How to choose the right LED headlight bulbs?

Choosing LED bulbs PSX26W

Choosing the LED bulb

Modern vehicles are produced with headlights that use light sources of four types of design: simple incandescent, gas-filled (xenon, halogen) and LED.

Recently, LED lamps (light-emitting diode) have become popular in the home, at work, as well as with motorists. The main reason for the increased demand for these lamps is that they have a higher luminous flux with less power, and longer life compared to conventional ones.

The main requirements for LED lamps for cars

Before you choose or buy LED bulbs, it is worth determining whether they are suitable for your type of headlights. Because structurally LED bulbs are longer than conventional. Or rather, not the lamp itself, but its shank. The reason for this is the need for radiators to cool the LEDs and the presence of a driver in this type of lamp. This is a device for stabilizing current. And increasing the length of the lamp may not allow you to install protective covers on the base of the headlight.

led vs halogen bulb

LED vs Halogen Bulb

Next, you must examine the light emitted by the bulb.

How bright and high-quality it will depend on several factors:

  • The power of the emitter
  • Luminous flux
  • Color temperature
  • The orientation of the light

The luminous flux of a lamp is the brightness of the beam emitted by the source and is measured in lumens.

If most lamps with power and luminous flux, all the same, the color temperature everyone chooses to his liking. But the directionally of light is the main problem of LED lamps for cars. Because of the differences in the design of the emitter is difficult to provide the same light distribution in halogen and LED-lamps. Hence, the problem, is that the optics are originally designed for halogen lamps.

led bulb construction

LED Bulb Construction

LED lamps are divided into two groups based on the type of LEDs:

  1. SMD – in this technology LEDs are fixed on the surface of the bulb. Therefore, they are easier to install, and they have less power consumption. This technology is used to make LED emitters with a capacity of 10 watts or more, giving a very bright light without additional installation of scattering lenses;
  2. COB – LEDs made with this technology, installed directly on the board, which reduces the volume, improves the uniformity of the light beam, provide greater heat dissipation from the diodes.

HID Halogen LED

HID, Halogen, LED Bulbs

Nominal power and luminous flux for each socket

The nominal power of the lamp is specified in the passport of the car, according to it choose fuses, as well as the cross-section of the wires. Luminous flux, in turn, must also correspond to the type of lamp and optics to ensure sufficient illumination of the roadway in front of the car.

Here is a summary from the OSRAM catalog of the various halogen lamp ratings:

  • H1 55w – 1550 lm
  • H3 55w – 1450lm
  • H4 60w – 1650lm high beam, 1000lm low beam
  • H7 55w – 1500 lumens
  • H8 35w – 800lm
  • H9 65w – 2100lm
  • H11 55w – 1350lm
  • HB2 60w – 1500lm high beam, 910lm low beam
  • HB3 60w – 1860 lm
  • HB4 51w – 1095 lm

HIKARI H7 LED Headlight Bulbs

HIKARI 2021 Acme-X 9004/HB1 LED Bulbs

Technical Details

  • Easy install
  • 10000 lm
  • 6000 K Cool White



Technical Details

  • Color Temperature 6000 Kelvin
  • Type of Bulb LED
  • Voltage 14 Volts

PHILIPS Ultinon LED H7 Bulbs

PHILIPS Ultinon LED H7 Bulbs

Technical Details

  • Type of Bulb LED
  • 6200K bright white light
  • 160% brighter

The power of LED lamps is an order of magnitude less than that of halogen bulbs with the same brightness. This means that the heating of the LED lamp will be less, and the power consumption, respectively, will be less. Power LED lamps to vary with each manufacturer.

Therefore, you can find an LED bulbs on the market of the same type, but with a different power: 5.5, 10, 12, 15, 30, and even write 50 watts.

The temperature of the luminous flux determines what color the lamp will shine. It is measured in degrees Kelvin. The table below shows the correlation between the shade of light and temperature.

Bulbs temperature

Tint of light Temperature
Warm yellow 2700–2800 K
Warm white 3000 K
Neutral white 4000 K
Cold white 6000 K

led bulb temperature

Bulbs temperature

The higher the color temperature of the light, the cooler its hue.

The temperature of the light determines eye fatigue when driving at night and the blinding effect on drivers of other vehicles.

Although the blinding effect depends to a greater extent on the proper adjustment of the lamps, the headlights themselves and the design of the lamps. Therefore, after installing the LED lamp, you need to adjust the direction of the light beam on a special stand.

Adjust Headlights

Aiming Headlights

Pros and cons of LED car lights

Before we explore the advantages and disadvantages of LED lamps, once again compare their performance with halogen and xenon light sources, but already on the life of the table below:

Parameters LED Xenon Halogen
Power Consumption 3,5 W 35 W 55 W
Lifetime 25000-50000 5000 500

Pros of LED bulbs:

  1. With less power compared to halogen bulbs, LEDs give bright light.
  2. The service life of LED emitters is many times longer than that of incandescent bulbs. In addition, LED lamps are less prone to breakage on impact and vibration.
  3. The lower heating temperature of LED lamps allows the development of more compact optics because it is less likely to melt the plastic parts.
  4. LEDs light up almost instantly, faster than halogen bulbs and certainly faster than xenon. Which increases the likelihood that you will be noticed on the road faster. Although this is a dubious plus, because in the latest generations of xenon lights ignition is fast enough, and you can even blink the light without any problems.

