What's a normal curve/rate of the 10% degradation in the 1st year look like?

[Daybyday]

All searches regarding battery degradation lead to, 10% average first year, got it. Question is, what's the normal loss curve look like? I ask because I feel my car's rate is extreme, but have nothing to compare to for reference. Estimated miles dropped off gradually the first 1,300 miles. I get this is driving habit, etc. Then at 1,400 miles, the estimated range has taken a nose dive. I loss range every other charge. I understand driving habits, but my driving habits are very very consistent. So, I'm not buying that at this point. It started at 315mi at 100% it's now down to 298mi at 100%. In fact my wh/m are down lately, most likely due to the 2 extra psi I added to the tires. I'm not so worried about the miles themselves as I am the rate of decline. Hence, what is a normal rate of decline.

For reference. I drive 3 days a week, the same route, distance, etc. each week, 98% of the time. I only put 80 miles a week on the car. I don't supercharge, and I only charge to 50%-65%. I do not charge every day, and I do not allow it to drop below 30%.

Thoughts??

 

[Black306]

Thoughts??

Switch the display to %, if it’s not already, and don’t worry about it. Tesla isn’t going to do anything until battery capacity is below 70% anyway. Enjoy the car.

 

[Daybyday]

Switch the display to %, if it’s not already, and don’t worry about it. Tesla isn’t going to do anything until battery capacity is below 70% anyway. Enjoy the car.

Thanks! In that case, sounds like I’m best to just enjoy it and see what happens.

 

[GHammer]

Thoughts??

I've been following Tesla forums for nearly 10 years and I've probably seen posts like this once a week so at least 500 times. It's totally normal, change battery display to percent and forget about it and just enjoy the car.

 

[jjrandorin]

For reference. I drive 3 days a week, the same route, distance, etc. each week, 98% of the time. I only put 80 miles a week on the car. I don't supercharge, and I only charge to 50%-65%. I do not charge every day, and I do not allow it to drop below 30%.

Thoughts??

@GHammer definitely more than 500 (waay more than 500).

OP

This "charging routine" tells me that you too have gone down the "battery care rabbit hole". Down that rabbit hole, in case you missed it, is the fact that only charging in a narrow band, while better for the battery long term, can sometimes also cause the Tesla BMS to get out of whack a bit and report capacity incorrectly.

In other words, your "only charge to 50-65%, etc etc is fine for the battery, but possibly can be causing the battery management system (BMS) to not report properly. Since you already went down that rabbit hole and determined you wanted to charge from 50-65%, you should just trust that is best for the battery, and ignore what the total capacity says.

You are not using it (the total capacity) so it doesnt matter in the slightest what it says. You can also read the threads about battery "balancing", but thats only to try to correct the BMS. If you get any range back at all, it was never gone to begin with.

TL ; DR, since you already determined what you want to charge to, and went down that rabbit hole, just drive, like the other posters said.

 

[Rocky_H]

Yeah, as @jjrandorin said, you just can't have this both ways. If you use a low charging limit and small refill cycles, that is healthier for the battery, but WILL confuse the software's estimation algorithm. If you do the other way, with running it down really low and refilling really high, that will give good visibility to the software to tune in the estimation, but is less healthy for the battery. Pick whatever feels comfortable for you, but you're going to worry yourself sick in a fruitless effort trying to get everything perfect.

 

[Sellout]

Mine went from 315 to 310 within the first month, then appeared to lose ~4% in the first year. Now I’ve got 50k miles on it and it’s degraded to ~91% of original capacity. Just over 2.5 years old.

I usually charge to 80% daily.

 

[DrChaos]

All searches regarding battery degradation lead to, 10% average first year, got it. Question is, what's the normal loss curve look like? I ask because I feel my car's rate is extreme, but have nothing to compare to for reference. Estimated miles dropped off gradually the first 1,300 miles. I get this is driving habit, etc. Then at 1,400 miles, the estimated range has taken a nose dive. I loss range every other charge. I understand driving habits, but my driving habits are very very consistent. So, I'm not buying that at this point. It started at 315mi at 100% it's now down to 298mi at 100%. In fact my wh/m are down lately, most likely due to the 2 extra psi I added to the tires. I'm not so worried about the miles themselves as I am the rate of decline. Hence, what is a normal rate of decline.

For reference. I drive 3 days a week, the same route, distance, etc. each week, 98% of the time. I only put 80 miles a week on the car. I don't supercharge, and I only charge to 50%-65%. I do not charge every day, and I do not allow it to drop below 30%.

Thoughts??

The BMS calibration is irregular so while the battery degrades smoothly the estimate does not, and jumps around. And I think there is a period at early ownership where the estimate is nearly fixed to the rated miles, and then it releases to its running estimate. I saw that on mine.

You probably have more than 298 miles range in truth and your battery is very likely degrading smoothly like everyone else's. It's also possible that by bad luck your pack had slightly less total energy capacity than others, so you never had 315 for real. There is always random variation.

You drive little so the BMS estimate might not be very good. When you set your charge limit, try a random number between 50% and 55%, seeing different limits might make BMS calibration happen faster. Make sure your car can fully sleep, i.e. no sentry mode, no cabin overheat, no apps pinging it, as that is when BMS calibration points get taken.

Calendar aging scales as the square root of time approximately. Degradation also happens faster in hot weather. Your driving is so minimal only calendar aging matters. I have about 4%-5% on my NCA batteries after 16 months. I keep charge limit to 50-55% virtually always unless going on a long trip, which might be 10-15 days per year.

