Daytime running lights waste gas MPG?

[ockey Fartgas]

Judge 4 yourself: http://www.howstuffworks.com/question424.htm

I'm going to try disconnecting the DRL resistor on
my 03 OBW just to see if there's a measurable change
due to less loading down of the alternator.

 

[JohnO]

Judge 4 yourself: http://www.howstuffworks.com/question424.htm

I'm going to try disconnecting the DRL resistor on
my 03 OBW just to see if there's a measurable change
due to less loading down of the alternator.

With the right tools anything is measurable, but for one car is it
meaningful?

The answer: LEDs.

-John O

 

[Mickey]

Judge 4 yourself: http://www.howstuffworks.com/question424.htm

I'm going to try disconnecting the DRL resistor on
my 03 OBW just to see if there's a measurable change
due to less loading down of the alternator.

Measured how? Improved gas mileage, I think not, too many other
variables will more than mask any savings from reduced power requirements.

Normal lights are going to take about 100 watts which is equal to
about 1/7 HP (754w = 1 HP). compared to the other power requirements
this is going to be small stuff.

Mickey

 

[Al]

Measured how? Improved gas mileage, I think not, too many other
variables will more than mask any savings from reduced power requirements.

Normal lights are going to take about 100 watts which is equal to
about 1/7 HP (754w = 1 HP). compared to the other power requirements
this is going to be small stuff.

Mickey

Yeah, until you multiply it by the number of cars on the road times the
number of hours they run.

100W times 10,000,000 cars times 2 hrs per day equals

2000 MWHrs.

It takes a lotta gas fumes to create that. It may be trivial to the
user, but a lot of power is needed to run those DRLs. Imagine the heat
that is captured by the earth's atmosphere.

And I'm sure the numbers are larger than those I used as examples.

BTW, my house's electrical usage was about 600 KWHrs last month. Put
that in perspective.

Al

 

[JD]

Yeah, until you multiply it by the number of cars on the road times the
number of hours they run.

100W times 10,000,000 cars times 2 hrs per day equals

2000 MWHrs.

It takes a lotta gas fumes to create that. It may be trivial to the
user, but a lot of power is needed to run those DRLs. Imagine the heat
that is captured by the earth's atmosphere.

And I'm sure the numbers are larger than those I used as examples.

BTW, my house's electrical usage was about 600 KWHrs last month. Put
that in perspective.

Al

Go ahead and put it in perspective. The DRLs run at 80% of the power of a
full-brilliancy light. If you slow down by 2 or 3 MPH, you'll probably save
more gas than the DRLs will use.

 

[Guy Macon]

Yeah, until you multiply it by the number of cars on the road times the
number of hours they run.

100W times 10,000,000 cars times 2 hrs per day equals

2000 MWHrs.

2 million kilowatt-hours a day, 730 million kilowatt-hours a year?
I think that 4.26 billion kilowatt-hours is a better estimate.
See http://auto.howstuffworks.com/question424.htm

It takes a lotta gas fumes to create that. It may be trivial to the
user, but a lot of power is needed to run those DRLs. Imagine the heat
that is captured by the earth's atmosphere.

Why imagine when we can calculate?

4.26 billion kilowatt-hours per year is 4.26x10^12 Watts/year.

The earth intercepts roughly 7.884x10^20 Watts/year from the sun.

So the total heat that all those daytime running lights are pouring
into the earth's atmosphere is around 0.0000005% of what the sun
pours into the earth's atmosphere.

With the sun pouring out about 1 KW per square meter and a car being
roughly 10 square meters, it would make more sense to increase the
number of white cars by 1% of the total number of cars, thus
reflecting solar energy back into space...

 

[Al]

Go ahead and put it in perspective. The DRLs run at 80% of the power of a
full-brilliancy light. If you slow down by 2 or 3 MPH, you'll probably save
more gas than the DRLs will use.

Not necessarily so. My XKE, which I bought new 34 years ago, gets its
best gas mileage at 3000 RPM; that translates to about 70 MPH.

