Elevation -- effect to battery usage?

[Wolverine]

Does anyone have experience or calculations to share about the effect of driving uphill on your battery depletion?

I'm contemplating a trip through Kings Canyon/Sequoia National Parks. Whether I enter the parks from north or south, it looks like I will have to drive uphill to about 7,500 foot elevation (and then down again). There is nowhere in the parks to recharge an EV! According to my ABRP planning, I should be able to make it through, but I'm wondering if the effect of the uphill drive may wipe out my charge before I can get out.

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[Phil-Springs]

Not sure but I drove up a Colorado mountain pass and hit like 1.2 mi/kWh on the way up.

 

[Thor2j]

Well considering you regen on the downhill.

 

[1969Camaro]

I drove from 1200 ft to 8000 ft. Up 1.8 mi/kw. Down 3.5 mi/kw.

 

[AZBill]

Generally it is a wash if you are returning on the same route. I did a trip recently where I had to go up and down a mountain to my destination. Going up the hill the GOM went below the distance to my destination, but on the way down the other side it gained all of my margin back.

 

[clhardy5]

I recently took my GT through Rocky Mountain national park - over the trail ridge road, and hit elevations of 12,000 plus.... The car did great. Overall got about 3.5 m/kwh considering the awesome regen on the way down.

 

[Blue highway]

Generally it is a wash if you are returning on the same route. I did a trip recently where I had to go up and down a mountain to my destination. Going up the hill the GOM went below the distance to my destination, but on the way down the other side it gained all of my margin back.

essentially the same result for me. My semi regular "mountain" loop goes from sea level to 4000' and back to sea level over 120 miles or so. The battery percentage gets hammered going up but I burn little to nothing going back down. the net is the loop ends up being similar to highway driving consumption...

 

[Mach-Lee]

Does anyone have experience or calculations to share about the effect of driving uphill on your battery depletion?

I'm contemplating a trip through Kings Canyon/Sequoia National Parks. Whether I enter the parks from north or south, it looks like I will have to drive uphill to about 7,500 foot elevation (and then down again). There is nowhere in the parks to recharge an EV! According to my ABRP planning, I should be able to make it through, but I'm wondering if the effect of the uphill drive may wipe out my charge before I can get out.

Definitely use the Ford Nav for that to see if you can make it before you go. See what % it shows you arriving at the top with. You want to get there with about 40% left if you're returning to the same charger. If you drop below 40% before getting to the top, turn around and go back down.

 

[Phil-Springs]

essentially the same result for me. My semi regular "mountain" loop goes from sea level to 4000' and back to sea level over 120 miles or so. The battery percentage gets hammered going up but I burn little to nothing going back down. the net is the loop ends up being similar to highway driving consumption...

In my very limited experience, same thing just depends on the exact nature of the downside. I

 

[Murse-In-Airy]

ABRP should be accounting for elevation changes.

 

[Wolverine]

Thanks everyone for your input! This forum is amazing.

I didn't realize that braking regeneration on the downhill can restore so much of your electric charge. Do I understand correctly that the re-gen will restore almost all of the charge that you lose on the uphill?

If so, my challenge seems to be to make sure that I have enough charge left to get me to the point where I start going downhill and start braking. If ABRP accounts for the elevation changes, then I should have 25% left over when I get to the next charger. But then there's the unpredictable amount of sightseeing detours within the the park.

For what it's worth to anyone, I found this great website that lets you plot the various elevation points on a trip: flattestroute.com

 

[BubGump]

Thanks everyone for your input! This forum is amazing.

I didn't realize that braking regeneration on the downhill can restore so much of your electric charge. Do I understand correctly that the re-gen will restore almost all of the charge that you lose on the uphill?

If so, my challenge seems to be to make sure that I have enough charge left to get me to the point where I start going downhill and start braking. If ABRP accounts for the elevation changes, then I should have 25% left over when I get to the next charger. But then there's the unpredictable amount of sightseeing detours within the the park.

For what it's worth to anyone, I found this great website that lets you plot the various elevation points on a trip: flattestroute.com

Yep, should basically even itself out, or very close to it. The energy lost to aero drag and friction is gone forever, you’ll never get that back. But that’s true on every drive. Other than those types of losses, you should get all the energy back you lost going up the hill, assuming you go back down the same amount.

 

[Mach-Lee]

Thanks everyone for your input! This forum is amazing.

I didn't realize that braking regeneration on the downhill can restore so much of your electric charge. Do I understand correctly that the re-gen will restore almost all of the charge that you lose on the uphill?

If so, my challenge seems to be to make sure that I have enough charge left to get me to the point where I start going downhill and start braking. If ABRP accounts for the elevation changes, then I should have 25% left over when I get to the next charger. But then there's the unpredictable amount of sightseeing detours within the the park.

For what it's worth to anyone, I found this great website that lets you plot the various elevation points on a trip: flattestroute.com

Summary is shown at 8:20 -



From a physics perspective, you are only going to get back the gravitational potential energy coming back down. The drag and rolling resistance losses you don't get back. So if you drive 50 miles up a mountain and 50 miles down, you will effectively use the same energy as driving 100 miles plus a little bit more to account for regen losses.

You can calculate gravitational potential energy required to go uphill: https://www.omnicalculator.com/physics/potential-energy?c=USD&v=g:1!g!l,mass:5000!lb,height:7500!ft (change energy units to kWh)

As you can see it takes about 14 kWh to go up 7500 ft which is about 15% of the extended battery. Let's say you average 2.8 mi/kWh driving on flat ground, we can calculate the energy and % required to go up and down.

Uphill:
50 mi / 2.8 mi/kWh = 18 kWh (drag)
+7500 ft = 14 kWh (elevation)
TOTAL = 32 kWh or 36% battery required

Downhill:
50 mi / 2.8 mi/kWh = 18 kWh (drag)
-7500 ft = -14 kWh * 80% efficiency = -11 kWh (regen)
TOTAL = 7 kWh or 8% battery

Add them together you need 39 kWh or 44% battery for the trip, so you should start with that % or higher to make it. Compared to about 40% battery to go 100 miles on flat ground.

 

[Murse-In-Airy]

Summary is shown at 8:20 -



From a physics perspective, you are only going to get back the gravitational potential energy coming back down. The drag and rolling resistance losses you don't get back. So if you drive 50 miles up a mountain and 50 miles down, you will effectively use the same energy as driving 100 miles plus a little bit more to account for regen losses.

You can calculate gravitational potential energy required to go uphill: https://www.omnicalculator.com/physics/potential-energy?c=USD&v=g:1!g!l,mass:5000!lb,height:7500!ft (change energy units to kWh)

As you can see it takes about 14 kWh to go up 7500 ft which is about 15% of the extended battery. Let's say you average 2.8 mi/kWh driving on flat ground, we can calculate the energy and % required to go up and down.

Uphill:
50 mi / 2.8 mi/kWh = 18 kWh (drag)
+7500 ft = 14 kWh (elevation)
TOTAL = 32 kWh or 36% battery required

Downhill:
50 mi / 2.8 mi/kWh = 18 kWh (drag)
-7500 ft = -14 kWh * 80% efficiency = -11 kWh (regen)
TOTAL = 7 kWh or 8% battery

Add them together you need 39 kWh or 44% battery for the trip, so you should start with that % or higher to make it. Compared to about 40% battery to go 100 miles on flat ground.

I love practical applications of physics and math. Thank You for sharing.

 

[nashbrydges]

As I understand it, ABRP considers elevation when route planning.

https://forum.abetterrouteplanner.com/blogs/entry/20-a-better-routeplanner-33/

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