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Actual rated wh/mi

Teefal

Member
Aug 11, 2020
165
240
Bethlehem PA USA
Hi all,

EPA says 2020 Model Y gets 265 Wh/mi city, 296 Wh/mi highway, 279 Wh/mi combined. Also a range of 316 miles

There's a solid line in the touchscreen energy consumption graph called "rated". What number is it?

Also, Teslafi refers to "rated miles" which it uses to measure efficiency. How does it get this number? (The API obviously ... but where does it come from)

Yes, I know the numbers are BS and vary for a hundred reasons. I'm just looking for these two specific answers.
 
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MY-Y

Active Member
Mar 4, 2020
1,243
1,418
MD
My lifetime average (~12k miles) is 247 Wh/mi. When the battery was new, that could yield 77.8 kWh / 247 Wh/mi = 315 miles. My car was rated for 316 when I bought it, now 326. Sadly, my battery has only 68.5 kWh now for some reason, so I could, in theory, go 277 miles.
 
I have a pretty short commute (30 miles round trip per day) at mostly highway speeds so I don’t put on much mileage. I charge every Sunday night..

In the 6 months I’ve owned my Y (I have 4200 miles on the odometer), I have never gotten more than 230 miles on a full 90% to about 10% charge. I have been averaging 255 watts per mile. If you run the numbers, you get: 75,000 watt/hr battery * 80% = 60,000 watts used battery power / 255 watts/mile = 235 miles.

Which is pretty close to the miles I can drive per charge. If I ran the battery to 0%, I could probably get to 250 miles.
 

Teefal

Member
Aug 11, 2020
165
240
Bethlehem PA USA
Ok, let's try this with numbers. Just drove 99.18 miles in the rain. TeslaFi tells me that's 125.26 rated miles which makes it 79.2% efficiency. Also says I averaged 280 Wh/mi, which LOOKS like it's the same as the "rated" line in the energy consumption graph in the car. EPA says the car gets 279 Wh/mi combined.

So why the 125.6 rated miles? Why the 79.2% efficiency? I don't need to know the theory or other people's experience or to learn the reality of Wh/mi in various conditions.

I just want to know about that solid rated line in the graph and the "rated miles" number in the API. If I'm getting 279 Wh/mi and the EPA rated 280 Wh/mi, why does TeslaFi say 80%?
 

jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
Just drove 99.18 miles in the rain.
Anytime you are driving in the rain you are going to take a large hit in driving efficiency. That could easily account for the 20% loss of efficiency.

Since 99.18 miles is close to 100 miles, did you use 100 miles X .279Wh/mi (~28kWh)? If you used more than 28kWh then the road conditions were a factor. Also any headwind and any elevation change would affect the results.
 

Teefal

Member
Aug 11, 2020
165
240
Bethlehem PA USA
Put another way, my question isn't "why am I only getting 80% efficiency?". My question is "EPA says 280 Wh/mi and I got 279 Wh/mi. Why isn't this called (near) 100% efficiency?"

People keep thinking I'm worried about low efficiency (must be force of habit on this forum). I'm asking why the b-s number doesn't match the other b-s number.
 

jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
Here is more B.S.

Originally the data Tesla submitted to the EPA for the Long Range Model Y resulted in an EPA range estimate of 316 miles. This was with the usable battery capacity of somewhere between 72kWh and 75kWh depending on where you shop your B.S. (The total battery capacity was somewhere around 77 to 78kWh.)

My Long Range Model Y came with a sheet of paper indicating that the battery pack in my vehicle had a capacity of 74kWh (At the time I purchased my Model Y (June 2020) the State of Maryland had a sales tax rebate program that was keyed to the size of the battery, so Tesla should not have B.S'd around this number.) 74kWh/316miles = 234Wh/mi. Tesla later restated the estimated EPA range of the Long Range Model Y as 326 miles. 74kWh/326mi = 226Wh/mi.

Your results (279Wh/mi) X 79% = 220Wh/mi which is close to the Wh/mile number for the restated range (226Wh/mi). Early on some had stated that the actual usable capacity of the battery in the Model Y was closer to 72kWh so then the Wh/mi number would be right at 220Wh/mi. So somewhere in there lies the true EPA combined City/Highway Wh/mi estimate and the reason your results are 79% of the rated efficiency.

