94 Miles on Gravity!

[Polly Wog]

I've posted several times on the Model S thread regarding the number of regen miles and energy gained during the drive down from the summit of Haleakala here on Maui, but I did something slightly different this time with our LR Model 3. My goal was to see how far I could go after getting to the bottom (nearly 10,000 ft elevation drop) before my energy usage went positive. On the 3, I usually gain a little over 30 miles on the drive down, but I once did 40, so that was what I was shooting for. I thought I might be able to get 80 miles if I did it right. I have to say that I was quite surprised to get 94! (first picture) By the end, I was a bit tired by the whole ordeal and vowed never to do it again. It was about 85 degrees for the last 55 miles or so, and with no A/C, I was sweating buckets (rolling down the windows would have negatively affected efficiency).

I did a 100% charge the night before, and had 322 rated miles of range when I departed for the summit for a morning hike. I turned the climate control off, knowing that I didn't want that to have an effect on the numbers.

The trip up obviously took a lot of energy, but really not that bad, 110 miles of range to go nearly 50 miles while climbing 10,000 ft.

Summit elevation:

It was a beautiful day at the summit:

I drove a bit more conservative than the trip energy estimator on the ascent:

Doing the math, I gained 9.4 kWh on the descent. Although it only shows a gain of 39 miles (212-251), it would have been more than that except Tesla only increments every ~3 miles gained, and I hit 251 with a bit left to descend.

For the entire trip, I averaged a very respectable 169 Wh/mi over the course of the 143 miles driven.

I think that if it weren't for the fact that I did this drive with the A/C off, it would have been more fun. Still, I'm not sure who would be able to break this record. Maui and the Big Island are probably the only places where it could be done

 

[ngogas]

Nice

 

[mswlogo]

Your too funny.

We did that trip once years ago in a rented PT Cruiser. We had sealed bags of popcorn or something and they exploded on the way up.

Did you stop to acclimate on the way up and down?

That is our favorite island.

 

[Polly Wog]

Your too funny.

We did that trip once years ago in a rented PT Cruiser. We had sealed bags of popcorn or something and they exploded on the way up.

Did you stop to acclimate on the way up and down?

That is our favorite island.

Hey, it's my favorite island, too! My only "stop" on the way up was to pay the entrance fee for the National Park, and that doesn't really count. On the way down, I didn't stop until I was close to zero on the energy usage. I was at the summit for just over 4 hours, doing a crater hike (11 miles round trip down/up the Sliding Sands trail).

 

[Polly Wog]

Another shot from the summit, with 2 of the telescopes in the background.

 

[mswlogo]

So was the regen enough to slow the car down the whole way or did you have to use brakes?

 

[Feathermerchan]

From the information you gathered, is it possible to estimate how much y\of the energy regenerated you can retrieve from the battery as a %?

 

[Polly Wog]

For reasons that I didn't fully understand, my regen was limited for the entire drive down and then some, so I had to drive extra carefully on the drive down so as not to use the brakes. There were two traffic signals where I got red lights near the bottom of the decent where I did need to use the brakes, though. If you look closely at the picture I posted at the bottom of the descent (34.8 miles shown), you can see the ........ on the top left under the D for Drive showing what my regen was limited to.

 

[mswlogo]

For reasons that I didn't fully understand, my regen was limited for the entire drive down and then some, so I had to drive extra carefully on the drive down so as not to use the brakes. There were two traffic signals where I got red lights near the bottom of the decent where I did need to use the brakes, though. If you look closely at the picture I posted at the bottom of the descent (34.8 miles shown), you can see the ........ on the top left under the D for Drive showing what my regen was limited to.

Yeah that does seem odd you were still regen limited especially after the trip up.

Maybe because you regen’d so long/hard, some component was getting too hot and it had to back off. You might be the very first consumer to test that code/hardware path

Was it regen limited when you first started to come down?

 

[ItsNotAboutTheMoney]

I can see that it was 55*F at the top from your display photo.

I'd suggest that the battery cooled while you were hiking, and then since you weren't having to work the car hard on the way down, the battery wouldn't warm up as fast as in normal driving.

 

[woodguyatl]

I've posted several times on the Model S thread regarding the number of regen miles and energy gained during the drive down from the summit of Haleakala here on Maui, but I did something slightly different this time with our LR Model 3. My goal was to see how far I could go after getting to the bottom (nearly 10,000 ft elevation drop) before my energy usage went positive. On the 3, I usually gain a little over 30 miles on the drive down, but I once did 40, so that was what I was shooting for. I thought I might be able to get 80 miles if I did it right. I have to say that I was quite surprised to get 94! (first picture) By the end, I was a bit tired by the whole ordeal and vowed never to do it again. It was about 85 degrees for the last 55 miles or so, and with no A/C, I was sweating buckets (rolling down the windows would have negatively affected efficiency).
View attachment 394725

I did a 100% charge the night before, and had 322 rated miles of range when I departed for the summit for a morning hike. I turned the climate control off, knowing that I didn't want that to have an effect on the numbers.
View attachment 394726

The trip up obviously took a lot of energy, but really not that bad, 110 miles of range to go nearly 50 miles while climbing 10,000 ft.
View attachment 394727
Summit elevation:
View attachment 394728

It was a beautiful day at the summit:
View attachment 394729

View attachment 394733

I drove a bit more conservative than the trip energy estimator on the ascent:
View attachment 394731

View attachment 394732
Doing the math, I gained 9.4 kWh on the descent. Although it only shows a gain of 39 miles (212-251), it would have been more than that except Tesla only increments every ~3 miles gained, and I hit 251 with a bit left to descend.

