Vampire drain again?

[thatredM3]

Hi jjrandorin. Can you explain what "30% capacity loss from starting" means? I charged to 80%, then drove 137 actual miles. My M3 showed a 196 mile decrease in range. That's a 43% "loss" of range! Can all that be explained by the heater being on or other systems? (I am in Los Angeles.) Trying to figure out if I've got battery issues that I should worry about?

That’s fairly typical if you’re doing any amount of highway driving. The typical Model 3 has a 200 mile real world range.

 

[Steve446]

That’s fairly typical if you’re doing any amount of highway driving. The typical Model 3 has a 200 mile real world range.

Are you referring to a standard range M3?

 

[clu-tn]

I would guess the SOC drops after driving is attributed under the "Vehicle Standby (VS) " consumption under Parking tab. Unless Tesla specifically states what exact is the "Vehicle Standby" consumption is, I guess that it is just a BMS Recalibration "buffer" number to cover its improper/inconsistent power estimation from previous driving. Under the tab of Parking, all power consumption for typical power usages is listed under separate lines. (Tesla Y Manual just ignores the "Vehicle Standby" word unless I missed it)

It is based on my 3 month detailed observation/documentation/interaction with Tesla on my 2023 Y Long Range (Austin Built). Since my notification of the VS consumption after daily-driving charger SOC upper limit changed from 90% to 80% (which affected my actual driving range per charge) by Tesla in late September, my VS consumptions (thus true SOC % drop) after park has been mostly between 5 and 15% of battery per charge circle (from 20-80%). It happened total randomly, often within 30 minutes after driving, in any condition, location, and temperatures, & can be up to 4-5% one time, and happened at all SOC range (down to 6% based on one recalibration effort). It especially happened after optimal (too good to be true?) trip consumption reportings (190 to 220 Wh/mile for a 25-30 mile trip).

I do not believe there is a device on Y (except the driving motors) can consume that much power for the short period (I had a more than 4% drop after parking once while only consumed 4% power for the previous 25 minute driving). Likely explanation is only the BMS correction/recalibration after driving.

Of course, My Y is perfectly fine according to Tesla "AI" response (blamed on 3rd party app to cause car not sleep which I never had any App) and beyond the level of local supporting staff. It still happens per charge circle but I just live with it while accepting it is just part of the Tesla BMS game play. Rather than reported driving efficiency of 262 Wh/mile shown by car for the 15000 miles had for my car, the true efficiency is really 315 Wh/mile based on total power charge received by the car as reported by the App. Not great but good enough considering cheap electric rate in our area (10.2 c/kWh). BTW, I hardly use any power consuming functions while parking and the car is mostly parked in the garage.

I may need to check out possible coolant effect based on one of the post.

 

[AAKEE]

It happened total randomly, often within 30 minutes after driving, in any condition, location, and temperatures, & can be up to 4-5% one time, and happened at all SOC range (down to 6% based on one recalibration effort). It especially happened after optimal (too good to be true?) trip consumption reportings (190 to 220 Wh/mile for a 25-30 mile trip).

I do not believe there is a device on Y (except the driving motors) can consume that much power for the short period (I had a more than 4% drop after parking once while only consumed 4% power for the previous 25 minute driving). Likely explanation is only the BMS correction/recalibration after driving.

Yes. A change in displayed SOC shortly after the drive is most certainly that the BMS get to measure the real SOC (which is defined by a cell voltage), and then adjusts the SOC after the real measured SOC.

During the drive the SOC can not be measured so the SOC during the drive is calculated using the energy onboard (estimated capacity x SOC) - used energy.

If the estimated capacity is overestimated the calculated SOC will be higher than the real SOC, and a drop in SOC can be expected 10-30 minutes sfter the drive.
(A single drop after a drive does not mean that the capacity must be overestimated, as the initial SOC could also be wrong. It should not be wrong if the car was sleeping before the drive as then there should been a good measure of the SOC.)

If the SOC often increases after the charge (overshooting the target) it is also probable that the BMS is being vereatimating the capacity. (And vice versa, if the SOC often is below the target close in time from the charging session, it might be a underestimate).

Over- and underestimation of the capacity seems to happen from time to time, there is also a possibillity for the capacity to actually go slightly down or up (capacity recovery).
So the SOC changing just after a drive would be a normal behaviour due to the normal under- or overestimation, and not a failure of any kind.