If there is a B.S. number it is 220 Wh/mi. 220Wh/mi / 79% = 278.5 Wh/mi (almost exactly your result.) No result outside of a Dyno test is ever going to achieve 220Wh/mi combined city and highway in a Tesla Model Y.
 
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Here is more B.S.

Originally the data Tesla submitted to the EPA for the Long Range Model Y resulted in an EPA range estimate of 316 miles. This was with the usable battery capacity of somewhere between 72kWh and 75kWh depending on where you shop your B.S. (The total battery capacity was somewhere around 77 to 78kWh.)

My Long Range Model Y came with a sheet of paper indicating that the battery pack in my vehicle had a capacity of 74kWh (At the time I purchased my Model Y (June 2020) the State of Maryland had a sales tax rebate program that was keyed to the size of the battery, so Tesla should not have B.S'd around this number.) 74kWh/316miles = 234Wh/mi. Tesla later restated the estimated EPA range of the Long Range Model Y as 326 miles. 74kWh/326mi = 226Wh/mi.

Your results (279Wh/mi) X 79% = 220Wh/mi which is close to the Wh/mile number for the restated range (226Wh/mi). Early on some had stated that the actual usable capacity of the battery in the Model Y was closer to 72kWh so then the Wh/mi number would be right at 220Wh/mi. So somewhere in there lies the true EPA combined City/Highway Wh/mi estimate and the reason your results are 79% of the rated efficiency.

If there is a B.S. number it is 220 Wh/mi. 220Wh/mi / 79% = 278.5 Wh/mi (almost exactly your result.) No result outside of a Dyno test is ever going to achieve 220Wh/mi combined city and highway in a Tesla Model Y.
I just got my Model Y and I'm kind of disappointed with the range with the AC on in 93 degree weather here in Florida.. Drove about 70 miles today, 50% city and 50% on country roads 60 - 65 mph and my average consumption today was about 285 wh/mile which translates to 3.51 miles/kwh. My 2019 Hyundai Kona Electric (with 52k miles on the clock already) got about 4.5 miles/kwh, about 220 wh/mile. I left the charger (with the Y) which is 25 miles from my house at 90% SoC and arrived at home at 82% SoC.
If I do the same trip in the Kona Electric, I leave the same charger at 90% and arrive at home at 84% SoC.. The Kona only has a 64 kwh battery and a 258 mile rated range while my Y is rated 326 miles and based on that comparison, I would actually get more range on a 90% charge in the 258 mile rated range Kona Electric rather than in my 326 mile rated Model Y... Without the AC on, I'm getting better consumption with the Y, close to 220 - 240 Wh/mile which is acceptable but the AC seems to eat up so much more energy than on the Kona. Sure, the Y is a bigger car, no doubt but the range drop with the AC seems to be disproportionate compared to the Kona.. Is there some kind of secret ECO AC mode??? It sucks up way too much charge.. Just for reference, I did drive in CHILL mode with HOLD setting..
 
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jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
Is there some kind of secret ECO AC mode?
In colder climates the secret to maximizing efficiency in winter has been to always fully precondition the Tesla vehicle's battery pack and cabin while still plugged in. Not sure how much preconditioning would save in warm weather, especially with all the glass on the Model Y. Have you tinted the windshield and the front side windows? There is a huge heat load created with all that untreated glass. The glass roof is already rejecting most IR and the UV rays, probably only transmitting 5% of the visible spectrum. Another factor is if you are driving into a head wind. The only truly accurate driving efficiency test is where you drive for 30 minutes to an hour in one direction and they drive the return on the same day, same road, traffic and temperature conditions.
 
