Complete Walkthrough for Car lights Modification

Whenever I find a lot of people want to upgrade their lights, but do not know how to start, online enquiry only, the information is not centralized, but controversial, there are opinions from experts and layman, don't know what to follow, so we came up with an idea, and write a professional car lights modification tutorial, gathering ideas and experience of countless people, as well as mistakes they made. Hope to be helpful for you.

I am engaged in car lights refit for more than 8 years, and will analyze the car lights overall from the professional point of view. The lights is a double-edged sword, you will be benefited a lot if making good use of them, but if making wrong of them, you will be the first to be hurt. As long as you read this article patiently, I believe you will have a brand-new understanding and knowledge of car lights.

This paper will elaborate car lights from three aspects, i.e., halogen headlights, xenon headlights, LED lights; I think you will have a comprehensive and detailed understanding of the car lights after reading, which will be of great help for you to install the car lights; If you have any question after finishing the article, please leave a message immediately. We (Nilight) will give you a satisfactory reply as soon as possible.


Halogen headlights accompany us for many years, and are still in widespread use nowadays, in fact, a single halogen bulb is 1000 lumens, more than 20 lumens per watt, luminous efficiency is a little low, with this kind of complex (R-plane) reflectors, its use ratio is about 40%, yes, you have no wrong, about 400 lumens can be really used, other light either is covered off or is eliminated, and the appearance of the left and right headlights must be symmetric, but the light pattern is exactly opposite, so very little light can be used indeed.


The standard color temperature is 3200 k for Halogen light , namely it is often called candle color, which is the best color temperature to pierce rain and fog, but the 3200 k color temperature is a little yellow indeed, because warm yellow can make people feel easy and comfortable, the most appropriate place for the color should be in the bedroom or living room in winter, and warm yellow can give people a kind of warm and cozy feeling. In fact, there are many color temperature can choose on the market, but higher or lower than 3200K bulbs are with a coating around the bulb glass, so as to change the color temperature of the bulb, but this technology is quite mature, but the service life of the bulb may be slightly shortened.


Above pic already contains most of the light bulb for halogen headlights, the specifications and encapsulation form of the light bulb is the general standard all over the world, which is not manufacturer's standard, that is to say the original car is Osram H1 bulbs, then changing to Philips H1 bulb is also OK, but only to pay attention to is the power must be the same. The package form of this kind of bulb represents the length of filament and the focus from all manufacturers must reach to that position, otherwise, it will cause light not to gather or beam of light to be out of shape, as to performance, that depends on the quality of each manufacturer.

If the original car is a 55W H4 bulb, now install 100W H4 bulb with same specification, although the shape and encapsulation are the same, you will face the following problems:

1. Headlight line aging in advance, do not trust individual manufacturers who say that can be directly replaced, in fact, this is a trap.

2. The connector at the tail of the bulb may be melted directly, causing short circuit.

3. The reflective cover of the headlight is baked to be out of shape or reflective layer falls off.

Of course, some people have used other solutions, such as after upgrading bulb power, changing the connector at the end of the bulb to ceramic base, and then add a headlight brightener, in fact, it is part of or all headlights draw power directly from the battery, but it still can't avoid the third problem, i.e., the reflective cover be out of shape and reflective layer be baked fall off, also headlight mask is baked yellow and other problems, because the halogen light is to emit light by heating, power from 55W up to 100W directly, the heat will rise a lot, of course, if the headlight is really cheap, you can try, but according to people who did that, the effect is just so-so.

As long as it is H1, it means that the specification and model is the same for every manufacturer, only difference is color temperature and brightness, that is, any H1 bulb can be installed in your H1 headlight.

If you still don’t know the headlight is a consumable, just come and read, the service life of halogen bulbs is between 500 and 1000 hours, in fact, even the light bulb does not burn, the brightness will decay away a lot after 500 hours, such as just below 30%, normally, down to 50% after one year, you need to consider replacing a pair of light bulbs at most two years. As for the color temperature, it can be seen from the above figure that Philips and Osram give us a lot of choices, of course, there are many other manufacturers, not name each one, for those who want to improve the brightness, for example, you can choose Philips Night Strength Light (3700K) (+130%), the brightness is increased by 130% based on the original standard bulb. But the color temperature is also raised a little, not so yellow.

There is also another case, after replacing the bulb, you find the replaced bulb isn’t so bright as the original one, that is, the reflective cover of the original headlight has also been aging, and the reflective efficiency is certainly not as good when the car was bought. There is also another possibility that it is a fake bulb, not genuine. Halogen headlights are characterized by good effect of piercing rain and fog, but in the place with street lights, especially light, just as you didn’t turn on the headlight, look ok on suburban dirt roads, the reason will be explained later.

Replacing a bulb is actually very simple, find the manual instruction of original car to read, specifications and model are written clearly on it, or take down the original one to check the specifications, or check on the Internet, or ask online customer service staff, then you could determine the type, and it is very easy to replace the bulb, open headlight dust cover, remove bulb holder fastener, take off the bulb, aim at gap to install, then done, if you couldn’t make it, you could also turn to car dealer for help, if feel troublesome, go to car dealer directly for replacement, no need to check, also simply matters, just spend more money.

If replacing by yourself, the model replaced differs from the original one, it may be out of focus, then you will find the following situation, can not find high beam and low beam, and this situation should be avoided.


Generally speaking, halogen headlights are not so bright, but they can be used. Some people say that I don't drive at night, so no need to replace them. Well, it depends on you. Let’s see the light used when raining first, regardless of day or night:

Light to moderate rain: low beam

Heavy rain: low beam + front fog light

Rainstorm: low beam + front&rear fog lights, a lot of people do not know there are rear fog lights.

In fact, it is very dangerous to turn on emergency lights when it is raining. In this case, the rear car does not know whether the front car is driving or is really broken down, so it will be too late to brake when it comes to the near. In addition, it is useless to turn on the small lights, parking lights or clearance lights when it is raining heavily.

So, do you still dare to say that you don't use lights because you don't drive at night?

Some people don’t add lens for halogen headlights, directly replace with xenon bulbs, commonly known as naked xenon lights, such modified lights do not shine on the road, but can make the opposite car instant blindness, basically harm yourself and others.


Car headlight masks will age after a few years of use, the surface has a layer of foggy aging layer, or accidentally scratched, both can be repaired with the following method. If it's aging inside the headlight,the method won't work.

1. First cover the car paint around the edge of the headlight with the textured paper, in order to prevent the car paint from being thrown off when polishing the mask surface with fine sand paper.

2. check the roughness of the headlight surface, you can choose no. 1200 waterproof abrasive paper first for rough grinding, and then polish slowly with no. 2000 waterproof abrasive paper, if the roughness is relatively small, you can directly use the polishing of no. 2000.

3. When polishing with sandpaper, you must add water simultaneously when polishing, otherwise it is very difficult to achieve the desired effect.

4. If you want better effect, you could spray a little headlight mask repair fluid.


As for those who sell headlight repair fluid, they say it will be bright after you spray, do you believe it? Above mentioned steps 1, 2 and 3 cannot be avoided.

Nowadays the car is becoming more and more high level of appearance, but the configuration couldn’t be same high level, especially the headlights, analogy as car's eyes, you look at models & logo to determine driving habits when daylight, while at night, you began to second kill any candles random, headlights become the only means of communication at night, plus many car fans are very tired when driving on highways at night, the torture is out of imagination for those who do not drive, and occasionally encountered the high beam, the mood of this day: unhappy!! So instead of breaking out in silence, we can't resist the desire to modify in silence. Let's see how to realize this bright dream step by step.


Xenon headlights are the mainstream three years ago, mainly due to the good-looking shape, and can be mounted with the evil eye/angel eyes, which makes the headlights look bright, more distinctive and individual, luminous efficiency is also good, the most important thing is the tangent line is great for low beam, it is very distinct for dividing line between brightness and darkness, when low beam is turned on, it won’t cause dazzling or glare for the driver in the car coming from opposite side, which will greatly improve the security and confidence of driving safety.


Regarding the utilization of light, the double light xenon headlights is not 80% as manufacturers promote , in my opinion, 60% should be a normal figure, and it is under the condition of high beam, if some low beam is blocked off, the utilization rate won’t be more than 40%, the light transmittance is not more than 90% for just half round lens in front, and light-leaking is also very serious for the distance between the reflective bowl and lens. After decorative cover is installed, the light is blocked in, but it is hard to be a useful light. Take a closer look at the picture below for a better understanding.


In addition, there is pocking or Fresnel mirror processing technology on the surface of the lens, these uniform light processing will cause some light loss. But 3200 lumens *60% = 1920 lumens, which is almost 5 times the effective use of 400 lumens for halogen headlights.

If you want to modify a xenon light, you have to do some research, otherwise it's easy to make a big mistake, you know

Let's go through them one by one.

Xeon Bulb

Xeon Bulb

Xenon bulbs are usually named with three characters "D# X".

The D stands for xenon lamp, High Intensity Discharge, similar to the H for halogen lamp.

"#" is the number "1, 2, 3, 4", singular number means with starter, even number means without starter. 1 and 2 are designed with mercury, while 3 and 4 are designed without mercury.

"X" stands for the letters "S, R", S for lens, R for reflective bowl.

For example, D1S stands for mercury-xenon bulb with a starter on the lens.

Take a look at the "R", D2R and D4R bulb match with car system without lens (such as 12 generation crown low beam, 8 generation Accord low beam and so on), with a layer of coating on the surface, block off some light, and the role is anti-glare;

D1S and D3S bulbs integrate the high pressure part and the bulb body, while  the high pressure part and bulb body is separated for D2S and D4S bulb.


D1S and D3S, D2S and D4S, although similar in appearance, in fact, these four are completely different, the gap of installation position is not the same, and the voltage is not the same, D1S and D2S are 85V with mercury, while D3S and D4S is environmental protection 45V voltage.

The concept of mercury-free design was first suggested by The Japanese, and was later accepted by Europe then widely promoted. That is to say, although the D1S and D2S with mercury are brighter and faster start than the D3S and D4S without mercury, the trend of environmental protection is irreversible. D1S and D2S may be discontinued in four or five years, but D1S and D2S will continue to be produced in these two years until D3S and D4S are brighter than D1S and D2S, D3S and D4S are the mainstream products of the future. Of course D1S and D2S are mercury-containing products, and improper handling will pollute the environment.

