Bi-Xenon headlights module
Here you will find useful basic information and handy tips relating to xenon headlights.
Important safety note
The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for use by suitably qualified personnel only.
Xenon headlights are comprised of the gas discharge lamp, the xenon ballast, and the reflection and projector-type system. Bi-Xenon means that high beam and low beam are realised by a projection module. This has the advantage that only one ballast is required. This means that two light distributions with a large luminous flux are realised within the smallest installation space.
Through the use of a moveable cover, a purely mechanical switch between the light distributions for high beam and low beam is possible. This means that, aside from the actuating mechanics for the cover, there is no additional outlay for a separate headlamp with its own control electronics. The high beam light also reaches further and the areas to the side of the road are illuminated better.
The electronic ballast (E) ignites the inert gas mixture in the bulb with a high-voltage pulse of up to 30 kV (4th generation). It causes a spark to flash over between the electrodes of the bulb. The electronic ballast controls the start-up of the bulb so the bulb reaches its operating phase quickly, and then controls the bulb power to a constant 35 W.
A DC converter generates the required voltage for the electronics and the bulb from the vehicle electrical system. The bridge circuit supplies a 300-Hz alternating voltage to operate the xenon bulbs. Several control and safety circuits are integrated in the device.
Several control and safety circuits are integrated in the device.
The system is switched off within 0.2 seconds in the event of:
To protect the ballast electronics, a counting circuit ensures that a faulty bulb is only ignited seven times. After this, it is switched off.
If the cable connector is removed during operation, the voltage connections are practically voltage-free (< 34 V) after < 0.5 seconds, meaning that there is no immediate danger of electric shock should the warning notice not be complied with.
|Features||3rd generation||4th generation||5th generation||6th generation |
|Burner||D2||D2||D1||D1 / D3|
|Filtered and shielded version||X|
|Fully shielded system||X||X|
|Longer cable possible||X|
|Improved ignition reliability||X|
|All AFS functions integrated||X|
A faulty ballast results in the complete failure of the headlamp.
Causes of failure of the ballast include:
In Europe, only complete xenon headlight systems may be retrofitted. These comprise a set of type-approved headlamps (with identifier E1 on the cover lens, for example), automatic headlamp leveling and a headlamp cleaning system (regulation as per ECE regulation R48 or compliance with national regulations).
Every headlamp is granted its design approval together with the light source (halogen or xenon) used for operation. If the light source is replaced by a different light source that has neither been granted type approval nor has been provided for in the design approval of the headlamp, the design approval is no longer valid, thus invalidating the general vehicle certification (§ 19 StVZO, section 2, clause 2, no. 1). Driving without general vehicle certification leads to restrictions in insurance protection (§ 5, section 1, no. 3 KfzPflVV, German compulsory insurance directive). Those who sell such lighting equipment which has no type approval have to be prepared for damage claims by buyers, too. Because when the seller passes on these parts, they not only guarantee that these may be used for the intended purpose, but they also possibly take over responsibility for the risk of damage as well – to an unlimited amount.