[reignofchaos]

The IIHS headlight study is a good scientific starting point for measuring headlight quality.

http://www.iihs.org/iihs/news/deskto...rginal-or-poor

[ashis89]

One of the best projector headlights that I can remember is that of first gen Laura. They were bright yellowish , well focused and had a nice cut off. Today, the lights with bluish hue drown in the flood of other lights.

https://youtu.be/hlSfZUW2lxs

Just wondering, how effective would the LED/HID be in such a case?

This is my WagonR which has Rally 100/90 bulbs. If you look closely the light is already whitish and hence less effective. There was a Xylo ahead of me that day whose lights were more yellow and seemed more effective. The Elite i20 with projectors was blindly tailgating both of us.

Originally Posted by autospeaker

But one thing for sure. Flashing these lights will definitely catch the attention of the driver in front of you and repeatedly doing so may even irritate him.

This is because of sharp cut off of the projectors. And the flash looks beautiful, creating a day/night simulation.

[Ricci]

It seems people expect projectors to magically improve illumination - they're not meant for that. Projectors are meant to produce sharp cut offs, to reduce glare and allow light only inside the desired shape/profile. Projectors also have reflectors with gather and focus the light, which is then defined by a shade/shield which defines the shape of the beam. Our office projectors are a good example - a rectangular frame of light which would otherwise be a broader spotlight. Good lighting is most dependent on a well designed reflector. Remember the Pulsar 220 - it has a projector for low beam, but the high beam is not and the high beam is one of the few beams on motorcycles that rivals cars. In fact, I think projectors waste/block a lot of light produced by the bulb ; the Pulsar 220 low beam is only a little better than a Karizma (old model with single headlight) low beam - I know because I've used both for 5 and 10 years.

The differences type of luminescent in terms of physics principle (black body radiation for halogen/incadescent vs electroluminscence for HID and LED ) are what cause the colour temperature to differ among them.
Incandescent bulbs seem inefficient to you - that's because we can't see in the infrared spectrum. Bulbs emit light in continuous frequencies, from infra-red to UV , most of the energy, ~90% is in fact concentrated in the infra-red band emission - which we can't see. If we could see in IR, all of us would unanimously prefer incandescent bulbs over LED and HID.

Incandescent bulbs emit across the spectrum, but less lumens for each wavelength/frequency band. For example, of 2000 lumens in the visible range, 300 lumens red, 300 lumens orange, 400 lumens yellow, 350 lumens green , 400 lumens blue , 250 lumens violent - all add up to 2000 lumens. Our eyes can see best in yellow-green and red-yellow range, where we have the most cones.
HID and LEDs have more selective spectral emissions. The color temperature of HID depends on the gas used, which upon excitement by electrical stimulation, responds by emitting packets or quanta of light in certain wavelengths , a sodium vapour emits characteristic orange glow, while mercury emits its chracteristic bluish white light - that's its chemistry and it can only emit in that narrow frequency band.

Likewise, LEDs too have selective wavelength - the electrical energy that stimulates the electrons of photoluminescent materials exits only in certain quanta, which depending on type emits a different color/wavelength, which is even narrower a band than HID. Now, the regular world is made up of varied materials, which absord most of the incident light and reflect back only small part of it (which is essentially why we see colors), this also means most of the light we throw is lost, absorbed and only a small fraction is useful as it returns to the eyes. Now let's say material A absorbs all light but reflects yellow, material B absorbs all light except reflecting blue, material C absorbs all light except returning red, material D absorbs all light except reflecting back green. So you're throwing spectrum materials A, C and D do not reflect.

Now with halogens, you're bound to get some light reflect back from some of various objects upon which the light is incident - less light of each wavelength , but you'll get a definite strong reflection from some part of spectrum and the halogen/incandescent throws a lot of wavelengths at everything. So even though most light is absorbed, some is reflected back helping you see. With HID/LED, that light thrown in of a narrow band of frequencies, with the bulk of it in the blue end. So objects like material A , C and D have little of their reflective frequencies to send back to you. While signboards and such reflective luminescent are designed to reflect light in the wavelengths we see (halogens also light these up well, but they're especially highlighted in LED/HID light), the rest of the world is not so conducive.

