Features October 15, 2003 Issue

LED Flashlights

The SureFire L1 Lumamax and the Tektite Expedition Star take Best Buy honors. Incandescents may not pale in comparison, but they're fading fast.

At the end of our last review of LED flashlights, only about three and half years ago, (March 2000) we said that the development of these lights was in its infancy, that we expected to see brighter white LEDs in the near future, and more entrants in the field. In the interim we've looked at low-draw LED masthead lights (May 15, 2000) and other developments like LED navigation lights, "SmartLytes," and nav station penlights (January 1, 2003). In an upcoming Chandlery we'll talk about some tough-as-nails LED trailer lights from SeaSense. 

LED lights. Top row: Streamlight 3C, SureFire L1, Tektite Expedition Star, SureFire E2o+KL1, Streamlight Twin-Task 2D, SureFire L4, Browning Odyssey 3000, Inova X5. Bottom Row: Golight Epoch 4, Inova 24/7, EternaLight 3M.

It didn't take any brilliant prognostication to see this trend barreling along, or to understand its implications for sailboats and beyond. LED technology continues to be one of the most promising elements in the move toward energy conservation, and now, in our opinion, it's delivering reliably and affordably on its promise.

It was time again to survey the field of serious LED flashlights that not only offer all the advantages of LEDs over bulbs, but can compete with the light intensity of traditional flashlights, too. Our goal was to sample the crop of higher-output models offering water-resistant housings—a tour of the state of the art.

Background
An LED is essentially a PN–junction semiconductor diode that emits light when current is applied. There would be no reason to introduce a diode in a flashlight, had not an engineer about 40 years ago developed one that emitted light when it passed current. Early LEDs were tiny and produced weak red light, but today a single LED and one or two small lithium batteries can produce intense whitish light better than that of a traditional flashlight lamp powered by multiple D cells.

LEDs enjoy orders-of-magnitude longer lives than incandescent bulbs, and aren't as fragile. Claims vary as to their lifetimes, but 10,000 hours (over 27 years at one hour use per day) is conservative.

A white LED produces color close to that of sunlight. After you use an LED flashlight for a time, light from incandescent flashlights will seem sickly and yellow. In the past, LEDs have not had the sheer illumination power or focusability than incandescent lights can produce. This, in many cases, has changed.

Power Talk (Batteries)
In the B.C. (before cellphones) era, the more powerful, longer lasting batteries were also larger and heavier. The modern contender for high energy density is the lithium battery. To quote one flashlight maker, the 123 lithium cell "can deliver over four times more power (watts) without overly excessive voltage decline over its discharge period; is about 30% shorter; is lighter, and has a 10-year shelf-life as opposed to about three to four years for the AA alkaline battery. It also stores almost 50% more usable energy than an AA alkaline battery and is the overwhelming performance choice for a primary battery in a flashlight application."

Until recently, these cells cost several dollars apiece, but we found that SureFire, one of the manufacturers in this evaluation, sells them for $15 per dozen ($1.67 each including shipping). Given the long shelf-life, buying 'em by the dozen seems a smart way to stock up.

On the other tack, we're strong believers here in rechargeable batteries. Today's nickel metal hydride (NiMH) and rechargeable alkalines perform much better than they did even a few years ago and can be recharged many times. In any case, buying dozens of disposable batteries at the supermarket and just tossing them out after use is neither cost effective nor environmentally wise.

Switch Features
Three types of electrical switches are used in these flashlights:

An intermittent–contact switch is like a doorbell button: pressing turns it on, and releasing allows an internal spring to break the connection. It's only stable in the off position.

Toggle switches are like those on conventional table lamps: pressing or turning lights the lamp, and when you remove your hand the light stays on. Press or turn again (perhaps in the opposite direction) and the light goes off. The switch is stable in either on or off position. In the flashlights here, a toggle switch might be on the barrel or integrated into the tailcap, the latter case being one you'd rotate. In some lights, both of the above switch types are supplied. We call this a hybrid.