For the entire trip, I averaged a very respectable 169 Wh/mi over the course of the 143 miles driven.
View attachment 394734

I think that if it weren't for the fact that I did this drive with the A/C off, it would have been more fun. Still, I'm not sure who would be able to break this record. Maui and the Big Island are probably the only places where it could be done

That’s really cool. Thanks for sharing. Could you drive over and do the same thing on Maunakea next?

 

[Polly Wog]

I can see that it was 55*F at the top from your display photo.

I'd suggest that the battery cooled while you were hiking, and then since you weren't having to work the car hard on the way down, the battery wouldn't warm up as fast as in normal driving.

@ItsNotAboutTheMoney, I agree with you that the battery would have cooled down during my hike, but I've done the drive down several times in the Model 3, and the limited regen normally goes away after about 10 miles or so. However, I normally have the Climate Control on. Without doing the research my limited regen may very well be caused by my NOT having the Climate Control on, given the 3's battery conditioning setup.

 

[Polly Wog]

From the information you gathered, is it possible to estimate how much y\of the energy regenerated you can retrieve from the battery as a %?

I'm not sure that I understand what you mean, but the 9.4 kWh of energy that I recouped would translate to about 12% of the batteries usable energy capacity.

 

[Magnets!]

Do you need to have the cabin AC on in order for the car to utilize AC to keep the battery cool?

Edit: I love that place. I hiked down to the bottom and camped back when I was in college.

 

[drj3]

@ItsNotAboutTheMoney, I agree with you that the battery would have cooled down during my hike, but I've done the drive down several times in the Model 3, and the limited regen normally goes away after about 10 miles or so. However, I normally have the Climate Control on. Without doing the research my limited regen may very well be caused by my NOT having the Climate Control on, given the 3's battery conditioning setup.

I would bet the climate system transfers heat from the cabin to the battery with the air conditioner.

 

[TexasGator]

folks in Las Vegas should try to do similar coming down from Mt. Charleston. One time I was coasting (at 70 mph) down from the top in a Ford Expedition - we reset the fuel economy and got 99.9 mpg for a good part of the way down

 

[PoitNarf]

Driving up Haleakala was one of the coolest things I’ve ever done. Definitely want to do it again next time I’m on Maui. When I did it I was driving a Mustang convertible. Would have been ever more fun in a Model 3. I’m sure seeing a sunrise there would be cool. When I was there I drove up for the sunset which was amazing. Stuck around for the stars to come out and for the telescope to shoot the green laser into the night sky.

 

[Magnets!]

I would bet the climate system transfers heat from the cabin to the battery with the air conditioner.

Not sure how that would work. As far as I know the heating of the battery when needed occurs through warming the coolant with heat from the motor and inverter.

 

[groovidad]

I've posted several times on the Model S thread regarding the number of regen miles and energy gained during the drive down from the summit of Haleakala here on Maui, but I did something slightly different this time with our LR Model 3. My goal was to see how far I could go after getting to the bottom (nearly 10,000 ft elevation drop) before my energy usage went positive. On the 3, I usually gain a little over 30 miles on the drive down, but I once did 40, so that was what I was shooting for. I thought I might be able to get 80 miles if I did it right. I have to say that I was quite surprised to get 94! (first picture) By the end, I was a bit tired by the whole ordeal and vowed never to do it again. It was about 85 degrees for the last 55 miles or so, and with no A/C, I was sweating buckets (rolling down the windows would have negatively affected efficiency).
View attachment 394725

I did a 100% charge the night before, and had 322 rated miles of range when I departed for the summit for a morning hike. I turned the climate control off, knowing that I didn't want that to have an effect on the numbers.
View attachment 394726

The trip up obviously took a lot of energy, but really not that bad, 110 miles of range to go nearly 50 miles while climbing 10,000 ft.
View attachment 394727
Summit elevation:
View attachment 394728

It was a beautiful day at the summit:
View attachment 394729

View attachment 394733

I drove a bit more conservative than the trip energy estimator on the ascent:
View attachment 394731

View attachment 394732
Doing the math, I gained 9.4 kWh on the descent. Although it only shows a gain of 39 miles (212-251), it would have been more than that except Tesla only increments every ~3 miles gained, and I hit 251 with a bit left to descend.

For the entire trip, I averaged a very respectable 169 Wh/mi over the course of the 143 miles driven.
View attachment 394734

I think that if it weren't for the fact that I did this drive with the A/C off, it would have been more fun. Still, I'm not sure who would be able to break this record. Maui and the Big Island are probably the only places where it could be done

 

[groovidad]

Very nice but, I know that was a tough drive back! I live on Oahu and have done the summit many, MANY times. I’ve also hiked the crater 3 times but, that’s for another blog.. Thanks for posting your effort!