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AWD efficiency boost with 2019.24.4?

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I drove my route again today. Not as good this time at 271 (vs 252 on Monday) over the 227 miles. Stronger winds today probably hurt, but still well below what I was averaging before the update (around 290).

I wonder what % of the fleet is AWD/P? It could be something as simple as limiting autopilot's acceleration to that of a RWD only car. I always felt it was a bit too jerky in braking and acceleration. Maybe they smoothed it out, or perhaps I am used to the phantom break then sudden acceleration back to the cruise set point.
 
I don’t see anything different. P3D-

Check your tires though. With hot weather you tires can go up quite a bit. And help your wh/mi a fair bit, but not 50 wh/mi.

One run doesn’t mean to much.

I will say though Phantom drain has been ridiculously good lately. Car sat for 6 days at 70% and basically didn’t lose anything.

When cruising along on an AWD I think only the rear wheels are pushing the car. Only in hard acceleration or when it senses slipping (e.g. snow) does the front motor kick in. All 4 wheels do appear to constantly apply regen though.
 
Since I do the run 1-2x per week I will get a lot more samples in. At the 25k mark my watts per miles is down to 295. Summer is helping a lot with the efficiency. Today's run of 271 may have been affected by a screw in my right rear tire. I do not know how much of my run was done with lower air pressure (most of the tires are around 42 PSI normally). It got down to 31 psi after charging a couple of hours at the office the next time I drove it after posting.

Next week I will drive it again and see what it does.
 
I was trying to think what else could have contributed to my good mileage since the update, and I realize that I also just aligned my tires, as the front toe was out of spec by 1 degree on both fronts. The roads around me have just been resurfaced, billiard-table smooth. Temps have been pretty optimal, around 80F. Other than that, nothing else to explain how I'm getting 190kW the last 140 miles, when I'd normally get in the 220s. Maybe that's all worth 15% better efficiency. Oh, I did mention my phantom drain continues to be remarkably low, in the 0.0x miles/hr range, when my historical average is above 0.2m/hr.
 
There are other threads discussing BMS changes and battery level displayed values on .24. The Wh/mile is likely a derived value based on BMS calculations. But it could be efficiency is measured directly at the motor. A very long commute as the OP has would be less likely to be influenced by a calculation/calibration change.
 
Sudden Rated Range Drop

Tesla giveth, and Tesla taketh away...

One one hand, you use fewer Wh/mi. On the other hand, you have fewer rated miles, perhaps?

It would be nice if at least one person reporting this would calculate their current Wh/rmi constant for a reasonably long drive.

Wh/rmi = Miles traveled * Wh/mi / (Rated miles used)

We know what it was before all of these claims so at least we can compare. It isn’t definitive but would help us understand what might be happening, if anything.

Stats continues to indicate that nothing has changed in any significant way.
 
My stats seem to indicate otherwise. I have put roughly 400 miles since 24.4 and recorded at least 280 miles on a 2nd counter. Weather has been consistent (hot 80 to 100 f) and traffic has been averaged over many drives on a variety of terrains but most is my day to day commute.

The lifetime counter was reset at 10,000 miles so tires were already significantly worn at this point.

275 lifetime (285 when tires were new).
261 since 24.4

I called the potential efficiency improvements in AWD over a year ago hahaha
 

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My stats seem to indicate otherwise. I have put roughly 400 miles since 24.4 and recorded at least 280 miles on a 2nd counter. Weather has been consistent (hot 80 to 100 f) and traffic has been averaged over many drives on a variety of terrains but most is my day to day commute.

The lifetime counter was reset at 10,000 miles so tires were already significantly worn at this point.

275 lifetime (285 when tires were new).
261 since 24.4

I called the potential efficiency improvements in AWD over a year ago hahaha

That specific data I would say that shows no improvement, based on the time periods that are being compared. Even without heat use the car is a bit less efficient when it is cold - not sure why. So that alone would be enough. In addition to any minor heat use in “winter”/ early spring, that would easily explain the difference.

Looks consistent with Stats data.
 
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That specific data I would say that shows no improvement, based on the time periods that are being compared. Even without heat use the car is a bit less efficient when it is cold - not sure why. But with any minor heat use that would easily explain the difference.