At the moment of startup, D1S and D2S are all bright and give off a dazzling blue glow, the brightness is about 150%, then slowly to 130%, and then to 100% stable about 5~8 seconds , which is why it is relatively stable in the startup process but looks whiter afterwards. Mercury is a stabilizer, which can make xenon continue to glow after ionization. However, mercury-free D3S and D4S tend to be red or yellow in the startup process. The startup moment is 40%, and then 70%. After 100% stabilization, the color will return to normal. So you will feel the startup time is relative a little bit longer, but all will reach to stabilization after about 5-8 seconds. These bulbs all support fast startup and flashing, like starting one or two seconds, turn off then turn on immediately, it will continue the startup process based on the original brightness, but it will reduce the service life, so do not pursue quick startup, the startup speed is almost the same for xenon lamp. When used for changing light to warn vehicles in front, it is also to switch between high beam and low beam. In fact, the xenon bulb stays on all the time during the process, just the dimmer in the lens flicking up and down, it's not the xenon bulb flickering, it's not reducing the service life of the bulb, but if you insist in switching between low beam and off low beam, I'm sorry, as mentioned above, it can affect the service life of the xenon bulb.

Generally speaking, D1S and D3S are for European cars, D2S and D4S are for Japanese cars, while D3S and D4S are mainly used in joint ventures. Most models are arranged in this way.

Relatively speaking, D1S and D2S with mercury have a longer service life than mercury-free D3S and D4S. Mercury-free designs generally have a service life of about two years.

The ballast and voltage is the same for D1S and D2S . Although it can be used universally, it must be with a converted connector. Therefore, D3S and D4S have the same logic, for example, when upgrading from D3S standard bulb to Philips D1S XV+, the ballast must be changed because the voltage is different.

Xenon bulbs in general will not burn, will slowly become dim only, this process is the process for drivers to enjoy, use 2 hours a day on average, good xenon bulbs generally are 3 ~ 5 years, of course what I meant is authentic brand new one. If it is used one or fake, service life is uncertain, and it also has a direct relationship with the time of using, If you barely use it, it'll be fine for eight or ten years.

When you purchase xenon bulbs, they must be packaged, i.e., with commercial packaging, the packaging of each product is not the same, if you do not know what it is, check more information, to buy on the formal website or store, in order to prevent the purchase of factory-packed or unpackaged fake.

In addition, it isn’t the same concept for the brightness of the bulb and the color temperature, the color temperature is 4200K for standard xenon lamp, while 5000K or 5500K will look more white, just dazzling, eye-catching, and the brightness is the lumen value provided by the bulb.

4200K standard xenon bulb appears on the market for many years, although it has been selling nowadays, but the follow-up brightening product is also quite good, and there is a choice of color temperature, the reference price is the price of TB and JD. In terms of bulb specifications, Osram CBI and Philips XV are both very good configurations. Of course, the subsequent OSram Night Starer XNB and Philips WHV+ also have some competition. Philips XV+ is basically the top xenon bulb at present, which appears on the market for not long time, and I will explain slowly afterwards.

When choosing bulbs, brightening up is one factor, and the color temperature is also an important factor to consider, American enterprises do have unique business philosophy during these two hundred years, that is to avoid direct competition, but to do a win-win market. Only from the point of color temperature and brightening up, the color temperature of Philips and Osram  is the same only for the standard model, while others are different, always allowing customers a different choice, instead of price battle on same field. When Philips launched the XV 4800K, Osram was selling the CBI 5500K. Now,  Philips launched the 5000K WHV+ (+120%), and Osram is selling the 4500K Nightwalker XNB (+70%). It seems that Osram is at a disadvantage position, but Osram also has 45W ballast for complement, so these two manufacturers allow customers two completely different differentiation programs in terms of color temperature + brightening + price.


Xenon lamp is without filament, only an arc after Xenon ionization glows in the center, after electrodes on both ends are with high pressure, it inspires salt material in center pill to produce light of this kind color temperature, so we can get desired color temperature by controlling the collocation of salts material,  but that is the secret of the manufacturer. Xenon lamp is usually equipped with constant power ballast, so only at this power, such as 35W ballast, the color temperature of the bulb will remain constant. If the ballast is raised from 35W to 45W or 55W, the bulb may not be the original marked color temperature, may be up or down. This depends on the product itself of each manufacturer.

Although they are both standard 4200K color temperature, Philips 4200K is whiter than Osram 4200K in actual use, which is verified by many car enthusiasts who make modification, so we should trust the judgment of the masses. If you don't like bulbs with very yellow color temperature, try not to use Osram ordinary 66144 4200K xenon lights.

Actually, there is a close relationship between brightness and focus , usually xenon lights with more accurate focus have a better brightness in the center area of high beam, Philips XV+ top xenon lights mainly have two improvements, one is ratio improvement for the central pill, directly improving bulb light brightness, while the other is accuracy improvement for bulb focus, which makes light out from lens more focused,  and actual effect is better. Hella's dual optical lens, of course, is also designed corresponding to Philips' xenon bulb focus.

headlightGenerally speaking, imported ballast is better a little, commonly used is Philips, Osram, Hela, Valeo (someone saidthe starting current was big, and affected the USB), Osram (Italian and domestic PRC), Denso (Japan with low failure rate), Panasonic (multiple D2S), Mitsubishi (some Audi BMW original car parts), Koito (domestic assembly which is the most used currently and most high imitation ) and so on.

At present, most of the imported ballasts are 35W on the market, only Osram has a 45W ballast, in terms of the efficiency:

Osram D1S 4200K + Osram 35W ballast =3200 lumens

Osram D1S 5500K CBI (+20%) + Osram 45W ballast = 5000 lumens

There is indeed a great improvement, but the color temperature of OSram CBI is 5500K when using 35W ballast, but when using 45W ballast, the color temperature will be reduced from 5500K to 5000K, which means it is not as white as before, and the effect will be slightly better in rainy and foggy days. So the xenon bulb color temperature labeled by the manufacturer is the color temperature under normal power, which is generally 35W. Whether Philips or Osram, the color temperature will deviate a little from the original, but not too much, if the ballast is lifted directly from 35W to 45W.

If you do not replace the bulb and lens, directly replacing with the 45W ballast, the upgrade effect is generally not much. Upgrading bulb and lens, if the original ballast has good effect, it can continue to be used. There will be something wrong with the ballast when it is just installed, it will be stable after a period time, and the repair rate is less than 2% for good brands.

When choosing ballasts, we must choose commercial package, factory package or loose package might be imitation goods or dismantling parts.

Automobile headlight lens means the whole of lens + reflective cup, it should be said as a lens assembly, but lens always refers to the assembly, there are two main types of lens on the market, namely single photon lens and double optical lens, the difference is that most of single photon lens are with halogen, applied to the car with high beam and low beam separated, while double optical lens are most used for cars with high beam and low beam integrated, halogen and xenon double optical lens are both available, the former is cheap, while the latter is expensive. The brightness is just so-so for Halogen single photon lens, the most are plastic reflective cups. It is fixed for separation blade in the middle of single photon lens, and there is no variable optical motor.


There is no need to add a variable optical motor for this kind of single photon in order to change to be a dual optical lens, because the effect is not good, the reflector design for single photon lens is to focus most of the light on the low beam, even if adding the variable optical motor, there is no much light on the high beam.


There is a variable light motor in the middle of the double optical lens, when low beam, the motor does not work, when high beam, the variable light motor sucks the sweeping light sheet down, so that the high beam could be shined out. The principle is shown as the figure below:



For those who still don't know the difference between a high definition lens and a pitting and Fresnel lens, please take a look at the picture below:


The HD mirror has the best transmittance, but it is not just bright to see clearly. The important thing is the contrast and uniform brightness, just like the mobile phone will automatically dim the screen brightness in the room, and automatically brighten the screen brightness in the sun, in order to maintain the same brightness as the surrounding environment, to ensure that you can see comfortably. Pitting and Fresnel lens have a very good uniform light effect and natural paving effect, which not only raises the difficulty of imitation, and reduces the processing requirements, such as HD lens have black spots impurities or bubble inside, which will be infinitely magnified, while pitting and Fresnel can reduce the machining flaws by utilizing uniform light effect, a bit like shadowless lamp for operating tables, whether hands block the light or not, you can see it clearly as well because the light is coming from different directions.

Currently, the best lens on the market is double optical lens of Hella series, such as Hella 5, Hella 6, here means Hella double optical lens imported from German with original packaging, and of course, Koito Q5, as for HD Hella 5, pitting Hella 5, Super Hella 5, Custom Hella 5, Special supply Hella 5, all of these are domestic Hella 5 double optical lens, namely high imitation. The quality is different, of course, some of domestic one are also good, such as G1S produced by Changsha SLPP. The key is you need to distinct by yourself, and there are also many lenses which are not introduced. Before modification, you could check online, how about the word of mouth for the lens to be installed, and then take action. It’s better not to choose those with bad quality, or short service life, or dismantling parts. Once the lens are encapsulated into the headlight, if something goes wrong, you could only open headlight, or replace the assembly, no other choice. If it is your DIY, that is better; if it is bought online and installed by the shop, the quality problem of this lens is not covered by the warranty of the modification shop.

The general problem that lens may appear is that the variable light motor is stuck after a short time, there is no high beam, or the lens is aging, leading to the reduction of reflective efficiency, so that the brightness of the headlamp is reduced a lot.


This is easy to understand, that is, the lens tail can be directly inserted into the hole of the halogen lamp reflective cover, can be fixed by tightening the screw, no need to punch holes on the reflective cover or cut tail to fix, DIYers can try, but the effect will be limited due to xenon bulbs. This kind of lens is mostly made in China, and the effect is different. There are two main points to consider here: a bad lens will be stuck, and the reflective cup coating will age in advance, after all, the working temperature is very high for Xenon lamp.

Low beam tangent, this is a very humanized design, especially the tangent of xenon lamp, it is not dazzling at all above cut-off line, which improves a lot of safety in the process of driving.


Low beam tangent is to give a safety sight to the driver coming from opposite side, if they can't see the road, our safety will have no guarantee, halogen tangent is generally 25 meters to the ground, while others are 35 to 50 meters to the ground, but no matter what standard of tangent, Hella tangent is still the most humane, with a gap in the middle, just miss the sight of drivers coming from opposite side, and the safety factor has been increased exponentially.


General dimming is between 35 meters and 50 meters to the ground, but in my opinion, as long as not dazzling to others, in fact, the far the low beam is, the better, and you will know that by looking at the distance of driving at night.

