Alvin’s Weblog

If you read the news previously, you would have known that someone smartly proposed a ban on Xenon headlights.

My say on this is simple. STUPID, STUPID and STUPID!!! If I may humbly ask that people please, please, please do some research before proposing a complete ban.

Now, I know there are a lot of road users out there who would agree with the ban, but I say NO! Why I say no? It’s simple, a proven technology should be here to stay and not to go.

“But the light is so blinding, I could hardly see when I drive!”

Yes, that is what a lot of people will tell me, but I say, that is only because you get so many fuckers out there who do not bother to adjust their headlamps after installing after market kits. Blame it on poor installation, because I’ll bet you to take a look at any Mercedes and BMW headlights that come with Xenons by default and it will not blind you. If it does, there is most likely something wrong with your eyes.

Since some people are so lazy to do their research, let me explain it here. Let’s start off by telling you how Xenon works. In comparison with a halogen lamp, these are some of the benefits you get:

• Up to three times less wattage is used (HID = 35w, halogen = 55-100w)
• Up to four times more bright light produced (HID = 2400-3200lu, halogen = 800-1700lu)
• Up to ten times more intense light produced (HID = 202,500cd, halogen = 21,000cd)
• Up to six times longer lifespan (HID = 2500hr, halogen = 400hr)
• HID light contains less infrared and ultraviolet light, which fatigues the driver and surrounding motorists
• HID light illuminates the road with better contrast and more lifelike tones of color
• Halogen filaments naturally produce a color of 2300K to 4000K (2300K is yellowish, 4000K is whitish) Anything bluer requires the use of light-dimming color filters
• HID produces a natural color of 4100K to 6000K (4100K is daylight white, and 6000K is slightly bluish white) Anything bluer requires the use of light-dimming color filters
• HID lighting produces a wider and deeper beam pattern with razor sharp cut off lines and autolevelling motors
• HID has low lumen maintenance, meaning bulbs do not dim down as much towards the end of their lives
• HID has high flux properties, meaning light is very evenly distributed when installed properly

With all these benefits in place, ban Xenon? ban Xenon?!?!?! BAN XENON?!?!?! You have gotta be kidding me!!!

Xenons are meant to be installed on Xenon based reflectors and projectors. Those aftermarket conversion kits can be used but provided the bulbs are designed with precise optic points. Some chinese made kits are so low in quality that the instance they are installed, the beam is not focused and light is being thrown in all directions. Yes, there might be some glare when used on a halogen based reflectors/projectors but it is really minimal, so much so that it’s not an issue here. I have seen a properly installed Xenon kit and not only are they cool and bright, it does not in anyway blind oncoming traffic.

I have told many people many times but I’ll say it again here. It has been timelessly proven that Xenons are a technological feat. Engineers worldwide have tirelessly designed and also researched the best lighting source, namely Xenon. It has been proven that Xenons operating at a colour temparature of 4100K is the most optimum. That is the reason all cars that come preinstalled with HIDs use the 4100K colour temparature. It provides the most light output (approx 3200 lumens).

A Philips Ultinon bulb operating at 6000K colour temparature yields only about 2400 lumens of light output. With all factors remaining constant, it is clear that as the colour temparature increases, the brightness reduces. Just for the record:

4100K = Daylight white
6000K = Brilliant white with a slight stinge of blue
8000K = Blue
10000K = Greenish blue
12000K = Purple violet

The worlds largest Xenon bulb manufacturers, Osram and Philips, produces nothing more than 6000K. It is not so much because it is not physically possible but more to the fact that anything above 6000K is not effective as a lighting instrument. Anything above that actually requires the use of light dimming colour filter. in fact a 8000K Xenon bulb produces about 2000 lumens of light, which is barely an improvement over halogens.

Brightness is one factor but when the colour temparature starts going higher, the colour begins to turn blue and then eventually purple. Colours like blue and purple are fatigue to the eyes after prolonged usage. It’s a known fact and that is why you DO NOT see map readers or campers read maps using blue light but rather, they use red light.

There are a couple of general misconceptions among most people which I’ll outline below:

• The higher the colour temparature (Kelvin), the brighter the light
• The higher the colour temparature (Kelvin), the hotter the bulb is
• Halogen bulbs coated in blue are Xenon HIDs

I’ll point out that the higher the colour temparature, the lower the brightness as can be seen above. The heat generated by the Xenon bulb is not determined by the Kelvin rating of the bulb. The colour temparature merely tells you what light colour the bulb will be producing. In fact Xenons operate at 35W as compared to 55W on halogens, and this logically translates to reduced heat in comparison. No, halogen bulbs coated in blue or halogen bulbs filled with Xenon gases are not Xenon bulbs.

