The decisive factor influencing the evaluation of a bicycle headlight is the illumination, measured in lux. This is quite a useful indicator: during the test, we checked LED bicycle lights with a calibrated luxmeter and only in one case encountered a value that was much lower than average. In several cases, the results obtained were even higher than those declared by the manufacturer.
Note: We only tested LED bike lights. Halogen lamps today are found only in cheap kits using a dynamo.

Bike Light: Luxes Matter
The illumination from the bike lights we tested, according to the manufacturer’s instructions, ranges between 10 and 50 lux. Logically, the higher this value, the stronger the light. However, it should be remembered that this indicator only provides information on how strong the illumination is at the brightest point of the light beam.
Equally important is how brightly and evenly lit the edges of the road and points in front of the bike and at the maximum distance from it. However, the brighter the front bike light, the better. With illumination between 40 and 50 lux, you will most likely be satisfied with the result.
In the above photo you can see the comparison between the Busch & Müller test winner Ixon IQ Premium Speed (42.2 lux) and the Trelock LS 350 (20.7 lux). The higher light intensity of the test winner illuminates the dark areas of the test track much better than the lower light Trelock. However, on well-lit streets, a bike light with a lower lux value will also work.
Bicycle spotlight: headlight without certification

Among other things, we studied three special type LED bicycle lights from the manufacturer Lezyne. Although they are quite expensive, about 8,000 rubles, they are significantly superior to all their competitors in terms of lighting power — so much so that their operation on public roads is illegal in some countries.
They do not meet the required standards, as they can dazzle oncoming drivers. However, this type of lamp is widely represented on the market — including those produced by other companies — and is freely available. However, there is a chance of running into a fine.
The stronger the light, the shorter the battery life

Even the brightest LED bike light will do little good if the battery is small and drains quickly. There are no surprises in this: the battery life directly depends on the battery capacity and the maximum brightness of the lamp.
Our test winner, a Busch & Müller front bike light with a light output of around 42 lux, can last just over five hours. But the Sigma Sport Lightster with its 27 lux holds the record for the duration of work — more than eleven hours.
Of course, it does not provide the best illumination of the roadway. Therefore, despite its record-breaking battery life and rather low cost of only about 1,500 rubles, it is not a good alternative.
By the way, about battery life: most headlights have an eco-mode. You can reduce lamp performance and automatically increase battery life. In this way, a compromise can be found between the brightness of the light and the duration of a night trip with light. In addition, for long-distance bike trips, we recommend using headlights with a replaceable battery.
Bicycle lamp: equipment and ease of use
Compared to the most important criteria such as lighting brightness and battery life, the equipment of a bicycle headlight plays a much smaller role. Models differ from each other, for example, by a different number of operating modes or status indicators of different complexity of execution.
Pay attention to the mount! As a rule, the front bicycle light is not mounted firmly enough on the frame. But to provide protection against theft, the bike light should be easy to remove and put back if you often have to leave your bike unattended for a short time somewhere.
Models from Trelock are exemplary in this regard: they can be removed even with one hand, simply by pressing a button. They are even easier to insert back into the mount. A negative example is Sigma’s front bike light: you need both hands to remove it. In addition, even short nails can be slightly damaged.