 

[Steve446]

Yes. A change in displayed SOC shortly after the drive is most certainly that the BMS get to measure the real SOC (which is defined by a cell voltage), and then adjusts the SOC after the real measured SOC.

During the drive the SOC can not be measured so the SOC during the drive is calculated using the energy onboard (estimated capacity x SOC) - used energy.

If the estimated capacity is overestimated the calculated SOC will be higher than the real SOC, and a drop in SOC can be expected 10-30 minutes sfter the drive.
(A single drop after a drive does not mean that the capacity must be overestimated, as the initial SOC could also be wrong. It should not be wrong if the car was sleeping before the drive as then there should been a good measure of the SOC.)

If the SOC often increases after the charge (overshooting the target) it is also probable that the BMS is being vereatimating the capacity. (And vice versa, if the SOC often is below the target close in time from the charging session, it might be a underestimate).

Over- and underestimation of the capacity seems to happen from time to time, there is also a possibillity for the capacity to actually go slightly down or up (capacity recovery).
So the SOC changing just after a drive would be a normal behaviour due to the normal under- or overestimation, and not a failure of any kind.

Just a question - do you think that "capacity recovery" would be that great (4-5%). That's quite a lot of kWh. Regards my own car I have seen minor display SoC changes but nothing like 4-5% (and hardly anything at all via SMT). Did I wrongly interpret that? (you can say yes or no, I'm not worried if I am wrong).

 

[AAKEE]

Just a question - do you think that "capacity recovery" would be that great (4-5%).

Nope.

From what I have seen I think we can expect 1-2% or so, if we did several superchargningsessions and after that start cycling the battery with shallow nice cycles.

It would be interresting to see a change of the NFP in a car that was charged to 80-90% for a couple of years and then started doing 50-55% with shallow cycles.

That's quite a lot of kWh. Regards my own car I have seen minor display SoC changes but nothing like 4-5% (and hardly anything at all via SMT). Did I wrongly interpret that? (you can say yes or no, I'm not worried if I am wrong).

No, 4-5% after a drive is most probably a SOC that was measured and updated.

 

[thatredM3]

Sometimes the SOC drops 3-4% 30 min after a drive, rarely does it go up. Today however it did, I went to bed with the car at 50%, woke up with it at 54% which was a welcome change.

 

[AAKEE]

Did you see it happening that fast?

Because wintertime and cold:

When the battery is cold the car displays a lower SOC.
Parking the car outside in freezing cold will cool the battery and then the car and app will display a lower SOC.
The opposite happens if driving (not that long) with a cold battery and parking in a warm garage. The displayed SOC will return to the real SOC value.

The amount the SOC has been lowered can be seen in the app by the blue part of the green SOC-line.

 

[DrChaos]

That’s fairly typical if you’re doing any amount of highway driving. The typical Model 3 has a 200 mile real world range.

Driving to LA in typical california weather (68-70F), I could get 320 miles likely from my 22 3LR. I did 275 from 100% to 15%, nearly all freeway miles. There was reasonable traffic so speed was more like 65 and not 75.

 

[Steve446]

Driving to LA in typical california weather (68-70F), I could get 320 miles likely from my 22 3LR. I did 275 from 100% to 15%, nearly all freeway miles. There was reasonable traffic so speed was more like 65 and not 75.

So, if you have that data, what was your actual average speed and Wh/mile?

 

[KenC]

Sometimes the SOC drops 3-4% 30 min after a drive, rarely does it go up. Today however it did, I went to bed with the car at 50%, woke up with it at 54% which was a welcome change.

Since I was going skiing today, last night I set it for 80%. It was 25° when I parked. When I got in my car, it was 45° and instead of 80%, I had 83%. As I've mentioned a few times, in my anecdotal experience, if the temp changes at night, you'll often find a different SOC in the morning. If it gets colder, the SOC is lower, if it gets warmer, the SOC is higher. At this time of year, you almost always have people complaining about losing SOC.

 

[AlanSubie4Life]

So, if you have that data, what was your actual average speed and Wh/mile?

Going be 230Wh/mi to 240Wh/mi. This is quite plausible with efficient tires in optimal traffic (lead vehicles help a lot) at 65mph with 3LR.

