LED Bike Lights 

When I first started in this industry over 13 years ago, LED bike lights were just starting to gain popularity. At that time they were not really that bright, but hardly chewed up batteries, and so for this main reason they rapidly gained popularity as bike lights.

So what actually is a LED bulb and how did its use for bicycle lights evolve?

What is an LED and how do they work?

LED stands for “light emitting diode.”

A diode is an electrical component with two terminals which conduct electricity only in one direction.

Connecting a diode to an electrical current excites the electrons within the diode, making them release photons, which we see as light. The color of the light is a direct result of the energy gap in the semiconductor of the diode. This means that LEDs produce a spectrum of colors easily and brightly while using very little electricity to do so.

LEDs present many advantages over other light sources in their application as cycle lights.

• Efficiency: LEDs emit more light per watt than other light bulbs.
• Color: LEDs can emit light of an intended color without using any color filters as traditional lighting methods need. This is more efficient and can lower initial costs.
• Size: LEDs can be very small (smaller than 2 mm2]) and are easily attached to printed circuit boards.
• On/Off time: LEDs light up very quickly. A typical red indicator LED will achieve full brightness in under a microsecond. LEDs used in communications devices can have even faster response times.
• Cycling: LEDs are ideal for uses subject to frequent on-off cycling, unlike fluorescent lamps that fail faster when cycled often, or HID lamps that require a long time before restarting.
• Dimming: LEDs can very easily be dimmed either by pulse-width modulation or lowering the forward current.
• Cool light: In contrast to most light sources, LEDs radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as heat through the base of the LED.
• Slow failure: LEDs mostly fail by dimming over time, rather than the abrupt failure of incandescent bulbs.
• Lifetime: LEDs can have a relatively long useful life. One report estimates 35,000 to 50,000 hours of useful life, though time to complete failure may be longer,partly on the conditions of use. Incandescent light bulbs, on the other hand, fail at 1,000 to 2,000 hours.
• Shock resistance: LEDs, being solid-state components, are difficult to damage with external shock, unlike incandescent bulbs, which are fragile.
• Focus: The solid package of the LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner. For larger LED packages total internal reflection (TIR) lenses are often used to the same effect. However, when large quantities of light is needed many light sources are usually deployed, which are difficult to focus or collimate towards the same target.

During the past several years the costs of LEDs has reduced, their efficiency has increased and together with the many advantages as summarised above, their increased use as cycling lights can be readily understood.