Headlights

[soko]

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746 watts is one horsepower. One 100watt light bulb is ~1/8HP at100% efficiency. A REALLY efficient motor/generator is in the 75% range. So find the average watts of a car headlight (google) and alternator efficiancy, then the HP/gallon of gas in an avergae car and you have the actual savings

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I read a report off google that said headlights can reduce MPG by 10%, yikes.

[FredBoots]

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I read a report off google that said headlights can reduce MPG by 10%, yikes.

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I think it is less than 1 mpg.

The answer to problems like this lie in the "Conservation of Energy". You can't get something for nothing, so the headlights MUST use gas.

For example, in California, they put up these fans along the freeway that took the wind created from the cars and generated electricity. They had to remove them because people noticed the mpg of their cars went down.

[vhawk01]

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I read a report off google that said headlights can reduce MPG by 10%, yikes.

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I think it is less than 1 mpg.

The answer to problems like this lie in the "Conservation of Energy". You can't get something for nothing, so the headlights MUST use gas.

For example, in California, they put up these fans along the freeway that took the wind created from the cars and generated electricity. They had to remove them because people noticed the mpg of their cars went down.

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A less obvious and more clever solution is there are these new "speed bumps" that convert the energy of your car, via a turbine, into electricity. Obviously, this will take away from your cars momentum, but they put them near intersections, where you waste a ton of your energy by braking anyway. I thought that was clever.

[CORed]

For any generator, including a car alternator, the torque, and therefore the power, required to turn it at a given speed increases as more current is drawn. Therefor, turning the headlights on probably does have some impact on fuel economy. OTOH, the power used by the headlights is pretty small relative to the power needed to move the car, so I think the impact is pretty small.

[CORed]

The voltage regulator does not change the speed of the alternator. The alternator is driven by a belt and operates at a fixed ratio (depending on the size of the pulleys) to the engine speed. The voltage regulator works by changing the amount of current running through the field winding (rotor) of the alternator, and keeps the alternator running at ~14V on a car with a 12 V battery.

[CORed]

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A less obvious and more clever solution is there are these new "speed bumps" that convert the energy of your car, via a turbine, into electricity. Obviously, this will take away from your cars momentum, but they put them near intersections, where you waste a ton of your energy by braking anyway. I thought that was clever.

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In conventional cars, braking wastes energy (by converting kinetic energy to heat). Hybrids and electric cars use regenerative braking, so some of the kinetic energy gets put back into the battery. So these "speed bumgs" are making use of energy that would otherwise be wasted for conventional cars, but stealing energy from hybrids and electrics.

[vhawk01]

[ QUOTE ]
[ QUOTE ]
A less obvious and more clever solution is there are these new "speed bumps" that convert the energy of your car, via a turbine, into electricity. Obviously, this will take away from your cars momentum, but they put them near intersections, where you waste a ton of your energy by braking anyway. I thought that was clever.

[/ QUOTE ]

In conventional cars, braking wastes energy (by converting kinetic energy to heat). Hybrids and electric cars use regenerative braking, so some of the kinetic energy gets put back into the battery. So these "speed bumgs" are making use of energy that would otherwise be wasted for conventional cars, but stealing energy from hybrids and electrics.

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I know jack about cars. I did not know this. Thanks.