10500 miles, 10% “degradation” already?

[djrodtc]

Hello there, my Model 3 Long Range AWD is one year old and is showing a 10% less range than day one.

I don’t know when this happened because I set the car to % battery and never locked back...until I did and didn’t like what I saw :/ When I got my car the range was 499km ( 310 miles ) and now my range is 451km ( 280 miles )

This are my charging habits:

I drive around 50 miles a day, when I got my car I couldn’t charge at home so I charged the car at work, as soon as I arrived at work I plugged in and started to charge, the speed was really slow, about 13A at 220V ( Europe schuko plug ), the car was charging for around 7-8 hours till It gets to 80% SOC, it would sit about 2 hours idle until I leaved work and then at home the car would be unplugged at about 60% SOC until the next day I could recharge at work again.

That was the case for around the first 4-5 months of ownership, then finally I could get my home installation ready so for the remaining time of this first year of ownership my car now gets charged from 65 to 80 at my off peak electric hours, from 1 in the night till 7 that I hop in the car and I leave to work where the car sits at about 70 % for about 10 hours, then Imgo back home and the car doesn’t start charging till 1 at night like I said.

I’ve tried different things, for the last 3 months with COVID we haven’t been allowed to use the car except to go to the supermarket and things like that, I stored the car at 50% SOC as I only drove 6 miles per week. That didn’t do anything to the range reported by the car.

I’ve tried to go below 30% and then go to 90%, I only did it once but didn’t do anything.

Since I’ve been able to get back to work, for the last 2 weeks I’m charging to 90% SOC. But hasn’t done anything to the range estimate.

I talked to Tesla and they say there is nothing wrong with my battery, that degradation is expected, etc.

Am I doing something wrong? It’s because I don’t charge the car when the battery is still hot from driving? 16A is too much? Should I try to charge as soon as I get home even if the electricity is 3X more expensive at that time of the day?

Any advice?

thank you!!

PS, I don’t live in a Cold weather since I live in Spain, if that makes any difference.

 

[Zoomit]

How long is the battery sitting each day after you charge it to 90%?

 

[djrodtc]

Monday to fridays, no more than 30 minutes.
Weekends, about 6 hours minimum, sundays maybe even more.

 

[djrodtc]

How long is the battery sitting each day after you charge it to 90%?

Monday to fridays, no more than 30 minutes.
Weekends, about 6 hours minimum, sundays maybe even more.

 

[Zoomit]

Monday to fridays, no more than 30 minutes.
Weekends, about 6 hours minimum, sundays maybe even more.

Because you were charging to only 80% for so long, there's a good chance your battery bricks were out-of-balance. Your recent regimen, of letting it sit at 90% for may hours on the weekends, will bring them back to tolerance. It could take many day's worth of leaving the pack sit at 90% however. I suggest keeping the same habit for a few more weeks (or just let it sit at 90% for a few days), then do a couple of deep cycles to ensure the BMS range estimate is calibrated. I don't know how deep would be required, but just to be sure, I'd discharge the battery to lower than 15% and charge it continuously up to 100%.

This process doesn't do anything good for the battery. They don't like sitting at very high or low SOC for long, nor do they like deep discharges. But the actual degradation will be insignificant doing it a few times. I captured more thoughts on this in this thread: Tesla Official Statement on Range

Please report back and let us know how the range estimate changes.

Also, you asked these questions:

• It’s because I don’t charge the car when the battery is still hot from driving? ...No, waiting to let it cool is preferable
• 16A is too much? ...No, definitely not. See: Low Amp Charging?
• Should I try to charge as soon as I get home even if the electricity is 3X more expensive at that time of the day? ...No

 

[jjrandorin]

Since @Zoomit is likely too modest to quote his own (excellent) recent post on the subject, I am going to do it for him. Please take a look at this information he put together, which can also be found in a stickied thread at the top of this forum called "tesla official statement on range".

Tesla Official Statement on Range

====================================

This is good advice. I did this before driving my car home the first time. Showing the battery state in terms of EPA range leads to a lot of confusion by owners when they see their “range” change expectedly and attribute it to battery degradation. Those owners then get confusing advice both from the Tesla community and Service Centers. I wrote the following for another thread and it might be useful here.