Looks consistent with Stats data.

Why would you say shows no improvement and not consistent?
My first 10,000 miles was 278 Wh/mi (9/28/18 ~ 4/30/19) (pretty sure I have a picture of this somewhere)
The dash counts above show 6600 miles at 275 Wh/mi (4/30/19 ~ 8/1/19) implying only a slight variation for the winter vs summer weather.
24.4 counter shows 280 miles at 261 Wh/mi (7/26/19 ~ 8/1/19). That's roughly 14 Wh/mi difference or about a 5% improvement.

I should also mention I use autopilot in 90% of my commute. It sounds like an optimization between the front vs rear motor.
 
Why would you say shows no improvement and not consistent?
My first 10,000 miles was 278 Wh/mi (9/28/18 ~ 4/30/19) (pretty sure I have a picture of this somewhere)
The dash counts above show 6600 miles at 275 Wh/mi (4/30/19 ~ 8/1/19) implying only a slight variation for the winter vs summer weather.
24.4 counter shows 280 miles at 261 Wh/mi (7/26/19 ~ 8/1/19). That's roughly 14 Wh/mi difference or about a 5% improvement.

I should also mention I use autopilot in 90% of my commute. It sounds like an optimization between the front vs rear motor.

It just looks really small, such a small difference that it could be due to a lot of factors. Obviously I did not know your timeframes, but I would say with the cool May (and June) we had in SoCal, it is easily possible it is due to temperature. It’s also a limited sample so far with the lower number. Guess you’ll know after another few thousand miles!

If you look at the Stats fleet data above, it shows a 3% improvement since May 1st. You see ~5%, obviously not an exact comparison. California cars are a big part of that dataset. My point is weather and other minor factors could explain it.
 
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It just looks really small, such a small difference that it could be due to a lot of factors. Obviously I did not know your timeframes, but I would say with the cool May (and June) we had in SoCal, it is easily possible it is due to temperature. It’s also a limited sample so far with the lower number. Guess you’ll know after another few thousand miles!

If you look at the Stats fleet data above, it shows a 3% improvement since May 1st. You see ~5%, obviously not an exact comparison. California cars are a big part of that dataset. My point is weather and other minor factors could explain it.

I've been hyperaware of my particular driving habits and look at my efficiency like a dog (which I suspect you do as well). I've never dropped under 275 Wh/mi over any long distance of driving. 261 (5%) is almost the difference between an AWD and RWD model 3 in the same configuration (7.5%) so 14 Wh/mile is pretty darn big IMO (roughly 12 miles more range for a P3D+). Especially if it stays consistent which of course I'll be monitoring. If my Wh/mi trends continue to 1000+ miles that I think that there is extremely high confidence that there was an change impacted efficiency in the 24.4 update.

When dealing with fleet data (can you link your source), it can take some significantly time for it to update. I'm also wondering if it shows up primarily in autopilot usage versus manual driving (since it might just be an autopilot optimization)
 
I've been hyperaware of my particular driving habits and look at my efficiency like a dog (which I suspect you do as well). I've never dropped under 275 Wh/mi over any long distance of driving. 261 (5%) is almost the difference between an AWD and RWD model 3 in the same configuration (7.5%) so 14 Wh/mile is pretty darn big IMO (roughly 12 miles more range for a P3D+). Especially if it stays consistent which of course I'll be monitoring. If my Wh/mi trends continue to 1000+ miles that I think that there is extremely high confidence that there was an change impacted efficiency in the 24.4 update.

When dealing with fleet data (can you link your source), it can take some significantly time for it to update. I'm also wondering if it shows up primarily in autopilot usage versus manual driving (since it might just be an autopilot optimization)

I'm unable to assess this change because I changed wheels exactly at the same time as taking the 24.4 update.

Definitely continued monitoring is good. Just note that temperature does make a difference - the optimal battery temperature is somewhere around 90-100 degrees from what I understand. So starting out at that temperature or close to it does help with efficiency, a little bit. To really know, you'd also have to compare your efficiency from an identical time frame (May 1st to July 31st) next year (obviously this is not going to happen). Even 1000 miles at this time of year is likely to look pretty good (unless it gets super hot and AC has to work hard and kills the benefits of the higher ambient temperatures) relative to results with cooler spring time temperatures.

