Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[Jeremy3292]

Where are you guys seeing these release notes? The only thing it showed me on my screen was improved immersive sound features.

2021.32.21 Official Tesla Release Notes - Software Updates

Tesla software update 2021.32.21 includes Sirius XM, Immersive Sound, New Language Support, Cabin Camera, Autopark, Adaptive Suspension Damping, Accessibility Update, Keyboard Improvements, Range Display, Speed Limit Mode, Refreshed QQ, Redesigned Controls Panel.

www.notateslaapp.com

 

[KenC]

When the car is parked, I have everything off; AC/heater, cabin overheat protection, sentry mode, etc. The car is parked right in front of my door and have nothing to worry about. Daily commute for the car is 2 miles each way, on a straight road. According to that trip calculator for my uphill/downhill runs, I should be using about 9 miles of range on the way down and 12 on the way up, using the streets instead of the highway. Let's just say 25 total to make up for some stop and go acceleration and overtaking. I've found that on the way up alone, the car goes through well over 20 miles of range no matter how conservatively I try to drive. Attached the readout as well, "Trip B" is the total I've driven.

One, your efficiency number while driving looks in the normal range. Two, you haven't driven a lot, and your tires are still in the break-in period. The efficiency number should improve when broken-in. Three, the part where you say, your commute is "2 miles each way" is confusing. Usually when there's lots of elevation, going uphill will use lots of energy, while going back down will use lots less. The net result should be fairly close to normal. It's important when looking at efficiency to use round-trips to factor out temporary elevation changes.

Just based upon your total efficiency number, I'd say your seeming loss of 100 miles of range has to be while the car is sitting. From Friday to Monday, you can lose over 1 mile of range per hour due, (I've seen up to 1.3m/h), to Overheat protection or Sentry, etc. When you say you turn it off, are you sure?

Since it's not looking like your car driving efficiency is out of the normal range, you can tell if it's the drain loss while the car is sitting, by looking at the range number when you get out of your car, at end of day, and the beginning range number when you start the day.

 

[Ren.OG]

Why charge to 90% every night?

I prefer to have as much range as possible, never know what could happen tomorrow. The last 10% I'm ok without but if something happens and i'm not able to charge for whatever reason, thats a 60k piece of junk sitting around.

 

[AlanSubie4Life]

Attached my consumption graph for reference. Any advice?

My advice is to ignore this graph, unless you are trying to calculate your actual battery capacity as outlined elsewhere here. That's all it is good for, really.

You'll see it gives you great projections after a downhill drive, for example. In fact, sometimes it will show 999 miles of range, which is a little optimistic. The way these numbers are arrived at is extremely deterministic - it's always the % of remaining battery * full battery capacity including buffer / recent efficiency over the chosen average window (and it's capped at 999).

Attached the readout as well, "Trip B" is the total I've driven.

Your vehicle has a 53.5kWh battery, of which 4.5% is hidden below 0 rated miles. The rest is spread across the 263 rated miles you have at 100% charge (if you have less than that at 100%, you have less than 53.5kWh and you must adjust accordingly).

So each rated mile displayed contains: 53.5kWh*0.955/263rmi = 194 Wh/rmi.

In addition, between the battery and the display on the trip meter, about 1% of the energy disappears (it seems uncounted). This is a little wishy washy.

Anyway, so in practice, that means 0.99*194Wh/rmi = 192Wh/rmi. So for each rated mile used, 192Wh will show on the trip meter.

Since you are showing 242Wh/mi average, you should expect to use 242Wh/mi/192Wh/rmi = 1.26rmi/mi. So for every mile traveled you'll use 1.26 miles of rated energy (the number next to the battery display - tap the % on the screen to switch it to miles, which are more useful for this specific purpose).

For your 25 mile round trip at 242Wh/mi, you should expect to use 32 rated miles.

The rest is feature loss and other standby losses, or losses when you were sitting in park (which are not counted). (Sentry, Summon Standby, Cabin Overheat, 3rd-party apps keeping car awake). So if you used 50rmi then that 18rmi went elsewhere, and it's 18rmi*194Wh/rmi = 3.5kWh. It's fairly easy to use that much energy over a day-long period - depends on temperature, features in use, etc.

 

[AlanSubie4Life]

order for you to get every EPA mile out of the battery, your average needs to be approximately 230Wh/mile.

For the 2021 SR+, it has a 53.5kWh battery (about, this is the approximate degradation threshold... FPWN is 55.4kWh for the NCA pack but we've never seen close to that for NFP/Nominal remaining, for the NCA) with 263 miles of range, so parity is achieved at:

203Wh/mi (201Wh/mi displayed). Including using all the buffer (an optimistic assumption).

194Wh/mi (192Wh/mi displayed). This is to 0 rated miles/0%, where you'll have ~4.5% of your capacity left.