50 yards for the speed will require 52.5 meters distance to ensure safety, while the speed of 110 yards, it has to be 131 meters to guarantee the safe distance, relatively car can adjust further, because the location of the light is low, while SUV has to pay attention, if low beam is too high, it may directly shine on the rear view mirror of preceding vehicles. High beam has to shine further distance. Car enthusiasts who often run at high speed must pay attention to the speed, especially when their lights are not bright, could only concentrate on to shorten the reaction time, to tell the truth, it is tired, the braking distance can not be changed, otherwise you can only modify headlights or install car spot lights to improve the night range of visibility.


The demon eye is installed in the inner chamber of the lens, bayonet down, close to the inner surface of the lens, wire harness through down the inner surface of the lens to connect the clearance or small light, you can be fix the demon eye with silica gel, it is best not to use the AB glue, otherwise when it is heated, it will volatilize and remain on the surface of the lens, causing cataract.

Angel eyes is a light guide installed in the headlights lens hood outer decorative guide rings, of course, can also be connected to the outer ring of headlamps reflective cup , there are two wires or three wires, two wires are red and black, directly connecting to the clearance light or small lamp will be OK, someone may connect to ACC, depending on your own actual situation, for three wires, one wire is connected to the headlight, when the headlight is on, Angel eye brightness will be halved.

This thing is also good-looking, but for those bad quality, one don’t work, the effect of mono-eye is also very attractive, if not believe, you can try.


Blue eyes, very obvious in daylight, certainly attract a lot of MM's attention, the probability of chasing after girls increases by 50%. But adding angel eye is not to have everything to gain and nothing to lose, if the quality is not good, it do not work after a short time, at that time, only an angel eye, that will annoy you. Also, when there is the car inspection, you have to take down Angel eyes in advance, otherwise it will increase the possibility of failure.

General speaking, if modifying light, for low beam and high beam separated,  the first choice is to change low beam, for high beam and low beam integrated, it has only one, so you could only modify this one, such as integration H4, you can choose H4 double optical lens, taking headlight apart, screwing, fixing the lens on the reflectors, that is done, you can also set a tube and install it into H7 double optical lens, both of them are nondestructive installation, i.e., not modifying reflectors of headlights. If you want to install D series dual optical lens, you must punch holes in the reflector of H4 halogen headlight, cut off some of the bottom to pass through the lens, such a complex process is best to modify in the modification shop, because it is too risky to modify by yourself.

Process for modifying headlights

Generally, the steps to modify headlights are as follows:

Remove hub pack or bumper - remove original headlight assembly - coating - bake - turn on light - remove glue - test lens - polish bracket or reflective cover - install lens - fix install ballast - connect power line - first lens focusing - fix lens for the 2nd time - glue after cleaning - bake seal light - Hit nail - install and dimming again, call it a day.

Now let's actually modify a set of lights to try, these pics are not taken from one light modification, and pictures are from the network, whose copyright belongs to enthusiastic car friends and sharers.

1. remove the hub pack and front bumper, there may be slight difference for the structure of each vehicle, so you need to remove according to the actual situation. If you go to the store for refit, before removing the light, you should check with the shop owner whether there is any trace on the face mask, take photos as proof, so as to avoid scratches in the process of modification, even hundreds of mouth difficult to distinguish. After removing the light, wrap the mask with plastic film first. Be sure to use the kind of good quality, not the packaging film used in the refrigerator. The plastic film should not only be high temperature resistant, strong, but also thick enough and wearproof.


2. heat light, when putting the light in the oven, you need to avoid direct contact with the metal in the oven for heat transfer, headlight has cold plastic and hot plastic, also called hard plastic and soft plastic, actually is the same thing, the difference is that the hot plastic is reversible, like water into ice, ice into water, hot plastic softened at 120 degrees or so, turn on the light directly. While cold plastic is irreversible, just as the eggs can't go back after cooked, the baking temperature of cold plastic is usually between 120-150 degrees, you can begin remove the light after baking for 5 to 15 minutes, if low temperature,  bake for more time. Note here that heating light is not really to make cold plastic melt, but the adhesion to the edge of headlights is not so strong after cold plastic is heated enough, and headlight shell will be not easy to crack. If modified by yourself, wrap the light well then put it into a carton, heat with the hair dryer, it is best to put a thermometer,  when heating, you have to blow left to right, up and down, to avoid some area is over heated, and light masks couldn’t be blown directly, if the plastic film is melting and sticking on the headlight masks, which will be trouble-some. You could remove the bottom of the carton, which is convenient for you to pick up and check at any time.

Above is most used two baking ways to open lights, there are both pros and cons, maybe there is another way to open the light, such as to use vacuum suction nozzle to suck on the headlight masks first, fix the rear of headlights, pull a rubber band for each suction mouth, provide a certain tension, and then use heating wire for opening headlight to glue around the light, as the temperature of the heating wire rise slowly, the plastic is heated, then the headlight mask is pulled apart, so it will be non-destructive disassembly of headlight mask, also no need to worry about the headlight mask aging after heating. Those interested can try.

3. open the light, removing the screw for fixing headlight masks or prying up the bayonet, if you have a professional tool, you could use a plier of opening headlights, if no professional tools, screwdriver is also OK, hard and dry, hot plastic is relatively easy to open, while for cold plastic, use needle tubing to put a circle of cold plastic separation liquid, to open cold plastic, bake one time may not work, then bake another one or two times, until it is opened, Pay attention to the corners where it's harder to open.


After open headlight, you need to thoroughly remove residual cold plastic for cold plastic, while for hot plastic, removing or not is both OK, the key is following steps of sealing the light, if you use the snake plate glue for sealing the light,  then clear it off, if you have same model hot plastic as headlight, it will be OK to fill up a little hot plastic when sealing the light. When clearing cold plastic, you can use a special tool, there is kind of electric on the online shopping platform, which is very quick for clearing. If you do it yourself, you can clean it slowly with an art knife.

4. check the bulb and ballast of commercial package(must be commercial package), and lens, start debugging lens, every time installing xenon bulbs on the lens, you need to adjust the focus slightly according to the light type of lens, in general, the focus of the Philips is more accurate than Osram, then usual tuning method for Osram is to put the bulb head down a little bit, and mainly use high beam for focusing, and the effect of low beam is also OK.


After adjusting the three-piece, there are three scenarios:

First, the low beam is lens for original cars, then you need to modify the bracket of new lens and then install on the position of original lens, there are a lot of lens bracket online, you can choose by yourself, also is special one for a special car, no need to be polished or just small modification, as shown in figure (12), if the distance is wrong, you can also put silica gel column on the bracket to adjust the distance.

Second, the original car is H4 or H7 reflecting bowl, install H4 or H7 double optical lens, this is the simplest, directly tightening the screw behind the reflecting bowl through the lens to fix.

Third the low beam is reflective bowl for the original car, but you want to use D series lens now, such as Hella 5, put reflectors on the punching mould first, fix the reflector with a nut, then flip the reflector to punch a location hole, normally there will be marked position on the mold, directly punch(14). After punching holes (15), install hole saw on the hand drill, insert hand drill into the center hole of the mould, firmly cut down(16), then round hole on reflectors is done, of course, the hole at the bottom of the reflector can also be made special shape, which depends on the size of lens to be installed and reflectors.  For special shape, you can mark a size and cut with a hand mill slowly(18).

When the lens is installed on the reflector, you have to put a silica gel column with diagonal plane on the screw to fix the lens(19). You also can use a ready-made sheet iron bracket (20) (21), which depends on the actual situation.


Fix the ballast, generally there are two cases for fixing the ballast:

1) The original car is high configuration, with xenon light, in this case, there will be space for the ballast on the headlight shell, you can make a hole to use reserved ballast position, install inward, or do not make the hole, directly install outward,  keep away from computer board of the original car as far as possible, in order to avoid interference, the space should be enough to install, avoid high temperature from machine, and then in the proper position, such as the position above the dust cover of lighting fixture, or other suitable position to make a hole and wire through.

2) There is no reserved space on the headlight shell of original cars, you could find a suitable location to make installation inward(22) or to install outward(24), and then find a suitable location to make a hole for wiring through(23). Most of the installation are these two cases, the key is the process, when selecting installation location, you must avoid the heat part of the body , also take into account the heat dissipation of ballasts. Normally, outward installation can avoid the heat radiation of xenon lights transferring to the ballast effectively, which is also a good way to improve the stability of the ballast.


The high pressure part must be wrapped with the high temperature tape of Desa, the variable light wire in the light body should also be covered with the heat shrinkable tube, so as not to expose the wire directly. You need to weld the joint of wiring well with the soldering iron, covered by the heat shrinkable tube, and then wrapped by the tape, staggering some space for two joints of wiring.


Whether the ballast installed inward or the position of the hole for wiring through, you should use Kraft K-5911 for seal, including the position of the dust cover, and filling up glue for the edge of the headlight, of course, there should be other types of silica gel can also be used.

wiring and dimming, headlights is away from the wall 7.6 meters, the focus of high beam is just at the height of low beam headlights, the height of low beam is 5 cm lower than that of high beam, the remote focus as shown in the figure:


The wire of xenon bulb is connected to the low beam of original cars, the wire of variable light is connected to the high beam of original cars, for those require decoding, you need to decode first. Then start debugging the position of the lens, the low beam focus of lens must be in accurate registration as the high beam focus of the original car, otherwise after lens are fixed, you could only make a fine-tuning for the dimming position of original headlight shells, and the high beam will move at the same time, so the dimming has to be very accurate, and then the lens is fixed.

After dimming, if you cut the reflective cover, you need to add steel soil to fix for a second time, after steel soil solidification, it is almost same effect as cement, not volatile, here it is best not to use AB glue (which isn’t high temperature resistance, and is volatile) to fix, and then install the decoration cover of lens, done.

Clear and seal the light, you couldn’t wipe the inside of the headlight mask with paper directly, if it is dirty, you could only wash with water, drying, as long as no dirty marks, it will be OK. Before installing the snake glue, check the pry marks around the headlight. If not OK, blow it with a hot air dryer and repair it. After that, set a circle of snake glue, bake it, use the light sealing plier, gun nail a round,done.


Large modification shops have plastic injection machine, if the original is hot plastic, then fill some hot plastic, if modifying by yourself, snake glue is a good thing, set a circle, bake with a hot air dryer, press with the mask, bundle with rubber rope is also OK.


The last step, installation and dimming. Up to now, all the modification process is over.


