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

[AlanSubie4Life]

Anyway I turned on the AC to LO, with windows open, and let it settle out (I think my fan speed was set quite high, though I didn't check). It went as low as 18mi/hr briefly, but once settled after about 1 minute was at 21mi/hr.

I was charging my car at the time, but that's kind of a dumb way to do it. It may well reduce the amps a bit in any case when you do it this way.

I connected my car to my WC with the doors open and HVAC still running and I saw 8A@240V, about 2 kW. I can't directly monitor power draw in my Tesla but I can in my PHEV and the compressor in that car consumes about 1.5-2.5 kW, once the cabin reaches the set temperature. If the cabin is far above the set temperature (like after the vehicle has been parked), the compressor will consume up to 4 kW.

Yes, this is a better way to do it. (Set charge limit below current limit and actuate AC from app with door closed but windows open.)

Since I remembered when I was with my car this weekend, I briefly set the AC set to "LO" (open loop), and I managed to get this up to 21A@237V apparently steady state (I only checked for a minute though, haha, no patience). And I didn't even play around with trying to alter the fan speed settings - though this was a fairly high fan speed.

That's 5kW, but you have to reduce it slightly by the AC-DC conversion loss (perhaps 5% - overall loss at 40A when charging is ~12% but a huge part of that doesn't apply here, because the battery isn't being charged), and the vehicle overhead of ~200W.

So that's 4.8kW*0.95 or about 4.5kW. Just very roughly. This is all on a Superbottle vehicle, no heat pump.

I'm curious about people's claims that the most efficient AC setting is to set to LO with fan speed 1 because it (allegedly) doesn't engage the heater. Probably could do similar experiments to figure it out.

Anyway, back to the OP issue - yes, it was very likely that AC was a huge contributor in this case, especially at 22mph at 100 degrees F. Lower speeds of course make it much worse.

 

[Onanto]

my tesla has 5000 miles and I always charge 85%. But i already loss 11 miles from it. It was 358 now i get 347. Is it normal?

 

[Perscitus]

Welcome first-time poster and recent new owner. You did not loose 11 miles of range at 5K miles, that's not how this works nor how you should interpret what the on-board guesstimators are telling you.

Please read the many threads on and off here about range and battery SoC estimates, degradation, pack balancing strategiesz etc.

 

[RayK]

Ignoring the usage of "loss" when "lost" should be used, and "loose" for "lose", a reduction in estimated range is just that: estimated. The EPA, along with Tesla, has thrown out a number which it believes can be achieved under certain conditions, most of which is probably not what the "average" driver will do. It's akin to the MPG numbers on new cars; one for city driving and the other for highway consumption. Some people will exceed those numbers (hypermiling), while the lead-footed drivers will never reach those values.

 

[AlanSubie4Life]

my tesla has 5000 miles and I always charge 85%. But i already loss 11 miles from it. It was 358 now i get 347. Is it normal?

Yes, it's normal. Your BMS estimates that you now have 76.6kWh including the buffer, rather than your starting capacity of over 79kWh. (347/358*79kWh). If you read from the CAN bus that's what you'll see. It's the best estimate in the world of your battery's capacity, no one has a better one.

These estimates can change over time (and go up and down), so look at the long-term average and don't pay too close attention to every change. You should expect continued declines for a year or two and then it will settle out a bit, probably around 320-330, maybe slightly more with a bit of luck.

The estimate definitely does reflect directly on how far you can travel (not the actual number of miles though - the miles here are a measure of energy, not distance) - though again, it's just an estimate. The BMS tends to be conservative of course.

 

[Onanto]

Yes, it's normal. Your BMS estimates that you now have 76.6kWh including the buffer, rather than your starting capacity of over 79kWh. (347/358*79kWh). If you read from the CAN bus that's what you'll see. It's the best estimate in the world of your battery's capacity, no one has a better one.

These estimates can change over time (and go up and down), so look at the long-term average and don't pay too close attention to every change. You should expect continued declines for a year or two and then it will settle out a bit, probably around 320-330, maybe slightly more with a bit of luck.

The estimate definitely does reflect directly on how far you can travel (not the actual number of miles though - the miles here are a measure of energy, not distance) - though again, it's just an estimate. The BMS tends to be conservative of course.

Thank you.

 

[AAKEE]

my tesla has 5000 miles and I always charge 85%. But i already loss 11 miles from it. It was 358 now i get 347. Is it normal?

A small add-on to AlanSubie’s excellent answer:

Your range loss will be more dependent on time than the miles driven, unless you drive very much which it seems you don’t.
The SOC you charge to also affects the degradation.

You can anticipate to loose about 6-7% battery capacity the first year if you live in a medium hot climate. Some (a couple of percent?) of the loss will probably be masked by the degradation threshold so range loss probably end up at about 4-5% range loss after one year. Out of 358 this means about 340 miles.

( A side note, lower SOC lowers the degradstion so If you dont need 85%, a lower charging target will reduce the range loss.)

