Model 3 SR+ LFP Battery Range, Degradation, etc Discussion

[AlanSubie4Life]

So it is better fo rbattery not to charge to 100% too often or?

No, it’s really totally fine. Just don’t leave it there.

Nothing matters but the storage charge level, to first order.

Would I charge to 100% all the time? Yes if it were necessary. I’d just use it right away, to below 65-70% for LFP. Which should be a non issue to do since the car was charged to 100% for a reason.

 

[DuncanM]

Interesting. Having not really been following LFP batteries before I am curious. Are there any research/graphs of degradation of LFP? Is it still the conclusion they degrade less than NCA?

There's no doubt that LFP degrades less per charge cycle than NCA, and CATL LFP batteries (as in the M3 RWD) have about twice the rated cycle life of NCA. However, it maybe that LFP has a higher calender degradation than NCA.

There's some interesting data in this report:

https://storage.googleapis.com/itp-renewables-website/documents/Battlab_Report_12_Final.pdf

 

[tgrobbo]

There's no doubt that LFP degrades less per charge cycle than NCA, and CATL LFP batteries (as in the M3 RWD) have about twice the rated cycle life of NCA. However, it maybe that LFP has a higher calender degradation than NCA.

There's some interesting data in this report:

https://storage.googleapis.com/itp-renewables-website/documents/Battlab_Report_12_Final.pdf

Finally someone else is saying this lol. A 7% loss as per the earlier post is no different to what you’d expect from an NCA battery at that age and mileage - perhaps even a little worse. But if it’s not cyclic aging causing this loss, well then it must be calendar aging. Even if you just say ‘as a percentage of total capacity loss, LFP loses more to calendar aging than other Tesla chemistries’ that’s surely a hard statement to disagree with.

 

[karlos22]

Finally someone else is saying this lol. A 7% loss as per the earlier post is no different to what you’d expect from an NCA battery at that age and mileage - perhaps even a little worse. But if it’s not cyclic aging causing this loss, well then it must be calendar aging. Even if you just say ‘as a percentage of total capacity loss, LFP loses more to calendar aging than other Tesla chemistries’ that’s surely a hard statement to disagree with.

It is very clear that LFP calendar ageing is comparable to that of NCA. There has been ample evidence posted in this discussion.

 

[Baluchi]

Interesting. Having not really been following LFP batteries before I am curious. Are there any research/graphs of degradation of LFP? Is it still the conclusion they degrade less than NCA?

There are graphs posted in this thread, multiple times...somewhere.

 

[tgrobbo]

It is very clear that LFP calendar ageing is comparable to that of NCA. There has been ample evidence posted in this discussion.

I don’t think so - graphs don’t mean anything compared to real life examples - it’s only now we’re starting to see LFP cars with a little bit of age. They’re three years old and they’ve got the same or worse degradation as NCA, therefore, they are calendar aging more, (as a percentage of their total degradation) because it’s clearly not cyclic aging. Cheers

 

[karlos22]

I don’t think so - graphs don’t mean anything compared to real life examples - it’s only now we’re starting to see LFP cars with a little bit of age. They’re three years old and they’ve got the same or worse degradation as NCA, therefore, they are calendar aging more, (as a percentage of their total degradation) because it’s clearly not cyclic aging. Cheers

I haven't really seen evidence of that, however if that was the case then it could be explained by LFP owners charging to 100% frequently (higher calendar ageing above 70%).

 

[tgrobbo]

I haven't really seen evidence of that, however if that was the case then it could be explained by LFP owners charging to 100% frequently (higher calendar ageing above 70%).

I don’t follow NCA cars that closely to be honest as we mainly just have LFP and NCMA in my country, but from what I’ve seen, a three year old NCA car is doing better or the same as a 7% loss. In fact there are some at 200,000 miles with only 7% loss. All I’m saying is calendar aging makes up a bigger portion of the loss in LFP - which has to be true if it has less cyclic aging than NCA - however I am suspicious that they might actually just have more calendar aging. If they are losing similar capacity over the same time period as NCA, then they definitely do. 100% charging would be the likely culprit for sure.

 

[Msaman]

Hi chaps,
I have a lfp 60kw and had 261 miles after 2 years. But after a 2-3 days not charging my buffer increased to 6 kwh.
I charged to 100% 3 times and it still the same. Haven't had the time to let it sit at low state of charge for any time.
Do you guys think that's the way to reset the buffer?
Ta,
Chris

 

[karlos22]

Hi chaps,
I have a lfp 60kw and had 261 miles after 2 years. But after a 2-3 days not charging my buffer increased to 6 kwh.
I charged to 100% 3 times and it still the same. Haven't had the time to let it sit at low state of charge for any time.
Do you guys think that's the way to reset the buffer?
Ta,
Chris

What are your charging habits? How often to 100%?

