8% degradation after 9k miles, wtf?

[Chewy986]

Hello everyone!

So, I read a lot about proper battery maintenance (or so I thought), but I’m sitting on 8% degradation after 5 months and 9k miles… which sounds like way higher than most people experience and is pretty worrisome.

I charge my battery to 80% everyday as soon as I get home from work. I drive about 80 miles round trip and use around 30% of the battery daily, so when I get home it’s around 50%. I have never charged it above 85% and have been down to 17% only once and very briefly. I charge with my 220v 50a garage plug. I have never supercharged.

Based on the above fact pattern I expected to be in really good shape, yet my results are so far sub par.

I did buy the acceleration boost but mostly drive on the highway and rarely use it. I typically cruise 70-80mph which may be part or the problem. I live in Houston which is a hot climate for the battery and I generally have the AC on pretty high. I suppose the hot environment mixed with AC load and 80mph cruising speed is a bit taxing but I haven’t heard much discussion on it.

Any advice on how I might curb this degradation? Did I get a lemon?

Today I read 57% battery yielding 170miles for a 298mi capacity (or about 8.5% degradation vs new). I drive a model Y LR which is quoted at 326mi new)

 

[jcanoe]

There is nothing wrong with your Tesla Model Y's battery. The battery typically can lose ~8% or even a bit more of its original capacity during the first year of use. After the first year the battery will lose capacity at a slower rate, i.e. just a few percent a year. This is totally normal, to be expected.

 

[Chewy986]

There is nothing wrong with your Tesla Model Y's battery. The battery typically can lose ~8% or even a bit more of its original capacity during the first year of use. After the first year the battery will lose capacity at a slower rate, i.e. just a few percent a year. This is totally normal, to be expected.

Thanks. I hope you’re right. When I look at the scatter plots it seems like I’m on the very high end of degradation. Do you know how much is “normal”?

 

[jcanoe]

Thanks. I hope you’re right. When I look at the scatter plots it seems like I’m on the very high end of degradation. Do you know how much is “normal”?

My Model Y was delivered in June 2020. As best I can determine the degradation of the battery in my Model Y after 14 months is between 9% and 10%. I've read of degradation in the first year of between 5% and 10%, even 12%. This is one reason to always purchase the largest capacity battery if you have a choice of Standard Range and Long Range. Another reason is the lower efficiency and range in cold weather.

 

[FloridaSun]

There is nothing wrong with your Tesla Model Y's battery. The battery typically can lose ~8% or even a bit more of its original capacity during the first year of use. After the first year the battery will lose capacity at a slower rate, i.e. just a few percent a year. This is totally normal, to be expected.

I'm at 9500 miles with almost 50% DC fast charging and my 100% range estimate is 328 miles.. One thing to look into is that the BMS only recalibrates when the car is in deep sleep.. So, if for example someone has SENTRY mode all the time, the BMS will never recalibrate and give you incorrect readings.. The best way to have the BMS calibrate the SoC correctly is to have the car sit without Sentry mode on for a few hours in deep sleep at different state of charge.. Ideally, you want to charge 90+ percent occasionally and then let the car get into deep sleep without Sentry mode and the BMS will recalibrate. I was down to 321 mile range at one point and then I started turning off Sentry mode at work, so that the car can also calibrate the BMS while at work.. Once I started doing that, my range came back from 321 to 328 miles.. Car showed 330 miles range when I got it on 5/27

 

[ftmaybe]

My wife has owned two Model 3 SRs and I have a Model Y SR.

Model 3 #1 = 220/250 range @ 10k miles in 6mos

Model 3 #2 = 220/250 range @ 6k miles in 10mos

Model Y = 231/244 range @ 12k miles in 6mos

this is using the same charging schedule of 90% daily.

/shrug. It has been said it is a battery lottery. Maybe that is true…

 

[Chewy986]

I'm at 9500 miles with almost 50% DC fast charging and my 100% range estimate is 328 miles.. One thing to look into is that the BMS only recalibrates when the car is in deep sleep.. So, if for example someone has SENTRY mode all the time, the BMS will never recalibrate and give you incorrect readings.. The best way to have the BMS calibrate the SoC correctly is to have the car sit without Sentry mode on for a few hours in deep sleep at different state of charge.. Ideally, you want to charge 90+ percent occasionally and then let the car get into deep sleep without Sentry mode and the BMS will recalibrate. I was down to 321 mile range at one point and then I started turning off Sentry mode at work, so that the car can also calibrate the BMS while at work.. Once I started doing that, my range came back from 321 to 328 miles.. Car showed 330 miles range when I got it on 5/27

Very good to know but not sure that’s my issue. I have sentry mode off at work and overnight in my garage.

 

[Rice&Curry]

.Also don't connect to the car from your phone. It will wake it up from deep sleep.

 

[Chewy986]

Interesting, thank you

 

[Fourdoor]

Very good to know but not sure that’s my issue. I have sentry mode off at work and overnight in my garage.

It is important for the BMS to get deep sleep readings at various different SOC levels. It sounds like you are doing the same routine every day for your normal commute. Since you use 30% of your battery daily, change the charge setting, use 50% one day, 75% a different day, then 60%, etc. You can even charge up to 95% once in a while and go 2 or 3 commuting days without charging by slowing down 5 mph on the highway that week to let the car get BMS reading at a wide range of SOC states.

