I agree with this. After 3 yrs and reading all the posts regarding the HV battery. It looks more like a battery lottery on how good the cells are in one‘s pack…than how they are treated/charged. I’ve given up and decided a long time ago to just charge to 90%. Why? Because I want the the maximum amount of power available. I think it’s too slow when the battery gets in the lower SOC lol. I dont think much about it other than stay under 90%, unless going on a long trip and stay above 20%. I plan on getting rid of it after 5-8 yrs and the HV battery will be under warranty during that time. Why not just charge up to 90 and enjoy it?
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Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health
- Thread starter KK_RedM3
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I agree with this. After 3 yrs and reading all the posts regarding the HV battery. It looks more like a battery lottery on how good the cells are in one‘s pack…than how they are treated/charged. I’ve given up and decided a long time ago to just charge to 90%. Why? Because I want the the maximum amount of power available. I think it’s too slow when the battery gets in the lower SOC lol. I dont think much about it other than stay under 90%, unless going on a long trip and stay above 20%. I plan on getting rid of it after 5-8 yrs and the HV battery will be under warranty during that time. Why not just charge up to 90 and enjoy it?
You are, of course, right. But there is to much information so I feel guilty! Just like I am weirdly proud of my 237 kwh/mi.
The most easy way if you like a relaxed carefree life is to just follow the simple rules Tesla set, and no more thinking.
(Stay below 90% unless on a trip, always charge when possible and charge asap if you arrive with less then 20%.
On the other hand, there is more than one research report showing that the highest calendar aging might be below 100%. At least two or three research reports I’ve seen shows this (worst calendar aging at about 80-90% SOC)and comparing that result with other research reports that doesnt really show this you can actually find signs of that in these as well.
So if one is interested there is a lot of possibilities to keep the degradation down.
It is not really possible that it is the coincidence that is the main driver in degradation. Even if it is a big difference in packs from the factory due to the manufacturing process(which I dont believe because other lithium cells I’ve used show very small differences in capacity) you still can take actions to minimize the degradation. If I bought a long range because I needed the range and got it from the store with a appeareblack of 4-5kWh, Id make sure I didnt loose another 5 kWh from using it in a way that cause more degradation than needed.
But of course the way of handling charging habits is a matter of choice everyone need to make by them self.
From research we know what cause degradation, which is more or less driven by the laws of nature. Tesla can only do a few things to keep the degradation down so these laws will affect NCA cells in the same way it do in research.
I know the model 3 doesn‘t use 18650’s but I’ve been using them for years before I got my P3D. I have a collection of LED flashlights and 18650 cells….and more recently electric longboards, scooter, bike. All of which use lithium ion cells that I do follow best practice with. I don’t dispute what research has been done. Owners will choose to follow it to a T, just supercharge everyday or something somewhere in between lol. IRL when it comes to the model 3 there seems to be plenty that follow those best practices and still lose the same amount of displayed range as those that just charge to their hearts content. Is it real degradation or just bms calibration? We all know Tesla‘s QC when assembling cars could use some improvement. How‘s the QC with building the cells? One thing tesla does do is manage the cell temps with its cooling system. Maybe that helps level the field to where charging practice doesn’t have as much of an impact? Maybe it’s their advanced bms that helps manage the cells and overall pack life? Who really knows. But one thing we do know.….Is that no matter how many times people bring their cars to tesla complaining about loss in range…in the end they won’t do anything unless you make the 30% threshold.
Max range is important to me as I take multiple long ski trips in the winter…conditions that impact range the most. But I also got the P3D because I wanted the power(have driven modified cars for the past 24yrs). At what point is the trade off of worrying about the range and how/when you charge it VS just enjoying the car? It’ll be different for everyone.
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I agree. I posted in another thread in the Y forum about my experience so far over 3 Teslas: two Model 3 SRs (my wife's) and my Model Y SR.
The first Model 3 I religiously kept the battery around 50% for about 5 months after new, even though my wife thought I was nuts. During that time we lost 10% capacity even though I thought I was doing right by the battery. After that and discovering the Elon tweet about "charge to 90% daily is no problem IMO" or whatever he said, I just started that routine instead (especially after reading some people on this forum who say they not only charge to 90% but top the battery off every time they park the car and have no reduction in range). I only had a few months of 90% charging (with continued reduction in range) before that car was totaled and we bought another Model 3. That car had about 10k miles on it when wrecked.
Both the new Model 3 and my Model Y have been charged daily to 90% since new. The Model 3 has lost 16% range and my model Y has lost a little over 5%. What's the difference? no idea. I have driven the crap out of my car and have run the battery down many many many times. I have put on 15k miles in 8 months and yet my wife's car has barely over 7k miles and worse "degradation". Is it the lack of "exercise" on the pack in the Model 3? is it the hours and hours it sits in the CA heat in our garage when my car might be elsewhere, out and about? Or is it just a battery lottery?
I do want to believe of course that there is scientific, proven data that following best practices will result in better battery life. But I am not seeing any consistency with our cars, which is frustrating.
Regular people will not want to dance around a "battery care" charging ritual. I really feel like mass adoption of EVs will have to either iron out this sort of unpredictability, make batteries so large people won't notice the loss, or make batteries so cheap they'll just replace them when they no longer provide enough energy for their purposes (or some combination of the the three). I do think I would care much less about any loss the battery is experiencing if I knew I could replace it at any time for say, $5000 .. once people start throwing around $15k or $20k numbers for a battery, the longevity of that particular part of the car understandably becomes a much greater concern.
