How is my LFP battery holding up after 2 years?

[kelvin 660]

I previously started a thread, How are LFP batteries holding up? about my experience with LFP batteries and felt it was time to give a short update. Also it is more relevant now that there are more LFP RWD 3's and Y's on the road.

My 55 kWh SR+ has now travelled 20,500 miles and average a 240 Wh/Mile over the past 2 years. When new, the car charged to 263-mile range and now charges to 251-mile range. That is a loss of 12 miles (or 4.56%) if I take the battery capacity it started with 53.97 kWh and is now at 51.46 kWh, as measured using the “consumption screen”. Where battery capacity in Wh = average Wh/mile x projected range ÷ SoC (best measured after charging to 100%). Example: 200 Wh/mile x 265 projected miles ÷ 100% SoC = 53,000 Wh or 53 kWh

So, my battery capacity has degraded by 51.46 ÷ 53.97 = 0.953 or 4.65% (or 2.33%/year). This result is also confirmed by TeslaFi’s Battery Degradation Report attached.



I guess that’s not too shabby, (and much better than my old SR+) but looking at the TeslaFi graph (blue line) my car continues to degrade at a constant rate, whereas others (green line) have started to level out! This might be because I have done less miles in the second year compared to the fleet average??

Looking in TeslaFi, Leaderboard, for highest Odometer readings for a 55 kWh LFP car, I found that user “Flinchy” has now done 132,000 miles, in a similar age car, and has only lost 4.88% of range. That result seems to suggest that LFP battery suffers more from calendar aging rather cyclical charging aging??

What are other LFP users finding?

Lastly, there was some concerns during the introduction of LFP batteries being able to cope when the temperature drops. Well, I have driven in temperature range from +39C and down to -7C and have had no real issues, apart from regen not being so strong in the low temperatures. However, maybe this is something that can be improved when Tesla bring in the function to automatically apply the brakes when regen is week… This may not be a bad effect as it does mean the brakes get some exercise in the winter that may stop them from seizing up!

 

[MrBadger]

Not LFP, but our Model 3 LR is reporting 296 miles vs 310 miles from new. That’s under 5% in 30k miles.

However, tbh, it’s been all over the shop over the years and I take the so called reported mileage’s calculated by whatever method with a large pinch of salt.

So what’s changed? Combination of events. Couple of firmware update issues (confirmed by Tesla, leading to), Tesla resetting the CAC (ie resetting BMS) and possibly a change in charging regime where since moving to IO, we allow the battery SoC to drop more before charging. It use to be little and often, now it’s a bit more of a charge and less often.

But I’m expecting it all to go south over winter again. Last winters dip coincided perfectly with winter tyre change.

But these values are more about how good a job the BMS does at guessing/estimating the stored capacity than anything concrete about battery degradation. And as I understand it, getting within 10% of true value is pretty good going.

 

[gangzoom]

So, my battery capacity has degraded by 51.46 ÷ 53.97 = 0.953 or 4.65% (or 2.33%/year). This result is also confirmed by TeslaFi’s Battery Degradation Report attached.

That’s pretty similar to our 75D X over the first 30-50K miles. At 70k it’s sitting at 5% degradation, and there doesn’t seem to be much change.

 

[kaimanson]

That's what I have heard as well. My 3 RWD with 6440 miles shows 265 at 100% from 273 at 100% originally.

 

[SteveH13]

That's what I have heard as well. My 3 RWD with 6440 miles shows 265 at 100% from 273 at 100% originally.

Same car and mine also shows 265 mostly at 100%, occasionally 266. 5.5k miles. But I’ve never seen 273 or anything above 267 since I’ve had it

 

[GeorgeSymonds]

Not LFP, but our Model 3 LR is reporting 296 miles vs 310 miles from new. That’s under 5% in 30k miles.

However, tbh, it’s been all over the shop over the years and I take the so called reported mileage’s calculated by whatever method with a large pinch of salt.

View attachment 980963

So what’s changed? Combination of events. Couple of firmware update issues (confirmed by Tesla, leading to), Tesla resetting the CAC (ie resetting BMS) and possibly a change in charging regime where since moving to IO, we allow the battery SoC to drop more before charging. It use to be little and often, now it’s a bit more of a charge and less often.

But I’m expecting it all to go south over winter again. Last winters dip coincided perfectly with winter tyre change.

But these values are more about how good a job the BMS does at guessing/estimating the stored capacity than anything concrete about battery degradation. And as I understand it, getting within 10% of true value is pretty good going.

Letting the SoC drop (and presumably settle) at lower levels is one of the steps recommended to help BMS calibration so that makes sense. I think these online health things can be somewhat variable and need to be treated with some degree of caution as cell balancing (not such an issue with LFP) and BMS calibration can have quite an impact on what’s reported.

