BeigeJournal

On this warm February 28, with temperatures near 15°C, I went out for a 90 minute, 30.5km ride. That brings the 2004 total distance to, um, 30.5km.

The last time I was out cycling was 2003-12-22, commuting. 2785km in 2003.

The ARC (bicycle mounted) and ARC Cabeza (helmet mounted, as the name implies) lights from Light and Motion use a 13.5 watt Welch Allyn Solarc metal halide arc lamp and either a NiMH battery or a 280 gram lighter Li-Ion battery. As I write this the NiMH version is selling for around $410 and the Li-Ion for around $500. I have owned a NiMH-equipped ARC Cabeza since last fall.

Miniature HID lamps are a difficult and correspondingly expensive technology, but are substantially more efficient than incandescent lamps. At best incandescent lamps give little more than 20 lumens per watt, while the small Solarc HID lamps manage 45 (perhaps more) lumens per watt. When watts are cheap it may be hard to justify the breathtaking price of the HID lamp, but when power comes from a battery strapped to your body or your bicycle and carried under human power, the improvement in efficiency is important.

This thing is bright. Not just compared to the 4-AA mini-lights but even compared to most of the big and expensive halogen bicycle lights. I never realized how much retroreflective material was out there until I strapped a powerful light to my head. With the high output and the small distance between lamp and eyes to maximize the efficiency of retroreflectors, it seems the whole world is retroreflective. The fact that many of these retroreflective surfaces went unnoticed by me until I bought this light should be a warning about the limits of reflectors.

The light pattern is a very wide, very even circle with a smaller, also very even, much brighter central spot. The circular pattern wastes light upward but does simplify the optics and ensures that the light is clearly visible to others even if aimed downward. The wide pattern both makes the user very visible to other road users and, in unlighted areas, provides surprisingly useful peripheral light. It avoids the tiny patch of light in a tunnel of darkness effect, and makes it possible to see potential hazards that are off to the side. The shear quantity of photons coming out of the lamp means that it is not necessary to focus the beam tightly. There is plenty of light to go around. The bright central spot seems to me to be just about perfectly sized. This light really makes night riding routine. I have ridden unfamiliar, unlighted roads at upward of 35 km/h and felt reasonably safe doing so. That would seem absurdly reckless to me with lesser lights. People see me, as well. Indeed, sometimes I can almost see the question marks hovering over the cars as motorists wonder just what that brightly lit object is.

Whenever HID bicycle lights are discussed some people always wonder if the lights are dangerously bright, dazzling other road users. If only the designers and operators of motor vehicles, with their far more powerful lights powered by engine-driven electrical systems, were as worried about blinding other people. Imagine how nice the roads would be at night. This thing is less powerful than a single car headlight. It is a very bright compared to the average bicycle light (as far as I can tell, the typical bicycle light is no light at all), but it is not really that bright compared to anything not powered by a little battery pack. Certainly, if you walk up to someone and aim the brightest part of the beam directly into that person’s eyes, you will annoy that person. So don’t do that. In traffic, the other people are farther away. The dim part of the beam, even at close range, is not unreasonably bright. At across-the-intersection distances, even the bright part of the beam, while very bright, is not going to set anyone’s retinas on fire. I don’t recommend routinely flashing the brightest part of the beam at people—the dimmer part should be plenty noticeable—but if you do so by accident, or to get a particularly inattentive person’s attention, no harm should come. No one is really dark-adapted when driving in the first place, except possibly in desolate areas. All urban/suburban/rural-but-near-the-suburbs road users are frequently flashed by the brightest part of car headlight beams, even with properly adjusted lights, as dips, bumps, and hills shine the lights into people’s eyes, and there are always the mis-aimed lights and the people using the high beams inappropriately. I think the risk of dazzling other people is greatly exaggerated. I find the helmet-mounted light easy to control, with only trifling attention required to keep the light pointed where I want it and out of people’s eyes.

The system has the appearance of sturdy, high-quality equipment. The company also makes underwater camera housings and dive lights, so one hopes they understand water resistance, though I have not used it in the rain (yet). The ballast electronics are integrated into the lamp assembly, with the power cable permanently attached to the lamp. The HID arc tube has a claimed median life of 1000 hours and is not user replaceable. The battery connector has pins that while fragile-looking have not caused me any trouble. The connector appears waterproof and sturdy once connected. I added some markings to the connectors with a white marking pen to aid alignment since the molded arrows are very hard to see. The lamp is controlled by a single push button on the back. A LED behind the button blinks to indicate low power mode and blinks more rapidly as a low battery warning. Double-click to turn it on, a single click switches between full brightness and a slightly dimmer setting, and holding the button down will shut the lamp off. All discharge lamps take time to warm up and are difficult to restart when hot. This lamp takes several seconds to warm up enough to produce significant light and perhaps 10–20 seconds to produced full output. After shutdown it cools enough to restrike quite quickly, less than 30 seconds. Part of the complexity and expense of automotive HID lights stems from the legal requirement to produce high light output almost instantly and to reliably restrike from full operating temperature. The ARC’s performance is perfectly adequate for a bicycle light. Battery life is claimed to be three hours at full power and 3.5 hours at low power. In informal testing this seemed approximately correct. Light and Motion warn that the lamp is designed to be cooled by the airflow of cycling and should not be operated for more than 15 minutes without airflow over the unit.

There is no quick release between the lamp and the helmet mount, so the Velcro-covered strap must be threaded through the helmet with each use. Fortunately this is reasonably easy. A quick release would be preferable, provided it was sturdy, easy to use, and light, which might be a somewhat difficult combination to achieve. I think the current arrangement is acceptable. The usual possibilities for carrying the battery (jersey pocket, backpack) don’t work so well on a recumbent. I have one of those orange reflective vests with pockets and keep the battery secured in a pocket with elastic straps.

The standard charger shipped with the NiMH ARCs is excellent. It is a proper NiMH charger, with dT/dt end-of-charge detection and, as far as I can tell, a suitably low trickle charge rate once full charge is reached. It can fully charge a fully discharged battery in 3.5 hours. A short lead connects the charger to the battery, and a standard IEC connector of the type found on computer gear connects the charger to 100–250 volts AC via the included cord. It’s really the minimum we should expect for anything with NiMH batteries, especially relatively expensive equipment, but good chargers are rare. Apparently most manufacturers view selling replacements for batteries destroyed by bad chargers a means to boost profits.

There are a great variety of bicycle lights of many types available. Different cyclists have different needs and the very bright, very expensive, battery powered lights are not suitable for all cyclists. If you feel that very bright, very expensive is what you want, the Light and Motion ARC series appears to be an excellent choice. I’m very happy with mine.

For more information on lights and reflectors, as well as safe cycling in general, I recommend John Allen’s web site, which has a bicycle reflectors and lights section, and John Forester’s site, which also has a nighttime equipment section.