Comments on: DAYTIME RUNNING LIGHTS

By: Teri

Teri — Wed, 31 Dec 1969 18:00:00 +0000

How would GM benefit by increasing fuel consumption? Is there some conspiracy whereby all GM executives or shareholders are also oil investors?

I would think that it would be to GM's benefit to REDUCE gas consumption, because even the tiniest nth of a teaspoon would adversely affect their CAFE averages. So, in other words, it seems silly to claim that GM is deliberately increasing fuel consumption.

By: James Joyner

James Joyner — Wed, 31 Dec 1969 18:00:00 +0000

Yeah, that puzzles me, too. I don't know if GM also owns fuel interests.

By: Fred Boness

Fred Boness — Wed, 31 Dec 1969 18:00:00 +0000

Any load on the alternator is a load on the engine driving the alternator. So, yes, any extra electrical load burns more gas.

My own opinion is that when a few cars have running lights they will stand out but, when all cars have these lights it is just more noise in the driving environment.

By: joy

joy — Wed, 31 Dec 1969 18:00:00 +0000

I actually burn my lights on my non-GM jeep during the day even though I have to pull the control myself.

I think that cars with lights are easier to see.

By: Kate

Kate — Wed, 31 Dec 1969 18:00:00 +0000

We've had a "lights on for life" campaign here for years, and now new vehicles are mandated to have running lights.

Having everyone put them on does not create more "noise", but it does put those who do not have them on at a distinct visual disdvantage. When you notice how much, it tends to make you reach down and put your own lights on.

Kate

By: James Joyner

James Joyner — Wed, 31 Dec 1969 18:00:00 +0000

I tend to run my lights, including fog lights, most of the time as well. I figure it can't hurt.

By: jen

jen — Wed, 31 Dec 1969 18:00:00 +0000

My Toyota has DRLs. I love the feature - mostly because the bonus is that when it's dark the regular lights automatically trigger on. I never have to touch that lever unless it's for the turn signal.

By: Fred Boness

Fred Boness — Wed, 31 Dec 1969 18:00:00 +0000

During WWII there was a camoflage scheme called Yehudi. (For you younguns, Yehudi is the little guy who turns on the light when you open the refrigerator door.)

Patrol bombers hunting subs in the North Atlantic could be seen a long way off. Yehudi hid the bombers in the background sky light.

It works like this: there was a row of lights along the leading edge of the wings and around the nose of the plane. The brightness of the lights was controlled by a rheostat to match the brightness of the sky. The bomber would blend into the background and could get a lot closer before being spotted.

So, you drive with your lights on all the time? Does that include when you are driving out of the sunset? A motorcycle can disappear completely under those circumstances.

By: Sam

Sam — Wed, 31 Dec 1969 18:00:00 +0000

I'd guess that running lights all the time may increase fuel consumption a bit, but it may be down in the noise. The alternator is basically always charging the battery, when the battery is at or near full capacity, almost all of the charging power gets turned into heat. With DRL, some of it gets diverted to powering the lights, but probably almost all of it would have been turned into heat anyway.
I'd believe that DRL would reduce the lifetime of the lights.

By: Bill

Bill — Wed, 31 Dec 1969 18:00:00 +0000

The batteries only use is to start the engine. After the engine is started, the alternator supplies the electrical power, e.g, keeping the battery charged and running all the other electrical doodads. The more doodads in use requires the alternator to work harder,which in turn puts a heavier load on the engine. Therefore gas consumption increases.
My car has had two headlight bulbs burnout in 80,000 miles(oddly enought it always the right side bulb.) To me,always on headlights are a waste of watts. This "feature" was useful when they first appeared, but now (from experience)they are mainly ignored by other drivers.

By: Director Mitch

Director Mitch — Wed, 31 Dec 1969 18:00:00 +0000

Keep in mind that power consumption from lights will be reduced to less than 10% of what they are today with the introduction of Light Emitting Diode (LED) headlights.

