Headlamp technologies in electric vehicles: System information, maintenance and repair instructions

Lamp technologies in electric vehicles: System information, maintenance and repair instructions

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Electric vehicles use various headlamp systems, which are characterised by their efficiency and technology in each particular vehicle class. Depending on the equipment variant, you will therefore find the classic halogen headlamp with a reflector or projection module, xenon headlamps and, of course, modern LED headlamps. And all this just in the same way as we know it from traditional vehicles with combustion engines.

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.

Which headlamp systems can be installed?

Halogen lamp with reflector — Halogen headlamp with reflector

Halogen lamp with projection module — Halogen headlamp with projection module

LED lamps — LED headlamps

Halogen headlamps are an older but still widely used technology – even in electric vehicles. Although classic halogen headlamps are used less in modern electric vehicles, they are still offered in the small car segment, particularly in the lower price categories. Halogen headlamps have a lower purchase and replacement price than modern headlamp variants. Changing halogen bulbs is relatively simple and can often be done without professional help. A halogen light source produces a warm, amber-like light that many drivers find pleasant. However, the light output and range are both less compared with more modern headlamp systems. Another disadvantage is that halogen bulbs generally have a shorter service life than xenon or LED bulbs and therefore need to be replaced more frequently.

Some vehicle manufacturers also offer xenon headlamps as an option in their equipment variants. These headlamps offer high light intensity and good illumination of the road, a bonus which improves visibility and safety during night-time driving. So it can well be that some early electric vehicles, such as the BMW i3, Nissan Leaf or Tesla Model S, are fitted with xenon headlamps.

Modern electric vehicles are equipped with advanced LED headlamp systems that offer outstanding light output. These variants are particularly popular because of their energy efficiency and long service life. LEDs deliver high luminous efficacy and can be integrated in various shapes and designs. Modern Matrix LED headlamps enable adaptive light distribution that automatically adjusts to the driving conditions. And furthermore, the illumination can be blanked out in certain areas in order to reduce the glare effect on other road users.

Headlamps with laser light offer an even higher light intensity and range than conventional LED headlamps and are mainly used in premium vehicles. LED headlamps not only offer better visibility and safety, but they also boast greater energy efficiency compared with conventional halogen or xenon headlamps.

What should I pay particular attention to?

Exemplary illustration of the component positioning of an electric vehicle 1. Vehicle electrical system battery 2. High-voltage battery

Position of the vehicle electrical system battery (1) with the bonnet open on an electric car

The LED headlamp systems are supplied with power via the 12 V vehicle electrical system battery of the electric vehicle. In contrast to the high-voltage main battery, which is responsible for the drivetrain, the vehicle electrical system battery supplies various electrical systems in the vehicle. These include, for example, the lighting system, instruments, comfort systems and various driver assistance systems. Without a functioning 12 V vehicle electrical system battery, the control units for high-voltage safety are not activated and the electric vehicle cannot be started.

Although the lighting system is supplied with power via the vehicle electrical system battery, the following maintenance and repair instructions are to be observed when repairing headlamps on an electric vehicle.

Maintenance and repair instructions

After selecting the vehicle, safety instructions are displayed in the diagnostic unit

Service and maintenance work (wheel changes, inspection work) on high-voltage vehicles may only be carried out in an automotive workshop by persons who have completed vocational training and who have previously been made aware of the dangers of these high-voltage systems and instructed accordingly by an "expert for work on high-voltage intrinsically safe vehicles."

In order to be allowed to drive a vehicle with a high-voltage system on company premises – even if it only means driving in or out of the workshop – the person concerned has first to be instructed.

In principle, each individual technician involved should be trained and certified specifically for working on electric vehicles in order to be able to work safely and effectively.

Safety precautions

Further safety information can be displayed in the diagnostic device.

Current electric vehicles have a high-voltage system with voltages of over 400 volts, which can be life-threatening. It is important to follow the safety guidelines and to ensure that the vehicle, if necessary, is de-energised by a high-voltage expert before the repair begins.

Against such a backdrop, it is imperative that the repair and maintenance instructions of each individual vehicle manufacturer are always observed. If an electric vehicle is parked in the automotive workshop, it must be clearly labelled with warning signs as such, and the work area must be demarcated.

Diagnosis and repair of the lighting system

If an LED lamp has been replaced, lamp setting, depending on the vehicle model, has to be carried out using a diagnostic device and beamsetter — If an LED headlamp has been replaced, headlamp setting, depending on the vehicle model, has to be carried out using a diagnostic device and beamsetter

The diagnosis in the event of a headlamp failure may vary depending on the headlamp type. If a halogen headlamp fails, this is usually recognised by the vehicle's bulb failure control, and the driver is then informed by an appropriate message in the instrument cluster. The warning headlamp goes out as soon as a new bulb has been fitted or the fault has been rectified.

The xenon and LED headlamps are monitored by higher-level control units in the vehicle electrical system. Any occurring errors are stored in the error memory of the relevant control unit, and can be read out using a suitable diagnostic device. The error is also shown on the display.

The causes for the failure of each individual headlamp system can vary. It was possible to replace a defective light source in the case of halogen or xenon headlamps, but now with modern LED headlamps this is significantly more complex.

LED headlamps can fail for various reasons, e.g. because of defective LED components, faulty control electronics or thermal overload. A thorough diagnosis to determine the cause of the failure is crucial for a successful repair. In contrast to classic halogen headlamps, only individual components mounted on the outside of the housing, such as LED modules, fans or control units, can be replaced in the event of a repair. After repairing or replacing individual components, it is important to calibrate and adjust the headlamps correctly in order to ensure road safety and optimum light distribution.

Headlights in electric cars: maintenance and repair information

In this video, we would like to give you some important information to bear in mind when replacing the headlights of an electric vehicle.

General repair instructions

General information on replacing a light source or a headlamp on an electric vehicle.

Read the vehicle operating instructions:

The operating instructions for each individual vehicle list the specific instructions and safety information required to replace, for example, a bulb on a halogen headlamp. It is also stated whether the repair should only be carried out by a specialised workshop.

Observe all safety instructions!

Repairs on or in the vicinity of high-voltage components may only be carried out in a specialist workshop by persons who have been instructed in electrical engineering and who are appropriately qualified.

Use suitable spare parts

One of the most important points for achieving a successful repair is getting the right spare part. A definite assignment of the spare part number is crucial to ensure that everything works perfectly in the vehicle after the repair has been carried out. After having been replaced, electronic components must then be adapted and adjusted to suit the vehicle.

Tools and equipment:

So as to avoid damage to the headlamps or the vehicle body, only suitable tools should be used to carry out repairs.

Adjusting headlamps:

After replacement or repair, the headlamps have to be correctly adjusted to ensure optimum illumination of the road and to avoid dazzling other road users.

Carry out a function test:

After the repair, the functioning of the lighting system has to be checked to ensure that all components are working properly.

Please always observe the safety and repair instructions provided by the relevant vehicle manufacturer!

Functional descriptions and also maintenance and service information may vary depending on the vehicle manufacturer and are dependent on each individual equipment variant or system configuration.

The various diagnostic options have been illustrated, as an example, using the mega macs X diagnostic device.

Schematic illustrations, pictures and descriptions serve to explain this text and cannot be used as a basis for vehicle-specific repairs.

Further information on the subject of LED headlamps can be found in the chapters " Adjusting and changing LED lamps " and " BMW LED lamps: Useful information, repair instructions and practical tips ."

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