Harvey Danger
Member
Just sold my 2016 X 75D with 20" wheels. 35,000 mi. Final Trip B (never reset, see pic) : 350 Wh/mi
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Model X: Average Wh/mile Tracker
- Thread starter MattXowner
- Start date
Royalpopat
Member
Does the car calculate usage based on what the motors are truely using? or it is based on how much the battery has drained in the duration?
Harvey Danger
Member
That's a really great question! Naturally it has been discussed at length over the years. I'll see if I can sum up what I've learned in a sentence or two.
The consumption figures people are reporting in this thread generally come from the "trip meter", and *those* values come from a Tesla firmware algorithm that only counts energy going out of the battery (and, during regenerative braking, into the battery) WHILE THE CAR IS IN 'DRIVE'.
Let's ignore the possibility for the moment that the computer misses some energy transfers that it *should* be catching. Some say the trip meter value is *always* slightly lower than it should be due to the practical difficulty of accurately recording these flows in real-time , especially with older MCU's struggling with memory issues.
But even setting that aside, the 'only while in drive' criterion also implies a whole lot of real-world energy transfers are not counted in this figure even when it is working as intended.
At a minimum, it misses any energy consumption while the car is unattended, aka vampire drain.
Importantly for anyone trying to track electricity *expenses*, it also ignores inefficiencies associated with recharging. You will pay your utility company for more kwh than what you see reported by the car after a charging session because of this discrepancy.
[Anyone with better info on this should feel free to jump in of course.]
Anyway, if you wanted to be really conservative and consider true 'wall to wheels' efficiencies, your car is probably under reporting it's true electricity consumption by a meaningful amount. When you add up all the possible errors, I would say a good conservative estimate would be a 20% error, at least until someone tells me otherwise.
To recap: after driving a certain number of miles the car will report a certain number of kwh used. These numbers are reported in the trip meter. (The car also reports, in the trip meter, for convenience, the result anyone would get from the simple calculation of dividing that many kwh by that many miles. This quotient is given in wh/mi. People love to talk about this number, but just be aware it is not directly measured by the car, it is simply derived from other measured numbers.)
The number of kwh reported will certainly be less than the amount of real electrical energy actually consumed by the car during the time it took to go all those miles. The difference could be as much as 20%.
PS
Real world example: over the last five years my car went 35,000 miles and WHILE IT WAS MOVING its computer tried to detect how much energy was used and came up with a total of 12,250 kwh. (This comes to 350 wh/mi)
Assuming I only charged at home (and never supercharged), I might naively expect to pay only for the 12,250 kwh reported by the car.
If electricity in my part of the world is 13¢/kwh, that would only cost $1592. What a great deal! But if I had a way of determining what my utility actually charged me (which is difficult my electric bill includes lots of other usage), I would probably discover it was something like 20% more than 12250 kwh.
I would not be shocked if i was actually charged (12250kwh increased by 20%) times (13¢ per kwh) = $1911
Obviously if you are supercharging a lot (either at more or less than home rates) these estimates would need to be adjusted, but this is the general idea...
Again, I'd love to hear if anyone has solid info that materially contradicts any of this. 'Sharing is caring.'
The consumption figures people are reporting in this thread generally come from the "trip meter", and *those* values come from a Tesla firmware algorithm that only counts energy going out of the battery (and, during regenerative braking, into the battery) WHILE THE CAR IS IN 'DRIVE'.
Let's ignore the possibility for the moment that the computer misses some energy transfers that it *should* be catching. Some say the trip meter value is *always* slightly lower than it should be due to the practical difficulty of accurately recording these flows in real-time , especially with older MCU's struggling with memory issues.
But even setting that aside, the 'only while in drive' criterion also implies a whole lot of real-world energy transfers are not counted in this figure even when it is working as intended.
At a minimum, it misses any energy consumption while the car is unattended, aka vampire drain.
Importantly for anyone trying to track electricity *expenses*, it also ignores inefficiencies associated with recharging. You will pay your utility company for more kwh than what you see reported by the car after a charging session because of this discrepancy.
[Anyone with better info on this should feel free to jump in of course.]
Anyway, if you wanted to be really conservative and consider true 'wall to wheels' efficiencies, your car is probably under reporting it's true electricity consumption by a meaningful amount. When you add up all the possible errors, I would say a good conservative estimate would be a 20% error, at least until someone tells me otherwise.