Obviously you'll never achieve these numbers in freeway driving, though they are quite possible with very careful flat slow surface street driving with no accessory use.

your 2 mile commute

I'm assuming @dr_frankfurt means a 12-mile commute and this is a typo.

 

[AAKEE]

In addition, between the battery and the display on the trip meter, about 1% of the energy disappears (it seems uncounted). This is a little wishy washy.

That percent must be the heat loss in the battery. So not really wishy washy

The softer the drive(less power output om the battery), the less heat loss is.
I think about 0.5% is a fair number for low C-rates when reading research/tests.

The heat loss isnt really possible to measure without measuring the heat coming from the batterys, so it will stay out of the Wh-logs.

 

[AlanSubie4Life]

That percent must be the heat loss in the battery. So not really wishy washy

Yes. When I say wishy-washy I mean it isn't always 1%. Just a good rule of thumb to use 1%.

so it will stay out of the Wh-logs.

Yes, it will. Though in practice Tesla knows enough about the battery characteristics that they could predict heat loss using all the formula inputs and include it in the trip meter if they wished. But they do not. It's probably just more trouble than it's worth.

Anyway, for the Wh hunters out there, it's important to account for this ~1% number when back-calculating trip results, projected battery capacity, etc.

 

[AAKEE]

Following as I am seeing the same with my model 3 with new battery pack

I prefer to have as much range as possible, never know what could happen tomorrow. The last 10% I'm ok without but if something happens and i'm not able to charge for whatever reason, thats a 60k piece of junk sitting around.

If you guys charge to 90% and let the car sit for time with 90% the your level of degradation is expected.
Calendar aging comes from [SOC x Time x Temperature] so if left at high SOC at elevated temps for long time, degradation will happen at a elevated level.

In many cases calendar aging(degradation from time) is the main degrader, and not the mileage/driving cycles.
Its of course everyones chioce how to handle the car/battery but I guess it is good to know the lomg term effects of ones actions.

Any degradation you cause will follow your car all the way. Getting a warranty fix on the battery will not restore the range to new. In most cases, the range will be the same, Tesla match a refurbished battery with the same range, or if going below 70% you most probably get a battery above 70% but not 90% or more.

 

[AAKEE]

Yes. When I say wishy-washy I mean it isn't always 1%. Just a good rule of thumb to use 1%.



Yes, it will. Though in practice Tesla knows enough about the battery characteristics that they could predict heat loss using all the formula inputs and include it in the trip meter if they wished. But they do not. It's probably just more trouble than it's worth.

Anyway, for the Wh hunters out there, it's important to account for this ~1% number when back-calculating trip results.

Good post!

( I hope its clear my 0.5% was just as a reference to research and not fingerpointing your 1%. I meant to reinforce your statement with ref. to research, so I think 1% is a good number to use )

 

[Muzikmiss]

How do you guys charge you cars?
To what SOC ? Charge every night or ?
When is the charging set to commence ? In the evening or in the latter part of the night ?

Whats the ambient temps at your home location Muzikmiss ?

I have the new battery pack that is to be charged to 100% charges every night. Overnight it gets to the upper 70s

 

[AAKEE]

I have the new battery pack that is to be charged to 100% charges every night. Overnight it gets to the upper 70s

For real?

 

[Sophias_dad]

For real?

Welcome to not-Sweden

 

[N54TT]

Why charge to 90% every night? Do you use all of that charge every day? If not then just charge to 50% or 60% every night. It’s better for your battery.

I prefer to have as much range as possible, never know what could happen tomorrow. The last 10% I'm ok without but if something happens and i'm not able to charge for whatever reason, thats a 60k piece of junk sitting around.

I don’t need any where near the distance for my typically daily commute, but I charge to 90% as well. Why? Because I bought the car for its performance and the decrease in power at 50-60% is noticeable to me. I’m not keeping the car past the 8yr 100k battery warranty so why worry about degradation. With the current degradation I do have ….I’ve taken the same road trips I did when the car was new and still stop at the same superchargers. That being said I do use scheduled departure so it’s not sitting at 90% for extended periods of time lol.

August 2018 P3D build, 40.5K miles, lifetime avg 313 wh/mile, my 100% is 277. I’ve read plenty of posts with people that baby their batteries and are careful to avoid charging behaviors that increase degradation….but STILL have the same displayed range as me. Just charge up and enjoy it! Lol

 

[AAKEE]

I have the new battery pack that is to be charged to 100% charges every night. Overnight it gets to the upper 70s

Ahh, we’re talking about a SR with a LFP Pack?

Then I can relax….thought *new battery* refered to 2170L, that was going to be destroyed by purpose

 

[AAKEE]

I don’t need any where near the distance for my typically daily commute, but I charge to 90% as well. Why? Because I bought the car for its performance and the decrease in power at 50-60% is noticeable to me.

Thats a fair reson to use high SOC.

I’m not keeping the car past the 8yr 100k battery warranty so why worry about degradation.

