Cycles of all sorts

LEDs

Cyclists that ride at night only occasionally opt for an inexpensive LED front light and rear LED flasher. Red or yellow LEDs suitable for use as rear lights have been available for many years. Recently, white LEDs which satisfy the requirements for a front light have come on the market, and some jurisdictions have or are considering making these legally acceptable. Very high-power LEDs are sensitive to overheating and over-driving, if the enclosure and/or driving electronics are poorly designed. Both of these conditions result in significantly shortened lifespan (dimming, or complete burn-out), and the LEDs are expensive to replace. Efficiency of the LEDs in lumens per watt is superior to most halogen lights, but the driving electronics can negate the advantage unless well designed.

Most riders will use alkaline cells to power inexpensive LED lights; these can have a life of anything from under a week to a year or more depending on the amount of riding, and brightness of the LEDs - life will be longer in flashing modes (even though many lights make the LEDs brighter when flashing than when steady to conserve battery life). The brightness of LEDs is rather sensitive to supply voltage, and rechargeable cells, of 1.2 V rather than the alkalines' 1.5 V, often give poor performance.

Low power LEDs are adequate for riding on well-lit streets, but they do not generally project a very bright beam as it is difficult to collimate the output from multiple LEDs into a single usable beam. This can be overcome by using a small number of very high power LEDs - each with their own optics - and it is now possible to get LED equivalents for halogen rechargeable systems (including drop-in replacement bulbs), as well as LED lights for dynamo power. One particular advantage of LEDs in dynamo-powered lighting is that they produce more light at very low speeds (down to 3km/h according to one manufacturer).

High power LED systems often include an option to dim the LEDs. LEDs are very well suited to dimming (running at half brightness will normally give you more than double the battery life), unlike halogen lights, where running a single bulb at half brightness will only give you a slight increase in battery life.

Efficiency is set to increase as white LEDs switch to emitting red, green and blue light to form a white output (current designs use a blue LED, with a fluorescent coating, much like conventional strip lights use). As very high power LED lights become available and major manufacturers start to adopt these high power LEDs to replace their halogen designs (a 3 watt LED offers similar light output to a basic 10 watt halogen bulb - compare this with current generation "very high brightness" LEDs at 0.05 watts), there are grounds to believe that LEDs will replace incandescent lamps whatever the power source. In the future they may even challenge HID lights.

Advantages of LEDs

• Can be cheap
• Long battery life in flashing mode
• Can be very visible
• Efficient
• LEDs last nearly indefinitely (as part of a well-designed light)
• LEDs can be dimmed, usually with a slight gain in efficiency

Disadvantages

• Limited light output, especially in steady mode for many models
• Some models do not run as long on rechargeable cells as on alkalines; environmental concerns
• Illegal in some jurisdictions
• Attractive to thieves. Especially removable types, particularly if not removed when parked.

Low power LED lights are mainly for "being seen", or as an emergency backup, and are the dominant choice for rear lights; higher power LEDs are now moving into the core market for illumination and are subject to rapid technical development at present.

Home Made LED lights

As with high-power halogen systems, high-power LED systems have attracted self-build enthusiasts, top-end commercial products tend to be similarly high priced - due to the relatively low production volumes for these high-end parts.

Low-cost battery lights

For occasional use a low-cost battery light can be a sound choice and usually meets legislative requirements. These lights are low power but compensate to this to some extent by using surprisingly good optics. Some newer models are available with LEDs instead of halogen lamps; this is not legal in all jurisdictions.

Advantages of low-cost battery lights

• Low cost
• Easily moved between bikes
• Readily available (both lights and batteries)

Disadvantages

• Cost of batteries (unless rechargeable ones are being used)
• If using rechargeable cells, limited burn time
• Generally low power

In summary, a standard halogen light can be a good choice for the less demanding occasional user. It can also be a useful emergency light if the usual lights are more exotic.

Rechargeable Flashlights

There are some high-power flashlights, with rechargeable lithium-ion batteries. Although not specifically designed for bicycle use these are a viable alternative to rechargeable halogen lights, though they are still expensive. They can be fastened to the bicycle handlebars with a device called a "Lock Block." Look for a flashlight that has an adjustable spot to flood beam. Although the optics of these flashlights are generally high quality they are still rotationally symmetrical (unlike motor vehicle lights).

Advantages of rechargeable flashlights

• Versatile - can also be used as a flashlight off the bike
• Portable, so theft resistant

Disadvantages

• Limited burn time
• Heavy (rechargeable systems generally separate the weight of the battery from the lamp); weight may be an issue for off-road riders due to vibration
• Optics not optimised for road use

Rechargeable Halogen Systems

Although these lights were primarily designed for off-road use, where they are almost universal, many commuters and transportational cyclists now choose to use high-power halogen front lights which operate from a NiMH, lead-acid, or Li-ion rechargeable battery pack.

The lights used by most halogen rechargeable systems are cheap, bright but fairly unsophisticated: they project a cone of light (wide and narrow beam options are available) which is good for off-road use but not ideal for road use as it can dazzle oncoming road users. This means that rechargeable halogen lights do not meet legal requirements in some jurisdictions.

Because they use standard commercial prefocused optics, a wide range of power and beam width combinations is available. Most systems allow simultaneous connection of different lamps - for example, a wide and a narrow beam for offroad riding, or a high and a low power beam for road riding.

Advantages of rechargeable halogen systems

• Bright, sometimes very bright
• Readily available
• Can connect multiple lamps to one battery pack; provides flexibility
• Reasonable battery capacity
• Very reliable
• Can usually be easily removed from the bicycle or to prevent theft
• Lamps are cheap, widely available, and come in many combinations of power and beam width

Disadvantages

• Relatively heavy battery
• Limited run-time between battery-recharges
• Hassle of being certain to keep batteries charged
• Batteries have limited life, typically 500-1000 recharge cycles
• Optics not optimised for road use

Rechargeable H.I.D. Systems

HID lights are the brightest lights currently available for bikes. They are efficient, very bright, but comparatively expensive. They also tend to have high power consumption, so a relatively limited burn time. Other than this they have the same advantages and disadvantages as rechargeable halogen systems, and like halogen systems they are designed primarily for off-road use, having rotationally symmetrical beams which cast as much light up as down.

If using a HID lighting system on the road, lights should be adjusted to avoid dazzling oncoming traffic.