Modification is a process for imagination and implementation, each modification shop has different process, it is not the case that only professional modification tools can implement modification, if so, there would be no atomic and hydrogen bombs. To complete the task under limited conditions is the embodiment of modified strength. Of course, not everyone is suitable to modify by themselves, first, you need to have free time, second, you need to have operation ability, third you need to have keen insight. I already wrote so detailed, if you still have no ideas, I suggest you not trying it. Modifying by yourself, even if you have free time, you need to have some ideas, it will take about 1 days for light modification, if there is something wrong afterwards, you need another 1-2 days for rework, whose cost is several hundred RMB. Therefore, it is risky to modify the light by yourself, you need to be careful, if you hand it over to the modification shop, when there is a problem, you could turn to them for solving. You do not need to spend time and energy any more. Each has their advantages and disadvantages. All depends on your actual situation.

Personally, there are three levels of modification:

The first level: lens + xenon bulb + ballast = configuration under 100USD, such configuration is not certain, choose by yourself, such as all domestic, or second-hand dismantled parts, the effect is just so-so, suitable for just having some fun.

The second level: Equipped with similar lens, for example, imported Koito Q5, domestic like G1S launched by SLPP, or Super Hella 5, the effect is also OK, those with relatively suitable price and longer warranty can also be modified. Xenon bulbs should not exceed CBI+45 watt ballast or Philips XV 4800K at most. Of course, this should be done at the modification shop, this kind is within 400 USD.

The third level: the top configuration, Germany imported Hella 5 or Hella 6, xenon bulbs should be with at least CBI+45 watt ballast, Philips XV 4800K or above, these are quite amazing configuration, you need to go to shop for modification, and to find an excellent shop, this kind is more than 400 USD.

Personal advice is that regarding the configuration within 100 USD, you can modify by yourself, just for fun, or motorcycle, a light to try, if the configuration is D series lenses and xenon bulbs, absolutely do not modify by yourself, this is not worth the loss. Generally, modification shops complete modification of two headlights in 3 to 6 hours, some may be more than 10 hours, which depends on the configuration and models, the workmanship is 500 to 1000RMB, and there may be higher, of course. In addition, you need to make a detailed inspection to find the modification shop, if it is introduced by someone, do not make modification when you go for the first time, take a look at first, like a lens, waterproof headlights, lighting debugging, the best is all these are lifetime warranty and service free of charge. To find a modification shop with good reputation. It is best to shop around. You could look at the process, not take photos, but you must ensure that the lens is the one you choose when sealing the light and during the process, in order to avoid that you pay for a Germany imported Hella 5 but get a fake one installed, which will be annoying. Therefore, you need to have a knowledge about the basic information of the xenon headlights configuration in advance before modification, otherwise, you will be cheated, not keen on getting things on the cheap, after all, you get what you pay, if too cheap, you need to think twice, such as imported Hella 5 lens, 200 USD a pair, including modification, do you know what quality it is, anyway, I do not know. Another case is they installed garbage lens specially in the dismantled headlights in advance, then broke it on site to show you. Even some experts could not distinguish, not to mention the average person. So you need to know some more information to prevent from being cheated. The technology of modification shop is very important, but the sense of responsibility is more important. If the workers are indifferent, just leave as soon as possible. Also those who do not show the process, there will be some problems more or less. Imagine that real skill and word of mouth can be learned by a layman who modifies the light every three or five years. Their purpose is self-evident.

LED Light

LED, also known as light-emitting diodes (leds), currently, single LED can achieve maximum power more than hundred watts, but the greater the power, luminous efficiency is lower, because the light emitting chip is too concentrated, heat dissipation is difficult to solve, the light-emitting way of LED differs from that of halogen and xenon light, for the LED, the diode emits ultraviolet or infrared first to inspire the fluorescent powder on the surface of the light emitting chip, The color temperature is controlled by controlling the ratio of fluorescent powder.

1) Luminous flux

In terms of the light flux of various bulbs, we are all familiar with it, lumens (LM), 55W halogen bulb is 1000 lumens, 35W xenon bulb is 3200 lumens, 10W LED lamp bead is 1000 lumens.

This is the ability of emitting light for each bulb, and high & low beam of car headlights have a fixed projection pattern, so...

Halogen light: 1000 lumens *40%(utilization rate) = 400 lumens

Xenon light: 3200 lumens *60%(utilization) = 1920 lumens

So xenon headlights are several times brighter than halogen headlights. It's almost five times in terms of figure alone.

However, in term of light bulbs only, lighten a xenon bulb, without lens, can it shine to the place above 100 meters away, the answer must be no, so the secondary reflective function of lens is particularly important, how many luminous flux the bulb emits, that is luminous ability of bulbs, lumen value as a unit of measurement, projecting the luminous flux away into the distance effectively, which depends on the ability of lens and reflectors. Reflective cover is also called reflection cup, also called reflective mirror or reflective bowl, all is the same thing. It is most called reflective cover of reflective bowl for halogen lights, while for xenon lights, the assembly of lens and reflective bowl is called lens, but it is most called reflective cup or lens for LED lighting fixtures. There will be detailed description in the following, almost same things. How far the light from bulbs could project or illuminate, that depends on the secondary reflective, namely reflective cover or lens. Every long shot lighting fixture has this spare part.

When car inspection, it is required that each illuminance of two headlights is above 15,000 CD, the highest is 220,000 CD, and the unit is Candela. What the low beam and high beam of headlights looks like, which has been determined by the light type, such as the tangent of low beam, the focus of high beam, then the Candela value becomes the only measurement of how far the headlights can shine, not the lumen value, but how did the Candela value come from?

2) Luminous intensity

light bar

The luminous flux emitted by a light source at a unit solid angle in a given direction is defined as the luminous intensity of the light source in that direction, denoted in I  Unit: Candela

How far it can shine, the luminous intensity is the lumens value per solid angle, which roughly means how many lumens of light flux from the bulb are projected into this solid angle, also known as luminous intensity or luminous intensity.

Take another look at the concept of solid angle.


The solid angle is 4π for the center of a sphere a circle outward, then the solid angle of China's local area to the earth is:

9.6 million square kilometers/square of the earth radius = 9.6 million /(6371 km *6371 km) = 0.2365 radians, accounting for 1.88% of the earth's 4π, the luminescence of bulbs is also 4π solid angle, as to how to focus the light on the desired solid angle, it depends on the design of the secondary reflection, such as reflectors of halogen headlights, lens of Xenon headlights, and reflective cups or lenses for LED lights.

If a 10W LED emits a light flux of 1000 lumens, with the reflector, the light will be reflected at an angle of 4 degrees, as shown below:

light bar

If only 60% of the light is reflected by the reflector and 40% of the light is directly irradiated out without reflection to form flood light, then the luminous flux at the central light spot is 1000*60% = about 600 lumens, and the angle of central light spot formed by the luminous flux of 600 lumens is 4 degrees, and the solid angle is:

ω = A/ R2 = π*3.5 m *3.5 m/(100 m *100 m) = 0.00382 radians(calculated from above formula)

In fact, due to the LED luminous efficiency and reflection loss of reflective cup, the light loss when penetrating the glass, the actual lighting fixture of this design can only reach more than 90,000 CD, 157,000 CD is pure theoretical value.

When the angle of the central light spot is 4 degrees, no matter how far it is, the luminous intensity is the theoretical value of 157,000 CD, so the CD value of the luminous intensity does not change with the distance. Such as 4 degrees 100 meters is 7 meters diameter for the center light spot, it can shiny at least 7 meters wide, up to 200 meters, it can shine 14 meters wide at least, let us see how it looks like if shining to 200 m, as the chart below, but these two 4 degrees more than 90000 CD, the total is nearly 180000 CDS, here to make clear a problem, that is the further the light shines, the wider it is, as a divergence angle of 4 degrees. If you do not understand, look at the picture below:

light bar

Since this CD value of luminous intensity does not vary with distance, what does it matter with distance.

As can be seen from the figure above, when the distance is five times greater than the maximum size of the light source, the above theorem applies. The unit is lux for the data from the illuminometer we usually use, can it also be converted into CD value of luminous intensity, according to the test data from a group of IcAR top car friends SLPP:

light bar

Luminous intensity = illuminance * distance from light * Distance from light = 10160 Lux *3M*3M = 91440 CD, more than 90,000 data from a single light proves that the Philips XV+ Hella 5 is quite good at high beam effect. But that is just the brightness of the focus, that is to say, the maximum, from focus outward, the luminous intensity will go down slowly, which is related to that the point light source of xenon bulbs is easy to make a very bright point, while LED could not make such a very focused point, because the LED is area light source, when projecting out, the luminous intensity is the same for all the center light spot, as shown in the figure below:

light bar

On the left is a 35W xenon light, about 137,000 CD, while on the right is a 10-watt LED light, more than 90,000 CD. There is a very bright line in the center of the xenon light, and the luminous intensity value is very high on the line , 137,000 CD, a little outward, it is far lower than 90,000 CD. Of course, the average of the high and low, the whole thing looks similar to the luminous intensity of the 10-watt LED lamp with more than 90,000 CDS, and its far-range capability is also similar. To distinguish, the 35W xenon light on the left has a color temperature of 6500K, while the 10-watt LED light on the right has a color temperature of 4300K, such as shown in the following figure:

light bar

You can clearly see the bright spot in the center of the light spot, and the light spot around the bright spot is much less luminous intensity than the central light spot, that is why Hella 5 has a very bright central bright spot.

light bar

It's hard for leds to do that, but there are other ways to make it,

As shown in the figure above, a 10-watt 4-degree LED spotlight is about a central light spot with 5-meter diameter at 100 meters distance, while a 20-watt 7-degree LED spotlight is about a 12.2-meter light spot at 100 meters distance. As shown in the figure below, two 4-degree lighting fixtures with more than 90,000 CD illuminate at the furthest distance, while two 7-degree lighting fixtures with more than 60,000 CD illuminate relatively close. We can still imitate the bright spot paving way of xenon lights to achieve the brightest effect in the center.

As shown in the figure above, a 10-watt 4-degree LED spotlight is about a central light spot with 5-meter diameter at 100 meters distance, while a 20-watt 7-degree LED spotlight is about a 12.2-meter light spot at 100 meters distance. As shown in the figure below, two 4-degree lighting fixtures with more than 90,000 CD illuminate at the furthest distance, while two 7-degree lighting fixtures with more than 60,000 CD illuminate relatively close. We can still imitate the bright spot paving way of xenon lights to achieve the brightest effect in the center.

