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Guangzhou LEDO Electronic Co.,Ltd > News > Tech Knowledge > How to Select the LED Projector Headlight Bulb? (2018 Upgrade)

How to Select the LED Projector Headlight Bulb? (2018 Upgrade)

326 Published by Ava 08 23,2018

We are all looking for a led headlight bulb that could produce strong hotspot, a perfect distribution of light and crisp cut-off line in xenon projector. But the inner structure of xenon projector is designed according to the focal length of the HID bulb. That means we gotta find a led headlight with similar focal length to HID bulb that most light from LED can be thrown down the road.

In this article, we will show you which led headlight work perfectly in xenon projector. And you will know the reason why this kind of led headlight works well in xenon projector so you can explore more similar led projector headlights on the market.


Here is the deal.

In this year, LED headlight is no double to be the hottest products in the automotive lighting industry. It gets the revolutionary improvement on technology to simulate the lighting of halogen bulbs. On installation, the LED headlight can replace the original halogen headlight bulbs directly, plug and play, lighting with a clear cut-off line on low beam pattern without projector lens. It isn’t like HID bulb, which has scattered lighting like a flashlight, if you don’t install a projector lens together, HID will dazzle the other drivers on the front of you, very dangerous. LED headlight has a great beam pattern in reflector bowls. Besides, a LED chip has the talents like long lifespan, low lighting decay, saving power, and less response time (while HID need at least 2 second response time while start), there are so many selling points on this product. So you can understand why LED headlight is regarded to be the future headlight to replace HID gradually.

Besides, now in this industry, we could find many new released led projectors for headlight housing from different suppliers. But installing the led projector, we need to cut original reflector to fit the projector in place. That has to have a little bit more skill and easy to damage the original headlight housing. We don’t want this. By comparison, we require a led headlight bulb directly replace the halogen bulb or HID bulb. So we need a led headlight better than HID bulb in xenon projector. So here come to a common question, what kind of led headlight fit in xenon projector?

If we want to figure it out, we need to understand how the structure of xenon projector lens is:

LED Projector Headlight Bulb

From the picture, we can see.

-  The lower surface of a projector is a shade zone; the light to this surface won’t be reflected.

-  The upper front surface is the reflector bowl surface. But on low beam pattern, light from the upper surface will be stopped by a cutoff shield.

-  The upper rear surface is also the reflector bowl surface, but, the light from rear surface won’t be stopped by the cutoff shield and can be thrown down the road on low beam pattern.

This is the inner structure of xenon projector. In order to figure out what kind of LED headlight fit xenon projector lens, we do the test below.

This is our CREE XHP50 LED headlight, named G8 led headlight, two-emitting-side, 4000Lm.

The light beam angel is shown below. It is around 320 degree.

LED Projector Headlight Bulb

As the socket of led headlight is adjustable, we can

Let ‘s try the first loading method.

LED Projector Headlight Bulb

We place Leds on left and right; put in projector lens, like the picture shown above. Let’s see the light beam pattern.

LED Projector Headlight Bulb

In this case, we see a dark spot on the center of light beam because G8 led headlight doesn’t have 360 light beam angle, light isn’t able to reach some area of reflector bowl.

We place LEDs on upper and lower.

LED Projector Headlight Bulb

Because LEDs are put on upper and lower, most light can rise on reflector bowl. There is no dark spot on beam pattern. But compared to the above case, the light is dim. That is because the light to lower surface won’t be reflected. All the light we see on the wall is reflected from the upper reflector bowl. That means 4000lumen, only 2000 lumen is used, another 2000lumen to down surface is wasted. So in this case, the light beam pattern is OK, but the light output is bad and can’t reach our requirement to replace the HID bulb.

LED Projector Headlight Bulb

After our testing above, we have a hypothesis. The light amount to upper reflected surface decides the light output of this led headlight in xenon projector.

Here is our another led headlight kit from the market, G8L LED headlight, same bulb body design to G8, Cree XHP70 LED chip, 4000 Lumen, the only different thing is the light beam angle, G8L only has one-emitting-side (180-degree light beam pattern).

LED Projector Headlight Bulb 

We will put the LED on the upper side, if our Hypothesis is correct, the light output will be strong because most of light can be reflected by the upper reflector bowl and thrown on the wall.

Like picture shown above, the brightness is improved so obviously. There is the clear cut-off line, no dark spot. 4000Lm lighting is totally reflected by projector lens and irradiated on the wall. Beam pattern is awesome, even brighter than HID. It is 439lux measured by Lux photometer, three times brighter than G8 led headlight.

LED Projector Headlight BulbLED Projector Headlight Bulb

Finally, we prove that one-emitting-side super bright led headlight is better to fit xenon projector.

Next we move to the underground garage. Here we will install G8 and G8F on car to verify our experiment result.

Experiment Subject: 2014 KIA SPORTAGE

LED Projector Headlight Bulb

This car has original HID headlamp and no retrofit history before. We will test our led headlight bulbs on this car and compare their light output.

Here we give an instruction that install led headlight on 2014 KIA Sportage. Open the lip, find the screw with red circle in the picture, take the screw out, you will be able to loose the headlamp and get enough space for your hand to replace the headlight bulbs.

LED Projector Headlight BulbLED Projector Headlight BulbLED Projector Headlight Bulb

The installation process is shown in above pictures. After finished, we measure the brightness of G8 LED headlight by professional Lux photometer. The center point of beam pattern is 210lux, while the light output on ground is 48 lux.

LED Projector Headlight BulbLED Projector Headlight Bulb

And we continue and test the G8L headlight. Same installation process. While we finish the replacement work and turn on the headlight low beam pattern, the lighting is so strong, giving an obvious comparison to G8. This is eye-can-tell brighter and stronger lighting. Very awesome! We measure by Lux photometer and know that the center point of the beam pattern is 443 lux, the light to the ground is 81 lux, double brighter than G8.

LED Projector Headlight BulbLED Projector Headlight BulbLED Projector Headlight Bulb

We believe even if we test more models, this result won’t be changed. Through analyzing the internal structure of xenon projector lens, we know most of light on the road is from the upper reflective surface of the projector, one-emitting-side headlight could throw all of the lighting on this surface to maximize the light output. That is the key point.

So G8F is better to fit the car with xenon headlamp.


We did this experiment in 2016. Now, in 2018, new generation led projector headlight bulb has been released and totally complies with xenon projector and bi-xenon projector. Compared the G8L led headlight, new led projector headlight has 4800 lumen output and produces a very wide beam pattern with a perfect distribution of light. It is truly developed according to xenon projector lens.


Wish my article will be helpful for all of people who want to modify your HID to LED headlight, helping you select right led headlight kit. If you have any question, we are welcome you to inquiry us.

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