Actually, if your alternator is in good condition, it only takes 3-5 minutes to recharge a cold cranked battery. I drive nearly EVERYWHERE because where I live it is 110 degrees(F) a huge chunk of the year.

Technically, using your lights DOES lower milage due to the extra load from the engine turning the alternator. But it is so miniscule that it really does not matter. Using your Air Conditioning dwarfs headlight power consumption - shut off your AC first...

My bits,
Landsknecht

PS - Inferior auto technology??? Come on - we burn dinosaurs just as good as you...

Yupp, but you need twice as much dinosaurs to run your cars...

Beside it I definitively agree to what you were saying Landsknecht!

BTW, ''Landsknecht doesn''t sound very english...

An alternator is a generator. It takes rotational mechanical energy produced by the engine, and turns a set of magnets that induce an electrical current in a coil of wires. The electrical current is potential energy, which can be used for a number of things. The primary reason for an alternator is to recharge the battery (which stores this electrical energy in the form of a chemical reaction). Now, if the battery is fully charged, then this potential energy goes to waste as heat. If the lights are on, then it will go to the lights, and some of the potential energy will be sent through a high-ohm resistor that heats up and emits light, draining some of this potential energy. If the amount of potential energy consumed by the lights is less than the amount of potential energy being produced by the alternator, then there is no increased load, and therefore no extra fuel consumed because of conservation of energy. If instead the air conditioner is on, which consumes more potential energy than is usually supplied by the alternator, then you have an increased load, and more fuel is consumed.

My input on this is:


Screw that, drive a bike. I dont know how you guys like to debate on car energy, but I have enough trouble debating my 12 times tables. So I will just get the heck outta here.

"I''''ve sparred with creatures from the nine hells themselves... I barely plan on breaking a sweat here, today."~Drizzt Do''''Urden

TANSTAAFL, this is true for the old DC alternators, but nowadays, maybe not in the USA , cars have a three-phase current alternator that uses several static coils and one rotating anchor to produce electricity. This way you don''t need any permanent magnets and the control can regulate the power output from zero to max power. This way you don''t need any resistor burning your energy overproduction, cause there is none.
BTW such a resistor would emit very little to no light, but mostly heat (yea you could call this also light...).
And yes, switching on the lights will drain more power from your cars power net -> regulator increases alternators power-production -> alternator needs more mechanical energy -> motor needs more gas in order to keep its RPM/speed.
Hope this was understandable

Yesterday we still stood at the verge of the abyss,
today we''re a step onward!

quote:Original post by kirkd
TANSTAAFL,

So we're back to the original question. Does increased electrical demand lead to increased load on the alternator? That is the fundamental quesion. Obviously the air conditioner has other issues including running the compressor unit which imposes a significant load and decreases fuel efficiency. But, something as simple as the radio, the lights, etc - is there any increased load?

TM: Not interested? Don't read.


-Kirk

Well being able to switch on the headlight without running the engine answer this question ??

This is tough to explain - In my car I can put in the key and give a turn. That puts a light on - then i can switch on any lights. When I turn the key a little more the actual ignition take place. So headlights and gas don't come into the contact at all. Its always the battery and headlight. So there is no load from the headlight on the motor I suppose thats how its to be said so there should be literally no effect on mileage due to headlights.





Edited by - flame_warrior on August 30, 2001 4:30:12 PM

And where is the power from the battery from? Yes right from the alternator which is attached to the motor!
And what difference does it make when the lights are directly attached to the battery? The alternator is attached to the battery too, so it DOES affect the load on the alternator and by this also the milage!


Yesterday we still stood at the verge of the abyss,
today we''re a step onward!