Range in the Mountains

[scottrichman9]

Does anyone have any idea of the percentage difference of range (extension) one might get at sea level vs 3500 ft in the Mountain states?

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[andyrross]

For me, the range is impacted by elevation, only the elevation changes - going up uses more power, going down extends the range. I'm normally at 7100 feet, driving to Albuquerque at 5K feet is downhill overall, so I use a lot less energy than when I come back.

 

[ChrisO]

This isn't an ICE car. It isn't affected by elevation. It is affected by elevation changes, and temperature changes though (and so are ICE cars for that matter, but in some cases they are less affected).

Note that the reason an ICE car is affected by elevation is because it uses the air mixed with the fuel to create the combustion to move the car. With less oxygen in the air at high elevations, the combustion isn't as powerful. This is also the principal of turbos and super chargers; they compress the air so that there is more oxygen to make for a better combustion.

 

[SpaceEVDriver]

It depends on what you’re asking.

You can get improved range at higher elevations once you’re there and if you’re not climbing a lot of hills. When you drive fast enough that drag matters (above about 35 mph), you’ll see lower drag at elevation vs sea level. At 3500 feet elevation, the air is approximately 10% lower density, so you should see approximately 10% less drag for any given speed compared with the same speed at sea level.

If you’re asking about climbing to 3500 feet elevation from sea level, then you’ll be fighting gravity the entire way up. And you won’t get it all back when you go down. How much that will cost you depends on a lot of factors.

 

[ChrisO]

@SpaceEVDriver That is an interesting observation. It didn't really think about the drag from the thinner air. I really wonder how that would really play out.

 

[scottrichman9]

It depends on what you’re asking.

You can get improved range at higher elevations once you’re there and if you’re not climbing a lot of hills. When you drive fast enough that drag matters (above about 35 mph), you’ll see lower drag at elevation vs sea level. At 3500 feet elevation, the air is approximately 10% lower density, so you should see approximately 10% less drag for any given speed compared with the same speed at sea level.

If you’re asking about climbing to 3500 feet elevation from sea level, then you’ll be fighting gravity the entire way up. And you won’t get it all back when you go down. How much that will cost you depends on a lot of factors.

Thanks - I am asking in terms of does the air density at high elevations (no hills etc per se) - but more about driving a MME flat in the Valley - vs driving MME flat at the beach. Which vehicle will have better ranges?

 

[SpaceEVDriver]

From my experience, I get about 15-25% better range while at 7000 feet elevation than others who have a similar setup to me but drive at lower elevations. I also get better range in our own vehicle (either Mustang or Lightning) at 7000 feet elevation than at sea level when we road trip. Sometimes it’s canceled out by various driving behavior adjustments (bigger cities might cause worse efficiency if I’m dealing with a lot of speed-up/slow-down traffic. All things equal, and for driving at speeds where drag matters, if I had the same driving conditions, I would get better efficiency at 7000 feet than at sea level.

 

[ChrisO]

This is interesting, it looks like it would be exactly backwards from an ICE car.

 

[music_cities]

I usually get more range in the mountains because the speed is lower with all the curves and reduced sight lines. Driving slower gives you more range. Zipping across the flat prairies my cruise control setting just keeps inching faster and faster. But in the mountains, I often turn off cruise control, and lane keeping, and work those slower curvier roads in unbridled mode. (I sometimes even turn off the graphic for collision assist so I can get the nice spedometer-centered unbridled display.)

 

[AZBill]

Air density chart versus altitude. Drag is directly proportional to air density, but rolling friction is not affected.

 

[SpaceEVDriver]

Air density chart versus altitude. Drag is directly proportional to air density, but rolling friction is not affected.

There’s a slight improvement to rolling resistance as well. But only IF you don’t purposefully adjust your tire pressure. Tire pressure (which is really interior pressure relative to the ambient air pressure) increases by about 1 PSI per 2000 feet of elevation gain. Higher tire pressure reduces rolling resistance. It’s not as significant as the reduction in drag, but it’s not nothing.

 

[4wheeldog]

For me, the range is impacted by elevation, only the elevation changes - going up uses more power, going down extends the range. I'm normally at 7100 feet, driving to Albuquerque at 5K feet is downhill overall, so I use a lot less energy than when I come back.

How strange. I live 20 miles East of ABQ at 7200’ elevation.

 

[Exordium01]

For me, the range is impacted by elevation, only the elevation changes - going up uses more power, going down extends the range. I'm normally at 7100 feet, driving to Albuquerque at 5K feet is downhill overall, so I use a lot less energy than when I come back.

Albuquerque to Santa Fe is rough but Santa Fe to Taos is great because it is relatively low speed. In the summer on a nice day, I can make the round trip from Albuquerque to Taos and back without charging, but I always chicken out and charge at the EA off Cerrillos. I’d imagine a non-GT extended range could comfortably make the round trip.

 

[tbrumleve]

No air is needed to run your EV. ICE’s require air + fuel. There is “less air” the higher you go. ICE is less effective with less air. EV’s are affected by air resistance. “Less air” = less resistance. That’s the short version.

 

[eastern refugee]

@SpaceEVDriver That is an interesting observation. It didn't really think about the drag from the thinner air. I really wonder how that would really play out.

I regularly drive from Bakersfield which is than 1000 to LA and have to drive over 4400 feet of the Sierra Nevada's, and I ALWAYS lose 40 miles of range. My best suggestion is to use your ford navigation. it will automatically correct the range of miles available based on both height and the way that you drive. it is an EXCELLENT tool I use it ALL of the time when i am driving out of town even if i know the route. It give sup to date traffic and makes suggestions on alternate routes. At the same time When i charge coming home i can look at how far to home and add roughly 25 miles of charging so that I can drive home without both worrying and over spending at the charger. Most of the time it is maybe 5 minutes of charge at a tesla station.

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