Re: Headlight use effect on MPG?

<putt (AT) webtv (DOT) net> wrote

The wallet-effect(MPG) on a persons vehicle having DRLs illuminated
is
exactly what the man posted....virtually nil.

Boy this would be hard one to prove, but I am willing to take a shot
at a rough estimate:

Say the DRLs consume 40 watts. Assume the average fuel to DRL
conversion efficiency is 25% (and it is not this good). Assume the
average person drives 12,000 miles a year and that 65% of this is at
times when lights are not otherwise required. Assume the average speed
is 35 mph (including highway, town, stop and go). I get the following
results -

Total hours of DRL usage = 12000*.65/35 = 223 hours (could be a lot
more, or somewhat less)

Energy expended by DRLs = 40*223 = 9 kwh (could be half this or twice
this)

Energy consumed to power DRLs = 9 kwh/.25 = 36 kwh = 122,000 BTUs
(range is probably 50,000 to 500,000)

1 gallon of gasoline = 114,000 BTUs

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline. Given today's
price of gasoline, that means drivers are probably paying from $0.30
to $30 per year to run DRLs, not including bulb replacement. So, for
an individual, DRLs are not all that significant. However, there are
over 200,000,000 million cars in the US. If they all had DRLs, that
would mean an annual use of over 200,000,000 gallons of gasoline to
keep the DRLs illuminated. That would be over a half a billion
dollars.

Ed

On Apr 16, 11:12 am, "C. E. White" <cewhi... (AT) removemindspring (DOT) com>
wrote:

p... (AT) webtv (DOT) net> wrote in message

news:12106-4623782C-78 (AT) storefull-3275 (DOT) bay.webtv.net...

The wallet-effect(MPG) on a persons vehicle having DRLs illuminated
is
exactly what the man posted....virtually nil.

Boy this would be hard one to prove, but I am willing to take a shot
at a rough estimate:

Say the DRLs consume 40 watts. Assume the average fuel to DRL
conversion efficiency is 25% (and it is not this good). Assume the
average person drives 12,000 miles a year and that 65% of this is at
times when lights are not otherwise required. Assume the average speed
is 35 mph (including highway, town, stop and go). I get the following
results -

Total hours of DRL usage = 12000*.65/35 = 223 hours (could be a lot
more, or somewhat less)

Energy expended by DRLs = 40*223 = 9 kwh (could be half this or twice
this)

Energy consumed to power DRLs = 9 kwh/.25 = 36 kwh = 122,000 BTUs
(range is probably 50,000 to 500,000)

1 gallon of gasoline = 114,000 BTUs

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline. Given today's
price of gasoline, that means drivers are probably paying from $0.30
to $30 per year to run DRLs, not including bulb replacement. So, for
an individual, DRLs are not all that significant. However, there are
over 200,000,000 million cars in the US. If they all had DRLs, that
would mean an annual use of over 200,000,000 gallons of gasoline to
keep the DRLs illuminated. That would be over a half a billion
dollars.

Ed

Its all a scheme by the




wait for it






illuminati.


Dave

"C. E. White" <cewhite3 (AT) removemindspring (DOT) com> wrote

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.

Ive did the calculations a year or so ago, Ed, and posted them here. My
figures were much
like yours. The consumption is insignificant, especially when compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars, poor
aerodynamics.

HLS (AT) nospam (DOT) nix wrote:

"C. E. White" <cewhite3 (AT) removemindspring (DOT) com> wrote in message
news:462392b0$1 (AT) kcnews01 (DOT) ..

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.

Ive did the calculations a year or so ago, Ed, and posted them here. My
figures were much
like yours. The consumption is insignificant, especially when compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars, poor
aerodynamics.



I believe the NHTSA has gathered figures in the 450,000,000 to

600,000,000 gallons of gas per year in the US IF DRL's were made
mandatory.

Most headlamps are ~55 watts each...so could consume ~110 watts per
vehicle (depending on the configuration, if they're dimmed some, etc.
would be slightly less)

jcr wrote:

HLS (AT) nospam (DOT) nix wrote:
"C. E. White" <cewhite3 (AT) removemindspring (DOT) com> wrote in message
news:462392b0$1 (AT) kcnews01 (DOT) ..

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.

Ive did the calculations a year or so ago, Ed, and posted them here. My
figures were much
like yours. The consumption is insignificant, especially when
compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars,
poor
aerodynamics.



I believe the NHTSA has gathered figures in the 450,000,000 to
600,000,000 gallons of gas per year in the US IF DRL's were made mandatory.