 

[Steve446]

Here's an end of first year estimation of the apparent degradation of my M3 LR AWD Q3 2021 MiC.
This is category E3CD EU with a 75 kWh M48 NMC battery.
I'd certainly be interested to hear from anybody else that has a similar battery spec regards their experiences!
---------------------------------------------------------------

Utilization pattern is hobby car, days out and road trips. The car has done just less that 8800 Km (about 5500 Miles).
Protocol adapted from @AAKEE recommendations starting about 3 months after delivery.
Apparent degradation is somewhere between 1.7 and 2%. It's quite difficult to judge with any accuracy since even the most stable parameter (NFP in the case of my M3) can bounce around a bit as a function of several things such as SoC, length of time in storage, BMS recalibration and supercharging.

•When M3 not used keep the SOC low:
~50% if < 20°C
~20-30% if > 20°C
•Charged only before use unless storage time requires a top up
•Only charged to a SOC % required for the journey:
generally, 50% SoC for < 200 kM
100% SoC for a road trip
•Charged just before the drive (always L2, 7 kW)
•Road trips L2 to 95% in 2 or 3 separate charges, then L2 to 100% just before departure
•Road trips use SuC or 50 kVA chargers (charge required added when there is a charger available)
•Estimated storage time ≡ about 11 months on 12 (ie continuous driving time/ total ownership time)
•Observations:
-NFP slowly drops with longer storage periods without charge and @ low SoC
-BMS calibrations (4 to 7) to (95 or 100)% SoC performed with and without subsequent Supercharging
-Supercharging after a BMS calibration appears to push up the NFP even further after initial impact of calibration.

 

[AAKEE]

This is category E3CD EU with a 75 kWh M48 NMC battery.

E3CD = Panasonic 2170, 77.8 kWh. In some cases ”derated” to about 75kWh to have the same range as E5D/E5CD.

LG M48 NMC have the 5 or 5C designation ( E5D or E5CD )

I’ll read the rest of your post later…

 

[Steve446]

E3CD = Panasonic 2170, 77.8 kWh. In some cases ”derated” to about 75kWh to have the same range as E5D/E5CD.

LG M48 NMC have the 5 or 5C designation ( E5D or E5CD )

I’ll read the rest of your post later…

You are quite right my bad typo

 

[AAKEE]

I'd certainly be interested to hear from anybody else that has a similar battery spec regards their experiences!

It would certainly be interresting to compare with others that did use the more standard 80% or so charging target.

Apparent degradation is somewhere between 1.7 and 2%.

•When M3 not used keep the SOC low:

Its not easy to judge your average SOC, but maybe somewhere around 40%?

For your 5C NMC cell, the degradation from calendar aging would look like this:

First 10 months at 25C / 40% would cost 2.5%. This means square root (12/10) x 2.5 = 2.7%.
A lower ambient/ cell temp like 20C ( a probable value for northwestern France) average cell temp would reduce the degradation slightly, maybe about 20-25% as 10C only cause half the degradation compared to 25C. We end up with about 2% calendar aging for the first year.

What about cyclic aging?
Research reports has showed that cyclibg at low SOC with small cycles cause very little degradation. For NCA, 6000 10% cycles around 30% ( 35-25% cycles) caused about 2% degradation. The 6000 10% cycles equals 600FCE and 600 FCE will be enough for 200.000Km.
The cyclic degradation for 8800km will be very low, a few 100% charges will not change this noticebly.

In total it is summing up to about 2% degradation, maybe a slightly more as average SOC isnt really known to me.

So, the average forum member start thinking that the battery lottery has a much greater impact and that we cannot know what lottery ticket Steve446 did get…?
The research does not support the battery lottery theory at all. Individual cells has a very small difference in the tests, and capacity between different batches seem to vary very little as well.

I have a similar calculation as the one above made for my car from the very beginning.
During the end of the spring my calc was 79kWh, and because it would be hillarious to estimate down to tent’s I called it between 78.5 and 79kWh during the summer. The actuall calculation was slighly below 79kWh.
Then I did a 100-0% test run and found the capacity to be 78.85kWh or so. Coincidence or? No. I have good data on the average temperature and SOC, and then I used the available research test data for similar battery cells.

 

[Steve446]

It would certainly be interresting to compare with others that did use the more standard 80% or so charging target.


Its not easy to judge your average SOC, but maybe somewhere around 40%?

For your 5C NMC cell, the degradation from calendar aging would look like this:

View attachment 852547

First 10 months at 25C / 40% would cost 2.5%. This means square root (12/10) x 2.5 = 2.7%.
A lower ambient/ cell temp like 20C ( a probable value for northwestern France) average cell temp would reduce the degradation slightly, maybe about 20-25% as 10C only cause half the degradation compared to 25C. We end up with about 2% calendar aging for the first year.

What about cyclic aging?
Research reports has showed that cyclibg at low SOC with small cycles cause very little degradation. For NCA, 6000 10% cycles around 30% ( 35-25% cycles) caused about 2% degradation. The 6000 10% cycles equals 600FCE and 600 FCE will be enough for 200.000Km.
The cyclic degradation for 8800km will be very low, a few 100% charges will not change this noticebly.

