Converting BMW Angel Eyes from Halogen to LED

Published: 24th February 2011
Views: N/A

BMW have been fitting Angel Eye lights to some models for over 10 years now. They are simply light rings around the outside of the headlamp which can be switched on independently of the headlight itself. They replace the more conventional side lamp. Angel Eyes are sometimes known as Corona Rings too.

Until recently, BMW Angel Eye light rings have been illuminated using normal halogen headlamp bulbs. Each pair of rings requires a single bulb because the light is transmitted along a channel using a fibre optic type principle. Therefore, a pair of bulbs illuminates all four angel eyes.

More recently, BMW have moved with the times and have replaced the halogen illumination of the angel eyes to a brilliant bright white LED light source. These new LED angel eyes look much better than the old yellowish glow of the halogen illuminated rings. They are especially popular because they are a much better match for xenon headlights. Previously, owners of BMWs with xenon lights had to put up with the slightly out of place looking yellow angel eyes around their very white xenon headlights. Now that BMW angel eyes have LED illumination, the rings match the xenon lights and complete the package.

No sooner had BMW started to produce these LED angel eyes than owners of BMWs with halogen illuminated rings started to ask how they could convert them to achieve this new bright, white LED light. It wasn't long before aftermarket LEDs were being produced which replaced the original halogen bulbs to achieve the white LED angel eyes that many so desired. These LEDs are often referred to as LED markers and are available in a variety of colours including white, red, blue and green.

Whilst most of these new LED markers require no more effort to fit than changing the original halogen bulb itself, some required slight modifications such as those for the pre facelift E90 models with halogen headlights. Good guides may be found on You Tube as to how these markers can be fitted.

However, one question that I often get asked is why BMW angel eyes with aftermarket LED markers are not as bright as those fitted to the latest BMW models. The answer to this is simply that the design of aftermarket LED markers is compromised to allow them to fit into lights that were never designed for them. Looking at this in more depth, it is to do with the ability of the LED to dissipate heat which is generated. It is a myth that LEDs do not generate heat because they do. The ratio of emitted light to heat generated by an LED is high, meaning that an LED generates far more light than heat. However, the heat still has to be taken away from the LED otherwise it will drastically shorten its life as well as the life of any other electronic components in the same circuit. The usual method of dissipating such heat is connecting the LED to a device called a heat sink. This is a piece of metal with a large surface area open to the air. The larger the surface area, the more effective the heat sink. It is quoted that for every 1 watt of LED light, there should be around 9 inches of surface area in a heat sink. By now, you should be starting to see the problem. Aftermarket LED markers have to be fitted into very tight spaces which were designed for halogen bulbs. It is very difficult to include a heat sink large enough to dissipate the heat so a compromise is made by reducing the power of the LED, thus producing a dimmer light than those fitted to new BMW models. It is true that some aftermarket manufacturers produce high powered aftermarket LED markers but they often last only for a relatively short time before they fail.

I also often get asked about the colour temperature of LED markers. Colour temperature is a measurement given to the colour of a light. It is measured in Kelvin K). Halogen lights have a relatively low colour temperature, possible under 4000K, and are a yellow or a warm white. As the colour temperature increases, the emitted light becomes whiter and eventually, it will start to include shades of blue at higher colour temperatures. Daylight is around 5500K - 6500K. LED markers that we sell are around 7200K. At this colour temperature, the light is generally white with only minor shades of blue. At colour temperatures higher than this, more blue light exists and in my opinion, it detracts from what we are trying to achieve in terms of brilliant white angel eyes.

The combination of a lower powered LED and light with a colour temperature similar to daylight often makes BMW angel eyes with LED markers look inconspicuous when used in the daytime. However, once daylight starts to fade, they become much more noticeable and will make your BMW look modern, stylish and far more dynamic than it did with those old yellow halogen bulbs.


Nigel Marston has been an independent BMW accessories and parts specialist for 21 years and a BMW enthusiast since the late 1980s. He is well known around the world for his knowledge and enthusiasm of BMWs. To see his range of BMW LED Markers and other accessories, visit his online shop at =>

Report this article Ask About This Article

More to Explore