Fleet sales manager at dealer says they expect 40% range reduction at 70 mph + , Is that possible?

[corradoborg]

I'm not a physicist or an engineer, so I must be misunderstanding you. Are you suggesting that a Tesla model 3 is 4x as efficient at 30 mph as 60 mph?

So using the 4x number, let's just say a Tesla Model 3 uses .07 Kwh per mile at 30 MPH.
And, let's say a Lightning will use .15 kwh per mile at 30 MPH.

If it takes 4 times as much energy at 60 MPH, then the model 3 would use .28 KWH at 60 mph giving it a range of 294 miles at that speed (as opposed to 1178 in range at 30 mph (82.5 / .07) and the Lightning will use .6 Kwh per mile at 60, giving the extended range battery a range of 218 miles at that speed (131 / .60) as opposed to 873 miles at 30 mph (131 / .15)

The math isn't that straightforward. Drag is quadrupled when speed is doubled, but not energy use. Your calculations are assuming that aerodynamic drag is the ONLY consumer of energy, when the reality also includes the demands of acceleration, gravity (when going uphill), rolling resistance, and electricity use by BMS and other systems in the truck.

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[jb56]

It isn't going to be 40% less range at 70mph. Probably more like 15% for 255 miles range.

Thats why you need the big battery.

You might see 40% range drop in cold weather, rain and driving 70mph with the heater blasting.

What do you base this on? I'm not saying you are wrong, but I just wonder if you have some reason to believe that their range estimates were similar to performance at 50 or 60 or 70 mph?

With the Mustang Mach-E, the 70 mph range test was 285 compared to an EPA estimate of 270 miles which I believe is actually above what the initial Ford estimate was before EPA testing.

The F150 has a way bigger battery option, so I'm hopeful that Ford is following a similar path with the lightning and that we'll actually see freeway driving range at or around 300 miles. But I was concerned by what the fleet manager said. He is going to be selling to businesses that put a lot of miles on the truck and range anxiety is particularly significant with those buyers.

 

[RLXXI]

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[hhulseman]

What do you base this on? I'm not saying you are wrong, but I just wonder if you have some reason to believe that their range estimates were similar to performance at 50 or 60 or 70 mph?

With the Mustang Mach-E, the 70 mph range test was 285 compared to an EPA estimate of 270 miles which I believe is actually above what the initial Ford estimate was before EPA testing.

The F150 has a way bigger battery option, so I'm hopeful that Ford is following a similar path with the lightning and that we'll actually see freeway driving range at or around 300 miles. But I was concerned by what the fleet manager said. He is going to be selling to businesses that put a lot of miles on the truck and range anxiety is particularly significant with those buyers.

I have no data for the Lightning. This is my intuition based on accuracy of other mfg estimates.

I think Ford is looking for customer satisfaction and that the range estimates are based on 2.3miles/kWh which accounts for the coefficient of drag. The 300 mile range estimate could be optimistic, but I doubt it's 40% optimistic. That would cause customer resentment and backlash.

 

[jefro]

Current real world testing examples of EVs.
https://www.edmunds.com/car-news/electric-car-range-and-consumption-epa-vs-edmunds.html#chart

I think on an F-150 at 70 flat road moderate temperature you'd be lucky to get two miles per kilowatt average.

 

[metroshot]

There are a few posts now with people suggesting by stopping and going regenerative braking leads to increased range compared to just constant speed driving. This is completely false. That's not how physics and energy works. Even with regenerative braking, braking is still going to use more energy than constant speed driving.

Regen braking decreases the amount of energy lost braking. If you want maximum efficiency, just drive at a constant speed. If you don't believe me, take it up with Isaac Newton or whoever made the rules.

Here are some other sources if you don't want to take my word for it:

"It is important to realize that on its own, regenerative braking isn’t a magical range booster for electric vehicles. It doesn’t make electric vehicles more efficient per se, it just makes them less inefficient. Basically, the most efficient way to drive any vehicle would be to accelerate to a constant speed and then never touch the brake pedal. Since braking is going to remove energy and require you to input extra energy to get back up to speed, you’d get your best range by simply never slowing down in the first place."

Source: https://electrek.co/2018/04/24/regenerative-braking-how-it-works/amp/

"But be warned - regenerative braking does not magically boost your EV's range. Instead, it is there to make your car more efficient. In other words, the most efficient way to drive any car, not just EVs, would be to drive to a constant speed and then never touch the brake pedal. Braking only removes energy, and drivers have to input extra energy to get back up to speed, so it is recommended to never slow down in the first place if a driver wants to achieve the best range for their car."