Here is the post from earlier. I just checked again and nothing much has changed. Install base is now 60.2% for 24.4 amongst Stats users. This is Model 3 data only.

Stats screen capture

I'm not claiming I "know" nothing has changed - I just am not convinced it is anything other than seasonal variation. It's entirely possible I am wrong.
 
I'm not claiming I "know" nothing has changed - I just am not convinced it is anything other than seasonal variation. It's entirely possible I am wrong.

Having owned and driven EV's for about 11 years, I'm quite familiar with seasonal variations impact on battery capacity and efficiency. One thing I've noted is that i'm not convinced the Trip meter counters track HVAC usage which helps understand the drive train efficiency more (than actual person usage). I've seen some inconsistencies among the various trip meters (especially one time I got stuck in a snow storm for 10 hours and drained my pack by 40% sitting in the snow).

In general though, the efficiency of the drive-train is minimally impacted by the weather. T The HVAC consumption and other auxiliary systems are the main systems impacted by the weather. he battery capacity (its internal resistance) is impacted by temperature but a 20F difference (26C to 37C) is not a large amount in a relatively flat region of the internal resistance curve. Higher temperatures reduce internal resistance. During the winter period, living in LA, our temperature was mostly (50-75F) which isn't much different than San Diego.

Dependence-of-internal-resistance-versus-temperature-for-lithium-based-batteries-LiFePO.ppm
 
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Having owned and driven EV's for about 11 years,

I've only driven my Spark EV for three years before this. But I can say that the efficiency improves perhaps 5% in the summer, irrespective of any AC and heat use (I've often turned both off entirely to see what the projected range comes out to be - and the mi/kWh displayed improves in summer), and controlling for tire pressure (I keep them consistent throughout the year). What the exact numbers are I don't know, but I can say that the silly guess-o-meter in the Spark (which is based on prior driving and AC/heat use) always shows the highest numbers in the heat of the summer. It does provide mi/kWh as part of the trip meter, which also goes up in summer.

Higher temperatures reduce internal resistance. During the winter period, living in LA, our temperature was mostly (50-75F) which isn't much different than San Diego.

The most relevant factor is the nighttime temp, since the battery can be cold soaked to that (if you park in a garage it is less of an issue, but it may still also track the outside temp fairly well).

At Ontario, CA, in May, nighttime temps were in the mid-50s. Notably, last week (concurrent with the rollout!), the nighttime low temperatures were in the high 70s! (July 25th minimum temp was 80 degrees - I remember that unpleasant evening, even in SD). Using your plot above, that is 13C to 26C. That takes internal resistance of the red line (not sure which line would be most representative) from ~120mOhms to ~70mOhms. It's not nothing. I have NO IDEA how much of an impact on efficiency that would have (I don't know how much of the loss is in the internal resistance of the battery), though.

One thing I've noted is that i'm not convinced the Trip meter counters track HVAC usage which helps understand the drive train efficiency more (than actual person usage). I've seen some inconsistencies among the various trip meters (especially one time I got stuck in a snow storm for 10 hours and drained my pack by 40% sitting in the snow).

The trip meter counts energy usage when you are not in Park, including from the HVAC. If you are sitting in Park, nothing is counted.

Anyway, we'll see, perhaps. I don't know how else to approach this problem and have some certainty but to look at fleet data (we can't switch back to the prior software build and control for it that way). The law of large numbers suggests that when looking at a bunch of different trips from a bunch of people nationwide (and worldwide perhaps), it'll be the best indicator of the effect of any change (not-withstanding any methodology changes on the app side). The differences due to some people driving in rain, others not, some pre-warming/pre-cooling, others not, some people driving fast, others not, all average out. The alternative is to have a well known benchmark course, but that's difficult too since winds and temperatures can change and they can make large differences.

I'd recommend checking your Wh/rmi constant and see whether it has changed, too. Hard to do accurately, unless you have a long continuous drive, though. I doubt it has changed, though - you'll get 230Wh/rmi.
 
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