Vast difference in range on return trip?

[A-A-Ron]

Huh, guess that's likely the culprit then. I just didn't expect it to have that much of an impact, especially since it's all very gradual over prairie land.

Doesn't matter if that climb is over 1km or 100km, you're still lifting 6000lbs 1200' in the air and you can imagine just how much energy that takes. Likewise, coming down, you are able to convert that energy into a charge that extends your range.

People tend to realize they're expending energy going up a hill but don't realize just how much potential energy you convert into kinetic energy coming back down too. You're not losing 80 km of range going up the mountain - you're losing like 40km going up and gaining 40 coming back down.

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[EffDeeEmm]

People tend to realize they're expending energy going up a hill but don't realize just how much potential energy you convert into kinetic energy coming back down too. You're not losing 80 km of range going up the mountain - you're losing like 40km going up and gaining 40 coming back down.

Yeah, that's a good way of putting it.

TBH I hadn't even thought about the elevation until recently. Even though we're on the doorstep of the Rockies, it still feels like we just live in the flat-ass Prairies, and you forget about how high up we actually are.

 

[Mach-Lee]

Hey Lee, those numbers are interesting to me, and I have no reason to doubt them, but I would have thought that the elevation change was a larger portion of the equation relative to the wind. Are those numbers assuming a lightly loaded car or heavily loaded, or since the elevation change deficit is minimal, the load effect would also be minimal? For us a light load would be about 450 lbs, and a heavy load would be 950 or so.

You can abstract the elevation change and think of it as the energy to lift a 5000 lb car 1200 feet vertically (the product is 6 million foot-pounds or 2.3 kWh). It would take the same amount of energy for the car to go straight up 1200 feet as it would take extra energy to climb a 1200 ft incline.

You can set this to output kWh if desired for trip planning: https://www.omnicalculator.com/physics/potential-energy

It goes by total vehicle mass; since the Mach-E is already pretty heavy, an extra 500 lbs load would only make a 10% difference in elevation change energy. So most people will not see a difference in efficiency under typical vehicle load situations unless there is extreme elevation change involved.

Wind is basically going to increase your velocity term in the drag equation, and since that term is squared, it can make a big difference. For example, if you are driving 70 MPH with a 15 MPH headwind, that's almost like driving 85 MPH. You would have 47% more drag. Drag is the largest energy loss at those speeds, so it would make a huge dent in your efficiency.

You're not losing 80 km of range going up the mountain - you're losing like 40km going up and gaining 40 coming back down.

Yup, that's how it works.

 

[rhougey]

You can abstract the elevation change and think of it as the energy to lift a 5000 lb car 1200 feet vertically (the product is 6 million foot-pounds or 2.3 kWh). It would take the same amount of energy for the car to go straight up 1200 feet as it would take extra energy to climb a 1200 ft incline.

You can set this to output kWh if desired for trip planning: https://www.omnicalculator.com/physics/potential-energy

It goes by total vehicle mass; since the Mach-E is already pretty heavy, an extra 500 lbs load would only make a 10% difference in elevation change energy. So most people will not see a difference in efficiency under typical vehicle load situations unless there is extreme elevation change involved.

That all makes total sense. Thank you!

 

[scottrichman9]

Hey all

I don't do a lot of long-range driving in my GTPE. I'm in Calgary, and the extent of my road tripping is the drive up to Edmonton to visit family. The one strange thing I've noticed over the few years I've had it, is that the range is vastly different going up than it is coming home. When I arrive in Edmonton, I often have like 100-150 KM remaining on my range....but on the trip back to Calgary, it falls anywhere from 20-60 remaining when I get home.

The route is pretty much identical each way, (give or take maybe 1-2km if I make a detour), the conditions are usually the same on each leg, I travel the same speed each way (I set the the cruise at 111 km/h), and the cabin usage is usually just a podcast playing on android auto and minimal climate control. I simply don't do anything notably different on the way there than I do on the way back.

One thing I'm wondering about is elevation. It's not a drastic change, but Calgary is about 1200 ft higher in elevation than Edmonton. That being said, it's not like I'm driving up a noticeable incline at all. The door-to-door trip is a hair under 300km, so the elevation change is only 4 ft per km. Could that be the culprit even though it's that subtle?

I'm certainly don't have genius-level knowledge when it comes to the science involved in these vehicles...so I thought I'd check and see if some of the true EV geeks might be able to enlighten me

I have a similar experience driving from Missoula to Bozeman, MT where the increase in elevation is 1600 ft (combine that with wind) and I am stopping in Butte either way to complete the journey. If I don't drive too much in Bozeman around town, I can return to Butte on same charge and make it back to Missoula. I have done that only once - range anxiety and lack of public chargers undoubtedly makes it a three charge round trip. If our MMEs had a reliable 400 mile range capacity - we'd be in heaven.

 

[Kamuelaflyer]

TBH I hadn't even thought about the elevation until recently.

Unless you’re dealing with it regularly or unless it’s a really steep gradient, elevation gradient can be a bit sneaky. Obvious things, like the last 8 miles to my house taking a full 10% soc, are obvious, but Edmonton - Calgary? Not so much.

 

[Bad Dolphin]

Hey all

I don't do a lot of long-range driving in my GTPE. I'm in Calgary, and the extent of my road tripping is the drive up to Edmonton to visit family. The one strange thing I've noticed over the few years I've had it, is that the range is vastly different going up than it is coming home. When I arrive in Edmonton, I often have like 100-150 KM remaining on my range....but on the trip back to Calgary, it falls anywhere from 20-60 remaining when I get home.

The route is pretty much identical each way, (give or take maybe 1-2km if I make a detour), the conditions are usually the same on each leg, I travel the same speed each way (I set the the cruise at 111 km/h), and the cabin usage is usually just a podcast playing on android auto and minimal climate control. I simply don't do anything notably different on the way there than I do on the way back.

One thing I'm wondering about is elevation. It's not a drastic change, but Calgary is about 1200 ft higher in elevation than Edmonton. That being said, it's not like I'm driving up a noticeable incline at all. The door-to-door trip is a hair under 300km, so the elevation change is only 4 ft per km. Could that be the culprit even though it's that subtle?

I'm certainly don't have genius-level knowledge when it comes to the science involved in these vehicles...so I thought I'd check and see if some of the true EV geeks might be able to enlighten me

Before I read your post after reading your headline, I suspected two things--wind direction or elevation change.

Elevation change is huge. Ours is more extreme than yours and over a much shorter drive, but indicative of what can happen. We live in the side of a mountain at 1950 feet. Driving into town and around town in the flats at sea level for a bit we'll average a wonderful 10-22m/KWh. But by the time we get home, we're at an average of 2.7 m/kWh or so.

when we drive from one side of our island to the other, there's a slight elevation loss going to the south side and the same gain coming back a north on what looks like flat highway. No measurements that suce made, but a noticeable difference whether driving On my way! If our two EV's or our remaining ICE car. We tend to get strong winds here (we're windsurfers and moved here for a reason!) and the are typically out if the North, further boosting the elevation effect.

Did you notice what wind direction and velocity were?

 

[EffDeeEmm]

This is exactly what I was hoping would happen with this post - people much smarter than me weighing in and making me a teeny-tiny bit smarter in return

 

[Jiji]

If only there was an app that logged your change in elevation, weather, wind, battery and much more.

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