The characteristics and lifespan of different car lights

Knowing the lifespan of different car lights makes it possible to anticipate when this accessory needs to be replaced. This gives the driver greater safety, especially when driving at night. Note that this lifespan is not the same for all types of bulbs. It varies according to the technology, conditions, frequency and duration of use, as well as manufacturing quality. You will therefore need to choose the most appropriate bulb technology from among the many halogen, xenon or LED models. Here’s what you need to know.

Halogen bulbs

Halogen headlights are old-fashioned incandescent bulbs. They are the oldest and most popular model. They work like those used inside homes, using a filament to produce light.

The halogen bulb consists of a glass capsule. Inside, a gas called “halogen” both increases the internal temperature and forms a chemical bond with the tungsten to produce a brighter light. At the heart of the bulb is a straight tungsten filament, made up of several coils stacked over a predetermined length and diameter according to the bulb’s lifespan and power: 35w, 55w, 60w, 65w, 100w, etc. When energized, the spiral filament offers strong resistance to the electric current, causing it to heat up and melt. The tungsten vapors, combined with the halogen gas, thus create a very powerful light.

Ordinary incandescent bulbs are a technology that is gradually disappearing from the automotive industry. In fact, the filament produces about 90% wasted heat and only 10% light. Halogen technology suffers a major energy loss due to red and infrared electromagnetic waves. This phenomenon is responsible for its high electricity consumption and short lifespan. These traditional filament bulbs have a lifespan ranging from 200 to 600 hours. Note that halogen bulbs are also very fragile and do not withstand impacts and vibrations well.

Xenon bulbs

Among the different car lights, xenon bulbs are mostly used on high-end vehicles. Unlike halogen bulbs, xenon bulbs do not have an incandescent filament. They use xenon gas instead of a halogen gas, such as iodine or bromine. Xenon is a very rare gas on Earth, belonging to the noble gas family and inert in most chemical reactions.

The xenon bulb, or discharge bulb, has a complex operating principle and cannot work without an electronic control module called a “ballast”. Equipped with a safety system, it acts as an amplifying “starter” and electronic regulator. When the bulb is switched on, an electrical discharge of approximately 25 000 volts is generated by the ballast and applied between the two electrodes. An electric arc forms and ignites the xenon gas enclosed in the small glass bubble, giving it its distinctive, slightly bluish lighting tint. A current of 85V is maintained to keep the electric arc at the predefined power. It is therefore possible to adjust the power to obtain a more or less white light, with a slight bluish or even violet tint, depending on the power of the current applied.

This explains the natural coloration of xenon headlights, since they emit blue light, unlike halogen bulbs, which emit rather yellow light. For the latter, the bluish-white lighting color is achieved using a colored filter incorporated around the bulb at the factory.

In summary, xenon bulbs are a complex technology, but they were a true revolution in their time, whether in terms of energy efficiency, power or lighting color. Their tint is close to daylight, unlike that of the halogen bulb. The xenon bulb does not waste energy heating a tungsten filament: it only creates an electric arc to ignite the xenon gas, which requires less electricity. Xenon headlights therefore last longer than tungsten-halogen bulbs, around 1 000 to 2 500 hours for xenon, compared with only 200 to 600 hours for a halogen bulb.

The main quality of xenon is its light intensity, with its 3 000 lumens and minimal electricity consumption of 35 W, compared with only 1 500 lumens from a halogen bulb consuming 55 watts. Xenon technology gives the driver better visibility and a brighter beam. Note that xenon headlights do have good energy efficiency, but suffer significant electromagnetic losses, particularly in the violet and ultraviolet ranges.

Different car lights: LED bulbs

LED is short for the English expression “Light-emitting diode”. An LED bulb is an optoelectronic system that emits light when an electric current passes through it. It converts electrical energy into light with a precise chromatic radiation. Unlike xenon and halogen, all the magnetic waves emitted by the LED are within the spectrum visible to the human eye.

The origins of LED headlights

Originally, LED technology headlights were reserved for high-performance sports cars and ultra-high-end vehicles: Audi, Lexus, etc. They were sometimes used only for daytime running lights, turn signals, reverse lights and brake lights. However, since 2020, they have been increasingly used in so-called “standard” vehicles. More and more vehicles offer the full LED option, meaning that all of the car’s lighting is LED. This is understandable given the potential of LED technology. It has one of the highest luminous efficiencies in the world, a response time of a thousandth of a second and offers a magnificent look. The only drawback for manufacturers: it costs more than a car equipped with halogen bulbs.

With the widespread adoption of LEDs and technical advances, LED bulbs for cars have made a real leap forward. They are nothing like the first LED bulbs to hit the market! Remember the first generations of aftermarket LEDs. These LED bulbs were equipped with COB (Chip on board) chips offering high luminous efficiency (100 Lm/W). Nevertheless, they did not provide good road lighting for low or high beams, because the light emitted by the COB chips had too wide an angle.

Most of the COB LEDs sold at the time made life a real misery for anyone unlucky enough to encounter a car equipped with them. Glare was unavoidable, even on low beams! The light was so diffuse and imprecise that it could illuminate a very wide area up to the treetops, without illuminating the essential areas. This resulted in a very low concentration of light directed toward the road, poorer visibility of obstacles, a shorter lighting distance and the inability to pass the roadworthiness test. This unsatisfactory lighting contributed greatly to the poor reputation of aftermarket LEDs in their early days.

LED technology today

Nowadays, among the different car lights, LED headlights are very high quality. They are mostly equipped with new-generation High Power CSP chips, most of which exceed 100 Lm/W and reach up to 180 Lm/W. The most efficient CSP technology is of the PIG type (phosphor in glass). It consists of ultra-powerful and precise mini LED chips, arranged in a eutectic bond on a very high-quality PCB board. A reduced and perfectly defined light angle makes it possible to achieve very precise lighting and ultra-high optical density. A true revolution in the world of automotive lighting.

Some LED bulbs achieve a very high luminous flux: up to 7 500 gross lumens and 3 900 lumens measured under real-world conditions, with only 45 watts of electricity consumption, compared with 2 200 actual lumens for a 100 W halogen bulb, which consumes a lot. The light output of a 35 W xenon bulb is around 3 000 actual lumens, and some current LEDs reach around 5 000 actual lumens.

Heat management, a real challenge

The biggest challenge with LED bulbs for cars is heat management. When operating, an LED chip generates a lot of heat at its core. A well-known phenomenon called the “Auger effect” dissipates some of the energy as heat. This phenomenon is even more pronounced with high-power LED bulbs. This is why researchers are developing many cooling systems integrated into LED bulbs in laboratories.

There are two types of cooling, depending on the luminous power of the LED bulb:

• Passive cooling, for low-power LEDs. Most often, they use a cooling system consisting of multiple aluminum fins or copper braids made with a very fine mesh.
• Active cooling, intended for LEDs delivering very high power, which uses fans coupled with “Cooling Tube” systems using superconducting liquid conduction.

The key to maximizing an LED’s lifespan is directly related to its ability to extract heat. Good cooling increases the LED’s lifespan and luminous power. It is important to point out that LED bulbs are the most durable. Their lifespan ranges from 2 000 to 5 000 hours. This is enough to cover the entire lifespan of many vehicles, which means you may never have to replace LED bulbs. They require less energy than conventional systems, making them attractive to use.

Halogen, xenon or LED, you now know all the characteristics and lifespan of different car lights.