In colder climates the secret to maximizing efficiency in winter has been to always fully precondition the Tesla vehicle's battery pack and cabin while still plugged in. Not sure how much preconditioning would save in warm weather, especially with all the glass on the Model Y. Have you tinted the windshield and the front side windows? There is a huge heat load created with all that untreated glass. The glass roof is already rejecting most IR and the UV rays, probably only transmitting 5% of the visible spectrum. Another factor is if you are driving into a head wind. The only truly accurate efficiency driving test is where you drive for 30 minutes to an hour in one direction and they drive the return on the same day, same road and temperature conditions.
I just got the car last Thursday, so I haven't had a chance to have the front windows tinted.. If that helps saving energy on the AC, then I'll have that done..
On the Kona, you can set the AC to ECO mode.. The main difference is that it takes a little longer to bring the car to the target temperature and once it's there, it consumes very little.. 0.5 - 1 kw draw from the AC (Kona has a screen where you can see how much energy each of the major components draws (drivetrain, electronics, HVAC and battery cooling) while driving). Haven't found anything like that on the Y.. Is there a detailed energy screen where I can see how much energy for example the AC pulls? I also wonder if battery cooling comes on in 93 degrees weather?? Also, could it be that on my way back from the Chademo charger, the car was cooling the battery as it likely heated up the battery for the charging session?? I could imagine that this is a possibility... Battery cooling would certainly reduce range and increase consumption.
 

jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
When you have some time there are threads re tinting the Model Y. Absolutely needed according to owners who live in SoCal, AZ, NV, TX and FL. I live in Maryland so tinting is not as critical.

If you want to dig into the inner performance and energy stats there are several aftermarket tools. TeslaFi comes to mind. There are several other tools. Some require that you install an app on your phone and also install an OBDII port BT accessory in the vehicle.
 
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When you have some time there are threads re tinting the Model Y. Absolutely needed according to owners who live in SoCal, AZ, NV, TX and FL. I live in Maryland so tinting is not as critical.

If you want to dig into the inner performance and energy stats there are several aftermarket tools. TeslaFi comes to mind. There are several other tools. Some require that you install an app on your phone and also install an ODBII port BT accessory in the vehicle.
Looks like front window tint will be my first mod!!
I do have a Bluetooth OBD2 reader and software that has car specific sensor readings (I would assume that it does have settings for TESLA too).. I haven't found the OBD2 port on the Y yet.. Usually it's under the front dash but I couldn't locate it.. Didn't really spend a lot of time looking for it though.. I just reached under the drivers side dash and didn't feel a bump that felt like an OBD2 port.. Where is the OBD2 port on the Y?
 

jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
Looks like front window tint will be my first mod!!
I do have a Bluetooth OBD2 reader and software that has car specific sensor readings (I would assume that it does have settings for TESLA too).. I haven't found the OBD2 port on the Y yet.. Usually it's under the front dash but I couldn't locate it.. Didn't really spend a lot of time looking for it though.. I just reached under the drivers side dash and didn't feel a bump that felt like an OBD2 port.. Where is the OBD2 port on the Y?
I believe it is located inside the center console, the access panel is on the left side of the console behind the driver's seat on that side. I would search Youtube for How To videos.

I'm pretty sure you need to use a wire harness like this one: https://www.amazon.com/OHP-Adapter-Tesla-Accessories-2019-2020/dp/B08DXY5KVX/
 
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jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
I used 27.74 kWh, so it's right in line with my Wh/mi, both actual and EPA estimated. So why are they calling this 80%?
Because according to the data that Tesla submitted to the EPA the Long Range Model Y should be able to travel ~100 miles using only ~22kWh. The only way this would be possible is if you drove on flat terrain, dry road, no head wind or traffic; not faster than 50 MPH and did not use the climate control (maybe just the fan setting.)
 

Teefal

Member
Aug 11, 2020
165
240
Bethlehem PA USA
Your results (279Wh/mi) X 79% = 220Wh/mi which is close to the Wh/mile number for the restated range (226Wh/mi). So somewhere in there lies the true EPA combined City/Highway Wh/mi estimate and the reason your results are 79% of the rated efficiency.

If there is a B.S. number it is 220 Wh/mi. 220Wh/mi / 79% = 278.5 Wh/mi (almost exactly your result.) No result outside of a Dyno test is ever going to achieve 220Wh/mi combined city and highway in a Tesla Model Y.

Getting closer, I think ;) So why does EPA say both 280 Wh/mi combined and 316 rated miles? (Original mid-2020 Y LR numbers)

Wouldn't that mean the battery needed to hold 88.4 kWh?
 

jcanoe

Active Member
Oct 2, 2020
4,403
4,588
Maryland
I believe that the data that is submitted to the EPA can be weighted for local driving. Manufacturers are free to submit multiple sets of data and average the results. So Local Test + Highway Test + Local Test + Local Test / 4 and Bob's your uncle. The EPA allows this, Tesla takes every advantage of the rules.
 

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