The best biking headlamps are bright enough to show you where you’re going, but not so bright as to dazzle other road and trail users. They should also have a range of settings to let you choose between long-lasting low power and bright eye-catching flashes that drain the battery more quickly. They’re typically rechargeable, with the option of an optional mains adaptor (though many can be juiced up from a USB port).
Small safety lights that use coin cell batteries are ideal as back-ups and for unplanned after-dark rides. For regular commuting you want something more substantial, and ideally one that can be recharged through a USB charger. The latest battery lights use lithium-ion rechargeable cells, which are durable and can be used for a long time between charges.
For off-road riding, it’s important to be visible to other riders and drivers, so you can avoid collisions. The best rear lights do this by shining a continuous red light in the center, and adding a bright outer ring that blinks in sequence. They’re usually powered by a rechargeable battery, with the capacity to run for up to 10 hours.
Some battery lights attach to the seatpost with a silicone band that’s tool-free and fits a wide range of seatpost depths, while others clip on to the top tube or frame. Depending on the type of bike you ride, you may prefer a different mounting system. Helmet mounts tend to be less secure and can easily get snagged on low-hanging bags or jackets.