But it's hard to understand the luminous intensity of incandescent bulbs. There is illumination all the way around a 4π sphere angle, you can figure out how many lumens a bulb emits , but it's too hard to figure out that, so we just say how many lumens for the luminous ability of bulbs. For example, a 55W halogen bulb is 1,000 lumens, a 35w xenon bulb is 3,200 lumens, 10 watt LED lamp bead is 1000 lumens. The same type of light bulb, the greater the wattage, the higher the lumens value is, such as 20 watts LED is much more brighter than 10 watts LED. The efficiency is almost the same for electrical energy is converted into light energy, so it is OK to check the wattage only, but it is difficult to compare 35 watt xenon light with 35 watts LED, and it is better to check lumen value directly, whose lumen value is more, which is brighter.

So, here is a summary, you could check the lumen value directly for the brightness of the bulb.

You need to check two conditions for lighting fixture: one is luminous angle, also call light angle, namely how wide it can illuminate, just as mentioned above, the spot light of 10 watts 4 degrees is a 7 meters circle at 100m distance, that is to say it can illuminate 7 meters wide, while the spot light of 20 watts 7 degrees is a 12 meters circle at 100m distance, that is to day it can illuminate 12 meters wide.

The other is luminous intensity, for example 10w 4 degree light is 93,800, 20W 7 degree light is 66,000, but the light between 4 degree beam and 7 degree beam is the light could be used effectively. Take one more look at the above 4 degree luminous intensity formula:

So now the actual luminous intensity value is 93,800 CD for 10 watts at 4 degrees. Calculate how many lumen values are effectively utilized in the angle of 4 degrees. The formula is inversed as follows:

Luminous flux = 93,800 CD * 0.00382 radians = 358 lumens

Equivalent to the high beam luminous flux of a halogen headlight is all concentrated at a 4 degree angle, that is, the circular light spot of 7 meters at 100 meters, then how about 20 watts at 7 degrees:

Luminous flux = 66,000 CD *0.01368 = 902 lumens, which is equivalent to 902 lumens is all concentrated in a circular light spot of 7 degrees at 100 meters.

It seems that 20 watts at 7 degrees is more effectively utilized than 10 watts at 4 degrees. Why is the luminous intensity still low? That is because the circle area of central light spot for 10 watts in 4 degrees and 20 watts in 7 degrees at 100 meters:

10 watts 4 degrees is: 3.14*3.5 meters (radius) *3.5 meters = 38.47 square meters

20 watts 7 degrees is: 3.14*6.6 meters (radius) *6.6 meters = 136.78 square meters

The luminous intensity of lighting fixture is like the pressure, you could not check the wattage only, the wattage is just the luminous ability of bulbs, but to check the luminous angle and luminous intensity, while luminous intensity is like the pressure, more gravity does not mean better, but also to check the area for bearing gravity, that is, the area that the light projects out.

A car spotlight, with a large wattage, can only represent the luminous ability of the bulb is very strong, if the angle of light is also very large, that is a shotgun, many bullets, large angle, but can not hit far, sniper rifle has only one bullet, but shoot after aiming, the angle of deviation is very small, let alone the range.

For example, spot lights with luminous angle of 30 degrees, the luminous intensity of 100 watts is much higher than 20 watts, just because the luminous angle is determined, same case, the the luminous angle is determined for high and low beam of cars, so you just need to check luminous intensity when the car inspection, that is a single light must be above 15,000 CD.

The naked eye can only see the reflect light on the surface of the object. Lighting fixture here can be divided into 2 kinds, one is close-up, the other is long shots, the close-up means the irradiation distance does not exceed 30m,  such as indoor ceiling lamp, spot light, desk lamp, tube lamp, sitting room lamps and so on, anyway, it will not be more than 30 meters, outdoors such as street light, industrial and mining lamp, project-light lamp, this kind of lamp have a relatively large luminous angle, generally between 15 degrees and 180 degrees, if the luminous angle is almost same, basically can also be the greater the wattage, the brighter, as shown in the following picture, the light from the lamp shine on the ground or objects, we can see it directly. The close-up lighting fixture is easier to choose. 

The luminous angle is between 0-15 degrees for long shots lighting fixture, generally speaking, the light shines on the object, then is reflected back, so we could see that. The reflectivity is 18% for general objects, such as vehicle headlamps, namely high and low beam headlights, headlamps of trains & subways, bicycle light, including flashlight, all is the same principle, it depends on the luminous angle, also called the light angle of the lighting fixture, and the other is the luminous intensity. The use of luminous angle and intensity will be discussed in more details in background glare below.


Here's a quick summary:

Bulbs are measured only by lumens, and for the same type, such as LED, the higher the power, the higher the lumens.

To measure the luminance of lighting fixture, close-up, the luminous angle of 15 degrees to 180 degrees, lighting fixture with almost the same light angle,  directly check the power, the greater the power, the better the brightness, such as downlight, ceiling light, living room lamp; long shots lighting fixture, light angle of 0-15 degrees, to see the luminous angle and the luminous intensity, namely how many candela (CD) value, not the greater the power, the farther it shine, which is why a single light has to achieve 15000 CD when car inspection, why not test lumens value and wattage, because when light type(light angle) is certain, just check the luminous intensity (CD), you will know how far it can shine.


Glare mainly includes head-on glare and background glare.

Head-on glare is similar to rogue high beam, as shown below.

The floodlight of lighting fixture, that is, the light from bulbs illuminate directly without reflection or transmission, such light are very dazzling within 30 meters, bluntly speaking, if you see the luminous bulb of cars directly within 30 meters, that is very dazzling, except for the day light and small light. Another is the main beam, the main beam is dazzling within 150 meters when head-on directly. This is why we must turn off the high beam within 150 meters when we meet other cars, because others’ eyes are in the main beam of our headlights, which is easy to cause invisibility and cause accidents. If the glare of high beam lasts for a while, it will also cause temporary functional blindness or acute keratitis and vision loss.

When encountering high beam glare:

1. You can switch back and forth high and low beam to hint the other to change the light.

2. You can also turn on a double flash to show anger, slow down and focus on the area in front of your car.

3. Stop on the right if you really can't see.

Of course, someone is a specially equipped with LED spot light to deal with rogue high beam. When you choose and buy, as long as referring to the figure above, you will understand. LED lighting fixture will be very dazzling when it is within 150 meters in the center light spot or within 30 meters at close floodlight angle of 58.82 degrees (the floodlight angle is different for each light), the degree of dazzling is relevant to the luminous intensity. General LED lighting fixture is enough to deal with rogue high beam, but in my opinion, do not to try so, it is very dangerous, but it will be OK to flash twice at far away and warn  the other party to change the beam.


Originally, we want to see clearly the vision within 200 meters in front of the car, but the nearby light is too bright, which causes the distant place hard to see, this is what many car friends say: the brighter, the darker the road is, and this situation is called background glare. In order to see the distance, you must keep your eyes wide open and concentrate on, but it also allows parasitic light with high brightness into the eye, scattering in the eyeball, which makes object resolution and contrast ration on the retina down, it is easy to cause disability glare, thus resulting in a decline in visibility, people often have a lot of absent-minded feeling of concentration, very uncomfortable, works in this state for a long time, it is prone to cataracts, just like welders.

It is very large for the flexibility of the brightness accepted by human eyes, but the perception of the same brightness is different between day and night. For example, when the ambient brightness is 10,000 CD /M2 in the daytime, the human eyes can distinguish the brightness range of 200 ~ 20,000 CD /M2, and the brightness below 200 CD /M2 is perceived as black. However, when the nighttime environment is 30 CD /M2, the recognizable brightness range is 1 ~ 200 CD /M2. At this time, the brightness of 100 CD /M2 will cause the feeling of being quite bright. Only brightness below 1cd/M2 causes a black sensation.

When eyes looking at objects, it is same effect as photos taken by camera, the object to see is focused, looks clear, while the background will be relatively fuzzy, but when the brightness of the background is higher than the object you want to see, you will feel uncomfortable. The ratio of the object and background brightness as shown in the table above, the most comfortable way is the object to see is a little brighter than the background.

The good vision of daytime driving is due to the same brightness and contrast between far and near.

The lighting at night also try to mimics the effect of daytime daylight paving, and the high beam focus of Hella 5 is made based on this principle to emphasize the paving effect.


Why the high beam focus is very bright when shining to the wall, while shining to the road, the front is little bit darker than the close range, that's because when the lights shine out, it has to reflect back in order to be seen by the eyes, as shown in the above pic, the angle is the same for two A angle, but the shining distance L is greater than l, when the lamplight is shinning flat on the road, the greater L is, the larger the illumination area is, then reflect back, the light loss is definitely greater than that at close range, so the close range looks a little brighter than far distance, but the visual effect is acceptable. At the same time, another problem is reflected, that is, the higher position the light installed, the shorter the L corresponding to the same angle, the brightness is better. At night, for vehicles installed Hella 5, that is why the vision field of the large truck is better than that of the SUV, while the vision field of the SUV is better than that of the car. Why the upper, left and right sides for high beam of Hella 5 are all black at close range (the area surrounded by red lines), that is to avoid glare from the close background.

The higher the speed, due to the concentration, the view will be more and more narrow, so we will not see the angle of view on the upper left and right sides of the car, just kind of scanning, the light is too strong for the upper left and right sides, it can also cause background glare. Those who install long light bar on the roof for highways and with sufficient flood light will have this problem, especially the reflect light of road signs close to slowly in front, very dazzling.

The headlights of the car are installed in the lowest position, and the angle of view is a little bit worse than that of the SUV or the large cargo. Does that mean that the car is really at a disadvantage? Not necessarily. Let us see the modification of Sagitar. The original headlights do not perform well when running at high speed, so a new pair of auxiliary headlights is installed, but still feel not enough, later, four 10W and four 20W LED spotlights were added.


This gap is relatively large for the grille, relatively speaking, the transmittance is high after installation, and not easy to be found.


Keeping the low beam of original car to use in the city, that is a must, no matter to add spotlights or not, the low beam needs to have good brightness, at least to ensure the night vision in the city.

On rainy and foggy days, turn on a group of 4 pcs 10-watt 4300K spot lights, and on sunny days, only turn on a group of 4 pcs 20-watt 6500K spot lights, both of which are very enough. If you wish, turn on two groups, total power is only 120 watts, all of which are more than 640,000 CD. Excluding the part blocked by the grille, at least 500,000 CD is more than enough. A pair of Hella 5+ Philips XV 4800K is only about 150,000-180,000 CD.