Jeremy3292
Active Member
AlanSubie4Life
Efficiency Obsessed Member
Yes, once your battery drops below the degradation threshold you'll see it there. However, this method will miss the initial degradation since your car shows full charge for quite a while even as the battery loses capacity, especially for the current 2021 LR. In general it's hard to tell exactly how much capacity you have when you're at the full number of rated miles. You either have to get SMT, or extremely carefully meter how much energy your car uses, for a given number of rated miles used, or extremely carefully measure and meter the energy put into your car (and back calculate using the charging efficiency - this method is prone to a fair amount of error but if used extremely carefully as a baseline, can show you changes over time).
Anyway wouldn't worry about it. Rated miles captures all but the first ~2-3% of capacity loss.
Things my non-EV-geek friends don’t want to wrap their heads around: battery degradation, optimal charging practices, and the taper on fast charge. Then when they do get an EV, those things become non-issues anyway.
Manufacturers have to keep care-and-feeding instructions dead simple. Most folks don’t read the manual anyway.
Manufacturers have to keep care-and-feeding instructions dead simple. Most folks don’t read the manual anyway.
Scottish mod3
Member
Great to see to see all the discussion.
... must not forget that degradation is also down to BMS , which I don't think is accounted for in academic studies.
The BMS and heat pump ie octovalve in Teslas should keep the batteries at optimum operating condition to minimise the deg, albeit within boundaries. I guess the way they operate will differ based on the chemistries.
for me its not just the batteries chem but more so the software and hardware, the reason why I went with Tesla..
ps if you like geeking out on the batteries, check out octovalve, it’s genius...
... must not forget that degradation is also down to BMS , which I don't think is accounted for in academic studies.
The BMS and heat pump ie octovalve in Teslas should keep the batteries at optimum operating condition to minimise the deg, albeit within boundaries. I guess the way they operate will differ based on the chemistries.
for me its not just the batteries chem but more so the software and hardware, the reason why I went with Tesla..
ps if you like geeking out on the batteries, check out octovalve, it’s genius...
AlanSubie4Life
Efficiency Obsessed Member
When the car is asleep (which is most of the time), this is a storage condition which impacts aging significantly, and Tesla does no active heating or cooling during this time (which is the vast majority of the time). (Maybe if it is extremely cold or extremely hot, it does, but I have never seen that or heard it reported.)
Yes, when operating, Tesla is very careful to treat charging and discharging conditions, by moving heat, to minimize degradation.
But mostly the storage condition is what is being discussed here, probably dominates capacity loss, and the BMS does not manage the temperature.
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While the octovalve is genious, the main focus from Tesla has been to keep the consumption low by using heat generated from the battery to heat the car cabin.
Id say the goal with the heatpump is not to keep the life of tve battery.
A lithium ion battery likes some 20-30C when being used for mow degradstion during the cycles.
But when not used (parked car, at sleep) it likes lower temps.
With the heat pump, when heat is needed heat is drawn from the battery in many cases. There have been power issues with the new 2170L packs because the battery pack has gotten cold and then they dont deliver power at low SOC.
Exactly.
No, it doesnt heat the battery when at sleep in cold. When you park it in cold WX I think it can take heat from the cabin and heat the battery. Main purpose of this should be to use the battery as a heat capacitor, reusing that heat when the car is started again.
I have parked my M3P outside at work at -30C and havent seen any heating during this time. Battery gets the blue snowflake symbol because it gets cold( if not preheated before going home).
From what I have seen Tesla fixed that bug via a firmware update and that no longer happens.
Not really. They seem to let the battery temps up at low SOC to make sure the battery can deliver power. At the same time, they also set the minimum voltage lower, letting the voltage drop more during full throttle. These two changes seemed to do the trick for the engine power at low SOC. The cell temps at normal SOCs still kept at 10-12C, as before if my memory doesnt fail on me. For low SOCs, about 20% or less, the battery temp is allowed to climb to 25C or so. (In this case the heating of the cabin probably ”cost” a little more). One of the main ideas with the heatpump is to use battery heat and save battery.
We had 5C today, and a village 100km or so away did get 7cm/ 3” of snow today.
Not long until I can test the winter stuff again
Tesla has quite a wide operating range when the car is on - in hot weather, the batteries will get quite toasty. Here are a few targets I saw on the diagnostic screens on my Model 3 - ScanMyTesla will also show these:
Active Cool Target: 55C / 131F
Passive Target: 30C / 86F
Active Heat Target: -7.5C / 18.5F
I haven't watched these too much while in use, but it will actively heat the battery up quite a bit to precondition for Supercharging - I don't recall the exact target, but I thought it was in the 50C ballpark.
If it's hot, the battery will easily reach 45-55C just driving on the freeway.
While this is good for fast charging and for efficiency, it's not good for longevity. For storage, you'd like temps to be close to freezing.
These temperature ranges are quite a bit wider than what most manufacturers allow, especially at the high end, but I also think that their batteries are significantly more sensitive to high temperatures than the chemistries Tesla has used in their cells.
it doesn’t? It’s been over 100 degrees for months where I am and both our Teslas are constantly running what sounds like the coolant pump when in the garage. But I don’t know what is happening there for sure
AlanSubie4Life
Efficiency Obsessed Member
Turn off cabin overheat protection and make sure your car is sleeping properly.
Once those contactors open there won’t be any thermal management happening. And they will open.
Unless the AC compressor is running or the ambient temperature is cooler than the pack temperature, all the coolant pumps do is equalize pack temperature when the car is just sitting there.
What model Teslas do you have?
AlanSubie4Life
Efficiency Obsessed Member
I’ve do not observe my car running any pumps when I leave it out in the sun in 90+ degrees and it goes to sleep (have to turn off overheat protection of course).
I absolutely concede that I have never experienced true extremes (over 105 degrees or below 30 degrees or so). So not sure what happens or whether the car will exit sleep in those circumstances. My understanding is that it will not except in very extreme circumstances.
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