MASTER THREAD: 2021 Model 3 - Charge data, battery discussion etc

[Steen2000]

High currents increase the wear.
But that is high current during longer times.

Shorts bursts doesnt really matter. Stay cool when SOC is below 20%, no long full throttles.

I have a performance, almost 12 months and I like to use power. If hard acceleration was bad I wouldnt have more or less full range after 30.000km and the degradation report wouldnt look like this:

View attachment 740220

Impressive !!

 

[conv90]

I don't know if Tesla will change constant.
In the Italian configurator an LR is at 614 WLTP (the max ever displayed since when they equipped the car with the E3LD then again now with the E5LD .
The strange fact is that 614 is for the 19" Wheels!
If you switch to 18" the range increase to 630.
The same for the SR+ with 510 WLTP with 18!
[EDIT : I know the constan is based on EPA.. so there is no need to change it for the diffent WLTP range for the same car
But, if "EPA advertised ranges" are with different wheels options too , the same car with the same battery (but different rims)need to have a different constant if the displayed ranges are different between the two cars ]

 

[AAKEE]

Hi, just joined this thread. Lot's of knowledgeable people and smart input here. I've only ready back a few pages and was wondering if all also applies to LFP chemistry when it comes to SOC/Temp and Battery Degradation? Thanks!

Research, quite recent but maybe not on the latest generation if LFP, shows this:

I havent read much about LFP so I can not say if thias is valid fotr the latest gen of LFP.

We know that LFP is not sensitive for big cycles, they can do many thousand cycles even when doing 100% DoD cycles.

My guess is that they still are sensitive for time @ SOC @ high temps.
Time probably degrades, but you can do 100% DoD without any second thoughts

 

[Dave EV]

Research, quite recent but maybe not on the latest generation if LFP, shows this:
View attachment 740258

I havent read much about LFP so I can not say if thias is valid fotr the latest gen of LFP.

We know that LFP is not sensitive for big cycles, they can do many thousand cycles even when doing 100% DoD cycles.

My guess is that they still are sensitive for time @ SOC @ high temps.
Time probably degrades, but you can do 100% DoD without any second thoughts

Nice data - I would probably charge to 70% regularly, then charge to 100% once a month to help calibrate the BMS because the discharge curve for LFP is so flat. Goal would be to let it get as empty as possible before recharging so average SOC is as low as possible. If you really want to maximize life, only charge to 50%.

Interestingly, 70% on a ~260 mile LFP pack gets you about the same rated range as 55% on a ~350 mile NCA pack (about 180-190 rated miles).

Interesting that the rate of capacity loss appears to be higher than NCA for the cells tested here. Would love to see how actual Tesla cells behave.

 

[Jejunjm]

We know that LFP is not sensitive for big cycles, they can do many thousand cycles even when doing 100% DoD cycles.

Why haven't the power walls been changed to lfp? Seems like they are the right implementation, weight doesn't matter as much and charging it to 100 is fine. Temperature can also (potentially) be easier regulated.

 

[AAKEE]

Thats right, volyme shouldnt matter( for LFP vs NCA)

Well, other brands use LiFePo4 ( LFP ).
Tesla use NMC that are better than NMC for deep cycling(in general). I would guess Tesla will change to LFP as soon as they can spare some LFP for this.

Cars: used a very little time per day: calendar aging is the limit.

Home storage: Expensive so most people use pack sizes that will give large cycles = NMC is(was) a good choise.

 

[Steen2000]

Does it impact battery in any way to pre-heat the car before using it (scandinavian weather)
I mean I am sure it is nice with a ready car and it drives longer I assume. It does cost some electricity so as I understand your trip needs to be of some distance before it makes sence from a range/money perspective
Anyway in term of battery preservation? Is it good for the battery to be prepared before take off?
(I am also asking because I am still thinking about home charging vs only charging at work and near my home on fixed monthly fee)

 

[jlz78]

One user in Germany sharing his LG 5C SuC V3 charging results with Update 2021.40.6

Tesla seems to have (unexpectedly) increased the charging speed!

Credits to user @ehrmoa of TFF Germany:

View attachment 738351

Hi all, just collected my UK M3LR today which is a Q4 car built around 17th October. Here is the battery picture after 47 miles of driving. I’m assuming it’s a standard 75kWh LG, but are you able to confirm?

 

[conv90]

Hi all, just collected my UK M3LR today which is a Q4 car built around 17th October. Here is the battery picture after 47 miles of driving. I’m assuming it’s a standard 75kWh LG, but are you able to confirm?

Yes, LG Chem 77 kWh (74.5)

 

[AAKEE]

Here is the battery picture after 47 miles of driving.

The sticker probably will look the same at any ODO (just kidding)

 

[AAKEE]

Does it impact battery in any way to pre-heat the car before using it (scandinavian weather)
I mean I am sure it is nice with a ready car and it drives longer I assume. It does cost some electricity so as I understand your trip needs to be of some distance before it makes sence from a range/money perspective
Anyway in term of battery preservation? Is it good for the battery to be prepared before take off?
(I am also asking because I am still thinking about home charging vs only charging at work and near my home on fixed monthly fee)

Well, the principle of degradation is that the battery like low temperatures when at rest (calendar aging) but it likes slightly higher temps when in use.
We know that the batteries do not like to be charged when being sub zero degrees( below the freezing level), but this is handled automatically by the BMS. It heats the battery before charging if needed.

