April 1, 2023 marks the anniversary of mandatory daytime running lights for e-bike riders in Switzerland. The legislator also allows removable battery lights. However, the (theft-) safer and more convenient solution is to screw the lights onto the e-bike and feed them directly from the on-board power supply. However, retrofitting an e-bike is not as easy as on a bicycle, because there is no uniform standard for voltage, power and connections.

Since e-bikes travel at higher average speeds than bicycles, the light is of particular importance in two respects. The light obligation, which has also been in force during the day in Switzerland for a year now, is intended to improve visibility. At night, the headlight should be powerful enough to illuminate the road brightly over a distance of at least 50 meters. It would be even safer if the headlight had a high beam, which makes the road visible over an even greater distance. Various specialized lighting manufacturers offer high-quality headlights and taillights for retrofitting. However, since there is a lack of uniform standards, mounting such a lighting system on an e-bike is significantly more complex than screwing lights onto a conventional bicycle.

This is what you need to consider when retrofitting:

  • When working on the electrical system, always remove the battery first so that there is no voltage in the system that could lead to a short circuit. If the battery cannot be removed, make absolutely sure that the system is switched off. Before working on the cables, check with the voltmeter whether voltage is present.
  • Check whether the e-bike manufacturer has already pulled in light cables in the frame/handlebars/rear triangle.
  • If not: Are special light cables necessary for the engine type? Almost all major engine manufacturers use special connectors on the engine that are not compatible with each other. These plugs must fit, otherwise water can penetrate, which leads to malfunctions.
  • How much voltage (volts) and power (watts) do the light cable outputs provide? These values can vary from 6 - 60 volts and from 6 - 40 watts.
  • These values must match the headlamp manufacturer's specifications.
  • How easy it is to wire the light to the interface on the motor varies from e-bike model to e-bike model. In the best case, you don't even have to remove the motor cover, in the more complicated case, you even have to remove the motor.
  • With certain manufacturers, such as market leader Bosch, the light interface on the engine must first be enabled via external software. As a rule, only specialist dealers with the appropriate representation have this software.
  • Make sure that the headlight is not set too high, as this will dazzle oncoming traffic.

Inexperienced mechanics are recommended to go to a specialist dealer. The more elegant and cost-effective solution is to ensure that the light is properly mounted on the e-bike and sufficiently powerful when buying a new one.

March 31, 2023