Cycles of all sorts

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.