Brick Balancing
A brick, in Tesla’s lexicon, is a group of cells in parallel within the battery pack. Rebalancing the bricks is needed when the bricks have voltages that vary more than an allowable level. This variability is caused by slight differences in cell manufacturing that leads to different discharge rates. This is a physical manifestation in the car. Unbalanced bricks result in a battery pack that can provide less energy than if the bricks were at optimal balance. This is depicted to the driver as a reduction in the miles available on the battery level indication next to the speedometer.

It can be remedied by leaving the car near or above 90% for a relatively long period of time, measured in many days depending on the brick balance disparity. It doesn't need to be continuous. The car applies a bleed resistor to slowly lower the charge on the highest brick, in successive order, so that all the bricks are within tolerance. The gory details on Brick Balancing is in the Model 3 Service Manual and can be read at the end of this post: Battery Management System - What I Learned At Tesla Service Center

BMS Calibration
The need to recalibrate the Battery Management System (BMS) is completely different. The BMS uses an algorithm to predict how much energy the battery pack is capable of discharging. This is equivalent to the gas gauge in an ICE car, except with gasoline you can directly measure the fluid level. This same direct measurement cannot be done in the battery. It needs to be discharged to demonstrate the energy capacity. The BMS updates it's prediction for battery capacity whenever you charge and discharge the battery. If you frequently use only a limited percentage of the total available capacity, the errors in that prediction grow. The BMS has to be conservative and will only show you the available capacity it's confident can be produced. This is depicted to the driver as a reduction in the miles available on the battery level indication next to the speedometer. (Note: This is the same as when the bricks are unbalanced, hence there’s frequent confusion!)

You can provide the BMS with better calibration data by discharging the battery to a low state and recharging it to a high state. I think for best effect, but don't know for certain, that this should be done in one uninterrupted charge session. I don't recall accurate and specific guidance from Tesla, but I suggest starting below 15% SOC and charging to above 90% SOC. This may need to be done multiple times depending on size of the errors. I should reiterate that this calibration process is not changing anything physical in the car, just the predicted range from the BMS algorithm. Stated another way, your car can drive the same distance, independent of the BMS calibration. Hopefully it's obvious, but BMS calibration errors have no effect on battery degradation.

Battery Degradation
And now we get to why everybody gets excited or emotional about this topic. Battery degradation, which happens to all batteries over time and depends on usage conditions, is depicted to the driver as a reduction in the miles available on the battery level indication next to the speedometer. (There's that sentence again.) Owners experiencing unbalanced bricks and/or BMS calibration errors interpret the reduced range as early battery degradation.

The challenge is that the above methods for balancing the bricks and calibrating the BMS are not conducive to a long battery life. The one-time effects are inconsequentially small, but habitually storing the battery above 90%, especially in hot weather, and routinely deep cycling the battery is not healthy for it. The battery would be expected to degrade marginally faster than one under less stressful usage conditions.

 

[SigNC]

• It’s because I don’t charge the car when the battery is still hot from driving? ...No, waiting to let it cool is preferable

I never really understood this. to me if the car is upset about the temp of the battery it would just cool it down. Also, charging off AC isn't really that much current going into the battery in the grand scheme of things.

 

[Zoomit]

I never really understood this. to me if the car is upset about the temp of the battery it would just cool it down. Also, charging off AC isn't really that much current going into the battery in the grand scheme of things.

Yeah, I should not have made the categorical statement.

It’s seasonal and climate dependent. In cold weather/climate, it would be preferable to charge when the battery is already warm. In hot climates, charging immediately would use extra energy to cool the battery. The net effect on battery life would be very, very small, basically nil; but it would increase charging efficiency to charge when the battery is closest to “room” temperature.

 

[SigNC]

That makes sense

 

[djrodtc]

Wow Zoomit you are a national treasure!

thank you!

my car is sitting now at 90% and would be like this till tomorrow at 7. I have a supercharger just by my work, should I charge there to 90 so car can sit at that SOC for all day?

 

[Zoomit]

my car is sitting now at 90% and would be like this till tomorrow at 7. I have a supercharger just by my work, should I charge there to 90 so car can sit at that SOC for all day?

It doesn’t matter how it’s charged. Per the Service Manual, “The best way to balance the Model 3 pack is to set charge limit to 90% or higher and let the vehicle sit idle for hours (plugged in or not).”

it doesn’t have to be strictly at or above 90%. It can be a little lower and still balance so you could charge to 90% and drive back a short distance to work. There’s some thought that it can balance as low as 80% but I’d keep it above 87% to be sure.

