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Is Model X's efficiency really this bad?
- Thread starter wk057
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- Driving Dynamics Model X
IdaX
Member
In theory the drag losses per mile should go as v^2. Meaning that by going 75 instead of 60, you should burn 56% higher Wh/mi! Now that's just the air resistance component, not including the baseline load from the air conditioner, computers and such. But still, you'll always get worse energy burn on fast freeways than on slower 2-lane highways.
Does anyone know what speed the rated mileage assumes? 60?
As I think I mentioned upthread, my experience says that rated is sometimes achievable on my 20" X75D at 70 in perfect weather, and usually achievable at 65 in decent weather.
From my experience, 60-65mph is where the sweet spot is at. Also, with regen set in low, the usage is about 20-30wh/mi higher.
MTOman
Member
I made about a 30 minute drive with my P100D, most of it was on I-85 with the speed set around 75. I didn't do anything special like drafting, just drove like normal. I averaged 356 Wh/mi:
Today I forgot to turn on the climate control for the most part of my drive to work and not too surprisingly the average draw was around 330 wh/mile. Temps outside today was similar to yesterday just no rain today. Yesterday it was 450ish wh/mile.
Clearly the climate control made a huge difference today.
Clearly the climate control made a huge difference today.
EarlyAdopter
Active Member
After doing our first long trip in the new Model X 75D, I have to say I'm pleasantly surprised at its efficiency compared to my Model S P85D.
This is a 300 mile round trip out to the coast we've done dozens of times in the P85D. In that car in these same conditions (50F, some rain, 65-70mph, range mode on) I average 390Wh/mi. This is on 21" Continental high performance summer tires.
In my wife's new Model X 75D with 20" Continental all seasons, same conditions, we averaged 330Wh/mi.
Tires and wheel size make a huge difference. So does the performance motor.
This is a 300 mile round trip out to the coast we've done dozens of times in the P85D. In that car in these same conditions (50F, some rain, 65-70mph, range mode on) I average 390Wh/mi. This is on 21" Continental high performance summer tires.
In my wife's new Model X 75D with 20" Continental all seasons, same conditions, we averaged 330Wh/mi.
Tires and wheel size make a huge difference. So does the performance motor.
For the first time yesterday I was able to get rated mileage in my XP90D. I had to average 55MPH on a mostly highway going 430ft downhill in 60deg weather. During normal driving I'm lucky to hit 75% efficiency. I'm still on my winter tires. In my previous SP85 I don't recall ever having an issue getting rated mileage during normal driving.
AndreyATC
Member
I'm on 22s with Goodyear Eagle summer rubber now. It definitely increases consumption, but it's hard to figure out exactly by how much. It's been really cold and I've been driving in freezing temperatures constantly through hills
Picture below is my last trip with net elevation gain of 2000 feet in rain
From my experience, in warmer weather summer rubber will do much better
I'm hoping to be back in 350-360 range, just like with my 20 inch winter setup
P.S. These 22s are not just for show. Car handles very well without comfort penalty. 20s are not even a close match in that department
Picture below is my last trip with net elevation gain of 2000 feet in rain
From my experience, in warmer weather summer rubber will do much better
I'm hoping to be back in 350-360 range, just like with my 20 inch winter setup
P.S. These 22s are not just for show. Car handles very well without comfort penalty. 20s are not even a close match in that department
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IdaX
Member
goneskiian
Active Member
I've had it down to 2. It was not a pleasant experience. Had to drive on a wide open freeway for long stretches at way too slow of speeds to even make it that close! Watch that wind direction when on 22's with bikes hanging off the back!
Racerx22b
@unplggdd on Instagram
1 mile to go? 2 miles to go?
Wimps! Still driving with 0 miles to go. That's how real men roll!
LOL!!
Wimps! Still driving with 0 miles to go. That's how real men roll!
LOL!!
AndreyATC
Member
Yes. I know my car that well
Here is today's drive with warm weather
1000ft net loss
285whm on XP90D with 22s
I beat the trip planer by huge margin too
It predicted 46% at destination, but i arrived with 58%
Yes, I was driving at speed limit (65mph)
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It has everything to do with how you drive. I'm getting around 300 Wh/mi on a 35 mi (each way) commute in a '17 MX. Flat, some traffic, speed averages 55.-60 with peaks of 70. In a Prius, I get 53 MPG on the same commute. In a Honda Accord, I get 39-42 MPG. If I drive aggressively in the Prius, it drops to 45 MPG. In the Honda, it drops to 34 MPG. It seems similar percentage drops occur based on how you drive.
FWIW, I learned to drive conservatively with a Prius. It was easy to do so because the Prius is essentially a vacuum cleaner on wheels. It's not fast, makes a constant vacuum cleaner noise and just goes. I also limit the amount of regen braking in the MX. Regen braking is inefficient because energy is lost in the transfer. I level out the accelerator to coast... so there is a certain degree of hypermiling, but it's not "hard" to do.
FWIW, I learned to drive conservatively with a Prius. It was easy to do so because the Prius is essentially a vacuum cleaner on wheels. It's not fast, makes a constant vacuum cleaner noise and just goes. I also limit the amount of regen braking in the MX. Regen braking is inefficient because energy is lost in the transfer. I level out the accelerator to coast... so there is a certain degree of hypermiling, but it's not "hard" to do.