Monday, November 09, 2009

Bicycle Headlights

Bicycle headlights can be divided into two groups:



  • Higher-end lights bright enough for a cyclist to see what they are rolling over.

  • Entry-level lights that cannot light up the road.


Higher-end systems start at $85, and entry-level lights are priced below that. OlyBikes sells both categories of lights, though we feature higher-end systems on our website.


 


Entry-Level Lights

We often refer to these as "defensive lights." They help make cyclists more visible to other road users, but simply are not bright enough to light up the road (so do not expect them to). They are fairly affordable, portable, lightweight, and make great backup lights for brighter systems, or even loaner-lights for a friend who has stayed past dusk.

Few of these lights are rechargeable, but you can always opt to use rechargeable batteries in them. Indeed, doing so will in short order pay for both the batteries and the charger -- especially if the light has incandescent halogen bulbs!


Last, but not least, defensive lights meet the nearly nationwide requirement that during evening hours, bikes be equipped with a white, steady beam (not flashing!), visible for 500 feet. Fines of $105 for breaking this law are not unheard of. That's more than enough for even a basic "high-end light" -- speaking of which...


 


High-End Lights


You'll need a pretty bright light to see what you are rolling over. Think about it -- as the beam projects out from your headlight, the great majority of it bounces off the road or trail and keeps travelling away from you a la the phrase -- "angle of incidence = angle of reflection". To really SEE what you are rolling over, enough light must reflect back from the road/trail to your eyes. That's tough considering how shallow the angle of the headlight beam is. Factor in limited reaction time at speed, potential ambient darkness (especially in more rural riding), and it's simply a challenge that not every light is up to.


Bicycle Headlight Reflection and Illumination

Several years ago, high-end light systems were solely the domain of incandescent halogen and High Intensity Discharge (HID) lights. Halogens were relatively cheap but somewhat inefficient. HIDs were much brighter, with 500-900 lumens (equivalent to about 45-65 watts of light), but with run-times up to twice as long as the highest-end incandescent lights. Halogen incandescent systems have largely left the market two years ago, forced out by LEDs (see below). Now HIDs are experiencing the same fate.


For years, LEDs were relegated to the low-end light category. They were dim and only put out light in a narrow plane that wasn't very useful to see by. Even the much-touted 1-watt LEDs that are pretty omnipresent today lack the output to allow a rider see where they are going, and those lights routinely cost around $50. When this article was first written, LEDs just didn't "pencil out" against bright halogen lights. Now they do, plus LEDs offer greater durability, smaller batteries and longer burn times. As a result, higher-end incandescent systems are almost completely gone from the market.

Super-high-end LEDs rival any HID system out there. Cygo's Trion 600 light is a perfect example of how LEDs are really maturing as a lighting category. With 600-1200 lumens of light, they cost less, weigh less and are more portable and durable than HID systems (HID bulbs are not very shock resistant and replacement bulbs can run $50 -- ouch!).  Such LED systems  cost from $300-$700 depending on brightness and feature set. While this might seem like a lot, consider the cost and inconvenience of either crashing solo from unseen debris/poor surface, or worse, from being hit by a car. The medical bill from even a minor trip to the hospital would likely cost more than the nicest LED light available.


Generator-Powered Lights


Battery-powered lights aren't the only option, of course. Dynamo (aka "dyno") light systems supply power via either a frame-mounted-tire-driven generator or a generator contained in the hub of a front wheel (dynohubs). Tire-driven systems are cheaper, but: they make some noise, can be knocked out of alignment (damaging the tire), can slip in wet/snowy conditions, and are usually slightly less efficient than dynohubs. On the other hand, they are less expensive, and are completely efficient when not in use (technically, dynohubs supply some resistance even when not in use). Dynohubs are more efficient in use, never slip, and their silent operation is a small mental boon, as the rider isn't constantly reminded that they are supplying light system power via noise.



Surprisingly, a 3-watt dyno system can supply as much usable light as a 10W battery-based system. How? Quality dyno lights, have high efficiency reflectors and lenses that focus all the light exactly where it will be usable for the cyclist. In contrast, most battery-powered headlights are adapted from the world of indoor halogen lighting. This approach is one of "sheer horsepower" applied inefficiently in order to get enough on the ground to see by.


Generators, particularly dynohubs get a big thumbs-up regarding their dependability. Own one, and you'll never wonder, "Did I bring my light? Is it charged?" If you can pedal, you have light!


