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In Part 1, we explained the basics of halogen and HID headlights, including how they work and how to replace them correctly.
In Part 2, we’ll show you how to choose the right projector lens, when a projector LED setup is the better option, and how to select the right LED headlight bulbs for your car.
If you’re planning to upgrade from halogen to LED or install projector headlights, this section is for you.
If you only need to replace your halogen or HID bulbs, you can simply go back to Part 1.
Índice
2.1 Projector Lens
A car headlight “projector” means the whole unit that includes the lens and the reflector. People usually just call it the projector. There are two types: single-beam and bi-beam projectors.
Single-beam projectors
A single-beam projectors is a lens module that provides luz de cruce o de carretera, but not both. Usually, it handles only one type of light. In most factory setups, single-beam projector systems are used for low beams, while the high beam comes from a separate reflector or another independent lens.
Dual-Beam Projectors
A dual-beam projector is a lens module that can provide both low beam and high beam in one unit. It uses a motor shutter to switch between the two beam patterns without changing the bulb.
Single-Beam Projector vs Dual-Beam Projector
Item | Single-Beam Projector | Dual-Beam Projector |
|---|---|---|
Function | Only low beam or high beam | Low + High beam in one lens |
How It Works | Fixed shield → only 1 beam | Movable shield (solenoid) → switches beams |
Switching | Uses separate lamps | One lens switches instantly |
Rendimiento | Low beam OK, high beam limited | Strong low beam, wide and long high beam |
Coste | Baja | Más alto |
HD Projector Lens VS. Fresnel Projector Lens
A clear HD projector lens has the best light transmittance, but brightness alone doesn’t guarantee better visibility. What really matters is contrast and even light distribution. This is similar to a phone screen that adjusts brightness based on your environment so your eyes feel comfortable.
Projector lenses with Fresnel patterns spread the light more evenly, giving smoother road illumination. They also make tiny defects—like dust or bubbles—less noticeable compared to HD lenses, which magnify every flaw. The effect is comparable to a shadowless surgical lamp, where multi-directional light ensures clear, unobstructed visibility.
When Should You Use Projector Lens?
Not every lighting problem can be solved by simply replacing with bulbs. In some cases, only a projector lens can deliver the beam quality, focus, and visibility you need. Here are the key situations when upgrading to a projector lens is the right choice.
1. Upgrading Halogen to HID Bulbs
Without a projector lens, your original halogen bulbs already produce a proper cutoff line because they are carefully designed by the manufacturer. However, if you retrofit HID bulbs, the results may change. HID and halogen bulbs have different light sources, so installing HID in a halogen housing can cause glare.
2. Upgrading to LED headlight bulb leads to glare light
When replacing your halogen bulbs with LED headlight bulbs, you may notice unclear cutoff lines or diffused light. In this case, consider using a projector lens, otherwise, the beam could blind oncoming traffic.
3. You car uses original halogen projector lens
Some customers have cars with original halogen projectors and assume they can just swap bulbs. But the results are often disappointing. Halogen, HID, and LED bulbs have slightly different light positions, and even a small shift can throw off the focus.
The most effective way to upgrade is to replace the entire halogen projector with a projector specifically designed for LED or HID bulbs.
2.2 Best Bi-LED Projector Lens Brands
OSRAM
A renowned German lighting brand, OSRAM specializes in high-performance automotive light sources and projector lenses, offering bright, long-lasting, and reliable solutions.
👉 Key Product: Osram LEDriving CBI PRO Retrofit LED Projectors
HELLA
A leading German automotive parts company, HELLA develops advanced projector lenses and OEM lighting systems with precise optics and durable quality.
👉 Key Product: Hella Bi-LED Projector Lens L 4565 Performance
PHILIPS
A top Dutch lighting company with extensive automotive experience, PHILIPS provides innovative LED and HID projector lens solutions for safety and high brightness.
👉 Key Product: Philips Ultinon Drive Projector lens
2.3 How To Install Bi-LED Projector Lens
1. Open the headlight:
Remove the headlight from the car and heat it to soften the sealant. Then separate the lens from the housing.
2. Install silicone base:
Place the silicone base on the projector lens for support and sealing.
