New model 3 owner - have questions about realistic Wh/mile

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#21
You are correct in that the rate of acceleration doesn't impact range as much. As for maintaining speed on the highway, there seems to be a sweet spot for max range/efficiency vs time tradeoff and to me it seems to be around 67-72mph. The difference in aerodynamic resistance between 60 and 70 is not as great as between 70 and 75.

But running the cabin heat is indeed the biggest waste of energy especially when driving at speed. Consider this, almost 50% of cabin surface area is glass that is directly in contact with exterior air which at high speed cools very quickly to the outside temperature so any heat you add to the cabin is almost immediately lost to the glass by radiating it outward. To add to that, there are the coatings that reflect UV and IR heat outward and away from the car and if you tinted your windows, those too have one sided reflective coatings to reflect heat energy away from the car. So the glass is basically a very efficient one way heat conductor, to the outside.

Solution? I tried this today and it made a significant difference in cabin heat retention. The Tesla sun shades on the middle and rear glass panels.
I have both sunshades as well and love them. But I bought them primarily for reduced cabin noise. It’s cold and loud driving down the highway in a glass bottle.

I’m not sure what your criteria is for “sweet spot” speed. But if you mean max efficiency. It’s MUCH lower than 67. More like 50 mph for max range. Now you might be arguing that the cost of going faster doesn’t start to hurt to much until around 67. If that’s what you mean I agree. Wind noise and tire noise (depending on road and tires) goes up quite fast too when above 65 mph.

I love my sunshades though. My wife can hear me better on phone calls. Stereo sounds better. Less road noise. And a tad bit warmer.

If you can get away with heat recirculate (you can’t always because of fogging) It saves a ton if recirculate is on). If that is off your heating fresh cold air and that takes a ton of watts.
 

Richt

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#25
Ok a few quick notes to add:

1. The tires need about 1,000 miles to break in. That is about 10% inefficiency. When we got our model 3 performance we saw 330wh/mile and was pretty depressed. Now at about 260Wh which is still high but the extra weight of dual motor and 20 inch wheels are a big factor.

2. Setting the car to chill mode and using EAP really helps. The acceleration and speed amich more constant.

3. Drafting helps. That is following trucks and other cars. Not too closely but that’s an easy way to cut down air resistance. This is hard in a model x but behind a semi, we find our model 3 does much better. Saves about 10%. This is a good use of all those gigantic pickup trucks that are everywhere now. Just follow them. :) not too close of course.

4. As others have said you even dropping from 75 to 70 is a big deal but we normally draft at higher speeds.

5. As others have said heating takes some but that’s why the seat heaters are important much more efficient.

6. The environmental factors are real. Rain and snow mean more resistance. And colder means more air density and less efficient battery. For short trips preconditioning matters (turn climate control on also turns on battery heating) and you are getting power from the grid.

5. Right now on our model x according to the Stats app we are in the 90 percentile on efficiency with our MX but only 39th for M3. That’s because the P3D+ is inherently less efficient and because we have two different drivers with different styles.
 

Wooloomooloo

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#26
It has already been said a few times but my 2 cents worth. Ignore the rated range completely, but the estimated energy usage under the energy settings showing usage over distance is fairly reliable.

I’m in the middle of a 5,000 mile road trip and I can tell you that the two biggest factors by far, when traveling long distance, is elevation gain and wind speed. Sure temperature plays a part, mostly because of the denser air, but nothing will kill your range quicker than gaining a few thousand feet and headwind of 10 - 20mph (which makes 60mph driving use the same energy as 80mph driving).

I left St Louis, MO with 81% charge and arrived in Springfield, MO with 4% and I turned the cabin heat off with 60 miles to go and sat behind a truck doing 62 for the last 80 miles to make it. And actually, the 287 Whr/mi I got is pretty good for the Performance model. Your numbers are not bad either.
 

Impactwrench

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#27
Short answer, 310 mileage is -:
Heat usage
A/c
Radio usage
Speed above average or below
Headwinds or tailwinds
Uphill/downhill
Starts/stops
Wet/dry roads.
310 is probably an average on all of these variables and really , who is going to run the 3 to 305 before having a charge point in eyesight.?
 

Frully

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#28
I'm really quite disappointed at my wh/km of late...This is not a *great* cold weather car (in contrast to how good of a car it is in virtually every other way).
When I'm bored I go driving on autopilot on the ring road at 3am listening to audiobooks.
Preconditioned car/battery on charger in heated garage
Ambient -20C (-4f)
LR AWD with winter rubber on aero rims

...recent trip, 107km (66 mi)
27kWh (I think if 'murrica is gonna use imperial they should have entirely imperial units and not borrow metric where it's convenient. if I have to convert anyway, that's...92127.8 btu)
251 wh/km (403wh/mi)

That was anecdotally averaging mostly highways/feeders at 50-100km/h Cabin set to 21C (around 73f), seat heat on 1, and occasionally popping defrost blue to deal with fog.

that means my EPA 500km car is a 330km car, before considering wind resistance at *real* highway speeds.


Also...
403 (watt hours per mile) =
4.50742663 × 10^-6 joules per beard second
 
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#29
I’m quite happy with my wh/mi

Winter is tough but I think folks will be overjoyed with summer numbers.

In winter heater and speed kills.
In summer it’s only speed that kills.

The rest is noise.

One trick I learned lately.

In order to keep your windows clear in cold temps you often need fresh air.

The fresh air is the killer because you need to heat it.

It bugs me that you can’t control how much fresh air like some cars.

But you CAN control how much fresh air you take in. It’s called the fan speed.

Turn your fan speed down when your bringing in fresh heated air. And your wh/mi will improve.
 
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#30
Here's a data point for you:
LR AWD purchased 12/31/18 Chicago IL
1600 mi, 410 wh/mi average.

Yes, it's been cold here. The car has generally been driven in temps below 32F (as low as -24F). Car is garaged. Mix of city and highway. Always preheat on shore power before leaving. Temp is usually set between 68-71. Ample use of heated seats.

Dying to see how warmer weather effects the efficiency.