LEDs are already used on all new traffic lights in the U.S, saving replacement and electricity costs (look at the next stop-light you are at and see that it is made of a bunch of smaller lights - these are the LEDs). In cars, LED headlights can already be found in the very high end. In five years or so, LED headlamps will become standard features, meaning you will probably not need to replace them during the normal life of your car and electrical consumption for this component will go down.

Ofcourse, total electronic use inside cars is dramatically increasing - GPS, airbags, ABS, etc. - making headlight power decreases sort of meaningless. Essentially the car is turning from a hydrolic-mechanical device into an electrical device, with "concept cars" being all electrical systems (so called "drive by wire").

Eh, I guess I should do a posting on this - I wrote a 50 page paper on this six months ago...

By: Anonymous

Anonymous — Wed, 31 Dec 1969 18:00:00 +0000

> My Toyota has DRLs. I love the feature - mostly because the bonus is that when it's dark the regular lights automatically trigger on. I never have to touch that lever unless it's for the turn signal.

Jen, better take a second look. While Toyota's may be different - most cars with DRL are headlights only - meaning, tail lights only come on with the manual switch.

> It works like this: there was a row of lights along the leading edge of the wings and around the nose of the plane. The brightness of the lights was controlled by a rheostat to match the brightness of the sky. The bomber would blend into the background and could get a lot closer before being spotted.

> So, you drive with your lights on all the time? Does that include when you are driving out of the sunset? A motorcycle can disappear completely under those circumstances.

I own a motorcycle. They all have running lights, and believe me, if your bike has left the ground in the manner you describe, the last thing you have to worry about is being seen by opposing traffic.

Kate.

By: Fred Boness

Fred Boness — Wed, 31 Dec 1969 18:00:00 +0000

Uh, that's wheels on the road driving out of the sunset. I owned motorcycles for years and discovered the disappear in the sunset effect more than thirty years ago when Wisconsin adopted a headlights on law for motorcycles ("safety" you know). People would turn in front of me like they didn't see me and well, they didn't.

By: Paul

Paul — Wed, 31 Dec 1969 18:00:00 +0000

WRONG WRONG WRONG WRONG

How can an alternator work harder? The alternator spins at the same rate off the engine no matter the load. There is no clutch or variable gear ratio, it is a fixed drive. The load on the engine will only change as a function of RPM.

I have no idea who at GM would claim it burns 10 bucks a fuel a year. Not an engineer for sure.

As another commenter said, it would just become heat.

The only way you could POSSIBLY make the case is if GM had to install a bigger alternator to handle the extra load. That is patently silly. At best they they use 20 watts of power. A typical alternator is making 720 watts of power at 35mph.

If you actually believe it burns gas then wouldn't your stereo burn more gas considering in a modern car they are about 40 watts.

Have ya ever heard someone say to turn down the radio to get better milage?

geeze.

By: Bill

Bill — Wed, 31 Dec 1969 18:00:00 +0000

Of course the alternator runs at some ratio of drive pulley sizes

Manufactors have installed higher capacity alternators to handle increased loads of computers, high energy ignition systems, more powerfull radios,etc. Typical alternators can generate over 900 watts in current cars.

A stereo can put out a claimed 40 watts, but it may take 100 watts to generate that 40 watts.
The missing 60 watts is heat-ever notice the large heatsinks on the high power radios and computer CPUs. I would not be surprised if the various computers did not use 200-300 watts. The ignition might use another 100-200 watts. the headlights and running lights another 150+ watts.

When all this stuff is running the alternator has to work harder to satisty the load.What makes it
work harder is back EMF (electomagnetic force)--there ain't no free lunch. The more demand on a alternator (regardless of speed) the higher the back EMF, which means more work to maintain the load, which makes the engine work harder.

Yes, you do use more gas playing the radio, the amount would be miniscule.

When I was in the service, we had a field radio powered by a hand cranked generator. When the radio was in receive mode-it has very easy to turn the crank. But when it was transmitting it was a bear to turn due to higher power demands and increased back EMF at the same cranking speed as when receiving.