Most headlamps are ~55 watts each...so could consume ~110 watts per
vehicle (depending on the configuration, if they're dimmed some, etc.
would be slightly less)

How could those figures be accurate? You have to take into account the
vast number of folks that use their headlights on full power when they
drive which turns on all the lights, not just the high beams on half
power that most DR's use.

When they don't have to do that, their consumption should drop radically.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain wrote:

How could those figures be accurate? You have to take into account the
vast number of folks that use their headlights on full power when they
drive which turns on all the lights, not just the high beams on half
power that most DR's use.

When they don't have to do that, their consumption should drop radically.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

High-beam DRL's are typically configured to operate at 50% to 60% power
(as you mentioned). Headlamp (or low-beam) DRLs are typically
configured to operate at 80% power to full power and make up the
majority of the configurations out there. (Volvo's and VW's
historically have used full power headlamps as DRLs, BTW). Turn signal
DRLs are always full power (albeit 23 watts each, so a bit more fuel
friendly, but burn out more often).

I don't know what assumptions went into the figures the NHTSA has
collected. Although I personally haven't noticed that many people
driving with marker and tail lights illuminated during the day (maybe
one in twenty at most or less than 5%). Do you see more than one in
twenty running with full lights in the daytime? "Vast numbers" seem to
imply a large percentage (say over half).

jcr wrote:

HLS (AT) nospam (DOT) nix wrote:
"C. E. White" <cewhite3 (AT) removemindspring (DOT) com> wrote...
Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.

The consumption is insignificant, especially when compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars, poor
aerodynamics.

I believe the NHTSA has gathered figures in the 450,000,000 to
600,000,000 gallons of gas per year in the US IF DRL's were made
mandatory.

These clowns can calculate this for light usage, yet they don't do
anything about traffic lights staggered so that every car on the frigging
road spends 50% or more of its time idling?

--
Music hath charms to soothe the savage breast.
That's why stereo has two channels.

clifto wrote:

jcr wrote:
HLS (AT) nospam (DOT) nix wrote:
"C. E. White" <cewhite3 (AT) removemindspring (DOT) com> wrote...
Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.
The consumption is insignificant, especially when compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars, poor
aerodynamics.

I believe the NHTSA has gathered figures in the 450,000,000 to
600,000,000 gallons of gas per year in the US IF DRL's were made
mandatory.

These clowns can calculate this for light usage, yet they don't do
anything about traffic lights staggered so that every car on the frigging
road spends 50% or more of its time idling?

Well, the open docket is for the study of DRL use. So it would stand to

reason that any data collected relating to DRL's use would be part of
that. My guess is that general fuel consumption isn't a safety issue
(one could argue the added pollution causes health issues, I suppose).
In any event, automobile fuel usage falls under the EPA, while auto
safety falls under the NHTSA.

On Apr 17, 5:19 pm, Mike Romain <roma... (AT) sympatico (DOT) ca> wrote:

jcr wrote:
H... (AT) nospam (DOT) nix wrote:
"C. E. White" <cewhi... (AT) removemindspring (DOT) com> wrote in message
news:462392b0$1 (AT) kcnews01 (DOT) ..

Running DRLs for 1 person for one year = 1.1 gallons of gasoline but
the range is probably 0.1 to 10 gallons of gasoline.

Ive did the calculations a year or so ago, Ed, and posted them here. My
figures were much
like yours. The consumption is insignificant, especially when
compared with
some of the
main causes of fuel consumption....high horsepower, large heavy cars,
poor
aerodynamics.

I believe the NHTSA has gathered figures in the 450,000,000 to
600,000,000 gallons of gas per year in the US IF DRL's were made mandatory.

Most headlamps are ~55 watts each...so could consume ~110 watts per
vehicle (depending on the configuration, if they're dimmed some, etc.
would be slightly less)

How could those figures be accurate? You have to take into account the
vast number of folks that use their headlights on full power when they
drive which turns on all the lights, not just the high beams on half
power that most DR's use.

When they don't have to do that, their consumption should drop radically.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)- Hide quoted text -

- Show quoted text -

For those who feel that DRL's are some sort of personal rights issue
then this kind of exercise will provide the justification for
unwiring the DRL connection. If fuel usage is really the issue there
are many other measures that can be taken that will have enough of an
impact in fuel usage that it can actually be measured in daily or
weekly mpg averages.

"clifto" <clifto (AT) gmail (DOT) com> wrote

These clowns can calculate this for light usage, yet they don't do
anything about traffic lights staggered so that every car on the frigging
road spends 50% or more of its time idling?

Good point... I dont believe that the mass of the driving public really
gives much
thought to fuel conservation. If we did, we would plan our trips more
carefully,
walk or ride bikes more, and buy more fuel efficient rides. We might even
carpool.