Bicycle Lights
And the Winner is...
Over the past year, the enthusiastic debate over the best kind of bicycle light has pretty much come to an end. Fantastic advances in LEDs (light emitting diodes) have made this technology the clear winner (for the moment) in bicycle lighting. Some new LED bicycle headlights and flashlights offer as much light as 3500 lumens, far greater than a typical halogen auto headlight (800-1500 lumens) and about equal to the new HID headlights. Various knowledgeable bike commuters have over the years maintained that from 300 to 750 lumens is adequate lighting for street riding in the dark - a level which in the past often required a greater cash outlay than the bike itself.
      Not only are LEDs brighter, they are lighter and less expensive (per lumen) than all other lighting technologies offered to cyclists. You'll probably find a lot of very good deals on other kinds of bicycle lighting systems as manufacturers scurry to liquidate their obsolete inventory, but you may find that a full-price LED is still a better deal than a fire-sale price on an old lighting system.
Two Reasons To Light Up
First of all, lighting allows you to be seen by drivers, pedestrians and other bikers at night. This means both headlights and taillights, so you can be seen from both directions. Nearly all bikers are most worried about being struck from behind by a car (even though this is a rare occurrence) and a really bright taillight (usually advertised as ultra-bright - such as a Planet Bike Superflash) helps prevent that. Many riders, myself included, use two - one on flash and one continuous. A decent headlight ($20+) with a disposable battery will do the same for the front. Many bikers use two in front as well - a flashing light is much more visible to drivers than a static one. This system works well if you know the route and are confident you won't hit a pothole or mailbox on the way.
      However, it takes a lot of light to let you see very far in front of you, and a cheap headlight won't cut the mustard. If you're just riding around home, you're probably OK without this, but bikers who tour and run late to their destination may find themselves riding in the dark in strange territory, and might need more. It's even more important for commuters who regularly ride through traffic in the dark early or late hours to work. Now, with extra bright LEDs which range from the 350 lumen NiteRider MiNewt 350 ($200, left) to the 1800 lumen Exposure Six Pack ($600, below right), we can reach that safe level of illumination at a somewhat reasonable cost.
How Bright Is Bright Enough?
Watts. Lumens. Candlepower. What do they all mean, and why don't manufacturers list the lighting power of their products in the same language, so we can compare apples to apples?
Watts   Watts is the measurement of electrical power delivered to the bulb by the battery.
Lumens  Lumens are the measure of actual light output from a lighting unit as measured at the bulb. This is the measurement of radience. However, the product ratings (which come from the manufacturers) tend to be of inconsistent quality.
Candela/Candlepower/Foot Candles   These are all terms for the same thing: the measurement of illuminance, and is done at the eye, measuring the amount of light reflected back from the object you shine the light on.
      These three all measure different things, and, unfortunately, there is no accurate rule of thumb conversion among them. In the absence of first hand testing, however, all three can be used as an indication of the quality of the lighting systems you are comparing.
       The more watts, the greater the power and the more likely the light will be effective. One estimate of the wattage needed to effectively light the way at night is 5 or 6 watts. In practice, commuters vary widely, using from 2 to 15 watts for this purpose.
      The more lumens, the more light you know is being generated. This is a better indication of effectiveness than watts. One estimate of "enough" light for a commuter is 300 lumens.
      Candela is the best indication of effectiveness, because this indicates the amount of light which actually helps you see the object being illuminated. This is a difficult measure to take, however, since the lights all have to illuminate the same object in the same conditions to be compared.
      So what do you do? Using any of these three to compare systems will help a little, but you need to do your own research on the web and look for reviews and experiences of other riders, particularly on the forums. You can also ask your local bike shop, although their opinions may be colored by the brands they carry. The technology used in a particular system can also be a guide in determining effectiveness.
      A lighting system is composed of two principle parts: bulb and battery.
Which Bulb Technology Is Best?
There are several practical options in bulb technology, such as LED, HID and Halogen. There are also new technologies on the horizon, such as plasma, and they are evolving so fast that this page may be obsolete next week.
High Intensity Discharge (HID)   HID continues to be the brightest bulb, but runs very hot. Forward motion is usually necessary to cool it and avoid damaging the mechanism, so it's not good as a camping light. Some systems will shut themselves off if they overheat, but if you're in darkness and need a light, you're out of luck. They are expensive but more efficient than halogen.