Go back to that sodium vapour street light -it's very bright when you look at it directly, but it shows little of the world. That's because it's emitting such a narrow band of wavelengths, most of it is not reflected but absorbed by whatever it's incident. You can't tell colors well in this light, that is what is meant by CRI - color rendering index, which is great rather best for natural light which has the widest spectrum.

Add to that, higher frequency radiation scatters more , especially in the presence of particulate matter - such as moisture, smoke, dust, making LED and HID more ineffective.
We're fooled by the immediate bright spot in front of us, in close proximity to the vehicle in demos, but what we need is less bright immediate proximity and more light focused at a distance, with say 90% of the light spread from 25-100 meters ahead, only 10% from 0-25 meters in front of use.
Too bright light focus in the immediate foreground also forces our pupils to contract, further reducing light entering the retina.

About why even the otherwise superbright LEDs seem inadequate in the face of oncoming traffic (with high beams), I've written about this earlier here :
http://www.team-bhp.com/forum/motorb...ml#post4160131


As for why wet conditions reduce the visibility, it's to do with increased internal/random reflection cause by the water film on wet surfaces. Ever see more strong reflections in water puddles or even on wet roads caused by lights of other vehicles , that you don't see as strong when the road is dry? That's because even less of the light from his headlights is reflecting back at him. Read more about this here :
https://www.victoria.ac.nz/scps/abou...kerwhenwet.pdf

[AShubrah]

Originally Posted by H_Dogg72

My Mamu has the Crysta. And I find low beam good, but since it's not bi-led the high beam is really lacking.

I too find the high beam on my Innova Crysta quite lacking when compared to the similar halogen high beams on my XUV 5OO. They aren’t effective in penetrating through the darkness to light up distant objects.
Thus, I’m thinking of going to HID way like fellow BHPian Lego28 did with his Innova Crysta.
Can other gurus please shed some light (pun intended) on this topic & help me out?

[H_Dogg72]

Originally Posted by AShubrah

I too find the high beam on my Innova Crysta quite lacking when compared to the similar halogen high beams on my XUV 5OO. They aren’t effective in penetrating through the darkness to light up distant objects.
Thus, I’m thinking of going to HID way like fellow BHPian Lego28 did with his Innova Crysta.
Can other gurus please shed some light (pun intended) on this topic & help me out?

HID for flashing not really a good option.
Maybe an LED bulb instead.
But if I'll be honest, I'm not completely sold on how good LED'S are in reflectors.
Maybe go to a shop and check in person how the LED bulb performs before buying it. HID in reflector I simply would not recommend.
I burnt my hands buying a Philips H7 HID kit that said it'll work perfectly in reflectors. Ended up getting proper bi xeons.

[Rahul Rao]

In early 90's my dad had a Contessa wth 4 lamp headlights. Outer ones were H4 with Philips 100/90 where as inners were H3 which lit up with the high only.
I haven't seen any current car that lights up the road the way that combo did.

Originally Posted by PrideRed

Another related query I have is w.r.to output. While 55/60W is legal output for Halogens, Is there something similar for HID’s/LED’s? I know they need much lesser power to generate similar output as halogens, but the intensities vary across cars. And what about number of lights? The Duster adventure addition came with 8 bulbs upfront! (Including high/low beams)

Max allowed for 12V system highbeam is upto 6 lamps of 60W or lower.
Max allowed for 24V system highbeam is upto 4 lamps of 75W
In addition low mounted fog lamps can be added and are not counted in the headlamp assembly set. Legally fog lamps are to be used with parking lights only.

Rahul

[sgiitk]

My Civic has 3000K HIDs and they are far better than the Halogens. I am not too sure with the LEDs. Remember the HIDs actually discharge in the UV and it is the phosphor which gets you the light. So in a way the HID may be purer in not having much (or even any) of the shorter wavelength component.