 

[KenC]

All searches regarding battery degradation lead to, 10% average first year, got it. Question is, what's the normal loss curve look like? I ask because I feel my car's rate is extreme, but have nothing to compare to for reference. Estimated miles dropped off gradually the first 1,300 miles. I get this is driving habit, etc. Then at 1,400 miles, the estimated range has taken a nose dive. I loss range every other charge. I understand driving habits, but my driving habits are very very consistent. So, I'm not buying that at this point. It started at 315mi at 100% it's now down to 298mi at 100%. In fact my wh/m are down lately, most likely due to the 2 extra psi I added to the tires. I'm not so worried about the miles themselves as I am the rate of decline. Hence, what is a normal rate of decline.

For reference. I drive 3 days a week, the same route, distance, etc. each week, 98% of the time. I only put 80 miles a week on the car. I don't supercharge, and I only charge to 50%-65%. I do not charge every day, and I do not allow it to drop below 30%.

Go to:
Degradation

 

[jim0266]

The BMS calibration is irregular so while the battery degrades smoothly the estimate does not, and jumps around. And I think there is a period at early ownership where the estimate is nearly fixed to the rated miles, and then it releases to its running estimate. I saw that on mine.

You probably have more than 298 miles range in truth and your battery is very likely degrading smoothly like everyone else's. It's also possible that by bad luck your pack had slightly less total energy capacity than others, so you never had 315 for real. There is always random variation.

You drive little so the BMS estimate might not be very good. When you set your charge limit, try a random number between 50% and 55%, seeing different limits might make BMS calibration happen faster. Make sure your car can fully sleep, i.e. no sentry mode, no cabin overheat, no apps pinging it, as that is when BMS calibration points get taken.

Calendar aging scales as the square root of time approximately. Degradation also happens faster in hot weather. Your driving is so minimal only calendar aging matters. I have about 4%-5% on my NCA batteries after 16 months. I keep charge limit to 50-55% virtually always unless going on a long trip, which might be 10-15 days per year.

I've gone far down the battery rabbit hole. Lots of good advice in this thread. My 2019 LR RWD Model 3 is now about 4.5 years old since delivery and exactly at 28,500 miles. Between WFH since COVID and my beater Nissan Leaf I drive around town, the car is a weekend and road tripper or anything the Leaf cannot reach.

At 6,642 miles back in January of 2020 I started tracking the car with ScanMyTesla and was still showing 322 miles of range. At that time the nominal full pack (NFP) was still reading from 77.6 to 77.4 kWhs depending on the day. The car started with 77.8 kWh. Since new I basically stayed between 70-30% SOC, even on long trips, and stored the car at 50% SOC for the first two years. The last two I've been storing the car between 30-40% mostly.

I always let the car sleep at various SOC levels from 70% down to 15% SOC when possible.

Around 9,300 miles it finally broke below 77 kWh. The NFP gradually slid down until it reached around 13k miles when the NFP was in the 73.x NFP range and the energy buffer had gone from 3.50 kWh to 3.30. It's stayed in this range for the past few years now. I saw as low as 72.8 in Oct of 21 and as high as 73.5 in March of 2023 when I did a charge to 90%, let it sleep 6 hours and walked the charge levels down with sleep sessions to calibrate the battery.

Due to road trips I've Supercharged my car 37% of the time. The last six months my average rated range is around 311 miles.

I had never charged to 100%. I'd gone to 90% a few times. A few days ago I finally charged to 100% to see if I could balance the BMS and bring down the cell imbalance. Drove it down to 50% that day, down to 38% yesterday and will trying drive it down to 15% this weekend so the car can sample from high to low. As stated above I assume my BMS struggles to be accurate because I don't feed it optimal data very often. The next morning after the 100% charge and drive down to 50%, the car's SOC went from 50.0 to 51.6 the next morning and the NFP jumped from 72.5 to 73, telling me the car was getting some better data. But it's a tradeoff knowing I'm doing the best I can to care for the battery but not having a perfectly accurate BMS as I plan to keep this car a long time.

Calendar aging is my biggest foe. Road trips and Supercharging seem to help the car's BMS balance and find local highs for some reason.

 

[wwu123]

In addition to BMS calibration that has been mentioned, it could be that you're starting to see the seasonal effect on range, which is also a temporary seasonal effect, not a true degradation. Since it seems you've only owned it about 4 months, through the hump of summer, the seasonal effect wouldn't be apparent over that short time. But as we head into fall, with the daytime and maybe more importantly nighttime temperature drops, you will see a seasonal loss of range going through winter, and then a seasonal gain starting in the spring.

The community fleet degradation charts won't show it, because guess what, everyone's mile 0 is spread throughout the year, so the seasonal effect cancels out. But if you use a data logger on your own specific car, you will see it over the course of each year. This is mine over 6 years on a Model S, but you can clearly see the oscillating ups and down overlaid on the long-term degradation - while the average fleet curve has no oscillations.

I'm in California, where winters don't get too cold - but even an overnight "cold-soak" of the battery in a fairly mild 60 degree garage will reduce range noticeably for shorter drives of less than an hour (because the battery doesn't get enough workout to warm up to optimal temps), compared to say 75 degrees in summer. Compound that if you're parked outside at work all day, and the battery cools down again for your commute home.

 

[Daybyday]

Thank you everyone for your time and information. As with anything new and for better or worse, the over whelming amount of information (1,000's +1 of posts out there), it's hard to know what rabbit hole to pick. It seems the best thing is, to enjoy the car and what happens happens.