Increasing speed from 70 to 80 probably costs you ~25% of your range/efficiency

[Shundi]

This explains why I almost ran out of battery on a trip to Yucaipa after charging to well over 70 miles of range. Was trying to make up time by flying and ended up with 40 mi of range going up to the camp site with no charger in site. One way was 25 mi of range up the mountain.

Thankfully I was able to use gravity on the way down to generate enough range to get to the nearest EVgo station.

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[Flint302]

Reminds me of when I worked in Florida, the old saying was: "Welcome to Florida, come on vacation, leave on probation."

 

[alexgorod]

If you can't go fast in Mustang, it is not a Mustang!

Case closed.

 

[thekat03]

If you can't go fast in Mustang, it is not a Mustang!

Case closed.

Oh, of course you can go fast. Just... Not efficiently. But I don't think Mustangs are known for efficiency.

 

[Teslaeata]

Beyond staying on top of maintenance, regular 4-wheel alignment checks, maintaining tyre pressures etc, don’t tend to think about stretching range by driving style until necessity dictates.

Certainly don’t [over] think this at all.

I tend to drive the car like it’s no different to any other I’ve ever had.

I bought it to work.

It works.

It had to work or, as I told the salesman on day 1, it would’ve been in Autotrader by end of week 1.

Don’t care about the impact on economy, the time or anything else.

It gets driven to each job and if it needs charging twice because I’m having to drive it hard to get stuff done in a day then so be it.

On the way home time don’t matter, can stop for charge or slow down to get home without but really don’t like to drive home with under 20-mile margin, though.

That 3-mile margin was a very uncomfortable experience.

The ‘Stang is just amazing, and now has another new windscreen and next Friday will have new rear wheel bearings, software updates etc

 

[ctenidae]

change in velocity/change in efficiency = worth it

Except when change in efficiency = walking to the nearest charging station with an empty electron can

 

[Garbone]

I just set my cruise at 8 over. Seems like a fair number to avoid getting pulled.

Efficiency is only an issue when EA comes into play..

 

[Teslaeata]

Except when change in efficiency = walking to the nearest charging station with an empty electron can

will NEVER happen

The ICEman’s top question is “oooh, yes but what happens if you run out of charge?”

I tell the ICEman exactly what he would do when his oil or spirit burner runs out, look an absolute idiot and walk though should really be shot & left to rot

In transport years ago we’d sack a “professional” driver who run his truck out of fuel

 

[Mach1E]

If you can't go fast in Mustang, it is not a Mustang!

Case closed.

My 69 Mach 1 disagrees.

Between the 8 mpg or 4000 rpm at 80 mph, speed isn’t its thing.

 

[Peugfan]

Since aerodynamic drag increases with the square of the increase in speed, the number of pounds of drag going from 70 to 80 is ~1.306 times higher at 80 than at 70. 30.6% more drag for 25% hit in fuel efficiency.

Yes, the drag force varies as velocity squared but the required power varies as the cube of the speed. (Wiki)

 

[Chris D]

100% agree. I drive mostly in The Netherlands which is very flat so no hills to influence the result. At 110km/hr (70mph) is mostly reach 19kw/100km and at 130km/hr(80mph) 23kw/100km. Difference between the 19 and 23 kw is a 21% increase.

I see the same, Maarten, driving a lot in Belgium (speed limit 120 km/h) and Netherlands (100 km/h limit).
I use 20kw/100km in Belgium, but only 18kw/100km in Netherlands. Both are flat, similar weather conditions.

 

[Mach1E]

Yes, the drag force varies as velocity squared but the required power varies as the cube of the speed. (Wiki)

Cube? Not quite.

http://physics.bu.edu/~redner/211-sp06/class-energy/carpower.html

And here is a calculator for fun-
http://www.wallaceracing.com/Calculate HP For Speed.php

We can nerd this thread up real nice.

 

[Peugfan]

Cube? Not quite.

http://physics.bu.edu/~redner/211-sp06/class-energy/carpower.html

A line from your source:
“Power required to maintain speed v is: P = Fv”
I dunno but was not your source talking about a car under constant acceleration. Would not driving at constant speed be zero acceleration? Calling all physics nerds to chime in! I have not viewed Tom's video yet but he is usually a honest facts guy.

A quote from wiki page:
Power
Under the assumption that the fluid is not moving relative to the currently used reference system, the powerrequired to overcome the aerodynamic drag is given by:

The power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[21] With a doubling of speed the drag (force) quadruples per the formula. Exerting 4 times the force over a fixed distance produces 4 times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, 4 times the work done in half the time requires 8 times the power.


When the fluid is moving relative to the reference system (e.g. a car driving into headwind) the power required to overcome the aerodynamic drag is given by:

Where

is the wind speed and

is the object speed (both relative to ground).

 

[Mach1E]

A line from your source:
“Power required to maintain speed v is: P = Fv”
I dunno but was not your source talking about a car under constant acceleration. Would not driving at constant speed be zero acceleration? Calling all physics nerds to chime in! I have not viewed Tom's video yet but he is usually a honest facts guy.

A quote from wiki page:
Power
Under the assumption that the fluid is not moving relative to the currently used reference system, the powerrequired to overcome the aerodynamic drag is given by:

The power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[21] With a doubling of speed the drag (force) quadruples per the formula. Exerting 4 times the force over a fixed distance produces 4 times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, 4 times the work done in half the time requires 8 times the power.


When the fluid is moving relative to the reference system (e.g. a car driving into headwind) the power required to overcome the aerodynamic drag is given by:

Where

is the wind speed and

is the object speed (both relative to ground).

The difference is dependent on the aerodynamics of the car.

If you’re shaped like a brick it may take 8x the power to double your speed.

But the low drag of our cars? It doesn’t.

The calculator I posted takes that into account.

 

[Teslaeata]

See attached

The Welsh have just increased all EV range by double

Just look out for all the horses & carts overtaking you

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