How to choose your bike lights?
Lights happen to be very useful when going out at nightfall or daybreak, especially in fall or winter when days are shorter. Night falls quickly understory and MTB amateurs must always think carefully about the end or their ride as it's not unheard of to come back in the dark in the middle of winter. For those who prefer the roads, lights make you stand out for drivers, in addition to the high-visibility vest.
Road lights' price range vary a lot, from a few euros to a few hundred euros. Some advice is indeed necessary to buy the one you need.
Power
First and foremost, the light's power is the first selection criteria. Its unit of measure is the "lumen".
The most powerful lamps produce between 1500 and 2000 lumens while the entry-level ones only produce about 25 lumens. You should also check if the number of lumens measured is specified, as it is always inferior to the one produced by the lighting system (a loss is expected). If it isn't specified, then it's the number of lumens produced by the lamp that's indicated.
Battery
The second element to take into consideration is the battery.
The battery determines your light's durability in use. Entry-level products use cells while all the other lighting systems adopt rechargeable batteries, either integrated in the light's housing or external (which allow you to carry bigger batteries).
The most powerful lamps have variable durability depending on the type of lighting you choose (powerful, normal, eco, flash) going from as little as a couple of hours (2-3h) to tens of hours depending on the model.
Position (front or rear)
A rear light differs from a front light in that it's not used to meet the same objectives. A rear light's sole objective is to improve visibility for the users coming from behind you, whereas the front light plays a dual role: on one hand, it lights up your path, and on the other hand, it alerts drivers coming in front of you of your presence. Red LEDs are therefore used for rear lights while white LEDs are used for front lights.
Where to put your lights
The user is provided with many solutions to put their lights in place. The bike generally serves as a medium (handlebar for the front light and seat post for the rear light), but a helmet can also be used to fix one's equipment. Check if the desired fixation system you want to use is included in the product you plan to buy.
Other criteria
You can opt for waterproof lighting to be able to ride under heavy rain without fear of damaging your equipment.
Other options are available to you before buying your lights, such as the presence of a LED to show the battery's charge level or an even more important number of lighting modes available.