Headwind effect yesterday

[flyct]

We drive a 125 mile trip between our cabin and house about 3-4 times per month. This trip normally uses 45% of our battery capacity. Yesterday we had an average of probably 20-25 mph headwinds and we used 60% of battery capacity with our ER Lightning. That‘s a whopping 33% increase in energy consumption.

I was very surprised at the amount of range hit it took with the wind effect. This truck (and all trucks) severely suffers from parasitic drag due to the lack of aerodynamic design.

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[Pioneer74]

It's tall, it's wide, and it's heavy. It's a truck. My wife's Mach-E doesn't fare much better.

 

[TheWoo]

We drive a 125 mile trip between our cabin and house about 3-4 times per month. This trip normally uses 45% of our battery capacity. Yesterday we had an average of probably 20-25 mph headwinds and we used 60% of battery capacity with our ER Lightning. That‘s a whopping 33% increase in energy consumption.

I was very surprised at the amount of range hit it took with the wind effect. This truck (and all trucks) severely suffers from parasitic drag due to the lack of aerodynamic design.

Head winds are the biggest enemy of range, for sure. Since aerodynamic drag increases exponentially, a 10+mph headwind at highway speeds is a big impact.

I travel Kansas interstates a decent amount. There's always wind and the traffic travels at 80 mph. You couple 80 and a 15 mph wind and the range sure treats you like you're going 95. I got 1.2-1.3 m/kWh yesterday on a 120 mile one-way trip in 50° weather. Slowed down to 75 mph and had no wind on the way back, got 1.7 in spite of cooler temps.

Wind (and speed) kills.

 

[Jimbalf]

The flip side is also true. A tailwind is awesome. Between Austin and Dallas on I35 with a tailwind I saw 2.4 mi/kwhr Going a couple miles over the 75mph speed limit. As luck would have it a cold front blew thru on my return and with a cold (45 degrees) tailwind I got 2.3

 

[Henry Ford]

I was very surprised at the amount of range hit it took with the wind effect. This truck (and all trucks) severely suffers from parasitic drag due to the lack of aerodynamic design.

Parasitic drag refers to any drag that isn't producing lift. Since cars don't fly all drag is parasitic. In the auto world you can reduce drag by making the frontal area smaller or reducing the coefficient of drag (CoD), i.e. more aerodynamic.

The earliest Hybrids and BEVs addressed both variables. Americans like big cars and the market for small efficient vehicles was niche. Tesla built larger, still very aerodynamic cars with clever packaging and big batteries and developed a new market.

When designers are tasked with building an efficient truck the options are limited. A truck can only be shrunk only so much before it's is no longer useful (or at least the truck market doesn't think it's useful but that's another discussion) so EV trucks are still pretty big. The open bed of a truck presents a CoD issue because air doesn't like to flow smoothly over sharp changes in surfaces and it's pretty hard to make a useful bed if it's covered. Tesla addressed this by eliminating the bed most of the time.

Ford had a legacy vehicle in the F150 that could be turned into an EV relatively easily but it had a frontal area problem AND a CoD problem. They put smaller mirrors on it but otherwise didn't address the frontal area problem. They completely reworked the bodywork ahead of the cab and smoothed the bottom to address CoD. In other words, they compromised. To make up for it they threw batteries at it.

To be fair, every popular EV has an enormous battery. Americans won't buy a small efficient vehicle in numbers larger enough for manufacturers to develop them.

That was a rant.

 

[sotek2345]

I was thinking about this the other day. I would love some kind of display (either directly in the truck or via android auto / car play) of wind speed and direction inside the truck so you can more easily know what is going on and what kind of efficiency hits, or benefits, to expect. In an ideal world this would be instrumentation on the truck to measure wind speed measured vs. speed of travel, but you can probably get close with just software and weather data.

 

[flyct]

Parasitic drag refers to any drag that isn't producing lift. Since cars don't fly all drag is parasitic. In the auto world you can reduce drag by making the frontal area smaller or reducing the coefficient of drag (CoD), i.e. more aerodynamic........................................

