| sd |
Today’s tip will hopefully help you save a bit of money on your car’s gas as well as help your headlights last a little bit longer.
Don’t use your headlights when it’s sunny out.
I got this idea from an article on HowStuffWorks.com, which was about how much gas Americans would waste per year if the Government required all new cars to utilize daytime running lights. According to the article, if every car on the road had daytime running lights, we (Americans) would waste over 406 MILLION GALLONS OF GAS each year!
With gas being roughly $3 per gallon, that would be a loss of over $1 Billion.
While I’m not going to go into how exactly the people at HowStuffWorks.com went about calculating how much gas would be wasted, the logic behind their numbers certainly makes plenty of sense.
With that being said, if you don’t want to add to the amount of gas wasted each year, I would strongly recommend keeping your headlights off during the day, unless it’s raining, you’re driving through a tunnel, etc., or it makes you feel safer to use your headlights all the time.
I certainly don’t think that the savings will amount to much for each individual driver (on average, it’s probably less than $10 per year), but like I’ve said many times before, all those little savings will add up to hundreds or thousands of dollars each year.
{ 24 comments… read them below or add one }
I don’t use my headlights when it’s sunny out, but if that sun goes behind a cloud for two seconds, my headlights are ON. It’s more that I want people to see ME, rather then me being able to see them. That’s just me being over-cautious I guess. If the sun comes back out, my headlights go off. Better safe than sorry, I say.
I think that’s a valid point, but at the same time, it’s not like it becomes DARK out when it’s cloudy.
True, but there is diminished (to a point)sunlight. Like I said, better safe than sorry.
Visibility > Savings. Savings mean nothing if some guy in a guzzling SUV barrels through your small, gray/silver hatchback on a cloudy day, killing you (okay, the gas you would have used in the future is now saved, maybe that’s what this article was getting at..). Treat everyone else on the road as if they’re blind, as they invariably seem to be. There are safer ways to conserve gas.
I don’t remember what television program I saw it on, but I remember a few years back I was watching a show and they were explaining how daytime running lights just add to the distractions and something with the way your brain interprets data, actually making it harder to see the other cars on the road if they all had daytime running lights.
I know this sounds like boggled up nonsense the way I explained it, but it made sense on the program.
I find having lights on all the time to be an advantage. I know for a fact that when on a bicycle, with the small rear view mirror on my helmet, cars coming up behind me are MUCH easier to see if they have their lights on. I suspect the TV program you saw had an agenda they were pushing.
I’m pretty sure this is complete horseshit because they make a simple error: thinking that the engine has to run harder to produce more electricity for the lights. That’s wrong. The engine charges up the battery all the time anyway with the alternator. There is no feedback loop that makes the engine rev harder whether or not the lights are on, and the amount of charge produced all the time anyway is plenty to light the headlights.
I could be totally wrong about this but I’m pretty sure I’m not, and having checked a few sources I’m confident that these guys don’t know their ass from a hole in the ground.
I think the concept is that electrical use causes the alternator to work harder, as it’s spinning under a stronger load. It’s a pretty small amount compared to the overall load on the engine though. Tire pressure, synthetic oil changes, clean spark plugs, cleaning out junk weight, shifting earlier, neutral coasting, etc all provide mpg boosts well above the electrical load increase on the alternator.
Retsudo: Both you and your sources are wrong, period. This issue is not open for opinions. The sience and facts are well established since well over 100 years now.
This is the case easy explained. An alternator is basically the same thing as an electric motor. The motor develop a higher output when fed with more electricity whereas the alternator will increase its resistance when you take out more electricity out of it. This is very clear since all cars drop in revs and you clearly can hear the increased workload on the engine when for example the electric cooling fan goes on.
The additional turning force on the alternator required to keep two 55w bulbs is exactly 55 x 2 watts. Nothing less and nothing more. The alternator of course doesn’t give 100% without loss but the losses from the belt and bearings and so fourth is already payed for since it’s there anyway. What I’m talking about is the ADDITIONAL force. 110W exactly.
The battery doesn’t do anything in this formula except smoothen things out a little but it doesn’t produce electricity by itself so it doesn’t help.
Now, how much gas is that? There are just as many answers as there are cars but a rough calculation could look like this. An average car could easily maintain a highway speed on a flat surface using around 40Kw (54HP). It could probably do that using up 0.6 liters in 10 kilometers. 100w / 40000w = 0.0025.
That is 0.25%
So if you drive 20000Km a year you will at best use up only 1200 liters of fuel.
1200 x 0.0025 = 3 liters. Those light bulbs will use up 3 liters which of course isn’t very much. But, if you took these 3 liters multiplied to millions of cars each year the amount of gas would be enourmous.
I’m sorry for using kilowatts, kilometers, liters and so fourth but I’m from sweden and all that gallon, miles, inches and feet stuff doesn’t mean anything to me.
i think that the battery does a little more than just smoothen out the current. It is a capacitor, yes, but a very big one that can deliver a lot of charge very quickly when needed, and while your statement about the alternator is true, in modern vehicles the over-sized alternator / battery combination really masks any increased load so it is almost imperceptible to the engine. So I really do not think your vehicle will burn any extra petrol just because you drive with your lights on all the time
I’m still a little confused by this. In traditional cars, alternators have a static ability. They produce electricity regardless of wether it’s used or not. It cannot ask for any more power and cant give any unused power back.
Is this still the case for newer cars or do they have fancy gadgets that can increase, decrease the laod on an alternator and thus reduce, increase it efficiency?