 

[tgrobbo]

There’s a car in Australia which is the same as yours and has done 147,000 miles with the same 5% approx loss of range. I’ve read hundreds of posts from LFP owners and the reduction in range pretty much only correlates with the age of the car not the mileage or charging habits. This has led some to even question the method of measuring ‘degradation’ purely by loss of indicated range. I agree it is wierd how the range loss is not tapering off - it doesn’t seem to be tapering off on any cars that I’ve seen thus far.

 

[doats1]

My car’s displayed range has dropped by about 8% overall in my 3-year ownership. But I’ve not noticed any real world degradation after 23,000 miles. I’ve never been able to achieve the displayed range anyway.

 

[Buzzliteyear]

Mine is about the same after nearly 2 years, or 14K miles. Part of this year the car sat unused at 90% while I was in hospital and then recovering. If the information that I read is true, then the degradation rate will slow down in another couple of years. This will still beat the ice cars that I have owned previously, where the range of a full tank reduced over the years.

 

[Kelculate]

I am a relatively new Tesla owner (took delivery just over 6 weeks ago). Are you saying that when the battery has some degradation, the car’s range as displayed next to the battery icon will be lower while the percentage is at 100%?

 

[GeorgeSymonds]

I am a relatively new Tesla owner (took delivery just over 6 weeks ago). Are you saying that when the battery has some degradation, the car’s range as displayed next to the battery icon will be lower while the percentage is at 100%?

Yes, that’s what happens. There’s a split amongst owners over showing % or miles and without opening that can of worms, one of the downsides to % is you don’t see degradation. That said both % and miles can lose where zero is if the BMS calibration has drifted which is why you’ll sometimes hear people going say10 miles after the range has dropped to zero, and others stopping not long after it’s reached zero.

To be honest, I wouldn’t worry, Tesla are unlikely to do anything unless your car has a real problem which will manifest itself in other ways than just the loss of a few miles indicated range over time. Doing the few simple steps to keep you BMS accurate (allowing the car to occasionally sit at lower states of charge over night, and regular 100% charges for LFP and maybe every 10k miles with non LFP batteries to cell balance) will keep your indicated range more accurate at both high and low states of charge

 

[Adopado]

I am a relatively new Tesla owner (took delivery just over 6 weeks ago). Are you saying that when the battery has some degradation, the car’s range as displayed next to the battery icon will be lower while the percentage is at 100%?

Being a new owner you will inevitably have a head full of such issues! My own recommendation would be to take a note of the predicted mileage figure now when at 100% and whilst the car is quite new ... note it somewhere and then forget about it! If at some point, a few years from now, you are wondering how it's going just compare the predictions. For day to day purposes your real range will depend on too many factors to be bothered with worrying about what that number says. (My advice: Set your battery to show percentage and then just use your car normally and forget about degradation. If your car doesn't have an LFP battery then generally stick to 80% or less for daily charging but feel free to use 100% if you are going on a trip that will challenge your range.

 

[Kelculate]

Thanks. Right now it displays the advertised 333mi range next to the battery icon when it is 100%.

 

[SR-Plus]

Nov-21 SR+ here with 60kwh LFP battery.
Lifetime average is 210 wh/mile across 13k miles.
A little concerned as my 100% charge has gone from 272 to 258 miles.

 

[Buzzliteyear]

Nov-21 SR+ here with 60kwh LFP battery.
Lifetime average is 210 wh/mile across 13k miles.
A little concerned as my 100% charge has gone from 272 to 258 miles.

I wouldn't worry too much yet, as mine is the same and it has been mentioned that it is time based rather than use. If the most loss is at the beginning then we should see a slow down in loss as more time passes. It happens to all of us and fingers crossed that we follow the norm.

 

[Kelculate]

Nov-21 SR+ here with 60kwh LFP battery.
Lifetime average is 210 wh/mile across 13k miles.
A little concerned as my 100% charge has gone from 272 to 258 miles.

That is 5.2% in almost two years, which I think is quite good?

 

[Jack Red&White]

I have 238miles left at 67,500 miles.
September 2021 SR+LFP “Unicorn”.

TeslaFi says “There is no matching fleet data at your current odometer reading.”

 

[Ivan Ivanov]

My tesla is with 54kw lfp battery, i bought it used at 24 000km . In tesie app shows 4% degeneration but on the screen at max charge shows only 404km which is around 10% degradation ?

 

[Adopado]

My tesla is with 54kw lfp battery, i bought it used at 24 000km . In tesie app shows 4% degeneration but on the screen at max charge shows only 404km which is around 10% degradation ?

You could try posting your question in Vendor - Official Tessie app talk
There's a fair chance you may get a clarification directly from James who develops the Tessie app.

 

[tgrobbo]

My tesla is with 54kw lfp battery, i bought it used at 24 000km . In tesie app shows 4% degeneration but on the screen at max charge shows only 404km which is around 10% degradation ?

Don’t think the smaller battery cars ever displayed 444km? I think they started at around 420km. The 60kw cars started at 445km or thereabouts pretty sure. Your range loss is identical to everyone else with a two year old 54kw car.