In total it is summing up to about 2% degradation, maybe a slightly more as average SOC isnt really known to me.

So, the average forum member start thinking that the battery lottery has a much greater impact and that we cannot know what lottery ticket Steve446 did get…?
The research does not support the battery lottery theory at all. Individual cells has a very small difference in the tests, and capacity between different batches seem to vary very little as well.

I have a similar calculation as the one above made for my car from the very beginning.
During the end of the spring my calc was 79kWh, and because it would be hillarious to estimate down to tent’s I called it between 78.5 and 79kWh during the summer. The actuall calculation was slighly below 79kWh.
Then I did a 100-0% test run and found the capacity to be 78.85kWh or so. Coincidence or? No. I have good data on the average temperature and SOC, and then I used the available research test data for similar battery cells.

Thank you AAKEE for the very informative reply. The all time average SoC for the car is 39.9%. I have a lot of data on that.
Here's a couple of extra charts for my M3 regards SoC over time since delivery (curve shows the average) and the average SoC and ambient (external) temperature averaged per week. It was over the very hot summer that I kept the SoC as low as possible (see graphs). After this data, I'm not so convinced about a battery lottery theory either.

 

[Steve446]

Thank you AAKEE for the very informative reply. The all time average SoC for the car is 39.9%. I have a lot of data on that.
Here's a couple of extra charts for my M3 regards SoC over time since delivery (curve shows the average) and the average SoC and ambient (external) temperature averaged per week. It was over the very hot summer that I kept the SoC as low as possible (see graphs). After this data, I'm not so convinced about a battery lottery theory either.

@AAKEE, I have not graphed the SMT battery temperature data. So I just averaged 2022 temperatures °C:
Jan to April
13 ambient and 18 battery mid (rounded)

May to mid Sept
22 ambient and 29 battery mid (rounded).

Just curious but could these temperature ranges during storage explain the differences between your calculation and the data.

 

[blackT3$!@]

Your range loss will be more dependent on time than the miles driven, unless you drive very much which it seems you don’t.

I have a LR AWD Model 3 build/delivery date of 9/21. I have 36k miles on it and two weeks ago I charged it to 100% before a trip and the guessometer said I had 353 miles. 99% of my charging is nightly at home on a level 2 Tesla Wall Charger set to 48amps to 90%.

 

[AlanSubie4Life]

I have a LR AWD Model 3 build/delivery date of 9/21. I have 36k miles on it and two weeks ago I charged it to 100% before a trip and the guessometer said I had 353 miles. 99% of my charging is nightly at home on a level 2 Tesla Wall Charger set to 48amps to 90%.

I believe your car should have shown 358 at some point, although it was sold with 353 technically if it was MY2021.

Anyway, about 2% or even 3%. But pretty good given the location.

 

[Steve446]

I believe your car should have shown 358 at some point, although it was sold with 353 technically if it was MY2021.

Anyway, about 2% or even 3%. But pretty good given the location.

So, @ 353 Mi which battery does he have? The Panasonic or the LG M50

 

[AlanSubie4Life]

So, @ 353 Mi which battery does he have? The Panasonic or the LG M50

US. Panasonic 82kWh.

These vehicles started with 353 but I believe the ones with 82kWh (earliest in the model year didn’t have that) were bumped in software to 358mi (which was just an increase in degradation threshold and nothing else, as I understand it).

(The veracity of this claim can be determined for sure by data from the vehicle, but I think we have confirmation from at least one vehicle already.)

 

[AAKEE]

@AAKEE, I have not graphed the SMT battery temperature data. So I just averaged 2022 temperatures °C:
Jan to April
13 ambient and 18 battery mid (rounded)

May to mid Sept
22 ambient and 29 battery mid (rounded).

Just curious but could these temperature ranges during storage explain the differences between your calculation and the data.

Tha average is close to 20C ( 21…) for those 9 months, and the first three should
not be slightly colder so I guess 20C is a decent estimate.
I had 10.X degrees average during the first year but I live very very far north.
It will need some colder than average climate to average much below 20C.

This means that the calc is probably valid/probable as is.

 

[AAKEE]

I have a LR AWD Model 3 build/delivery date of 9/21. I have 36k miles on it and two weeks ago I charged it to 100% before a trip and the guessometer said I had 353 miles. 99% of my charging is nightly at home on a level 2 Tesla Wall Charger set to 48amps to 90%.

What SOC do you have normally in the evening when the days drive is done, and when do you charge? In the evening or during the morning?

If the car is at 90% for most times during the days, its quite likely that the real degradation would be around 6-7% or so after one year in a warm climate.

 

[blackT3$!@]

What SOC do you have normally in the evening when the days drive is done, and when do you charge? In the evening or during the morning?

About 45% remaining when arriving back at home. I schedule charging to start at 00:00hrs. I have time-of-use rates and I like to have the car charged within an hour of leaving in the morning at 0530.