Source: https://www.hotcars.com/everything-you-should-know-about-regenerative-braking/amp/

"Aggressive drivers, for example, might see more benefit from the system. This doesn’t mean going full-throttle and braking like you’re competing in a rally won’t decrease your range. Cruising at a set speed is still the most effective way to save on batteries. It’s just that sporty driving will cost you less in an EV than it would in a gasoline engine car."

Source: https://www.autoevolution.com/news/ev-regenerative-braking-for-dummies-149745.html

Sorry, but in the real world, a PHEV or EV will get more miles per charge if you drive in the city compared to the highway.

Remember the Toyota Prius Monroney sticker that shows higher EPA miles on the city driving vs highway and shocked everyone ?

My PHEV gets much more miles per charge - actually exceeding the manufacturer's range by 10-20% when driven under 45MPH, climate controls off, and using the regen paddles.

The Chevy Bolt, Nissan Leaf, and Tesla EV all have regen braking built in to some degree that regenerates energy back into the traction batteries.

My PHEV has very minimal brake wear (less than 2mm) after 40,000 miles of driving - normally a comparable ICE car will have significantly more brake wear (4-6mm) - attesting to the fact that regen braking has a significant impact on both increased miles and decreased brake pad wear.

 

[TF1000]

Sorry, but in the real world, a PHEV or EV will get more miles per charge if you drive in the city compared to the highway.

Part of that was with the earlier priuses the ICE was running at higher speeds no matter what. My 2006's ICE runs at highway speeds (sometimes with EV assist) unless I'm going downhill. Our 2018 prime can run in total EV at highway speeds even after the larger battery is depleted.

As an experiment do some stop an goes at highway speed and see that regen will not be as efficient as keeping a steady speed.

My PHEV has very minimal brake wear (less than 2mm) after 40,000 miles of driving - normally a comparable ICE car will have significantly more brake wear (4-6mm) - attesting to the fact that regen braking has a significant impact on both increased miles and decreased brake pad wear.

Can't remember exactly when we changed the pads for the first time on our 2006 but it was well over 100,000 miles (but almost all of our driving is highway driving).

 

[Sklith]

Sorry, but in the real world, a PHEV or EV will get more miles per charge if you drive in the city compared to the highway.

I'm sorry but this isn't true in the slightest. I know this because I own an EV. Driving in a constant speed of 70 MPH will always beat out urban driving.

 

[TF1000]

I'm sorry but this isn't true in the slightest. I know this because I own an EV. Driving in a constant speed of 70 MPH will always beat out urban driving.

Curious. Are you known to mash the accelerator pedal when the light turns green? That will kill your urban driving range. I definitely see a drop-off in range above about 65+ mph. Sweet spot for me is around 40 to 50mph.

 

[Sklith]

Curious. Are you known to mash the accelerator pedal when the light turns green? That will kill your urban driving range. I definitely see a drop-off in range above about 65+ mph. Sweet spot for me is around 40 to 50mph.

No. I also make sure to regen to a full stop without using the friction brakes. Physics is a bitch, and we can't convert 100% of the kinetic energy into our batteries when stopping.

Edit: I experience the sweet spot at 40-50 mph as you mentioned when I'm driving on country roads where stopping is a lot less frequent. In those cases, my car's efficiency goes through the roof, and exceeds its rated range.

 

[hhulseman]

Current real world testing examples of EVs.
https://www.edmunds.com/car-news/electric-car-range-and-consumption-epa-vs-edmunds.html#chart

I think on an F-150 at 70 flat road moderate temperature you'd be lucky to get two miles per kilowatt average.

Looks like most mfg estimates were actually pessimistic. Rivan was at 2 miles per kWh so if we assume about the same I estimate 250 mile range at 70 mph. But that's trying to guess based on data that isn't solid. It may actually do much better than that.

 

[jefro]

We currently don't know what motors are being selected for the F-150. There are some newer motors that are quite efficient but I don't think it'll significantly do better than a Rivian. I'd look to the technology in the Mach E and use it for consideration

 

[EVTruckGuy]

Sorry, but in the real world, a PHEV or EV will get more miles per charge if you drive in the city compared to the highway.

I agree the mileage is better in the city. It's your reasoning as to how this occurs that is not accurate. EVs only get better milage because in the city because your speed is lower...not because of regen. Physics is physics. The best part about facts and science is that they are true whether or not you believe them.

 

[MickeyAO]

Basic rule of thumb in EV testing...you can only regen the energy needed to accelerate to speed (minus, of course, the inefficiencies) but not the energy you use to maintain the speed.

 

[jefro]

On my ev's I have rough guessed 1/5 Regen rate. It's something but nowhere near 1:1 return. Huge losses until superconductor motors.

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