This installation method is also quite exquisite, lighting fixture installed in the grille, so the floodlight upward and around, those light which are not suitable for use are basically blocked in the grille inside.

During the test of 4 pcs 10 watts and 4 pcs 20 watts, a car happened to enter the industrial area. The filter of the camera was serious, but the effect could be seen by comparison.

Color picture is too big to upload, use black and white under the condition of ensuring that you can see clearly, directly second kill the opposite car at 100 meters away , the effect is still ok.

Nowadays, most of cars are in shortage of high beam, a lot of person choose to mount spot lights directly for filling in. How to fill in in specific? Let us to continue from above two points that are not finished, luminous intensity and luminous angle. The average car, now matter how poor headlights are, you can see clearly within 50 meters of high beam, so to the field of vision beyond 50 meters. The beam is slightly forward and down a little for most of added spotlights are light beam, shining on the ground, at most can only be horizontal installation, impossible to the sky.

As shown in the figure below, the spot light is installed on the roof of the car, and the height is estimated to be 2 meters. Then horizontal installation of spotlights on the car with a luminous angle of 7 degrees, the horizontal downward is 3.5 half angle. The central light spot has fallen to the ground at 32.7 meters, while on the car with a luminous angle 4 degrees, it will also fall to the ground at 57.3 meters when the spot light is installed horizontally.

According to our test data, in terms of high beam fill-in, the angle of the roof should not be more than 9 degrees at the most, otherwise the reflect light of the oncoming road sign on the highway will kill you first, and something like the following will happen.

light bar

High beam does not fill much distance, it has been unbearable when looking at the nearby glare, but the long light bar can be called the best in the outdoor off-road, large luminous angle, coupled with the sufficient floodlight, shining to the sky and ground, no problem for climbing and wading. For example, installing long light bar for the following two cases, the effect is also great.


If it is installed in the front bumper or grille, and the license plate frame to fill in light for high beam, then the angle is best not more than 7 degrees, the smaller the angle is, the better. From modification of Sagitar above, we already see the effect of 7 degree spotlights installed in the grille. If fill-in low beam, then the angle should be not more than 15 degrees at the most, and the power should not be more than 100 watts. If you want to use a light greater than 7 degrees in the grille to fill-in the high beam, the following situation will happen, the following is 150 watts spotlights with about 12 degrees:


The distance is 130 meters or so you can see, but the brightness is too high for light spot falling on the ground at close range, causing glare, it will affect the sight of the distance, such glare is ease to cause visual fatigue, and on the highway or national highway, a head-on signpost, the reflect light give you a feeling of killing yourself, so the maximum angle is not more than 7 degrees for fill-in high beam in grille.  If using it for off-road or as fog light, then the angle could not be less than 15 degrees. So different kinds of usage, different choice of lighting fixture specification. From the above pic, we can find lighting fixture for far illumination can also be used in off-road, but a special off-road lighting fixture can't be used as high beam fill-in, and the difference probably is right here. Of course, there are also customers who installed 4 pcs 10 watt 4 degrees and 3 pcs 20 watt 7 degrees, along with the above mention 180W light bar, which can cope with all the night situation.

If you only use a small angle as supplementary of high beam, the following will happen.

At first, we installed two 10 watts 4 degrees 4300K, and found that the effect is ok for the distant light , but the light filling on both sides is obviously not enough between 50 meters and 100 meters. Later, we added two 10 watts 7 degrees, which has greatly improved.


From the figure above, we can find if two lights are added, then 7 degree is the priority, if4 lights are added, the effect of two 10 watts 4 degree+ 2 pcs 20 watts 7 degrees (i.e. package C) is better. If more is added, you can choose our upcoming 15 watts 3 degree 150000 CD, smaller angle, only fill-in the point at the center of far distance, if you want to install 8 lights, it is best to choose the one with a small angle, such as 4 pcs 15 watts 3 degrees + package C, you can also directly choose 8 pcs 10 watts 4 degrees or 15 watts 3 degrees, which depends on the actual demand, the light is more, the floodlight will be very sufficient, only floodlight can illuminate within 50 meters.

Relatively speaking, the smaller angle, the higher luminous intensity (CD) value, the higher price for LED spotlights, that is, the farther the LED spotlights shine, the higher price it is. Instead, the greater the angle is, the cheaper it is, because the LED is the surface light source, if you want to make the angle small within a certain size, it requires considerable experience and technology, otherwise, black center will appear at central light spot, which will affect vision.


Maybe we are not the most professional for the application of lighting fixture, but we can always meet folk masters, in order to find a suitable size and good cost performance light, spend a lot of time, or you can install the following xenon spot light:

light bar

The long-range ability is good for this xenon light, but the problem is it can not startup quickly and flash, the spotlight shell is plastic, easy to have water in, and the service life of xenon light is much shorter than LED, the most critical is too big, only big truck can match this size.


Do you think the lamps in Figure (2) are obviously brighter than those in Figure (1)? In fact, this is the same lamps, but the actual effect is too dazzling, so we deliberately shorten the exposure time, so that the photos can be more clear and softer. Look at figure (3) and figure (4), there are many such figures(4) online, but such brightness is believable? , not necessarily, from the left figure (3) to the right figure (4), there are two ways to realize that, one is to deliberately prolong the exposure time, or raise sensitivity on a camera or cell phone camera, the other is to adjust the exposure intensity via PS directly, so easy, so regarding those abnormally bright images, you should distinguish carefully, perhaps it is treated, in fact, it's not that bright at all. Is there any way to identify, yes, contrast to see, i.e., take the one you know or heard about brightness to compare with the lighting fixture, just like above compare Hella 6 + Philips XV 4800 k (+ 50%), the brightness of this configuration is known for all, can't do fake, moreover, check the dynamic video, you can make photos brighter via PS, but the video is multi-point dynamic, there is no way to change that, as diagram below:

Such a contrast can identify whether this lighting fixture is bright or not directly, checking one lighting fixture itself only, it is not easy to find the brightness of lighting fixture. For example when the photo was taken, a car happened to drive into the industrial zone, which caused low beam was invisible, we immediately switched into high beam, but it's still no use, thanks to look at the image below, then you will know that. You could only see yellow red light on left&right walls regarding high beam, and could not see any high beam effect on the ground. Based on the height of yellow red light on the wall, you will know it is high beam, because low beam could not be so high, even could not be over the roof of the car on the right side. 

light bar

As we all know, there are only three basic colors, red, green and blue, while other colors are just made based on different content proportions of these three basic colors, as shown in the upper right corner of the picture:


Visible light can be divided into the maximum wavelength of 780nm, red, orange, yellow, green, blue, indigo and purple and the shortest wavelength of 380nm. White light is a mixture of these colors with different proportions. As can be seen from the figure above, blue light occupies a high proportion at a color temperature of 6000K, while yellow and red light occupies a high proportion at 3200K. There is a direct relationship between the wavelength and the refractive index, the wavelength of blue light is shorter than that of yellow and red light, so it is easy to scatter, that is why the sunny sky is blue when the sun light shine to the earth, that is blue light is scattered to the whole sky. Taking another example of the low beam of Koito Q5, blue cutting line, there is actually blue light in the low beam, but was mixed into white by other colors, different tangent position and refractive index of light, so the blue edge is left, which is like the effect of prism. Do not think it is specially made, the blue tangent line actually affects the sight, and you will feel tired if you look at it for a long time. In the same situation, the scattering ability of blue light is more than five times than that of yellow red light. Yellow red light is hard to scatter, so it penetrates better, it shines through and then is reflected back.


Blue light gives people a more striking feeling, while yellow light is more likely to give people a comfortable feeling. For example, in bedrooms, restaurants and relaxing occasions, light with high color temperature will give people a feeling of vitality and concentration, that is why to choose the high color temperature in office or formal places, as well as car lights. But it is not the higher the better, 6500K is a limit, more than that will give a person dizzy feeling, and comfortable color temperature is 4000K to 6500K. Why does 4500K on the above picture look so yellow, while 4500K on the following picture looks white? Yellow can only be seen when it is hit on a white wall or white paper, but when it is actually illuminated, just as following situation, it is not so yellow, so we should pay attention to the difference. The color temperature contrast among each manufacturer is also slightly different. For example, Philips with the same color temperature is a little whiter than Osram. You can refer to the actual situation or ask other buyers for help.

In addition to color temperature, there is also a color rendering index:

When using a illuminometer to test, it will be found that under the same conditions of other parameters, 2700K is 95,3000 K is 96,4500 K is 99,6000 K is 100, that is, high color temperature is a little brighter than low color temperature, but definitely not more than 5%, and more than 5% is human illusion. As mentioned above, the content of blue light is higher in white light, which makes it look more conspicuous, but the color rendering index is lower, while yellow light has a higher color rendering index, and color rendering is the ability to restore the color of the object itself.


Balancing color rendering and illuminance, in fact, they are the same bright, the high color temperature is just a feeling of brighter, this brightness is not the actual brightness, but is eye-catching. Do not have a superstition that white light must be brighter than yellow, bright or not depends on illuminance value (Lux. Illuminating far or not depends on Candela (CD) value the luminous intensity.


We have seen these three light, think back, white light is a mixture of light with several kind of colors, more white is because more blue light, yellowish is because more red and yellow light. Look at 3500k and 5400k in the picture, you will understand it, if you want light with specific color temperature, even if the factory don't have the color temperature, you can also DIY, approximate calculations are as follows:

You add up the percentage of light color temperature at each point and you get the actual color temperature at that point.

For example, as shown in the figure above: 4300K*1/(1+1)+6500K*1/(1+1) = 2150K+3250K = 5400K, the total luminous intensity 1+1 here is the flood light irradiated directly without reflection of the reflector, and the power of LED lighting fixture is the same, which can be considered as 1. Real calculation, if upgrading the original halogen bulb, replacing with a bulb with higher color temperature, whether to replace low beam or high beam, what color temperature to set, which can be set according to your preference, there is a small overlap for the low&high beam of the original halogen headlight, and the color temperature is generally no more than 4500k to 4800k, the effect is OK to pierce light rain and fog, but for really heavy rain, believe me, turn on the low beam and front&rear fog lights, then drive slowly, you can not drive very fast, so there is no need to pursue a color temperature of 3200K to pierce rain and fog, except for those who like yellow light. The color temperature will be mixed when the light comes together, two kinds of similar light, the color temperature of their mixed light is between them, which is why a lot of drivers with halogen headlights feel they could not distinguish whether it is light from street lights or light from headlights, due to mixture of color temperature, when driving under the street light, especially the yellow light street lights, just feel the headlights are very light, like off. While when it is white light street lamp, the white light is more eye-catching than the yellow light of the headlamp, you will also feel the headlamp is very light, and the reason is also here.