This is a typical halogen bulb with the 9006 base:

And this is a typical Xenon bulb with a D2S base:

See the difference? They work on a totally different basis. This is how a halogen (incandescence) bulb works and I quote:

“First of all, halogen bulbs produce more heat than they do actual light (incandescence), which translates to an inefficient usage of potential energy. Secondly, as the halogen bulb is used, tungsten atoms begin to evaporate from the filament due to the extreme heat. When the tungsten evaporates, it deposits itself on the relatively cool surface of the glass bulb (this is why dead light bulbs are often black), and the filament becomes thinner and more brittle. Sooner or later the filament will evaporate enough tungsten particles that it snaps in two pieces and breaks the electrical circuit. In simple terms you have a dead light bulb.

Now stepping back to the gas filling as mentioned earlier. Because tungsten evaporates away rather quickly, researchers learned to fill the bulbs with inert gases like argon, krypton, and yes the infamous XENON! The sole purpose of these heavy gases is to create a level of pressure within the bulb that deters tungsten evaporation. Once a tungsten atom leaves the surface of the filament, it is immediately blocked by giant xenon particles that are crowding it and pushing it back towards the surface of the filament. Xenon is most commonly used because it is the heaviest of the inert gases and is also tied to HID lighting; therefore an opportunity for marketing deception arises. The reason why xenon-filled halogen bulbs don’t work indefinitely is because tungsten is a smaller atom and still manages to escape the xenon, redepositing itself somewhere else on the filament, which still thins the filament where the atom originally evaporated from. Halogen bulbs can also be broken by a forceful jolt strong enough to fracture the filament, or by overpowering/mispowering bulbs to a degree that flash-boils the tungsten.”

Now, just how does a High Intensity Discharge(HID) bulb works? Again I quote:

“HID technology also known as gas discharge is quite different from halogens. HID uses a capsule (bulb) with two adjacent electrodes positioned in close proximity to each other. The capsule sends these two leads to an electronic HID ballast. The ballast is an electronic module that has a circuit board lined with several small high current capacitors, transistors, and resistors. This ballast acts as an ignition box to fire up the gas discharge process, and as a control unit to regulate a steady power flow. The HID capsule is filled with a rich mixture of noble gases as well as alkali earth metal salts. In this setup, the noble gases and metal salts are actually used as part of the lighting processes instead of as a buffer (as with halogens). For quick ignition, the ballast takes in a small amount of input power of 35 watts at 12 volts and inducts a solid-state charge of 25,000 volts to the positive electrode. This creates a very high-powered arc of electricity across the electrodes, which excites xenon gas into discharging photon particles (light). This process is known as the Gas Discharge Principle.

The light is relatively cool burning compared to halogen, consumes much less power, and produces much more light at a much higher color temperature. Halogen lighting in automobiles has become an archaic technology and is steadily being replaced by HID lighting systems in more and more automobiles. They are no longer limited in availability as high-end luxury amenities. Nissan, Toyota, and Ford are already offering factory HIDs in some of their cars.”

Having said that, lets get back to the colour of the light. A lot of people fancy blue and purple light most probably because they have seen the flickering effect on a BMW for instance. For your information, this flickering effect is actually a “prism effect” caused by the curvature of the lens at the edge which bends the white light producing the purpleish and bluish effect.

The Xenons used on a BMW is still in essence a 4100K Xenon and is daylight white on the road. Fitting a blue or purple HID to mimic the effect is only a waste of money as the brightness and performance of the lamp is just terrible. What is worse is that the light endangers traffic around you.

As an example, look at the picture below:

The driver’s side fog light was intentionally left intact with the halogen bulb. The rest had been converted to a 8000K HID lighting. Notice the glare by the 8000K blue light as compared to the minimal glare by the halogen? The wavelength energy of the blue light is just so strong that it radiates out of the beam pattern and blinds oncoming traffic.

Notice the poor cut off in the picture above? There is no proper beam cut off and there is also a severe colour bleed around and above the cut off line. Notice that even the top of the railings are lighted even though not brightly? This is what will be translated as glare to other motorists.

A properly installed HID will produce a beam pattern like the one below:

Now my friend, this is the Audi A6 ECE projector retrofit. This is what I call a superb beam. Notice the sharp cut off line above which prevents light from brightening the top part which will blind oncoming traffic?

Notice how far this car’s headlight can shine and how the sharp cut off prevents light from shining upwards?

Notice how the light shines below the trunklid and car windows? This does not affect other motorist’s ability to drive and the light still manages to brighten up a considerable amount of road.

This post is getting rediculously long so I’ll end it by saying this, Xenons does not blind oncoming traffic, provided a projector retrofit is done, which will be optimum. Or, if you just wanna convert the bulbs, do it with good and precisely engineered bulbs and I’d say, go with Philips and you can’t go wrong, albeit a little more expensive. True that halogen based reflectors/projectors are not meant for HIDs but if done properly, it can still produce proper light with very minimal glare.

I hope considerations can be done objectively by the authorities and based on my post alone, we can see that Xenon HIDs do no real harm. For HID users, please do not be fooled by all this higher performance on higher Kelvin rating. This is just a BS marketing gimmick.

Last but not least, I’d like to give credit to the author of this site for his superbly intellectual post on Xenons. I have used some of his words and ideas in my post here and I’ll give him credit for that. I would also like to point out that images used in this post is also courtesy of the same author.