How much does elevation climb and drop affect range?

[SageBrush]

I was under the impression that, except maybe perhaps in the case of very tight switchbacks, that Tesla's regen was stronger than that. That short of something like a 15% grade, with your foot full-off the accelerator the drivetrain would end with a net dropping of vehicle speed.

I don't have any experience with Tesla yet, but my intent is say that the hill slows you down rather than regen.

This exercise is to limit regen; let the mountain soak up the excess KE (ahead ot time.)

 

[ForeverFree]

Attached is a potential route leg. Missoula, MT to Lethbridge, AB. Net elevation across the leg is a drop of approximately 200'. A lot of the trip is along river valley bottom. However there is at least one pass that I've identified, at Summit, MT. It's elevation is 5338'. What's the rule of thumb on losses for up-down, assuming dry highway and mindful driving to avoid friction braking as best as possible?

Assuming a full charged fresh M3 LR, high summer months so hopefully no snow, does this leg look like it could be an issue?

Here's what we've discovered about uphills and downhills in our 3.

 

[dgpcolorado]

I don't have any experience with Tesla yet, but my intent is say that the hill slows you down rather than regen.

This exercise is to limit regen; let the mountain soak up the excess KE (ahead ot time.)

Much the same result can be obtained by just slowing down on the climb, assuming lanes and traffic permit. If conserving energy is needed, slowing down to reduce losses due to drag works as well on hills as on level ground.

Coasting vs. regen going downhill is another matter. Coasting at terminal velocity is obviously way worse than using regen. On steep descents it is usually best to regen to near the bottom and then coast to conserve kinetic energy at the bottom. While fun — I do this every time I leave home if there isn't a car in front of me — these sort of EV hypermiling techniques are pretty small beer compared to just slowing down a few mph over the course of a long trip leg.

...I was under the impression that, except maybe perhaps in the case of very tight switchbacks, that Tesla's regen was stronger than that. That short of something like a 15% grade, with your foot full-off the accelerator the drivetrain would end with a net dropping of vehicle speed.

In my S60 full regen on a warm battery is plenty to slow the car on a grade like that — I descend a 14% grade into a pair of hairpin turns. With a regen-limited cool battery I have to keep my speed down when approaching the hairpins to avoid using the friction brakes. This is easy when the regen is limited to 30 kW but requires a bit more care when the regen is limited to 15 kW. Even 15 kW of regen is enough to slow the car a bit on a 14% grade IIRC.

Question, does anyone know if you use the accelerator pedal to signal to the system that you want to maintain a certain speed but the motor doesn't require energy input to do so, will it draw zero current from the battery? Is it smart enough energy management to flip between regen braking and zero draw coasting, as needed? If not will cruise/TACC handle that better?...

I'm not clear on what you are asking. It is very easy to fine tune the "go pedal" from acceleration to zero power (coasting) to regen, depending on where you hold it. Yes, cruise control will use regen to hold a precise speed (assuming that your regen isn't limited by a full or cold battery).

However, if you shift to neutral going downhill, the considerable mass and low CdA makes for a disconcerting experience because the car will accelerate a LOT faster than any other car you are likely to have driven. You get used to it but the first time is a bit like going over-the-top on a roller coaster!

 

[dgpcolorado]

Here is a plot of the trip with a doubled X axis and compressed Y axis, to make the hills and mileage a bit more distinct:

The reason I prefer to use a twelve thousand foot scale is that there are few roads (four paved, I think) that go higher than that and it puts hills into perspective. Compressing the Y axis exaggerates hills. Here is an extreme example of a trip I have done in the PNW:

^ Looks exciting, right? Here is what the trip looks like to a Coloradan:

 

[ℬête Noire]

^ Looks exciting, right? Here is what the trip looks like to a Coloradan: <flatline>

IKR?

In the big scheme of things this road is looking mild, it barely breaks 1mi elevation at the top.

Is there a dy/dx feature I’m missing, where rather than elevation it’s taking the derivative & plotting road slope vs distance? That’s what I was having difficulty reading.

 

[ℬête Noire]

I'm not clear on what you are asking. It is very easy to fine tune the "go pedal" from acceleration to zero power (coasting) to regen, depending on where you hold it.

That's what I was looking for, whether it was binary in/out or if there were three states of electricity flow including a zero/no flow. With an ICE you don't really have that 3rd state (unless you've got some fancy new tech), you're always bringing fuel through.

 

[dgpcolorado]

Out of curiosity: why wouldn't you take the much shorter route through Glacier National Park? The "Going to the Sun Highway" through the park would be slow going but it is very scenic IME. The slow speeds would also help with range.

The elevation plots:

While I couldn't do this trip in my S60 it ought to be quite easy in a Model 3LR.

 

[mspohr]

I skied there a few times, in a century past.

That charger is a Sun Country Highway one, right?

Yes, according to Plug share
PlugShare - Find Electric Vehicle Charging Locations Near You

Beautiful part of the world. Interesting that the town was built by coal mining but now is a bit of a hipster enclave.

 

[ℬête Noire]

Out of curiosity: why wouldn't you take the much shorter route through Glacier National Park? The "Going to the Sun Highway" through the park would be slow going but it is very scenic IME. The slow speeds would also help with range.

Boom, that's it!

The reason I hadn't considered it is that Google Maps didn't list the option (instead it was listing the 100mi longer route to the East ) and doesn't show that road through until I zoomed way down in. Ironically there's also a Tesla destination charger listed on that route at Crystal Ford (call ahead reservation required).

Maybe parts of it are considered seasonal so Google is avoiding it right now, I wonder? Hmmm...yup. "The road is generally open from early June to mid October, with its late opening on July 13, 2011 marking the record for the latest opening since the inaugural date of July 15, 1933." In any event that's the summer solution right there.

Aaaaannnnd doing a bit of digging now with fresh keywords, here's a 2013 article on Tesla's site where someone used exactly that route for their Model S. Glacier National Park and Beyond They were doing it slow-boat touring style, though.

Time to wrap this thread, I think. Thanks for all the great info everyone!

 

[ℬête Noire]

Beautiful part of the world. Interesting that the town was built by coal mining but now is a bit of a hipster enclave.

That's the essence of the whole of British Columbia, right there.

It's a funny, beautiful corner of the world.

Once I'm past Calgary to go East it looks like I'm on the Sun Country Highway, [free, 24/7] 40A/9.6kW J1227 plugs. Or I could head East from Fort McLeod to Medicine Hat and link into their main route down T-Can Hwy1. If I travel with patience, they've got me covered.

 

[mspohr]

That's the essence of the whole of British Columbia, right there.

It's a funny, beautiful corner of the world.

Once I'm past Calgary to go East it looks like I'm on the Sun Country Highway, [free, 24/7] 40A/9.6kW J1227 plugs. Or I could head East from Fort McLeod to Medicine Hat and link into their main route down T-Can Hwy1. If I travel with patience, they've got me covered.

All the best.
Have a great trip!

 

[rogerbohl]

I'm going from Boise to Sun Valley in my Model 85S. I'd like to use the scenic route via Stanley. Has anybody made that run. Miles left upon reaching destination?

 

[David99]

I'm going from Boise to Sun Valley in my Model 85S. I'd like to use the scenic route via Stanley. Has anybody made that run. Miles left upon reaching destination?

I've just done that in my 70D. No problems at all.