If my car stands on neutral and I turn on lights do I use more gas when lights on?

Question

I want to know if I waste energy (gas) when I turn on lights in my car.

Answer 1

All the lights on a normal car consume about 50W
This comes from the battery. So as the lights run..the battery vooltage drops and then the alternator must charge it to it's nominal voltage of 13.8V
The short answer is Yes..because the alternator is driven off the engine accessory belt and the increase load will cause a VERY SLIGHT rise in fuel consumption...but you'd need pretty precise fuel flow meters to pick it up.

Answer 2

If you leave your lights on with the engine off, the battery will die and the lights will go out. Clearly that would never happen while the engine is operating at idle or any other higher speed. Except for the energy already within a fully charged battery when you buy and install it, all energy used by the car comes from the gas it burns in the engine. When the car is idling, turning the lights on is detected by the voltage regulator that provides energy to the lights using the battery and then from the generator (or alternator) if voltage gets too low. The energy drain from lights is relatively small and not a waste of energy (or gas) if you need the lights. That said, you can save gas by not idling too long at one time, perhaps shut the engine off if you are going to park for more than three minutes.

Answer 3

Yes, your car will use more gasoline when idling (sitting still in nuetral) with the lights on than it would with the lights off. Your cars engine actually charges the car battery and provides electrical energy for the other components. The generator is most often belt driven along with several other components. With the lights on, the generator puts more of a load on the engine when it generates electricity.

Now, the increase in consumption is actually quite small, something that you would not even likely notice over a tank full of gas. Probably something like an extra 15 cents of gasoline.

Running the airconditioning tends to use much more gasoline than the lights will. However, at highway speeds, the extra drag generated by rolling your windows down will generally cost more gasoline than running the AC.

Don't try to save a few cents and operate your vehicle without your lights on when you need them. Lights are a safety feature and should not be compromised to save a few cents (if that). One accident that your lights may have prevented would quickly cost you more than the few cents of gasoline that you might save.

Finally, there is an interesting argument about electric cars. Many are buying them as environmentally friendly, when in fact the electricity they consume comes from power plants. I'd be curious to compare what the total net savings in environmental impact would be. Remember, nothing in life is free.

Answer 4

This is not a simple 'yes' or 'no' question.

As pointed out above, the lights use electrical energy and not gas, and the electricity is produced by the generator (usually an alternator). The law of conservation of energy will ensure that you don't get electricity to run the lights for free.

If you are idling in neutral, your question on whether you use more gas or not depends if your car is carbureted or fuel injected (and assuming you have a conventional internal combustion piston gasoline engine with an alternator that charges a battery).

An engine with a carburetor will indeed slow down a little due to the increased engine load from the alternator as the lights draw electrical current from the battery. However, since the air/fuel flow is regulated by a fixed butterfly valve setting in the carburetor, the fuel consumption is constant. As the load on the engine is increased, the engine will just continue to lose RPM until it stalls, unless more air/fuel is added. Therefore the fuel consumption of an engine with a carburetor is not affected by turning on the lights.

A fuel injected engine (at least a modern one) has an RPM sensor that will automatically maintain RPM to the most efficient level as the engine load increases and decreases. Therefore an engine with a fuel injection system will burn more fuel with the lights on at idle, as compared to the lights off at idle.

The vast majority of the fuel used in an idling engine is used for compression, to exhaust the burned air/fuel mixture, to move the reciprocating and rotating internal engine components such as cams and pistons, and to overcome friction. The amount of extra fuel used by turning on the lights will not be measurable except by very specialized instrumentation.

For a car in motion, the extra fuel used by the lights becomes proportionately even less, as the internal friction of the engine increases with RPM, and the moving car needs energy from the engine to overcome the physics of moving its mass, rotating the wheels, overcoming drivetrain/axle/tire friction, and the aerodynamic drag, etc. I would think the extra safety of driving with your lights on (as opposed to the parking lights) far outweighs the few pennies per year of extra fuel consumption. In Sweden and Canada, it has been proven that cars using headlights in the middle of the day are involved in less accidents than cars that don't, and those countries have made it mandatory to use headlights all the time.

Answer 5

The answer is a resounding YES. The lights require energy, and that energy will come from the battery or alternator. If the engine RPM is at idle, the energy will come from the battery. But the battery then must be recharged when you begin to drive which takes energy from the gas. Unless your car is solar powered, we do not get energy for nothing.

Answer 6

Yes...but not noticably much.

Any vehicle's electrical system has a battery and while it's true this powers the lights (and stereo, etc...) this battery has to be charged from somewhere.

The charge is from the alternator - which is driven by a belt from the engine.

Of course...when more load is placed on the electrical system (say, through lights) - its natural that the alternator will work harder to ensure that the system remains charged.

To do so...it places more strain or load on the engine - which has to also work (slightly) harder - with more fuel required.

However...the actual amounts are not particularly noticable - they are more so with sustained airconditioner use.

Answer 7

Yes, only if you don't charge the battery from the charger in the garage.Ultimately, all energy source in a car is the gas.

Answer 8

lights come on with the battery not the gas. but if u r parked for a long time it is always safer to put it on park and turn the lights off other wise ur batteries will go dead

Answer 9

The 50 watts that your headlights use is equivalent to 0.067 horsepower. Your engine is already making about 1hp idling, so the additional energy usage is negligible. If you're concerned about wasting energy, turn off your engine instead of letting it idle.

Answer 10

No, the lights are powered by your battery, not the gas.