I posted Parasitic drag because I my long history of trying to reduce it as a aircraft owner and long time pilot. Little modifications would go a long way to reduce parasitic drag which would increase efficiency. This increased efficiency resulted in either increased cruise speed for same power or increased range with reduced power and same speed.

I also tow a 14,000 lb 5th wheel with our F-450. The wind effect due to poor aerodynamic frontal area and has similar +- 20% fuel burn with this combination.

Our Tesla's also suffer from reduced efficiency due to headwinds but not nearly as much as the high drag F-150L. Mind you I am not complaining. I love the truck, the way it looks, handles and what it does. I was just surprised at the how much headwinds affected the efficiency.

 

[flyct]

I was thinking about this the other day. I would love some kind of display (either directly in the truck or via android auto / car play) of wind speed and direction inside the truck so you can more easily know what is going on and what kind of efficiency hits, or benefits, to expect. In an ideal world this would be instrumentation on the truck to measure wind speed measured vs. speed of travel, but you can probably get close with just software and weather data.

It wouldn't be that difficult to engineer such a device to measure headwind/tailwind component. All you would need is a sensor that measures airspeed on the front of the truck and compare it to the GPS groundspeed. Then difference would be the headwind/tailwind component. But would "normal" owners really care?

 

[daveross1212]

https://holybro.com/products/digital-air-speed-sensor

 

[Henry Ford]

It wouldn't be that difficult to engineer such a device to measure headwind/tailwind component. All you would need is a sensor that measures airspeed on the front of the truck and compare it to the GPS groundspeed. Then difference would be the headwind/tailwind component. But would "normal" owners really care?

Realtime mpkWh would be a whole lot simpler and could be done with a software update. We already have a brake coach, how about a highway coach?

 

[Maquis]

The aerodynamics are irrelevant. The % increase in drag will be the same.

 

[Maxx]

What was your average speed?

I have not done the math but I am guessing there is a sweet spot. If you are doing 80 and add 20 headwind to go 80 miles, truck will be fighting 100 mph wind for an hour. On the other hand if you drive too slow like 10 mph, the truck is fighting 35 mph wind for eight hours. Even though drag impact is lower at lower speed, it will be fighting that extra 20 for a lot longer. Would be cool to know what is the optimal speed for OP. Anyone itching to do some math specifically for Lightning?

 

[Henry Ford]

I posted Parasitic drag because I my long history of trying to reduce it as a aircraft owner and long time pilot. Little modifications would go a long way to reduce parasitic drag which would increase efficiency. This increased efficiency resulted in either increased cruise speed for same power or increased range with reduced power and same speed.

I think Ford has done everything economically possible on a legacy platform. Next generation should be much improved and very different looking.

An owner who was interested in reducing drag could start by retracting mirrors. Solid wheel cover might increase laminer flow at the expense of brake cooling but that's probably not a concern to someone willing to fabricate solid wheel covers. Taping panel gaps would yield a little better CoD. The biggest issue with a truck - aside from frontal area - is the massive low pressure areas behind the cab and tailgate. I imagine a bed cover that sloped from the top of the cab to the top of the tailgate would reduce CoD a little.

There has to be a way to use the power in the bed. How about a set of electric fans to replace the tailgate? Maybe the energy used would be less than the energy saved!

I have no interest in implementing any of my crazy ideas but it's a fun thought experiment. Maybe an enterprising YouTuber will try to hypermile a Lightning Mythbusters style.

 

[Bwanapete]

I don’t want to compromise my big frunk. I do have a Revolver bed cover but in sustained heavy rain, water gets in. No water gets in my frunk.

 

[Adventureboy]

I was thinking about this the other day. I would love some kind of display (either directly in the truck or via android auto / car play) of wind speed and direction inside the truck so you can more easily know what is going on and what kind of efficiency hits, or benefits, to expect. In an ideal world this would be instrumentation on the truck to measure wind speed measured vs. speed of travel, but you can probably get close with just software and weather data.

I hope there isn't too much wind inside the truck.... . That could get ugly.
Seriously though, we have them for boats. Apparent wind direction and speed on the moving vessel minus the direction and speed of the vessel gives you true wind direction and speed. You would need an instrument (anemometer) that could handle Lightning speeds.

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