Bike Lights
From MORC Wiki
There are many types of bicycle lights on the market. The two basic uses are for commuting or off-road riding. In general a commuter light is not bright enough for off-road riding. While riding off-road it is important to see all the trail features. You need a powerful light when off in the woods with no outside lighting. A commuter light is mostly designed to allow others to see you, not so much to light your way. So choosing the right light is not as easy at things may seem.
Power
Most bicycle lights require a battery, which can be contained within the lamp unit or attached with a cord. Sealed lead acid batteries used in the original Niterider systems were replaced by nickel-cadmium, nickel-metal hydride, and lithium-ion. Lithium ion batteries currently provide the highest runtime-to-weight ratio and are less prone to memory effect.
When halogen bike lights first appeared, a 10-watt equivalent light was used by some to describe the minimum amount of light output required for off-road riding. After HID and LED lights became widely available, the measurement of light in terms of watts became less meaningful, because light output per watt of power can vary widely. However, power, combined with lamp efficiency and temperature, are still the primary determinants of runtime.
Lamp
Lamps and housing continue to evolve. The beam pattern, brightness and color vary widely from system to system. One difficulty in comparing the output of halogen, HID, LED, and superbright LED systems is the lack of standard measurement for lumens. Published manufacturer specifications may rely on lumen output measurements taken on the bulb outer surface, on the surface of the reflector, in front of the reflector, or by another standard.
Mounting Position
Many people ask whether it's best to have the light handlebar mounted or helmet mounted. If the light is mounted on the handlebar, shadows will outline trail obstacles, making them more visible, improving depth perception. However, you can't see around corners before you start to turn into them. Also, the light bounces with the bike. When mounted on the helmet, the light will shine where you look and be more stable, meaning less shaky, but since the light source is directly above your eyes, depth perception is reduced. If both a handlebar mounted light and a helmet mounted light are used, the lights should have a similar amount of power. A high-powered light will make the pupils constrict, causing a low-powered light to appear much darker.
There are many brands to choose from. Not everyone agrees on which ones are best. Here are some links to popular light brands.