To recap: after driving a certain number of miles the car will report a certain number of kwh used. These numbers are reported in the trip meter. (The car also reports, in the trip meter, for convenience, the result anyone would get from the simple calculation of dividing that many kwh by that many miles. This quotient is given in wh/mi. People love to talk about this number, but just be aware it is not directly measured by the car, it is simply derived from other measured numbers.)
The number of kwh reported will certainly be less than the amount of real electrical energy actually consumed by the car during the time it took to go all those miles. The difference could be as much as 20%.
PS
Real world example: over the last five years my car went 35,000 miles and WHILE IT WAS MOVING its computer tried to detect how much energy was used and came up with a total of 12,250 kwh. (This comes to 350 wh/mi)
Assuming I only charged at home (and never supercharged), I might naively expect to pay only for the 12,250 kwh reported by the car.
If electricity in my part of the world is 13¢/kwh, that would only cost $1592. What a great deal! But if I had a way of determining what my utility actually charged me (which is difficult my electric bill includes lots of other usage), I would probably discover it was something like 20% more than 12250 kwh.
I would not be shocked if i was actually charged (12250kwh increased by 20%) times (13¢ per kwh) = $1911
Obviously if you are supercharging a lot (either at more or less than home rates) these estimates would need to be adjusted, but this is the general idea...
Again, I'd love to hear if anyone has solid info that materially contradicts any of this. 'Sharing is caring.'
Harvey Danger
Member
Sorry, I got carried away there. You can tell I love this topic. But it was a crazy long response to a simple question. Here's a more succinct answer:
It tries to, yes.
No.
It tries to, yes.
No.
Royalpopat
Member
@Harvey Danger thanks for the amazing explanation. I will any day prefer your first reply to the second. It does help users like myself grow on some knowledge and set the right expectations. The Service Team does not help with these things and I feel cause they don't know themselves.
Sounds like I am on the right track then. I record the power used from the charging machine when possible cause that is what I am paying for, and from the car's screen when charging at home. My app says the car is giving 4.25kms/kWh with 28K kms on the clock. When buying the car for some reason I was expecting this to be 5kms/kWh at worst. But then I guess 4.25 is what I have to be happy with. The 4.25kms/kWh capture all the phantom and other drains as much as possible and thus is as close to the real picture as possible for me.
Sounds like I am on the right track then. I record the power used from the charging machine when possible cause that is what I am paying for, and from the car's screen when charging at home. My app says the car is giving 4.25kms/kWh with 28K kms on the clock. When buying the car for some reason I was expecting this to be 5kms/kWh at worst. But then I guess 4.25 is what I have to be happy with. The 4.25kms/kWh capture all the phantom and other drains as much as possible and thus is as close to the real picture as possible for me.
Harvey Danger
Member
Ok, I've put 5000 miles on the "new" Sig X and I'm getting 335 Wh/mi. I have a screenshot. Or you can trust me.
20" wheels. Part of the 5000 was on Nokian WRG3's and the rest was on Michelin Pilot Sport 4. Same consumption for both. Note the Michelins were put on later in the year when the weather was warmer, so if the average didn't appear to change even though conditions were more favorable, that *could* mean the Michelins are inherently a little less efficient, apples-to-apples.
The whole average appears somewhat lower than it should be because it does not incorporate the seasonal variations across an entire year: The 5000 miles were driven during first three quarters of the calendar year Jan-Sept: obviously the average is going to go up after I start running the heater hard for Oct Nov and Dec.
Dealer did a factory reset so I can't compare my driving to previous owner. But ScanMyTesla reports crazy high lifetime historic numbers like >500 Wh/mi. Maybe the guy towed a lot.
20" wheels. Part of the 5000 was on Nokian WRG3's and the rest was on Michelin Pilot Sport 4. Same consumption for both. Note the Michelins were put on later in the year when the weather was warmer, so if the average didn't appear to change even though conditions were more favorable, that *could* mean the Michelins are inherently a little less efficient, apples-to-apples.
The whole average appears somewhat lower than it should be because it does not incorporate the seasonal variations across an entire year: The 5000 miles were driven during first three quarters of the calendar year Jan-Sept: obviously the average is going to go up after I start running the heater hard for Oct Nov and Dec.
