D'Lumotec Oval
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The Busch & Müller D'Lumotec Oval is a dynamo-operated LED bicycle headlight. All headlights in the Oval series have a maximum luminosity of up to 16 lux [1], which meets the German lighting requirement of 10 lux[2]. The headlight illuminates the path ahead at a speed no more than 3km/h (1.9mph) [3] and reaches full brightness around 10km/h (6.2mph) [4]. It offers a claimed LED service life of up to 100,000 hours [5], requiring no bulbs to change (as compared to 100 hours for halogen lights driven by bicycle dynamos). Lights in the Oval series have an integrated cooling unit [6] to prevent overheating and also feature over-voltage protection. Additionally, the headlights have a built-in reflector at the top of the unit enclosure.
Other lights in the D'Lumotec Oval series include the Oval Plus, Oval Senso, and Oval Senso Plus. "Plus" is used to indicate that the light has a "standlight" feature, which is a built-in capacitor used to power the light for up to seven minutes (albeit dimly) while stopped; its purpose is primarily to provide added visibility when the bicycle is not moving, such as when stopped at a stop sign. The capacitor is fully charged after approximately 3 minutes of riding at 20km/h (12.4mph) [7]. "Senso" is used to indicate that the light has a built-in sensor switch, used to automatically turn the light on and off when lighting conditions change (i.e. entering a tunnel, or when day changes to night). This feature is intended to be used with a hub dynamo, as a bottle dynamo acts as a switch in and of itself, requiring the user to stop the bicycle and engage it to turn on the lights. If a taillight is wired into the headlight, it too will be turned off and on by the sensor.
The D'Lumotec Oval lights can be used either independently or with a wired taillight. However, early models of the D'Lumotec had a design flaw that caused circuitry to overheat and desolder itself under high speeds when riding without a connected taillight [8]. This has since been fixed in recently manufactured lights [9]. The D'Lumotec can also be used with a secondary headlight, such as the Schmidt E6-Z Secondary or Lumotec Secondary. Only headlights intended to be used as secondaries will work, however.
These headlights are commonly mounted at the fork crown of a bicycle, though many mounting options exist.