If the car stands outside for long time in freezing the battery will cool. The lower ambient temps the faster it cools.
If you plan the drive in the car or the app, the car will handle this by itself by heating the battery if needed.
The target for the battery temp seems to be about 12C( last winters late value, havent checked this winter) and if you drive away with a not conditioned car, the battery will be heated at least so you do not get the ”Low battery temp snowflake”, and for highwaydriving it seems to heat quite quick by itself to the 12C level.

So, best for battery life would be to plan the trip and get the battery and car preconditioned. If you live in a very cold climate( like up here close to the artic circle) it might make a noticavvle difference, maybe , to have it conditioned.
Otherwise, medium cold or even less, its probably not possible to notice any degradation from driving a slightly cold battery. If you have a performance/ or the power upgrade, use high power with care when the battery is cold.

 

[FredMt]

Hi all, just collected my UK M3LR today which is a Q4 car built around 17th October. Here is the battery picture after 47 miles of driving. I’m assuming it’s a standard 75kWh LG, but are you able to confirm?

Yes, LG 5C
(For information
Style 8B (P) 1522312-00-D in Q2 2021).
What maximum range on screen do you have?

 

[Jonte89]

Yes, LG 5C
(For information
Style 8B (P) 1522312-00-D in Q2 2021).
What maximum range on screen do you have?

 

[Jonte89]

Hi,
Was the advertised WTP 580 km? If not you should have got the new LG E5LD battery pack which is 80,5 Kwh and has a WLTP of 614 km.
Brgds Jonte

 

[MrT3]

Was the advertised WTP 580 km?

Yes, all UK LRs are 580 km. But at some point they will hopefully run out of them and switch over to the higher capacity pack.

 

[Thdj]

Hi Guys,

Question: iI have been doing some calculations lately based on the % used and the Kwh consumed lately. All of the tests I did lead to the conclusion my 2019 M3P @ 48000km has about 65kwh usable capacity (left).

Yesterday, I charged to 100% (for the test), drove to relatives, stayed there couple of hours (no sentry! / app usage) and drove back. According to the screen i used 27 kwh in 42% which leads to -> 27÷ 0,42 -> 64.28 kwh capacity at 100% (of the 72 net it should have). Off course i could have had some drain while standing still, but not much.

Range @ 100% is 438km of the original 500.

I haven't supercharged much (about 7000-8000km of the 48000) and mostly charge to 80%. I make sure I never leave it at low or high SoC.

Stats from TeslaFi (I haven't had an account for all the Km's):
View attachment 735989


I find this quite disappointing, or am I missing something?

Another follow-up question: i also have the SOC behaving strange. This morning, i charged to 80% and a few hours later the soc is 76% (5deg c outside), no sentry etc. The opposite also happened: arrived with 29% charge, next morning, it’s 33% (also quite cold night)

Could this indicate the BMS is a bit confused?

 

[jlz78]

Yes, LG 5C
(For information
Style 8B (P) 1522312-00-D in Q2 2021).
What maximum range on screen do you have?

I haven’t charged to 100%, but app showing 100% at 335 miles.

 

[AAKEE]

Another follow-up question: i also have the SOC behaving strange. This morning, i charged to 80% and a few hours later the soc is 76% (5deg c outside), no sentry etc. The opposite also happened: arrived with 29% charge, next morning, it’s 33% (also quite cold night)

Could this indicate the BMS is a bit confused?

Its not that strange, I think.

After charging, the battery cools. Causes a shift to appearent lower SOC.

After a drive if the battery SOC normally increases slightly when the battery rests if it notbis too cold outside(above freezing or so).

In cold weather, the battery cools after a drive, if the car was parked inside a heated garage before. I regurlary see some percent lower SOC after the car has been parked outside during a work day.

If the car was parked outside, with a cold battery before the drive, the SOC is at the “lower value” because of the cold battery.
A cold battery probably show a lower SOC value during the drive due to increased internal restisrance that cause a lower voltage reading( voltage is the base for SOC calculations).
When at rest again, the SOC-calue may climb

 

[Jejunjm]

A cold battery probably show a lower SOC value during the drive due to increased internal restisrance that cause a lower voltage reading

But cold decrease electrical resistance

 

[AAKEE]

But cold decrease electrical resistance

No. We are talking about internal resistance, it increases with low temps in all known batteries.
The reason for preheating before supercharging is to reduce the internal resistance so the current can be higher.

For a given load (current) the voltage drops more the higher the internal resistance is.
Example: At 90km/h you might read 3.7V/cell with a warm battery with 50% SOC.
A cold battery might drop to 3.5V in the same situation, same SOC.

This is a chart over the internal resistance vs temperature(just *any* chart, the first I found, not Tesla NCA-specific but the principle is like this).

The Supercharging target is above 50C, as it lowers the internal resistance and increases current = higher charge power/lower charging time.