If modified into a double optical xenon headlights, the high beam has to be matched, there is some overlap between the high beam of xenon and that of original halogen, but the luminous intensity of xenon headlights is much higher than that of the original halogen high beam, so you need to pay attention to color temperature when choosing halogen bulbs, not more than 4800k after color mixture, or it will be blind when raining, for example, if you choose the CBI5500K for xenon light, then you need to choose below 4000K for halogen, so the mixture will be about within 4800K, if you choose 5000K of bright white or blue diamond series, then the color temperature can not be mixed down, when it rains, try not to drive at night.

There is no absoluteness for everything, no any color temperature could be suitable for all the conditions, just optimization, for example, the scattering of light is more serious in rainy and foggy days, and the optimal color temperature is 3200K-5000K. The higher the color temperature is, the penetration will be weakened. In heavy haze days, it will be better to use within 2800K-3500K. Dirt road in the countryside, including snow field, too white color temperature will be very dazzling, while the reflection rate is low for the high speed, yellow light is not eye-catching, it will be lighter, so the preferred 4200K-6000K will be more appropriate.


Rural dirt road > urban road > sate & provincial road > highway > rainy road

Soil is a good thing, the soil on all roads can enhance reflectivity, which allows the driver driving at light a good field of vision, or why the reflective rate is very low on the air dried high-speed road surface, after the heavy rain at night, which is also why many drivers feel their car lights very bright on the dirt road, but just like off on the highways. 

Some people prefer white light, then let us take a look at the picture below. If you want to be comfortable, the color temperature is high, the corresponding illuminance must also be high, which means that the luminous intensity should also be increased accordingly.


With the growth of age, the cornea and crystal of eyes will become cloudy, so the requirement for brightness will be higher, when parents can not see clearly, do not blame them, really not intentional, in addition, you’d better to choose brighter light for parents’ home, while for children's room, brightness can be a little bit lower.

For those 10 years old children can see clearly, 30 years old adults requires 2 times of illumination to see clearly, 3 times of the brightness for 40 years old, 6 times of brightness for 50 years old, which is why we really can't answer how far the light can shine when asked by many people at most of the time, the same light, the age and eyesight is different for each person, so the long-range people can see also differs for each person, plus different driving road condition, we will not deceive buyers like other merchants. After all, conscience is more important than making money. But as far as the lights are concerned, it is not a bad thing to be able to shine a little farther, safety comes first.


After modifying the xenon light, or having installed top xenon headlight package, why do many people still feel that their lights are not bright enough, or not look as bright as expected, and why others are very bright after being installed those lights?

First of all, you can see light, which means there must be light coming into your eyes, then there are basically three ways as below:


Direct light from the light source, transmitted light and reflected light after the object is irradiated by the light source can be seen by us. Then the car is installed with xenon lights, and the irradiation situation is shown as the figure below:


Car B modified the xenon light, in fact, most of the light irradiated is reflected forward, only a small part is reflected back, which is seen by the driver of car B, and the driver of car A at this time can see much more light from car B than the driver of car B. This is the case, after refitting the xenon light, others look very bright, but yourself feel just so-so, not so bright as IMAGINED.

Analysis of refitted lighting fixture at home and abroad

Relatively speaking, foreign modification market is already quite mature, after all they have gone through many years of development, but domestic market is just emerging for a short time. Most of foreign modification is violent modification and modification for outdoor traveling, while the domestic violence modification, outdoor travel, fill-in light for high beam (the response to rouge high beam), but no matter how modify, it all requires case by case. Violent modification is similar at home and abroad. In terms of workmanship and professional light distribution, most people don't understand that, could only find professional modification shop to make it. For outdoor travel, fill-in light for high beam(including response to rouge high beam), all of these are modified in accordance with your own ideas. Some people do exceed, quite professional, and what we do is to conclude those exquisite program and wonderful conception for your reference, may be not the most authoritative, but there is definitely a certain reference.

In terms of installed auxiliary lighting fixture itself, we divide it into two categories, one is shining far, so-called far is a small angle and concentrated central light spot.


While the other kind is the shining wide, that is, the angle is large, the irradiation range is relatively broad, used for off-road, mountain climbing and wading, just these two kinds, in fact, it is very easy to distinguish, usually we use these two kinds of lighting fixture for collocation, in order to achieve the effect of auxiliary lighting.

light bar

Other lighting fixture are between these two kinds, how to distinguish them after all, also very simple actually From the design.

light bar

Comparison and analysis of LED lighting fixture design :

We all know that a parabola can make the light coming from the focal point go out in parallel, so it shines far, while the focal point is actually a virtual point. In reality, many sources of light are not points, but a little bit bigger than the virtual point, so the light coming out in parallel will go out at an angle because the focal point becomes larger.


Only two factors decide the angle of the light coming out, one is the size of luminous point at light source, the other is the size of the reflective cup, both determine directly the angle of the emergent light of lighting fixture, angle of emergence directly determines how far the lighting fixture can shine, since each light source have no endless luminous flux, but limited flux, how to reflect to a small angle so as to achieve long shots, it depends on the concentrated degree of each lighting fixture, normally the manufacturer of lighting fixture get almost same LED light source, so they could only do something on the reflective cup, but both lens and reflective cups must follow above principle, just like the principle of conservation of energy, no one can transcend the theorem. Therefore, car spotlights on the market are mainly divided into three kinds:

The first is the reflector version:


The central light spot on above pic is the light reflected by reflective cup shines at the certain angle, and the angle of floodlight is easy to understand, that is the light shines from light source directly without reflection by the reflective cup. The central light spot is 4 degree for the reflective cup with the opening diameter of 70mm(this is not nonsense, but the value measured by the optical darkroom distribution photometer). The same 10 watts CREE bead, supposing both is 1000 lumens, the floodlight angle is the same for two reflective cups, the floodlight angle is 58.82 degrees, it is the same for reflected flux reflected by the two reflective cups, just the center light spot is 4 degrees for reflective cup with 70 mm diameter, while it is 14 degrees for reflective cup with 35 mm diameter. Regarding the illuminance at the same distance, the illuminance of the central light spot from a 70MM diameter reflector is more than 10 times that of the central light spot from a 35MM diameter reflector, because the cross section of 14 degree at any distance is more than 10 times that of 4 degree in area.


So, a 10 watts 4 degree can have the range of 100w light bar, just a small light spot, a big light spot, so LED lights of reflective cup with large diameter is particularly suitable to be installed on the roof or grille as fill-in light for high beam, while light bar of reflective cup with small diameter is especially suitable for installation in the front bumper or on the roof, forming a broad vision. But the wattage should not be too large for the light bar installed on the front bumper. Specific installation methods and ways will be detailed in the following practical applications.

Some light bars use 5W beads, the diameter of reflective cup is reduced by 1/2, to be very thin, so the overall light angle is also in the range of 15 to 60 degrees, this kind of light is excellent for floodlight or close lighting , such as engineering vehicles or tractors lighting within 50 meters. So if the reflective cup is too small, no matter single row, double row, or 4 row long light bar, it could not illuminate far, but do not mean it won’t work well for close lighting . Therefore, to shoot long distances, there are only two ways, one is to reduce the size of the light source, while the other is increase the size of the reflector. With lower cost, these two methods are the most direct and effective. For lighting fixture of reflective cup, the most amazing is that the light emitted by LED can be used 100%, either in central light spot, or on the floodlight, at least can also be as auxiliary lighting, but the angle of the central light spot is different, and you should pay attention to distinguishing when using.

It is also easy to distinguish whether LED reflector is spotlight or floodlight type, as shown below:

spot flood light bar

Within 15 degrees can all be called spotlight, but does not mean the spotlight lighting fixture will be able to shine far for sure, in fact, the design itself is very relevant. It's like "Not every kind of milk is called Terenzo."

Let us look at another group

light bar

It is the original CREE bead with 25 watts spotlight on the left, which is much brighter than the imitation beads(that is, the low price product) on the market. The comparison picture with the small light bulb with 10 watts and 4 degrees is as above:

It is obvious that the small light bulb of 10 watts 4 degrees is much more focused, and the center brightness is also much higher, this is the origin of the long shot, but do we still check the watt to determine whether it can shine far?

Take another look at the comparison of the small light cannon series with the 25 watt spotlight.

The angle of this lens itself is already beyond 15 degrees, plus the actual tolerance and technology, more than 10 degrees is a small angle for these long spotlights, of course, there is the larger angle, that is better floodlight. The advantage of this program is that the light emitted by the LED light source is 100% used, but the lens itself has a transmittance problem according to the different material, and the transmittance is about 65~95% for the general lens. That is to say, the LED emits 100 rays, only 65-95 rays shine out, but the raw material of high transmittance lens is imported at dozens of RMB a kilogram, those lens sold at one, two or a few cents, transmittance is self-evident.

The advantage of this convex len is: can really make angle at about 12 degrees, but use ratio is too low, on above pic, regarding the light from LED before upgrading, only those conforming to focus can be utilized, the light around angle A at pink area is abandoned directly, after the upgrade, with the reflective cup, combined with the convex mirror, utilization rate is not improved a lot, because the light irradiating in parallel through lens is still from point light sources, while light reflected through reflective cup still do not conform to the logic of receiving the light for lens, and has been mercilessly abandoned. Whether upgrading or not, there is a circle of yellow halo outside light spot, which is design flaws the lens can not overcome, because it is hard to avoid dispersion after the light is refracted, which will affect the sight a bit, of course, there are benefits, that is the penetration of yellow light is better in rainy and foggy days. If this kind of lighting fixture is used for far-range lights, the wattage of the same light can not be too high, otherwise the long strip spotlight is almost same lighting effect as lens flashlight with a bit larger wattage, there is no floodlight at all. Those who used telescopic flashlight will know how the light spot is like. Of course, there are also advantages, that is super cheap, the so-called you get what you pay, but since ancient times, there has never been good quality and cheap price.

Most of lights of lens version, regardless of a few D or a few F, there will be a situation, that is, it is bluish for the center of light spot, white for the outer ring and yellowish for the outer edge, this is because the white light is dispersed when the lens concentrate the light, which will affect the line of sight a bit, but it is also said that the yellow ring on the outer edge has a better penetration in rainy and foggy days.