 

[Zoomit]

I don't know how deep would be required, but just to be sure, I'd discharge the battery to lower than 15% and charge it continuously up to 100%.

I forgot to mention that the pack needs to be at rest before and after this charge cycle. The Service Manual doesn’t say how long. I think an hour or two would be sufficient, but that’s just my guess.

If you start charging immediately after a drive, or drive off immediately after charging, that charge cycle will not be used to update the range prediction algorithm.

 

[bohenriksson]

My 3 with 11 000 miles showed (extrapolated) average 295 range. Charged to 90 % and had it sit for maybe 12 hrs. Next time I got 303 miles, so less than 3 % degradation!

 

[camalaio]

I have both good and bad news for you.

There is a steeper drop in capacity at the beginning of a Li-ion battery pack's lifetime. This is actually shown very well in various graphs that show Tesla degradation specifically. This levels out over time (until true battery end-of-life, where it drops suddenly).

While imbalance or re-calibration may be part of the story for you, I think it's beneficial to consider all or most of that as permanently lost. Very few people on here have ever noted a significant increase in reported range after trying all the balancing and calibration tricks.

So. Bad news? It might be actual battery degradation. Good news? This is probably normal, if frustrating, and your degradation should start to flatten out (if it hasn't already).

I think something often left out is that the very same sources that imply calibration may not occur in some cases can work both ways. It's not only for rediscovering "lost" capacity. I think this is what happened to my car - it was reading near-new capacity for a very long time, and very suddenly dropped at once. And honestly, that's probably more correct given that it's over 22,000mi.

 

[Zoomit]

While imbalance or re-calibration may be part of the story for you, I think it's beneficial to consider all or most of that as permanently lost.

I'd like to see data that indicates 10% loss over the first 10k miles is typical and too be expected.

While there's certainly variation, 280 mi is at the very tail of what would be expected looking at a sample of the TeslaFi fleet data, which include cars with actual degradation plus BMS cal errors and brick unbalance. To be "in family" I'd expect an estimated range of over 295 mi at that mileage. The car is currently showing a loss of double that value.

 

[AdamMacDon]

In my experience the best way to "rebalance" the BMS is to drive it as hard and fast as you can down to 10% or less, then supercharge to 100%. A good example of when I magically "gain" more range is on long road trips. Since I have an SR+, going below 10% is often required to hit the next supercharger, and waiting 10-20 minutes more to hit that 100% in the name of accurate SOC readings is worth it to me. I usually "get back" around 5% more range (about 20kms) after a session or two like this.

 

[1.21GW]

Mine is at 284 miles range (310 original), it is 1.5 yrs old and has 18k miles

I charge to 90% on most days.

Seems excessive, but I never use all the range anyhow. As long as I still get my 0-60 times I’m content

 

[djrodtc]

Little update, the car’s been sitting for 12 hours with sentry mode off to prevent the SOC to go down and now the app shows 456km ( 283 miles) for a 100% charge. Tomorrow ( 11pm here now) I’ll leave it another 10h at work sitting at 90% and will report back if today’s minimum gain is more than a mirage or simple coincidence.

 

[smatthew]

It takes 24 hours to fix 1mv of cell imbalance. If you have a friendly local Tesla ranger who will connect your car to toolbox and find out, or someone with a ScanMyTesla setup... you could know how imbalanced you are. With a 10% drop, you could easily be out of balance by 50mv. Your car needs to spend as much time as possible with the Battery SOC >85% and the car asleep. If you're in balance range for 10 hours a day, it could take you over 108 days to get to 5mv charge imbalance level.

btw:I'm at 41000 miles, and 100% rating is 309 miles. When I bought the car, it had a rating of 310 miles. LR RWD.

 

[turnto643]

It takes 24 hours to fix 1mv of cell imbalance. If you have a friendly local Tesla ranger who will connect your car to toolbox and find out, or someone with a ScanMyTesla setup... you could know how imbalanced you are. With a 10% drop, you could easily be out of balance by 50mv. Your car needs to spend as much time as possible with the Battery SOC >85% and the car asleep. If you're in balance range for 10 hours a day, it could take you over 108 days to get to 5mv charge imbalance level.

btw:I'm at 41000 miles, and 100% rating is 309 miles. When I bought the car, it had a rating of 310 miles. LR RWD.

Smatthew...

How do you see cell imbalance with ScanMyTesla? Can you provide details?

Thank you