[NiInJa]

In Indian road conditions where lanes and shoulders are not marked and there can be potholes aplenty, I feel halogens are the best because the high beams focus brightly on the portion which is directly in front of the road, the cut off is poor but can be compromised. For low beams, projector HIDs are good. The problem with LED light is the color temperature, 4200K is yellowish white much like daylight and is the most soothing to our eyes. White light tends to get ‘absorbed’ by other colors, so if you are driving under yellow street lights like sodium vapor lamps, it gives you an illusion of poorer illumination. I have tried a lot of color temperatures on my bike and car and realised that 4300k is the sweet spot, anything below 4300k is better in rains and fogs but is a bit stressful and on long drives. Blueish White light in semi lit up roads is just ‘show shaa’.

Another important factor that we usually miss is the bulb alignment inside the reflector case and also the headlamp beam level. I changed the bulbs on our Linea and found that they were not illuminating the road as before, found that the bulb was pointing upwards by just a few degrees ! Plus my brother had adjusted the height of the car slightly so at 0 position, the high beam is pointing parallel to the road.

[T-Bone]

I'm no engineer or diplomat (diploma ). My first and only car that I have driven is my beloved Tata Nano 2012 model. One of the good thing I like about Nano is its headlights, still running on stock bulbs. Its bright and the throw is too good. Have done several trips to my native (650kms one way) and never felt the need for upgrade.

I have tried to explain my thought via the pic. The reflectors enable/helps in channelizing the light throw/spread but in LED there is no such arrangement. I sometimes take a look at the parked cars in my office (best place to find new cars ), with LED lights and I feel the LED itself is enclosed in a case/box which may or may not have internal reflectors but the lens in front is where the light exits which does not help much in channelizing the lights throw/spread.

With this in mind, I strongly believe that, the reflector also greatly decides the coverage of the light throw/spread and not just the wavelength/lumens of the bulb.

[audioholic]

Originally Posted by T-Bone

I'm no engineer or diplomat (diploma ).

With this in mind, I strongly believe that, the reflector also greatly decides the coverage of the light throw/spread and not just the wavelength/lumens of the bulb.

What you have totally missed out is that there is a lens that sits between the LED and the outside world. Hence, your diagram doesnt actually represent what actually happens. Please go through this link https://en.wikipedia.org/wiki/Headlamp

[T-Bone]

Originally Posted by audioholic

What you have totally missed out is that there is a lens that sits between the LED and the outside world. Hence, your diagram doesnt actually represent what actually happens. Please go through this link https://en.wikipedia.org/wiki/Headlamp

Yes, that is what I meant when I said "is where the light exits". May be my mspaint drawing was misleading. The thick line in the middle is the LED diode and NOT the entire box.

By the way, Awesome to see my drawing in wiki also

[Dr.Naren]

Originally Posted by T-Bone

IOne of the good thing I like about Nano is its headlights, still running on stock bulbs. Its bright and the throw is too good. Have done several trips to my native (650kms one way) and never felt the need for upgrade.

Agreed. Nano has really good headlights

I have tried to explain my thought via the pic. The reflectors enable/helps in channelizing the light throw/spread but in LED there is no such arrangement. I sometimes take a look at the parked cars in my office (best place to find new cars ), with LED lights and I feel the LED itself is enclosed in a case/box which may or may not have internal reflectors but the lens in front is where the light exits which does not help much in channelizing the lights throw/spread.

I do not agree here. Many cars have poorly designed reflectors. LED / HID projectors do have better focus, width and reach than halogen reflectors. The problem is most of the LED / HID projectors present in mass market cars are just average. After market projectors or OE projectors in luxury cars are really good.

[audioholic]

Sorry to nitpick, but this has to be clarified, both for your understanding as well as an information which isnt very new but feels necessary.

Originally Posted by T-Bone

The reflectors enable/helps in channelizing the light throw/spread but in LED there is no such arrangement.

The LED headlamps are not simply LED diodes placed behind a lens. This is where your misunderstanding lies. Even in the most basic LED headlight assemblies, you can see that there is a TIR reflector like in the Duke, Honda Grazia, etc. The LED diode is never exposed in such a way that its light source faces the direction of the beam.

The more complicated ones have a TIR reflector bowl to gather all the usable light, and then the light is focussed by a lens. Hence, contrary to what you say, there is a good arrangement in any OE led setup.

