE]

Which is best for overall ageing:

MYLR 2023
Charge to X% is almost always followed by driving. So storage charge no more than X-3%

Charge limit 55% (as displayed by BMS)
1) 45-55% every day
2) 35-55% every second day
3) 25-55% every third day

There is a plateau between about 30-55% where the calendar aging is very similar meaning that there is very small differences in this region.
If you only need very little, any charge setting at or below 55% if NCA (made in US) or 60% if NMC (made in China) will be fine.
I would use 50-60% and charge every day.

Per definition, smaller cycles are better but the cyclic aging will be minimal anyway.

Charge limit 45%
4) 35-45% every day
5) 25-45% every 2nd day

Lowest possible setting is 50%.

I don't want to go below 20% because I use Sentry but no problems if sometimes less than 20%

Easy to go to 100%, as I have lots of charging options too.