Bluish for the center of light spot, white for outskirt, yellowish for the edge



We have detailed the relationship between angle and installation position on above, and there is another important reference value, that is light intensity, the figure below is the reference value of the angle and light intensity for some lighting fixture, such as the long light bar of 300 watts diameter 35MM reflective cup version is:

(8835CD /10 watts) *300 watts = 265,000 CD,

The 120-watt 5D all-spotlight model is:

(12,000 CD /10 watts) *120 watts = 144,000 CD


The reflective cup with same size, the revolving reflective cup has the best spotlight effect, namely the kind of small light cannon, the long-range effect is poor for square and anti - buckle type, but the anti - buckle type can make low beam tangent and good appearance effect.


If high beam is made in such shape, the results will not be particularly impressive. Take an overall consideration of price and room for next upgrade, it should be slightly better than the previous halogen, can only say more modification, the better, but there should be a far distance compared to Hella 5.

work light

Some people say that the imported light from big companies shine far, I just want to say, please believe above-mentioned science, of course you can also spend money on experiences, which is the fastest, several thousands even tens of thousand, 20 watts rectangular light on the left is auxiliary light installed on the front bumper of Raptor, the light is auxiliary light that shines within 80 meters in front of the car, if the original car has a good low beam, such light can be not installed. It is 111 watts LED spot light on the right, the light angle is above 20 degrees, bright enough, but whether it shines far or not, not sure, although it is reflective cup + lens design, but the middle lens is of no use, as mentioned before, such big lens could not concentrate lights, let alone the small one.

The key here is coming, those lighting fixture which use single LED lamp bead, the effect is that of the reflective cup, this effect here is the light angle and the luminous intensity of lighting fixture, while for those with multiple beads, such as the above light is four small lens, and the long light bar is a row or two, three or four rows of beads, how to know these ones, see the figure below:


It is α for the angle of central light spot projected out by single bead, forming a light spot with diameter D in the distance. Let us take 10 watts 4 degrees as an example, this is lighting fixture with very small angle, L for 10 watts four degrees = it is D at 100 meters = 7 meters light spot, then putting two 10 watts four degrees auto spotlights together(as position in above picture). The distance between the central axis of the light spot is about 0.085 meters, that is to say, two 7-meter light spots overlap at 100 meters, and it is 0.085 meters for the distance between the center of two 7-meter light spots, which is two light spots come together. 0.085meter can be almost ignored compared to 7 meters. When it reaches 200 meters, 0.085 meters is compared to 14 meters, only 0.6%. So, see, either four or eight, or 30 beads, a row, two, or four rows when installed, the distance of small d could be negligible. Will you still tangle whether the bead is square, or a single row or four rows for lighting fixture? The final effect is the effect of a single bead + reflective cup or lens, and the total light angle is same as that of the single bead + reflective cup or lens. The greater the power, the luminous intensity will increase, but the angle is the same, see it clearly, also called light angle.

So to buy long spotlights or spotlights with a number of beads, if a single reflective cup or lens is the same, the light effect is the same, only considering the installation and appearance, as for the shape of the light spot, it is all the same, do not tangle those unclear information.

Taking the high beam as another example, when proofreading on the wall at 7.6 meters, the center distance between two high beams is the width of two high beam headlights, but two light spots overlap together after dozens or a hundred of meters. Although it is still about 1.2 meters for the distance between the center of two headlights high beam, the width of high beam is at least above 30 meters at the distance of 100 meters, and 1.2 meter can be ignored. And even if the distance is 1.2 meter between two light spots, it actually looks like they're together, as shown below:


No need to worry too much about where to install the lights on the top of your car, and the effect is almost same. Take a look at below image:


The installation position of the four lights 100 meters away can be ignored because of the overlap of light spots.

The light spot is overlapped, the farther the distance is, the less influence the installed position of four lights will have, as mentioned above. Therefore, the spotlights should be installed as wide as possible on the crossbar of the roof rack, so that the visual sensation will be more comfortable, as shown below:

light bar

The wiring harness is divided into two kinds, switch wiring harness and remote control wiring harness, in fact, the difference is there, regarding remote control wiring harness, Unplug 2. the wire terminal and plug into each other, then the 4. remote control & control box are removed, and it is turned into a switch wiring harness. Such wiring harness is not waterproof, so.. it can only be used in the car modification, and you have to install control box and relay and so on in the nosing cover. Someone used this modification wiring harness before, but the remote control was burned after the car was washed. There is no such thing as an innate knowledge of experience. It is all learned step by step. It is important to share.

wire harness

Many people may not understand why to use such a professional modification wiring harness. Generally speaking, such as 100W light, 12V power supply, the light will consume almost 100W/12V=8.3A, while the ordinary switch, pass through 8.3A after a long time, it is too small for the shrapnel contact surface of the switch, so it will heat, even can cause fire. Therefore, switches in the car are generally to control signal line, so as to control the relay to switch the large current. Modification wiring harness must have the relay, even if the wire is modified by yourself, you must also add the relay.

Fuse box is also a must, once accidental short circuit occurs, the blown fuse inside the fuse box can save a life. When installing the wiring harness, you must connect the light first, check the wiring, and then connect to the negative electrode of battery, the positive terminal is touched the positive terminal pile of battery, the light is on when touching, there is no problem then connect it, otherwise the fuse will be blown if any accident, but that is fine, the fuse is for cars, which can be bought anywhere, no need to worry.

fuse holder

The maximum carrying power is about 280W for the general remote control wiring harness. On the one hand, the national standard copper wire of 2 square can support the current of 25A, which is near the upper limit. The relay is 30A, and the power is about 360W. The wire must be covered with silicone insulation tube, otherwise the wire is easy to age.

Modifying switch

Switches in the car can be diversified, it is best to use the reserved switch of the original car, of course, you can also choose your favorite style, as shown below:


The device is on only when the light is on, the way of connection is when the light is turned on, the light on the switch is also on, and all is off when the light is off. In fact, the installation position depends on your won preference, some make a hole directly on the right side, install a cat eye switch, and it is also OK.

Way of connection

Connection way, there are two optional choices, one is the switch + strobe remote control, namely, both switch and remote control can control the light, and they can even control each other, that is the light turned on by the switch could also be turned off by the remote control, actually strobe is used seldom, most of the time the light is turned on or off with remote control, such as you go out of the car and turn off the spotlight with remote control at 30-50 meters away, or when you're looking for your car, it is also OK to turn on the strobe. Normally, the chance of strobe is low. Wiring is very simple for both.

The relay and control terminal of remote control is live 24 hours for such wiring way, otherwise, the light could not be turned on by the remote control, but do not worry, the standby power is about 0.8 watts for relay and remote control module, the power is about 2 watts for starting up, still relatively small.

The other way is follow-up with high beam, the advantages of this way is a switch is connected in series in the circuit control, when the switch is on, high beam on, spotlight on at the same time, when the switch is off, high beam on, but spotlight off, and the switch in the car also has an indicator light. When the spotlight is not used at night, just turn off the switch, the indicator light is off accordingly, relatively speaking, it is suitable for driving on highways, and also suitable for flashing lights in urban areas.

Here to pay more attention, the positive and negative of control line for relay and the switch draw electricity from the high beam, total power is about 2 watts, not very big, not affecting the use of high beam, but the spotlight take electricity directly from the battery, be sure not to let the relay take electricity from the positive pole of high beam, while negative pole takes electricity from the battery, it will form a loop, may burn the control panel or computer board of headlights directly, be sure to keep in mind. It was original, but it came at a cost

For three meters long wire, the place where to connect the exposed wire, be sure to keep away from the exposed wire, to avoid two wiring heads hindering each other, wiring is best to use soldering iron welding, if there is no condition, it should also be twined several more laps, increase the contact area, in order to reduce the heat generated by the contact resistance.

Wind resistance

Generally speaking, spotlights installed on the roof should take the wind resistance into account, as shown below:

The flow direction of wind speed on the roof, and the wind can pass through the side of the roof spotlight, so that the wind noise is the lowest and almost can't be heard.


When spotlights of the small light cannon series are installed on the roof, the air flow can pass through the side of the spotlights, as shown below:

light bar

This will not produce the wind noise, if the spotlight is installed on the roof directly, such blocking one row, its wind noise is very large, as shown in the following figure (1), making holes directly on the two bars of the roof rack to install strip spotlights has the same effect as such one.

light bar

Strong magnetic pattern in figure 2 also has big wind noise, but there is another problem to pay attention to, when putting on the solid iron, the magnetic force of strong magnetic is very big, but the roof is generally a thin layer of iron sheet, the magnetic force will be reduced greatly, which should be pay attention to. Some roof is thick, then the suction is strong, while some roof is thin, the suction is small. You need to test by yourself.

No matter cars, off-road vehicles or other vehicles, when installing spotlights on the roof, you’d better to install them as far back as possible. The farther forward, the closer to the position of the windscreen glass, the higher the wind noise is, as shown below:


Besides, the farther forward, the higher the brightness of the floodlight hit in the head cover, there will a risk of background glare, installed backward as far as possible, keeping the floodlight out of the nose cover, which is the most ideal effect. When installing backward, you should pay attention not to let the roof block off the main beam, for the moment, installing four spotlights of small light cannon on the cross bar of roof rack, whether installed on the roof of cars or suv, You can't hear a sound at 110 yards if you close the window. Relatively speaking, the wind noise is very low.

In addition, after all spotlights are installed on cars, it does not take only one time to tune the lighting effect. Basically speaking, tune to be an approximate effect first, after driving for a few days, fine-tune it according to your own habits, usually it can be true-up after tuning two to three times. Secondly, LED auto spotlight belongs to the electronic products, so you need to light it up a few minutes every other month, if off too long, the light is probable not to work.

The above content is the principle and steps for modifying halogen headlights, xenon headlights and LED lights. I believe after you read, you will benefit a lot. We hope you can continue to follow our nilight brand. We not only sell high quality car lights and accessories, but also continue to post high quality blogs of car lights.

You can find more details below these articles:

 1. How many amperes does the led light bar consume 

 2. Fuse sizes for 12v LED lights: Use and Prevention

 3. Is the light bar legal

 4. What size wire should I use for my LED light bar

 5. My light bar has completely or partially stopped working 

 6. How to choose the best LED light bar for your vehicle

 7. How to Wire a Light Bar with a 5 Pin Rocker Switch 

 8. Best placement for auxiliary LED lights 

 9. Why do you need a harness kit for Off-road LED light bars 

 10. How many watts of good LED light bars are suitable for car use 

 11. Offroad Led Light Bars Installation Manual

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