Originally Posted by T-Bone

with LED lights and I feel the LED itself is enclosed in a case/box which may or may not have internal reflectors but the lens in front is where the light exits which does not help much in channelizing the lights throw/spread.

In continuation to my explanation above, the Lens definitely does a better job in focussing light compared to a reflector. All that the reflector does is to gather the light from the light source.

Originally Posted by T-Bone

By the way, Awesome to see my drawing in wiki also

The drawing in wiki is what is the actual representation. The details are where the differences lie between that and yours. Please take a second look.

[Lobogris]

HIDs are definitely the best. The only exception is very high end LEDs and laser lights.
When I got my Toyota Prius a long time back in the US, it came with HIDs in reflector headlights. The light output changed my driving life. I used to be unhappy driving at night and my eyes would feel some strain but after I got this car, I loved driving at night as the road markings and signs were beautifully lit up. It felt easier to drive at night compared to driving during day time. Since then, I have always found HIDs to be substantially better than any halogen lamps.

The problem in India is the tremendous amount of light scatter than blinds drivers due to the rampant use of high beams and improper headlight alignment. No matter how good your lights are, when you are faced with a bunch of high beams blinding you, you just won't see well and your lights would feel inadequate. I dread driving at night on the highways in India due to this blinding light scatter. The only exception is proper expressways and some major highways where the plants in the median help mitigate this issue. Even though you are not fully blinded due to the median plants or barriers shielding you, your headlights appear dim due to so much light being up in the air instead of being focused down on the road. In addition, the air quality tends to be often poor in India and the suspended dust and a bit of smog also scatters light all around at night. That is why you can see the true light output only on empty roads.

[Tassem]

I have 50W 5500K HID installed in my vCross' H11 low beam projectors. 24W 5500K Fanless LED installed in my 9005 High beams and also in my 9006 fog lamps. The park bulbs are 6000K Osram 2880CW 1W which, even though marketed as 6000K and cool white, is 5500K and pure white.

No blue cast here. They're all perfectly matched as my OCD needs that. I cannot handle four different color temperatures across my markers, low, high and fogs. Right now, they're all pure white (maybe, just maybe ever so slightly warm, like sunlight is) and perfectly matched.

The LED runs cooler at the die as the fins are very effective at pulling heat away. When running halogens, the lens used to be extremely hot for the fogs. This also explained why they're real glass. Now, they're ambient temp and cool to the touch.

The projectors ensure perfect cut-off with an uber wide, extremely bright beam. The LEDS in the fog have the flat wide beam as the standard halogens, but like twice the width. The LEDS in the high beam have an oval beam pattern that just lights up everything in front of you for quite the distance.

They're at least three times as bright as my halogens were. And to put things in perspective, for us to notice a perceivable difference in output, more often than not, the lumens will have to be double. I'm a flashaholic and learnt this while racking up my high output collection.

The sheer amount of light output is staggering. With the fogs and low beam on, my headlights easily cover 4 lanes widthwise on a highway. I rarely have to use the high beam if at all. And being LEDs, when I flash, it's almost like a camera flash going off. Even the nastiest trucks dip their beam on highways. I just love how much safer my night drives are because of this. As much fun as it is, I'm very uncomfortable using high beams except for flashing. But when I do, there isn't a single dark patch in front of me.

I have to add that the highbeams are not as focussed as their halogen counterparts because the LED chip is placed further forward in the optics and do not reach out as far as the original. But, the sheer brightness makes up for it. It's very much like a lightbar. I may get pencil beam aux lights for reach if I feel the need to see beyond 700-800m. When I say the reach is less, please don't think it's a bad thing. The beam is much more usable now with some amount of spill instead of the almost pencil like original high beams. Again, if you've seen a lightbar in action, you'll know what I mean.

The brightness of LED/HID is comparable if you get high quality kits and know exactly what you're looking for. Cheap and/or poorly manufactured LEDs or HIDs will 100% leave you disappointed either in brightness or beam pattern or both.

I'm currently using 50W Morimoto ballasts paired with 5500K RSR globes. The LEDs are LEDWAY 24W with dual Cree XHP 50 chips.

Will add some pics later on. You gotta see this to believe it. I'm never going back to halogen ever again.