 

[DrChaos]

So, if you have that data, what was your actual average speed and Wh/mile?

It was a few months ago now, I didn't write it down. I think Wh/mi about 235-240, a little bit above rated. 18" aero wheels of course, tire pressure checked and nominal. My lifetime is 235 and I was surprised and pleased that a long mostly freeway trip would be that low.

The RWD and LR 3 are efficient with the 18" aeros. I notice is was all models other than the 3 which had their EPA ranges and presumably efficiencies downrated just now. And I notice on this website anecdotally people complaining about range were often MYP owners. The Y has a bigger real world efficiency gap vs 3 than the previous Tesla EPA figures would suggest. I think Tesla pushed the edge/fudged for the Y as it's more profitable to them to sell. And the 20/21" P wheels and tires are a big blow to efficiency as well.

 

[Sti-g]

Since I was going skiing today, last night I set it for 80%. It was 25° when I parked. When I got in my car, it was 45° and instead of 80%, I had 83%. As I've mentioned a few times, in my anecdotal experience, if the temp changes at night, you'll often find a different SOC in the morning. If it gets colder, the SOC is lower, if it gets warmer, the SOC is higher. At this time of year, you almost always have people complaining about losing SOC.View attachment 1007789

I wish Tesla compensate for the droop in SOC in cold mornings. It’s not a huge deal, only few % but would be nice to actually get the SOC I wanted to charge to.

 

[AAKEE]

I wish Tesla compensate for the droop in SOC in cold mornings. It’s not a huge deal, only few % but would be nice to actually get the SOC I wanted to charge to.

You doo, actually.

The real SOC is the set.

The displayed SOC is altered (most probably) to reflect the loss of range due to the cold battery.

Looking into the BMS would tell you that the SOC is the set level.

 

[Sti-g]

You doo, actually.

The real SOC is the set.

The displayed SOC is altered (most probably) to reflect the loss of range due to the cold battery.

Looking into the BMS would tell you that the SOC is the set level.

I meant that let’s say I set the SOC to 80%, but due to cold it is reduced to 77% (and as such shown as 77% in the display). So in that case I wish the car charges to 83%, and display 80% and therefore make up for the reduced energy.

 

[Steve446]

Since I was going skiing today, last night I set it for 80%. It was 25° when I parked. When I got in my car, it was 45° and instead of 80%, I had 83%. As I've mentioned a few times, in my anecdotal experience, if the temp changes at night, you'll often find a different SOC in the morning. If it gets colder, the SOC is lower, if it gets warmer, the SOC is higher. At this time of year, you almost always have people complaining about losing SOC.View attachment 1007789

Informative thank you. If I've understood correctly, your SoC change fits well with a previous discussion around this in one of the other battery threads:
Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health .

 

[Steve446]

Going be 230Wh/mi to 240Wh/mi. This is quite plausible with efficient tires in optimal traffic (lead vehicles help a lot) at 65mph with 3LR.

Sure it was just my curiosity. I totally agree, I've observed similar figures too. The reason I mentioned average speed is that there's nothing like a 5-10 minute section at the start or end of the drive at lower speeds which rounds down the motorway/highway real value.

 

[Steve446]

It was a few months ago now, I didn't write it down. I think Wh/mi about 235-240, a little bit above rated. 18" aero wheels of course, tire pressure checked and nominal. My lifetime is 235 and I was surprised and pleased that a long mostly freeway trip would be that low.

The RWD and LR 3 are efficient with the 18" aeros. I notice is was all models other than the 3 which had their EPA ranges and presumably efficiencies downrated just now. And I notice on this website anecdotally people complaining about range were often MYP owners. The Y has a bigger real world efficiency gap vs 3 than the previous Tesla EPA figures would suggest. I think Tesla pushed the edge/fudged for the Y as it's more profitable to them to sell. And the 20/21" P wheels and tires are a big blow to efficiency as well.

Thanks and that's ok. I'm just a geek over data Interesting comments too about the range changes and efficiency!

 

[KenC]

I meant that let’s say I set the SOC to 80%, but due to cold it is reduced to 77% (and as such shown as 77% in the display). So in that case I wish the car charges to 83%, and display 80% and therefore make up for the reduced energy.

I don't use it since I'm retired, but I thought the best way to minimize any differential is to program the car to charge in the morning before any commute.