Dealer did a factory reset so I can't compare my driving to previous owner. But ScanMyTesla reports crazy high lifetime historic numbers like >500 Wh/mi. Maybe the guy towed a lot.
For the last 16k miles. My average is 300 wh/mile. Pretty happy with that. That includes winters and some towing.
Harvey Danger
Member
Dang that's low. That's below rated in conditions that normally lead to much worse than rated consumption. You must be a hypermiling wizard. Respect.
During the hot spell 95 - 100F I was averaging around 350 - 375 WH-Mile. Now that the day time temps are around 60 - to 70 degrees and freezing at night, my WH -Mile averages any where from 280 - 320 WH per mile. The car is kept in the garage so it stays fairly warm at night. Also our driving habits and where we go has not changed so the only variable it the outside temps. Once it gets cold where the garage is also cold, zero and above outside, we will see how it does. I was surprised and happy to see it go as low as 280 and a bit lower at times. We are driving a 2016 Model X P90D, dual motor, ludicrous & ludicrous+ with 50,000 miles. The only modification that I have done to the car was during last July, I had the N2itive’s Alignment Kit 1 installed which got rid of the shudder, and also lowers the car about 1” in standard without wearing the inside of the tires. The shudder issue is caused by the drive shafts being at too large of an angle from the wheel to the gear box, which destroys the CV joints. No different when as a kid I put a lift kit in my pickup, but ended up destroying the universal joints in a short time. So to avoid this happening, you can lower the car to reduce this angle, but then the car will wear out the inside of the tires very quickly but the outside tread looks like no wear. So this kit replaces the linkage in both rear wheels so the camber can be adjusted and the lowering links are installed at all 4 wheels. I had to drive 400 miles to the coast to a shop to do this install and align the car and the first thing I noticed after installing the kit and aligning the car is my WH-Mile improved quite a bit. I attached the alignment sheet showing the alignment before the kit was installed and not able to adjust the camber. (A side note, I had the Tesla shop align the car right before I drove to the coast in the hopes this would reduce the wear on my tires) and the bottom of the page shows after the kit was installed and the final alignment. Hope the link works. Please let me know if it doesn't.
Thats not bad at all considering my Model Y is close to 270 wh/mile for the 8k
miles since I bought it.
miles since I bought it.
Yes, it takes these into consideration. When you drive an ICE, these affect how much fuel you are consuming, so it would be very odd not to take them into consideration. That having been said, general consensus is that these factors are only considered while the vehicle is NOT in Park, and even if that is inaccurate, they are definitely not considered when the vehicle indicates "Car Off" so vampire drain or preconditioning are not factors.
Ctein
Member
I averaged 325 WH/mi over the last 2800 miles. That's also what I've set ABRP at for 65 MPH, which seems to produce pretty accurate results on trips. Varies considerably with the kind of driving, natch. On my runs from Daly City down to Santa Cruz or up to Santa Rosa, where the majority of the trip is at 75-80 MPH, it's more like 375-80 WH/mi. Range drops down to 260-270 miles. Driving from Daly City to Berkeley, it's consistently under 240! Yeah, if I had to commute (shoot me now, please!), I'd be seeing 420 mile range!
I would kill for that. While I was right around 300 wh/mile during later Summer and early Fall, now that temps have dipped below 40°, my wh/mile has ballooned to about 500 wh/mile.
Part of my low numbers is lots of long trips. I mostly go back and forth between my main home in MA and a cabin in NH (120 miles with no traffic) Short trips in the winter will really kill things. I also have an attached garage so it’s not quite as hard on it. And I never preheat battery or cabin which would favor even better wh/mile stats (even KWh at your meter would be worse)
It's looking like my one-year, 16,000 mile adventure will have averaged right at 302 wh/mi on the dashboard. 12/7 was our delivery date IIRC.
11/2020 build Long Range Plus 7-seater with 20" wheels
Biggest expense so far will be two new front tires on Monday. Oh and the one I killed on a curb.
Even applying a 25% fudge factor to that consumption, I have spent more on sandwiches while driving this year than on fuel, which is a first
11/2020 build Long Range Plus 7-seater with 20" wheels
Biggest expense so far will be two new front tires on Monday. Oh and the one I killed on a curb.
Even applying a 25% fudge factor to that consumption, I have spent more on sandwiches while driving this year than on fuel, which is a first
Similar threads
