Vast difference in range on return trip?

[EffDeeEmm]

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

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[E90alex]

Elevation

 

[RickMachE]

Elevation, and if it's cold and you set a departure time while plugged in, that would improve efficiency.

 

[astrorob]

also wind, i find that driving back and forth to davis from the bay area always results in an asymmetrical energy situation.

 

[EffDeeEmm]

also wind, i find that driving back and forth to davis from the bay area always results in an asymmetrical energy situation.

I am going to make a more conscious effort to pay attention to which way the wind is blowing on my future trips, but thanks to the proximity to the Rocky Mountains, it can be coming from all different directions in the span of a few hours.

 

[Maui]

Wind hammered me on my last trip. Driving into 38 mph wind

 

[rhougey]

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

As others have said, it’s elevation, wind, and possibly temp. I drive a similar round trip very often. Driving to our cabin, it is 230 miles with an elevation gain of 1300 ft, and more often than not into a headwind of anywhere from 2-22 mph. The drive back down is downhill with a tailwind. 1300 feet is not a lot over 230 miles, but the difference between the trip up and the trip back is double that. And a 5mph headwind becomes a 10mph difference on the way back with a 5mph tailwind. A lot of the time we drive up in the morning (cooler) and drive back in the afternoon (warmer), so the temps also often contribute. We have always seen the difference in efficiency, even before we had an EV, but of course we all measure it and obsess about it more with the EV.

 

[EffDeeEmm]

As others have said, it’s elevation, wind, and possibly temp. I drive a similar round trip very often. Driving to our cabin, it is 230 miles with an elevation gain of 1300 ft, and more often than not into a headwind of anywhere from 2-22 mph. The drive back down is downhill with a tailwind. 1300 feet is not a lot over 230 miles, but the difference between the trip up and the trip back is double that. And a 5mph headwind becomes a 10mph difference on the way back with a 5mph tailwind. A lot of the time we drive up in the morning (cooler) and drive back in the afternoon (warmer), so the temps also often contribute. We have always seen the difference in efficiency, even before we had an EV, but of course we all measure it and obsess about it more with the EV.

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.

 

[rhougey]

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.

Usually we get to the cabin with 3-5% remaining, but get home with 20-25% remaining. Always set cruise control at 75.

 

[Mach-Lee]

Elevation change would take an extra 2-3 kWh compared to flat, which would be a difference of 4-5 kWh comparing the two directions. So elevation would be probably around a 25 km range difference. Anything further would be wind most likely.

 

[SonicBlue]

Even a 10mph headwind takes a significant toll on my efficiency at highway speeds. Also elevation may not even be noticeable but it adds up.

 

[rhougey]

Elevation change would take an extra 2-3 kWh compared to flat, which would be a difference of 4-5 kWh comparing the two directions. So elevation would be probably around a 25 km range difference. Anything further would be wind most likely.

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.

 

[kodiakng]

adding to the elevation+wind+battery_temp effect discourse, note that your stated variation in each direction is quite high with 50km variance in one direction and 40km in the other. the effects due to elevation will be pretty constant (also you'll gain a little in one direction and consume a little in the other) for each round trip so the major variation you're seeing is most likely coming more from the wind and battery_temp effects.

 

[ipca204]

https://share.google/SzMGctGHJZguB6Xyf

 

[devmach-e]

also wind, i find that driving back and forth to davis from the bay area always results in an asymmetrical energy situation.

I have the same issue commuting from Pacifica down to SJC via 280. Going to work always results in slightly better mi/kWh than coming home.

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