That is also a fair reason.

That being said I do use scheduled departure so it’s not sitting at 90% for extended periods of time lol.

That’s really good. If you dont charge it until you are about to drive, you wont cause any calendar aging at the high SOC.

I also have a M3P for the power( earlier Performance oriented Audis).

I have yet to learn more about lithium ions in the performance application.
I have used li ions long time for less demanding applications( low current).
I have a lot of experience with lithium polymer batterys in high power applications.
These loose the punch if left at high SOC for longr times. If stored correctly (not high SOC) they keep the punch and deliver a lot of power during long time/many cycles.
If stored at high SOC they loose the punch.
This is caused by increased internal resistance.

From research reports, its quite clear that the internal resistance increase in about the same way with Panasonic NCA cells as the lipo-type does from aging with high SOC, so I guess that they behave about the same way. I havent seen any tests or posts about this concerning Teslas so I do not know.
One of the reasons I stay at low SOC is to be sure the power is there the day I like to have it.

It would be nice to do some performance testing ( 0-100) with a M3P that has been around a while to se if the power is about the same two year or so from new.
In Teslas application it seem like like it us the battery that set the limitations for power, and not the electrical engines. I guess the first sign of lost punch in the battery would be with medium to low SOC and a cold battery.

 

[N54TT]

Thats a fair reson to use high SOC.



That is also a fair reason.


That’s really good. If you dont charge it until you are about to drive, you wont cause any calendar aging at the high SOC.

I also have a M3P for the power( earlier Performance oriented Audis).

I have yet to learn more about lithium ions in the performance application.
I have used li ions long time for less demanding applications( low current).
I have a lot of experience with lithium polymer batterys in high power applications.
These loose the punch if left at high SOC for longr times. If stored correctly (not high SOC) they keep the punch and deliver a lot of power during long time/many cycles.
If stored at high SOC they loose the punch.
This is caused by increased internal resistance.

From research reports, its quite clear that the internal resistance increase in about the same way with Panasonic NCA cells as the lipo-type does from aging with high SOC, so I guess that they behave about the same way. I havent seen any tests or posts about this concerning Teslas so I do not know.
One of the reasons I stay at low SOC is to be sure the power is there the day I like to have it.

It would be nice to do some performance testing ( 0-100) with a M3P that has been around a while to se if the power is about the same two year or so from new.
In Teslas application it seem like like it us the battery that set the limitations for power, and not the electrical engines. I guess the first sign of lost punch in the battery would be with medium to low SOC and a cold battery.

I’ve used lithium batteries for a while to….18650 led flashlights, lipo RC heli’s etc.

That would be interesting to see if there are any differences in power. There’s got to be some out there running 2018’s in the 1/4 still lol. Dragtimes posted a video on a p100d that was over 3yrs old and had 100k miles. The 1/4 mile Et and trap speeds were slower….and I think he estimated about 50hp loss.

 

[Murti]

Hello, I just took delivery of new Tesla3 long range. I am a bit confused about the charging philosophy. The manual says keep it plugged in all the time but some other advice from other sources says to the contrary. Currently I am only driving about 10 miles a day roughly 5 days a week. This will be the mileage for a few months before some regular long distance travel kicks in. Should I keep it plugged in with charge limit at 90% or should I be charging it only when it falls below, say, 50%? Advice is hugely appreciated.

Murti

 

[Bryantm]

Lower you max charging to 50%-60% it only doing 10 miles a day then plug in every night. If doing long trip then up it to 80-90% and set a departure time so it charges when it needs to and your not sitting at high soc for to long.

 

[Amped412]

Keeping the car plugged in but not charging allows the battery to maintain a healthy temp using the power from the grid and not the battery.

 

[Tam]

Hello, I just took delivery of new Tesla3 long range. I am a bit confused about the charging philosophy. The manual says keep it plugged in all the time but some other advice from other sources says to the contrary. Currently I am only driving about 10 miles a day roughly 5 days a week. This will be the mileage for a few months before some regular long distance travel kicks in. Should I keep it plugged in with charge limit at 90% or should I be charging it only when it falls below, say, 50%? Advice is hugely appreciated.

It's better
Murti

I listen to Tesla and plug it in as soon as possible. Non-Tesla sources would have different opinions.

I stick to Tesla graphic set limits: Anywhere from 50 to 90% is fine. Over 90% for road trips.

It's fine to drop below 50% if I have to but not because I want to.

It's better to have a shallow discharge than deep one if I don't have to: It's better to charge everyday after using 10% than wait to do it once a week after using 70%.

If you can monitor your plugged in Model 3 after it completed its charge like 90%, you would notice that it doesn't wait for a deeper discharge like 89, 88, 87, 86%... to restart the charge again. After a few hours, it would restart the charging again well before reaching down to 89%.

But don't be overly obsessed about it because Tesla battery is pretty durable despite ignoring the rules.