What's a good kw per mile range (on highway) for extended range battery?

[Greddy1]

Hello all,
Can anyone explain what good highway range should be on the extended range battery? took a 120 mile trip yesterday and paying attention the KW usage it seems like 2.7 miles per KW was about average if I was going 75 mph or less anything more than that and it dropped down to 2.2 to 2.4 Around town it seems to be in the 3.1 to 3.5 Is this normal use?

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[sborsch]

It certainly seems that you are achieving the correct range for your driving styles and speed. It is definitely normal use.

I find that Whisper mode and easy acceleration and 1-pedal driving from light-to-light around town gets me in the 3.8 to 4.5 KW range (and sometimes A LOT more). I try to stay at or under 70mph on the freeway, but here in California find that even the HOV lane people driving 80mph or more (or as fast as they can whenever they can).

 

[Kabish]

Yup its normal, EVs are incredibly inefficient at freeway speeds when compared to city driving. You have to remember, you are pushing the motors at 75 and basically have no regenerative power going back into the battery.

 

[Maquis]

Energy required is proportional to the cube of the speed.
Regen is only helpful when it is being used in lieu of friction brakes. It is not responsible for better low speed efficiency.
Energy is measured in kWh, power in KW.

 

[AKgrampy]

Hello all,
Can anyone explain what good highway range should be on the extended range battery? took a 120 mile trip yesterday and paying attention the KW usage it seems like 2.7 miles per KW was about average if I was going 75 mph or less anything more than that and it dropped down to 2.2 to 2.4 Around town it seems to be in the 3.1 to 3.5 Is this normal use?

It really comes down to air resistance that increases with velocity squared. So resistance increases exponentially and not linearly.

 

[Vulnox]

Yeah as noted, air resistance is your biggest enemy. It is for ICE vehicles also. EVs don't struggle as much with weight itself, but anything added to the air profile or additional resistance to the existing profile has a huge impact.

AKgrampy also nailed the biggest thing, that it's an exponential increase. So 65 to 70 is a smaller impact than 70-75. In our F-150, I can hit 24 MPG every highway trip, sometimes have had exactly 24.3 MPG on multiple trips on the nose, if I stay in the 70-73 range. If I try to do 75-77, it can be 22 MPG for the exact same route and conditions (although high 22).

EVs have the same issue. But you're not working with as much margin as with a truck like mine that can get 700 miles at 24 MPG, so you realize it more.

 

[RockwallRick]

Hello all,
Can anyone explain what good highway range should be on the extended range battery? took a 120 mile trip yesterday and paying attention the KW usage it seems like 2.7 miles per KW was about average if I was going 75 mph or less anything more than that and it dropped down to 2.2 to 2.4 Around town it seems to be in the 3.1 to 3.5 Is this normal use?

That sounds about right to me for those conditions. I drove about 90 miles today starting at 90% and finishing at 60% SOC. For this trip I was mainly driving below 60 mph with a lot of stop and go city traffic.

 

[mkhuffman]

Hello all,
Can anyone explain what good highway range should be on the extended range battery? took a 120 mile trip yesterday and paying attention the KW usage it seems like 2.7 miles per KW was about average if I was going 75 mph or less anything more than that and it dropped down to 2.2 to 2.4 Around town it seems to be in the 3.1 to 3.5 Is this normal use?

Your efficiency data looks normal to me.

I can get 2.5-2.6 at around 79-80 mph if my tires are at 39 psi cold. I had my front tires at 32 psi cold and was getting 2.4 in the same route and speed.

Rolling resistance impacts efficiency at all speeds, while drag gets exponentially worse the faster you go, as others have posted. Keep your tire pressure at the recommended pressure to get the best range.

 

[JohnnyForensic]

As everyone said, sounds right. Now (summertime), I’m getting about 3.3-3.5 on the highway which is 55-60 mph for me where I am. If I’m on the few 70 mph highways we have here, that comes out to be closer to 3.0-ish, so I’d say you’re right on par.

 

[Dave-O]

Our battery pack is the standard range but with AWD, maybe relevant maybe not. At 65mph it achieves 3.0 miles per kilowatt. Throw in some stop and go/low speed Houston traffic and it can go as high as 4.5.

 

[Guss-E 2021]

Hello all,
Can anyone explain what good highway range should be on the extended range battery? took a 120 mile trip yesterday and paying attention the KW usage it seems like 2.7 miles per KW was about average if I was going 75 mph or less anything more than that and it dropped down to 2.2 to 2.4 Around town it seems to be in the 3.1 to 3.5 Is this normal use?

That's about the level of efficiency I'm seeing (Single occupant, very little cargo, 70-80 degrees F, AC set to 70, fan between 2 and 4). It also depends on how aggressively I accelerate onto on-ramps and the mix of up hill, down hill and level travel.

Not resetting Trip 1 or 2 over a month can give you a better idea of your overall efficiency based on your personal conditions.

 

[Guss-E 2021]

Yeah as noted, air resistance is your biggest enemy. It is for ICE vehicles also. EVs don't struggle as much with weight itself, but anything added to the air profile or additional resistance to the existing profile has a huge impact.

AKgrampy also nailed the biggest thing, that it's an exponential increase. So 65 to 70 is a smaller impact than 70-75.

This absolutely explains why my efficient at 70-72 is markedly better over time than my efficiency at 75+; especially with hard acceleration from 72 to say 80. But, like it has been said, this was the case in my ICE though 80 mph was the sweet spot between speed and fuel efficiency in my Acura. I would get 35 mpg at 80.

 

[Guss-E 2021]

I do wonder if Ford has gone back to the wind tunnel on the Mach-E.

 

[daemonic3]

That sounds about right to me for those conditions. I drove about 90 miles today starting at 90% and finishing at 60% SOC. For this trip I was mainly driving below 60 mph with a lot of stop and go city traffic.

I do love that the Route1 and Premium ER, we get to work with some round numbers as good first order approximation. Yours fits right in line with my rules of thumb.

100% ≈ 300 miles (give or take)
1% ≈ 3 miles

100kWh of energy from a supply will fill approximately 0-100% of a 91kWh battery due to a little bit of charger loss, which leads to:

6kW station ≈ 6% charge per hr
10kW station ≈ 10% charger per hr
50kW station ≈ 50% charge in 1 hr, ≈25% charge in 1/2 hour, etc
150kW station ≈ 75% charge in 1/2 hr
etc....

Always easy for approximations and expectations. For GT or SR batteries it is a little less whole-numbery

 

[daemonic3]

This absolutely explains why my efficient at 70-72 is markedly better over time than my efficiency at 75+; especially with hard acceleration from 72 to say 80. But, like it has been said, this was the case in my ICE though 80 mph was the sweet spot between speed and fuel efficiency in my Acura. I would get 35 mpg at 80.

That's interesting. Is that one of the infinite gear ratio transmission cars? I know in my F150, once it kicks into the final overdrive gear (10th) around 52mph, then the efficiency is all diminishing as I increase speed. There is nothing further to reduce drive train resistance and it is all wind drag.

I know nothing about Acuras but that would be interesting if your model has less resistance in the drivetrain at higher speeds (again, I'm dumb on this) like those infinite gear transmissions. Or if the airflow just becomes most laminar at that speed.

I know when I commute to the bay area in my daughter's Hyundai Venue (shaped minicooper-ish) I would expect lots of drag but whether I'm in a congested commute averaging 65mph or free flowing 80mph, I consistently get 38mpg on a trip!

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