 

[Msaman]

What are your charging habits? How often to 100%?

Almost every other day, but still hasn't balanced

 

[karlos22]

Almost every other day, but still hasn't balanced

What about before the buffer increased? How often to 100%? Weekly?

Maybe discharging to 15% or less and leaving it there for a few hours, then charging to 100% might help.

 

[gtg465x]

I don't think we know the true degradation of CATL LFP batteries in Teslas yet. I think the range Tesla shows is mostly based on a predetermined algorithm, not actual measurements, because keeping SOC at 50% all the time, like I do, seemingly makes no difference compared to people that leave theirs at 100% all the time. I will continue to keep mine at 50% most of the time and charge to 100% about once every 2-3 weeks, only before long drives, but so far it doesn't seem to have made any difference, at least in the displayed range. Mine is exactly where everyone else's is when you compare by age. 18.5 months, 261 miles displayed at 100%, 272 miles rated when new.

 

[eevee-fan]

I don't think we know the true degradation of CATL LFP batteries in Teslas yet. I think the range Tesla shows is mostly based on a predetermined algorithm, not actual measurements, because keeping SOC at 50% all the time, like I do, seemingly makes no difference compared to people that leave theirs at 100% all the time. I will continue to keep mine at 50% most of the time and charge to 100% about once every 2-3 weeks, only before long drives, but so far it doesn't seem to have made any difference, at least in the displayed range. Mine is exactly where everyone else's is when you compare by age. 18.5 months, 261 miles displayed at 100%, 272 miles rated when new.

Despite Recurrent thinking I should only have 258 miles range, my Tesla EPA range shows 264 miles at full... 272 when new. Just passed one year from purchase... might be a few months longer compared to mfg date.

Update: Just checked my Recurrent web page, it shows 263 miles now. This closer matches what it shows in my car. Guess there was some kind of data issue. Also, battery health updated from 97% to 99%. And my 3 year old range est is now 252 (was 247 a few days ago).

 

[gtg465x]

Despite Recurrent thinking I should only have 258 miles range, my Tesla EPA range shows 264 miles at full... 272 when new. Just passed one year from purchase... might be a few months longer compared to mfg date.

Update: Just checked my Recurrent web page, it shows 263 miles now. This closer matches what it shows in my car. Guess there was some kind of data issue. Also, battery health updated from 97% to 99%. And my 3 year old range est is now 252 (was 247 a few days ago).

Yep, 264 is where I was at the 1 year mark too. Everyone is, unless they never charge to 100%, in which case the BMS gets conservative and underestimates.

 

[DrChaos]

I don't think we know the true degradation of CATL LFP batteries in Teslas yet. I think the range Tesla shows is mostly based on a predetermined algorithm, not actual measurements,

Unfortunately that may be true because as the SOC estimation in LFP is not easy, probably the full pack energy estimate in LFP is not easy either, and any algorithm other than a full discharge and recharge will probably be inaccurate.

And then people will panic when the algorithm shows a big range loss but because of uncertainty. So from a customer service point of view the choice is probably right to prevent needless panic and unneeded service calls.

Nonetheless, down in the world of atoms, the iron laws of chemistry still apply and lower SOC results in less degradation. But you'll have to take it on even more faith than those with NCA/NCM.

 

[karlos22]

I don't think we know the true degradation of CATL LFP batteries in Teslas yet. I think the range Tesla shows is mostly based on a predetermined algorithm, not actual measurements, because keeping SOC at 50% all the time, like I do, seemingly makes no difference compared to people that leave theirs at 100% all the time. I will continue to keep mine at 50% most of the time and charge to 100% about once every 2-3 weeks, only before long drives, but so far it doesn't seem to have made any difference, at least in the displayed range. Mine is exactly where everyone else's is when you compare by age. 18.5 months, 261 miles displayed at 100%, 272 miles rated when new.

Possibly, it is a theory that has been floating around for a while but there is little proof other than we all have similar range loss regardless of charging habits

My opinion stands that it isn’t worth worrying about. If you can’t accurately determine the range loss, then does it really matter?

 

[eevee-fan]

Possibly, it is a theory that has been floating around for a while but there is little proof other than we all have similar range loss regardless of charging habits

My opinion stands that it isn’t worth worrying about. If you can’t accurately determine the range loss, then does it really matter?

When Tesla moved on to structural battery, I think that is a signal that the batteries are reliable enough and long lasting enough, that an owner would not have to worry about degradation or cell failures. It will still happen, just a super low probability event. Now, if we start doing V2H with the EVs, that might be a different story, but probably not by much since an EV has a much higher instantaneous demand requirement than a house and cycle life would probably only double for a 1 EV house and only 50% for a 2 EV house.