3. Mount the projector:
Insert the LED projector lens into the reflector opening and lock it using the threaded shaft.
4. Add bulb base:
Attach the correct bulb base (H1, H4, H7, 9005, 9006, HB3, HB4).
5. Fix with screws:
Secure the projector in place and make sure it’s aligned.
6. Wire it:
Connect high/low beam wires following the diagram. Use the included adapters if needed.
7. Reseal the headlight:
Apply butyl sealant and close the headlight to prevent moisture.
8. Reinstall:
Put the headlight assembly back onto the car.
2.4 LED Headlight Bulb Modification
Why LED Headlight Bulb Becoming Popular?
LED headlight bulbs are quickly becoming the go-to choice for car lighting, and it’s easy to see why. Compared to halogen and HID, they last longer, shine brighter, and light up the road farther ahead. Over time, they can also save you money, making them a smart investment for any driver.
Experts now expect car makers to make LEDs standard, and in the next 30 years, up to 75% of all car lights could be LED. In the meantime, a quality, affordable LED headlight kit can give you years of clearer, safer night driving.
👉 Click our previous blog to learn 10 benefits of using LED headlight bulb in your car.
Can Original Halogen Upgrade To LED Headlight Bulb?
When switching to LED headlight bulbs, the question we hear most from customers is: “Can I install LEDs in my halogen headlights?” The answer is yes! But before you switch, make sure to check your local regulations, and choose LED bulbs with proper certifications like DOT, RoHS, or E-mark.
Besides local regulations, some customers worry about compatibility. In most cases, LED headlight bulbs are designed to be direct plug-and-play replacements for halogen bulbs.
However, for certain sensitive vehicles, like German cars, Korean cars, or older models, it’s recommended to choose low to medium wattage LED bulbs to avoid headlight bulb blowing fuse and Canbus error codes.
Upgrade To LED Headlight Bulb, Should I Need Projector?
When upgrading to LED headlight bulbs, many people wonder whether LEDs work well without a projector. The truth is—it depends on your headlight housing, the quality of the LED bulb, and what you need.
If your car already has a projector headlight, you don’t need to add a projector lens.
If your car uses a reflector housing, you can choose a high-quality LED bulb with a good cutoff line, and you won’t need a projector either.
But if you are not sure if LED headlight bulb will emit a standard beam pattern, then using a projector lens is a better option. Just keep in mind that some reflector headlights require more complicated modifications to install a projector.
Tipo de faro | Do You Need a Projector? | Notes |
|---|---|---|
Original Projector Headlight with LED bulb | No | The projector already controls the cutoff line. |
LED bulbs in reflector headlights produce a clean cutoff line | No | Choose LEDs that provide a clean cutoff line in reflectors. |
LED bulbs in reflector headlights that produce glare | Sí | Use a projector if LEDs cannot produce a clean cutoff. |
3 Factors To Consider When Choosing LED Headlight Bulb
There are countless LED headlight bulbs on the market, making it confusing to choose the right one for your car. To help you decide, here are 3 important factors to consider before making your purchase.
1) Standard Beam Pattern
Only an LED headlight bulb designed with a 1:1 lighting position like halogen can produce a clear cutoff beam pattern. This means the LED you choose should have the same light source position and narrow emitting area as the halogen bulb.
2) Compatibility
Before upgrading to an LED headlight bulb, make sure to select the correct bulb type. For example, if your original halogen bulb is H4, you should choose an H4 LED bulb. If you buy the wrong light bulb, it won’t fit in your car.
3) Brightness
LED headlights aren’t always better just because they’re brighter — the best choice is the one that fits your needs. If you have a tight budget and just need enough light to see at night, low to medium power (20–55W) is sufficient. If you drive frequently at night and want upgraded brightness, choose a high-power LED bulb (above 55W).
👉 Also Read: Cómo es una buena bombilla LED para faros delanteros
2.5 Step-by-Step LED Headlight Bulb Installation Guide
- Find The location of original halogen bulb
- Open spring up, take out halogen bulb
- Take off the metal base from the LED bulb and put it on vehicle housing
- Install the mental base and fix it with spring clip
- Install headlamp into chuck, make sure the lamp beads face vertically
- Connect the headlamp wire with car battery.
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