Like battery-powered systems, dyno lights have benefited from the evolution of LEDs. The latest ones use multi-watt LEDs that reach full brightness even at low speeds. LED emitters are orders of magnitude more durable than incandescent lights, meaning that you'll never have to replace the emitter (from use or shock). Efficiencies are high enough that many cyclists leave their dynohub LED lights on all the time. There is little downside to it for around town commuting.



Generator systems are usually used to power headlights, but can also power rear lights too. The wiring for a complete system is a bit more complicated and vulnerable. Many folks simply run a standalone battery-powered taillight. If you want a dyno-powered taillight, make sure that the dyno and the headlight can accommodate one (some are not designed to work with taillights).

One of the longstanding downsides of generator systems has been a lack of visibility when the rider stops at traffic lights or stop signs. This too has been overcome by using a "standlight" wherein a capacitor (like a short-term battery) powers either the main light emitter or an auxiliary LED emitter. Standlights usually provide a couple minutes of "defensive-visibility" (allowing other road users to see the cyclist). Standlight circuitry is "in the light", not the generator, so if you want that feature, make sure you are getting a headlight or taillight that has a standlight.


OlyBikes has the following recommendations about lights:




  1. Head-mounted lights, assuming that their beams are more perpendicular to the ground, may allow more light to reflect back to your eyes (increasing ground-visibility). However, low-mounted lights provide more shadow detail -- a handy perceptual cue in uneven terrain (some riders like fork-mounted lights for that reason). Head-mounted lights have other advantages though. Simply look at a driver on a side street or pulling out of a parking lot and they get your light's full brightness directed at them. You also get hands-free illumination for dealing with mechanical trouble or to better see keyholes at night. Plus, if you have multiple bikes, you'll probably use the same helmet, so no extra light mounts are needed. When you lock up your bike, your light system is already WITH you, so it wont be stolen or be yet another thing you have to carry in your hands at your destination.

    The downside to helmet-mounted lights is that the batteries are usually carried in a jersey or jacket pocket and some folks don't like the weight or necessity of wearing a garment with a pocket. A few cyclists use helmet-mounted lights with bike-mounted batteries. If you try that, remember to disconnect the wire before walking away from your bike (ouch + crash = doh)! Perhaps the best helmet-mounted lights are those with internal batteries, like the Cygo Milion 150 or Cygo Milion 200 (the former is compatible with an optional helmet mount, the latter comes with BOTH a bar mount and a helmet mount).

  2. In terms of brightness, you need at least 10 watts of incandescent light or 150 lumens of LED output to begin to see what you are rolling over. That translates into at least $85 for a 12-watt system like the Cygolite Night Rover. There is plenty of reason to get a nicer system like the Cygo Milion 150 or Cygo Milion 200 though. They are lighter-weight, have longer "burn times", fast and smart chargers and batteries that provide more consistent brightness as they discharge.

  3. Keeping it simple is a good thing. Avoid lights with excessive bells and whistles. Remote switches are more likely to fail (besides being another thing to secure to, and remove from, your bike). Features like fuel gauges seem nifty, but in reality, any competent person can keep track of how long their light has been burning. Plus with fast and smart chargers becoming more common, batteries can be easily "topped-off" before being fully discharged (and by the way, "battery memory" is largely a myth).

  4. Exceptions to the "Keep it Simple" rule are "fast" and "smart" chargers, and lights with multiple brightness settings. These are worthwhile features. A 10-11 hour recharge time may work well for some, but for busy folks with tight schedules, a fast charger, with 2-5 hour turnaround is more convenient. Smart chargers help protect batteries by shutting off when their job is done. This is an important feature because overcharging batteries easily damages them, resulting in dramatically reduced burn time and/or battery life (often thought to be "battery memory", which it is not). Protect your investment by getting a system with a smart charger (they're usually fast chargers too). Perhaps of lesser import, multiple light levels can be handy for increasing burn time (at the expense of brightness, of course).








The world of bike lights is changing rapidly and for the better. Today's systems are smaller, lighter, brighter and more efficient, while prices are dropping. Expect that in another year or two, that LEDs will have advanced to the point where not only incandescent sytems are gone from the market, but HIDs as well. We're already seeing LED dyno lights that are as bright as HIDs coming out now. With such dramatic gains in technology, the future of bicycle lighting looks quite bright indeed! Joking aside, investing in your safety is the smartest thing you can do -- get a derailer decent enough to do the job, but get the brightest light you can afford.


Take a look at the light systems featured on our website.