And no DRL, no airbags, no ABS, no GPS, no PS, no CDs, no nothing but
fun.

And, BTW, never in an accident.

Al

 

[Mickey]

Yeah, until you multiply it by the number of cars on the road times the
number of hours they run.

100W times 10,000,000 cars times 2 hrs per day equals
...
Al

Your info matter little as the original Q was could they measure the
difference in fuel consumption due to this small load. The figure I
gave about power consumption of the headlights amounts to less than 2%
change in load compared to what it take to move a typ car along the
road at 40 mph. Far too many other variables like, grade, wind,
traffic, etc. to measure the difference in fuel consumption by gauging
the fuel usage.

You may feel different.

Mickey

 

[Mickey]

Al wrote:
.....

Not necessarily so. My XKE, which I bought new 34 years ago, gets its
best gas mileage at 3000 RPM; that translates to about 70 MPH.

And no DRL, no airbags, no ABS, no GPS, no PS, no CDs, no nothing but
fun.

And, BTW, never in an accident.

Al

Let's see. Air resistance is the biggest load on needed power to get
from point A to point B. Mathematically speaking, wind resistance is
a cube factor in the total equation to calc power requirements. What
this means is it takes 8x the power to go 70 mph and 35 mph just for
wind resistance. You trying to tell us you had a car that could
produce 8x power on less fuel. Damn, perpetual motion does exist!

Mickey

 

[JohnO]

Not necessarily so. My XKE, which I bought new 34 years ago, gets its

best gas mileage at 3000 RPM; that translates to about 70 MPH.

You may very well get the best power at that speed, but unless you're
driving a torpedo-shaped super-slippery car with a tail wind on sealed
blacktop, I *guarantee* your gas mileage increases as you get near 50 mph.

-John O

 

[Al]

Al wrote:
....

Let's see. Air resistance is the biggest load on needed power to get
from point A to point B. Mathematically speaking, wind resistance is
a cube factor in the total equation to calc power requirements. What
this means is it takes 8x the power to go 70 mph and 35 mph just for
wind resistance. You trying to tell us you had a car that could
produce 8x power on less fuel. Damn, perpetual motion does exist!

Mickey

Well it's been my experience driving it for over 30 years. And did you
ever see an XKE? It is slippery. Check out it's drag coefficient
compared to your standard box, aka Forester.

And I do own an Outback and the Jag gets better gas mileage. I must
admit my wife drives the Outback exclusively.

Al

 

[Guy Macon]

...could they measure the difference in fuel consumption due to
this small load...

...Far too many other variables like, grade, wind, traffic, etc.
to measure the difference in fuel consumption by gauging the
fuel usage.

Those affect *measuring* the difference in fuel consumption, but not
*calculating* the difference in fuel consumption.

http://auto.howstuffworks.com/question424.htm puts it at about
2 gallons a year.

 

[Tom Kelly]

Wanna sell that Jag?

Tom

Not necessarily so. My XKE, which I bought new 34 years ago, gets its
best gas mileage at 3000 RPM; that translates to about 70 MPH.

And no DRL, no airbags, no ABS, no GPS, no PS, no CDs, no nothing but
fun.

And, BTW, never in an accident.

Al

 

[Al]

Wanna sell that Jag?

Tom

Nope, my son is getting it. I'll sign it over to him as soon as he gets
a garage for it. It hasn't gotten wet all over in about 20 yrs.

Al

 

[My News]

But wouldn't it use more gas to push the light emitted as well as the car
through the air?




(for those of little knowledge, this is called a joke)

 

[JohnO]

But wouldn't it use more gas to push the light emitted as well as the car

through the air?

Those photons "grease" the air by generating positive ions, which are parted
more easily.

-John O

 

[My News]

Ahhhh

so therefore running on high beam will be akin to warp drive?
May need to invest in some spot lights.

"I don't think she can take any more Cap'tn"