Disadvantages of LED lamps:

  1. High cost, compared to halogen bulbs. But good halogen bulbs are expensive, comparable with average quality LED bulbs.
  2. Incorrect choice of light sources with too high brightness, and even more so with the wrong positioning of the emitter, can dazzle drivers of other cars.
  3. Over time, the brightness of LEDs diminishes, which reduces the visibility of the road and the car itself. Although halogen bulbs also shine worse at the end of their lifespan.
  4. Due to the cooling radiators may not fit to the car headlights, and the lamps with a cooler – it can jam. This will lead to overheating of the light sources, hence their premature failure.

LED dipped beam bulbs

As low beam bulbs are often used: H1, H7, H8, HB4, H11 bulbs.

LED high beam bulbs

High beam bulbs can be different, usually use: H1, HB3, H9, H11 bulbs.

In fact, the emitters of LED headlights themselves may not differ (although they should), the manufacturers only install different bases (shanks) directly on the device itself, or take it out on a wire, if a massive radiator or cooler for cooling is used.

Combined models of LED lamps

The distinction of these LED-lamps is the combination of two diode light emitters in one car headlight: the dipped (in the headlight is located on top of the bulb) and the far beam (in the headlight is located at the bottom of the bulb).

This arrangement of light emitters in the headlamp allows you to direct the beam of light in the desired direction:

from the source at the top of the bulb the light is reflected from the reflector and is directed in front of the car (dipped beam)
the light source below the headlamp is reflected by the reflector and directed forward

The road is thereby illuminated at a greater distance (high beam). These light emitters usually have an H4 base.

If on the box or on the bulb with H4 base one value of luminous flux is indicated – 3000, 3800 or 4500 lm, you should understand that this value is given for the two sources together.

Keep in mind that the actual brightness will be half as much, that is: 1500, 1900 and 2200 lumens.

In addition to H4, there are other dual-lumen halogens and their LED counterparts:

  • H13 (55/60W) – used in most American cars.
  • HS1 (35/35W) – Reduced wattage, used in motorcycles. Almost interchangeable with H4 (HS1 can be replaced by H4, but vice versa – requires minor modifications).
  • R2 (45/40W) – double filament incandescent lamps, almost never used as obsolete. Used in twin headlight systems for high and low beam.
  • HR2 (45/40 W) – halogen analog of the previous one.
  • P21/5 (21/5 W) – two strands used for brake light and parking light.

Combined LED Bulbs

Combined R2, HR2, H4, HS1, H13 LED lamps and their double-helix halogen equivalents

LED bulbs for fog lights

Fog lights shine straight ahead to illuminate the roadway in fog and bad weather. What are the best LEDs to use in fog lights?

In fog lights use a variety of bulbs: HB3, HB4, H1, H2, H3, H7, H11, H9

The light is dispersed due to the grooved glass and reflector. However, lamps with a spiral, which is located perpendicular to the optical axis, namely H3, are often used.

Halogen types of lamps provide a flux of about 1500 lm. Accordingly, LEDs should provide no less. In this case, do not choose bulbs with too high color temperature, which shine a bluish light.

For fog lights preferably a warm glow with an abundance of yellow and red shades in the spectrum, namely 2400K, 3000K, 4300K. Recommend something specific can not be, as in the regular PTF of each car uses its own type of bulbs. In those PTFs that are mounted independently on the bumper, it can be anything.

LED bulbs for parking lights and taillights and front and rear lights

To indicate the lights of the car at the front and rear use recessed W5W (aka T10) and T4W (sometimes designated by the type of socket ba9s) capacity of 5 and 4 watts respectively.

If rear parking light is combined with stop lamp, you can use double-helix lamps type W21/5W or P21/5W with power spirals of 21 and 5 watts respectively. And for individual brake lights the single-helix P21W.

The luminous flux of parking light bulbs is usually in the range of 50-100 lm, and stop light bulbs about 150 lm and more.

LED bulbs for interior and dashboard lighting

In the cabin light bulbs are often used 5-watt C5W, less often 10, 18 or 21 watts. They are called soffit lamps because the base is at both ends. The same are often used for license plate illumination. Apart from them, the W5W bulbs mentioned above are also often used.

The dashboard illumination also uses bulbs with W5W (T10) and T4W socket. They are used for control lights, but sometimes miniature with a T5 socket (like T10, only smaller in diameter). But in modern cars the dashboard illumination is often non-replaceable – in the form of SMD LEDs soldered to the board.

What problems can arise when installing LED bulbs?

The main problem faced by motorists when replacing the car bulbs is the control unit errors. Can light up “Check”, for example. This is due to the fact that the control unit monitors the current consumption of the lights, and the LED bulbs consume little. “Brains” when polling the bulbs think the bulb has burned out or another malfunction has occurred, and notify the driver of the problem with the lights. In some cars, you can not pay attention, and drive as is, but it happens that the headlights with LED sources do not shine at all.

There are two ways to solve this problem:

  1. Complicated. Contact the service: and if there is such a possibility, in the control unit will prescribe LED lamps. Usually, this is possible if there is a complete set of this model with LEDs.
  2. Simple – install a ballast. In this case, the advantage of LED lamps in their low power consumption disappears, but you get from them bright white light. These are called differently in the stores, as simply “LED lamp shifter” or “LED can-bus”.

LED CANbusadapter


CANbus adapter

HIKARI PAIR LED Conversion Kit Headlight Canbus

Technical Details

  • Anti Flickering Resistor
  • Decoder: 9012/9005/9006

If you are installing LEDs instead of passing lights or fog lights, you will need to buy a CANbus Adapter. When choosing bulbs, consider their type (H7, H3, etc.).

David West
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