Keith

 

[Chewy986]

It is important for the BMS to get deep sleep readings at various different SOC levels. It sounds like you are doing the same routine every day for your normal commute. Since you use 30% of your battery daily, change the charge setting, use 50% one day, 75% a different day, then 60%, etc. You can even charge up to 95% once in a while and go 2 or 3 commuting days without charging by slowing down 5 mph on the highway that week to let the car get BMS reading at a wide range of SOC states.

Keith

Will give it a try this week and report back. Thank you much!

 

[ftmaybe]

My wife has owned two Model 3 SRs and I have a Model Y SR.

Model 3 #1 = 220/250 range @ 10k miles in 6mos

Model 3 #2 = 220/250 range @ 6k miles in 10mos

Model Y = 231/244 range @ 12k miles in 6mos

this is using the same charging schedule of 90% daily.

/shrug. It has been said it is a battery lottery. Maybe that is true…

Model 3 #2 now at 209/250 range. 7100 miles, 16% loss.

Is that real? I dunno, but that's what the car is reporting. I guess I'd have to take a long drive and run it all the way down to see how much capacity is actually there to be sure. But I'm too lazy for that so instead I'll just come here and make a dramatic sounding post.

 

[FloridaSun]

Just hit 10k miles yesterday.. Lost 3 miles since 9500 miles.. Now I'm at 325 mile range @ 100%.. 1 mile below rated range..

Almost 50% of my charging is DC fast but I have never actually charged to 100% (99% one time) and only ran the battery down to 7% once and once to 8%.. Most of the time, I don't let it drop much below 30%

 

[adrieng1977]

@Chewy986 any update on this?
this is my story

The usual Battery Degradation Topic

Well here is the usual battery degradation topic. To start with, I have a 05/2019 LR Model 3. I have been tracking the data since pretty much the beginning, first with TeslaFi then with an in house solution Teslamate. I am aware that the BMS can underestimate the actually max battery charge...

teslamotorsclub.com

 

[BreatheEasier]

Just hit 10k miles yesterday.. Lost 3 miles since 9500 miles.. Now I'm at 325 mile range @ 100%.. 1 mile below rated range..

Almost 50% of my charging is DC fast but I have never actually charged to 100% (99% one time) and only ran the battery down to 7% once and once to 8%.. Most of the time, I don't let it drop much below 30%

You are very fortunate - and my guess is that you have the 82kWh battery pack. My early build (VIN 9xxx) is down ~8% at 15 months, 15K miles.

 

[FloridaSun]

You are very fortunate - and my guess is that you have the 82kWh battery pack. My early build (VIN 9xxx) is down ~8% at 15 months, 15K miles.

I have the 82.1 kwh pack.. Maybe the BMS releases some of the additional capacity as the battery degrades.. I used to own a Hyundai Kona Electric and it had a 5% buffer. Degradation was moved to the buffer and until the buffer is used up, you won't see reduced range.

 

[mangrove79]

How do you check battery degradation? I googled it and the only relevant post that came up was the suggestion of letting the battery run down to under 10% then charge it back to 100%. If that's the only authoritative way to do it, then I'll give it a try closer to 10K miles. I'm on 5K miles now after about 4 months of driving my MY. I also see the OP used consumption numbers (170 miles for 57% of battery) to arrive at the total range. Is that accurate?

The other thing is phantom drain if you always have the car plugged in. Does anyone know whether more electricity is lost when always plugged in or not? I noticed a loss of range of about 4 miles every 12 hours (typically overnight) when my MY is not plugged in - i.e. sitting in my garage. When it's plugged in, of course, I can't tell because it's typically fully charged. But I could, and probably am, still paying for a phantom drain from the charger.

 

[buyleonard]

You can get a quick estimation of what the BMS thinks by opening the Tesla app, select charging, and then slide the charging limit all the way to the right. It will be display miles as a small number on the green portion of the battery, just don't forget and leave it there or it will charge to 100%. And as other have said, this value can be battery degradation, but is just more likely that the BMS needs to be recalculated.

 

[jcanoe]

The following will cause your Tesla Model Y to use additional power while parked:

Sentry Mode
Cabin Overheat Protection
Summon

Turn these off to minimize the power used while parked.

Set Sentry Mode to not be active at your home location
Set Cabin Overheat Protection to Off or No AC.
Set Summon to be off when parked at home.

Here is one method of computing the capacity of your Tesla vehicle's battery (in kWh). You can compare this result with the capacity when new to estimate any degradation.

Calculating Your Battery's Estimated Capacity Using the Car's Energy Screen

 

[BreatheEasier]

I have the 82.1 kwh pack.. Maybe the BMS releases some of the additional capacity as the battery degrades.. I used to own a Hyundai Kona Electric and it had a 5% buffer. Degradation was moved to the buffer and until the buffer is used up, you won't see reduced range.

I think that is the primary reason they moved to the 82kWh battery, given the estimated full-charge mileage was never updated. That's OK for me, though. My plan was to own my 2020 for 3 years and buy a 2022/2023 from Texas with undoubtedly a significant number of improvements, while the value of my 2020 would remain very high, I see this as a win/win for me.