If so, this could be were the confusion lays.
Ok guys, numerous studies show dramatically decreased accident rates when compulsory daytime running light laws are enacted. Average about 20% accident reduction. Looking at the fact that over 42,000 Americans die annually, this would potentially save approximately 8,400 American lives every year.
And regardless of the fact that this would cost one billion dollars in gas, please don’t try to tell me that 8,400 lives are not worth 1 billion dollars. That’s 1/515th of our defense budget, which arguably is not saving any lives.
The point of turning on lights during the day isn’t to see better; it’s to make others see you better. It creates a starker contrast between car and background. Try to notice cars with & without headlights on during the day. you’ll find the ones with headlights on are significantly easier to immediately recognize. and considering the average driver spends only a tiny fraction of a second looking up and down a street before turning onto it, this extra visibility could really help.
at least, those are my thoughts. let me know what you think.
on my car the headlights are on all the time? I can’t shut them off so I can’t help.
ESPECIALLY when it’s sunny out you should be using your headlights. No matter what… keep them on!
If a driver is oncoming while the sun is behind you (VERY common in the mornings/evening), if you don’t have your headlights on, THEY CANNOT SEE YOU.
Run your headlights all the time. Daytime running lights are OK, but unfortunately many people assume that they’re the same as their headlights and use them at night as well (!).
You don’t get something for nothing. Burn the
lights, pay for it. Lights in day time not much
if any safer. It just distracts and makes the
other cars harder to see.
Bowen, you are an idiot. How would having lights on make a car harder to see? And if you are that easily distracted by headlights, please get off the road. We don’t want you there.
Just because someone prints something and ads their rational to something doesn’t make it true. The physics behind elecrical generation in a car are fundamental. Driving with your headlights on will not increase your fuel consumption one iota. Any mechanic or auto engineer knows that the generator or alternator turns in direct relationship to the speed of the cars motor. A fast moving motor will drive an alternator or generator at a higher speed. Thirty years ago an idling motor with a generator would produce just enough current to keep headlights lit. However, today when we design alternators and balance them with a battery we ensure that the electric load being drawn from the battery is less than that being generated by the alternator. In short when we drive our car it is always generating far more current than we need. The speed of the motor does not change when we turn our head lights on. The only time someone will experience a change in motor speed due to electrical current load is at idle, and not when driving the car. We design electrical generators to generate way in excess of the amount being drawn by a load such as headlights from a battery. If this wasn’t the case we would find we had a flat battery at the end of our journey and would be unable to start our car. Even then it wouldn’t increase the load on the motor cars engine.
Hey Trevor,
I’m an electronics engineer and lights use energy. That energy has to come from somewhere, and the only energy input to the car is from fuel. If the battery supplied the energy it would go flat pretty quickly. Try leaving the lights on with the engine off and see what happens.
Trévor you are completely wrong.
You say “The speed of the motor does not change when we turn our head lights on”
The speed of the motor might not change, but the load on it does.
This is a basic law of physics, “Energy can not be created nor destroyed, it can only be converted”
So if the only energy we put in cars is in the form of gasoline, then everything, ABSOLUTELY everything in the car is powered by this gasoline. It may account to trivial amounts of gasoline, perhaps a few gallons per year, but gasoline in fact powers everything in your car, even the tiny LED on your dashboard.
Alejandro, the alternator wastes so much power that what would be an increased load on the engine simply becomes just a smaller power loss by the alternator. So when you turn your lights on the current tthat would otherwise be wasted goes to the battery and the lights and everything else connected. when you turn your cars lights on you are choosing to lose electric power through the light bulbs and not throu the alternator. So I’m afraid that driving with your lights on will cost you nothing extra in petrol but only in a few more burnt-up light bulbs.
The alternator puts the same load on the engine whether you are using the power it is outputting or not, turning off you lights will not do anything to save your fuel mileage.
I really don’t understand where people get the notion that by using electric devices in their vehicles, they are using more gasoline. The gasoline will be used whether the devices are provided with power or not, the load from the alternator doesn’t change.
Save $10 a year in gas, raise your risk of dying. I will pay my $10 per year and then some if necessary.
Lights on day and night.
I agree, people don’t realize it’s not about being able to see, its about others being able to see you. When I drive my car, people have a terrible habit of not noticing me, either because the car is small or silver and blends in with the road.
Either way, “Lights on for safety!” is my motto.
Also, I really don’t understand how they figure that using less electricity in your car will use less gas, it’s not like the alternator is harder to turn when you are using more energy, its the same whether you are drawing all the amps it can output, or none at all. Seems like a marketing ploy to me.
Daytime running lights make it harder to see those who do not have daytime running lights on. So the possibility that using daytime running lights increases accidents needs to be quantified. Furthermore, if every vehicle on the road were to have daytime running lights on, would we see the accident rate be the same as if they all were off?
With gas a $4.00 per gallon in the US, the savings is likely more than $10 per year. And for ‘Rafal’ he does not understand basic mechanics nor physics. Energy is not ‘free’. Turn on all headlights, crank a radio with a lot of base, and plug in a device into the cigarette lighter. You will see that the engine runs hard to power these devices, because of the extra load the alternator.
Look at the battery / alternator required for those who use massive steroes. If electricity were free (and was not converted from gas) then these specialized sound vehicles would not need to modify the size of their alternator.
If we quit looking at this from a single car POV, and begin looking at this from a global view, everyone running with their daytime lights on is wasting significant amounts of fossil fuels, polluting our atmosphere, and making our air harder to breathe.