Halogen   Advantages include a high power output, general availability, high reliability and relatively lower cost. Their brightness tends to dazzle oncoming traffic, though, so they are not street legal in some jurisdictions. They have a limited burn time and somewhat lower lifespan than other technologies. Halogen lights also run hot and require forward motion to cool them.
Light Emitting Diode (LED)   There has been an explosion of advancement in LED technology in the last year. Not really a traditional bulb, LEDs are lighter, less fragile and now very powerful. Cadillac began using them in their auto headlights last year. These units are the most efficient in delivering light (today's 3 watt LED is as bright as a typical 10 watt halogen bulb), have a very long lifespan, can be turned on/off instantly and can be dimmed with a marked gain in efficiency. They may also have a heat problem with higher power units. This is definitely the bike light of the immediate future.
Beam Shape/Pattern
The shape of the beam has much to do with the efectiveness of the lighting. A beam too broad doesn't effectively light the road straight ahead; a beam too focused will not provide enough visual depth for a clear view of both close objects and those farther away. Some beams may have dim spots or bands. Beam shape and pattern are a function of bulb angle and shape, reflector shape and lens shape. This is a good reason many riders use two strong headlights: by pointing them in slightly different directions, you can compensate for dim areas. Some riders wear their second light on their helmets, so there is always a light pointing in the direction they're looking.
Batteries: Disposable Or Rechargeable?
Cheaper, less powerful "see me" lights use disposable batteries, but there is a new generation of higher powered lights which use them, as well, and these may be adequate for lighting the road ahead. These lights may be initially less expensive, but batteries cost money over the long run.
Rechargeable Batteries
Other lights come with rechargeable batteries. Rechargable batteries are also expensive. In high end lighting systems, the battery will be by far the greatest cost. Things to look for are battery life (how many times it can be recharged), burn time (how long it will provide energy on one charge), ease of recharging (read recharging directions before you buy), weight, size and potential dangers (batteries involve chemical activity, and some will explode or catch fire if misused; a number of models have been recalled for those reasons).
      Some batteries are incorporated into the light housing, others have a power cord and are designed to fit into an extra water bottle cage.
      Batteries usually come in 6 volt and 12 volt flavors; 12 volt units have greater capacity and usually come with more powerful bulbs.
Lead Acid   Lead acid is the oldest and cheapest technology, and comes with low-end lighting units. Lead acid batteries lose voltage over time and your light dims accordingly to let you know it's running low. NiCad and NiMH batteries keep their voltage until the last minute, then dim severely. While this gives you longer periods at full power, you must turn off your NiCad or NiMH battery-powered light immediately to avaid damaging the battery. You'll need to check/charge NiCad and NiMH batteries regularly.
Nickle-Cadmium (NiCad)   NiCad is a better and more expensive technology and comes with more expensive units. Just a few years ago it was state of the art technology.
Nickle-Metal Hydride (NiMH)   NiMH is an even more efficient and expensive technology and comes with high-end units. It provides greater energy capacity and can be recharged up to 1000 times.
Lithium-Ion (Li-ion)    Lithium-Ion technology is currently the newest entry into the market. These batteries offer the greatest enegy per weight and a higher voltage, making them the best choice for long operating periods. They are also very slow to discharge when not in use. They are the battery of choice for high-end consumer electronics.
Charging Batteries
Charging batteries seems a simple thing, but you can destroy your battery if you don't do it correctly. Make sure you use the charger recommended by the manufacturer (many batteries come with their own chargers, as well). Follow the instructions carefully.
Hub Generator
Perhaps the best solution is a generator built into the hub of the wheel. The best generators have virtually no drag when the light is off and very little when it is on. They also have unlimited run time, since you are providing the power. Most also provide "stand time," meaning that the lights continue to shine for a few minutes after you have stopped pedalling. Of course, this is initially the most expensive option, but you won't have to buy batteries. A hub will run $100 - $150, plus the cost of building the wheel. If you can do it yourself, a generator hub can be a very efficient and inexpensive solution.
Flashlights
An alternative to bicycle-specific lights is a high-power flashlight with rechargeable lithium-ion batteries. These lights may be a little less expensive than traditional systems and they can be fastened to a helmet or 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 and may not provide the best beam shape. Obviously, they make excellent general and camping lights.

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