Rotary–selector switches are like mode controls on electric ovens: each detented position of the dial selects a different function. The switch is stable in any position.

Regardless of type, a switch can be turned on by accidental pressure during wear or transport. A lockout feature guards against accidental activation. It's important, especially if you carry a light in your pocket.

Measuring Light Intensity
Few LED flashlight manufacturers make claims about light intensity, focusing instead on the long service life of the LED or shelf life of the batteries. We therefore determined to measurelight intensity ourselves.

First, a caveat. Just as with most other measurable characteristics like horsepower, on-time flights and even the speed of light, there's no "true value": A flashlight's intensity value is just the result of applying a measurement procedure. There are many procedures, and there's disagreement on what's currently the best, as well as on photometric units. But since only a few of these lights came with intelligible claims, we thought we'd better provide something better than "bright," "very bright," etc.

In a dark area, we used a Wavetek LM631 digital light meter, held one foot from the end of each flashlight, and took its peak beam reading in footcandles (fc), a unit of measure approximating the amount of light received by 1 square foot of a surface that's 1 foot from the source of light.

Some manufacturers measure in lumens, units that express total light output in all directions, and require specialized equipment to capture. We've shown lumen values where provided by manufacturers.

Beam Patterns and Quality
Most LED flashlights provide a flood type of beam. Some have reflectors; others simply have an array of LEDs. A theoretically optimum flood beam would create a flawless bright central area surrounded by a perfect corona of softer light, making it most useful at fairly close distances, e.g., inspection of boat compartments, or working on your engine or electrical system. Lacking filaments, LEDs typically produce much more even patterns than incandescent flashlights.

Whatever the type of beam, quality denotes how well it's executed.

Housings
The models presented here have bodies of rubber, ABS/Lexan, polymer and aluminum. On aluminum bodies look for Type III Hard Anodizing, a MIL–SPEC process that creates an extremely dense surface with hardness and resistance to abrasion and corrosion as primary characteristics.

How We Evaluated
These flashlights shed new light on what's important in personal lighting. First, size and weight need no longer be correlated with illumination power. Second, given their ability to use energy evenly, and the practically indefinite lifetime of LEDs, we can concentrate on measures that reflect efficiency in the use of power, such as a choice of light levels to fit the task. Although LED beam quality in these samples is superior to most tungsten bulbs, we can now hope for the ability to vary light intensity and regulate power use.

The performance criteria in the accompanying table will be self-explanatory, except perhaps for footcandles per ounce (fc/oz.), meaning how much illuminating power you get for each ounce of flashlight you carry, and footcandles per dollar of purchase cost (fc/$), meaning maximum amount of light per dollar of flashlight price.

The Flashlights (alphabetically by brand)

Browning Odyssey 3000. A famous supplier of firearms, Browning now offers a range of LED flashlights. The 3000 has a traditional shape, with 7 LEDs protruding from the front, protected by a thick overhanging bezel. The body is rubberized black polycarbonate that appears heavy-duty.

A hybrid switch is provided on the forward part of the barrel: press softly for intermittent light; press-click to toggle continuous on/off. No lockout feature is provided, nor is there adequate protection against rolling.

Browning claims a 10,000-cycle switch, and a 600-hour run time, but no indication of light levels during those 600 hours.

EternaLight ErgoMarine 3M. About the size of a pager or a fat cell phone, the 3M combines four in-line LEDs with a multifunction microprocessor. Three click-buttons provide control, and their use is easily learned. Seven modes are provided: timer, twelve levels of light using 1-4 LEDs, flasher, strobe, dazzle, SOS signal, and user-controlled pulse. The lowest light setting uses only 1.7% of maximum power, yet is useful for reading. The housing is two plastic clamshells separated by a thick gasket, held together with four screws, and it is the subject of careful statements of both watertightness and shock resistance. The 3M has only one stable position, flat on its back (or front). It runs on three AA alkaline or lithium cells.

Despite the linear arrangement, the four LEDs converge nicely into a circular flood pattern. While not strictly a lockout feature, the first light mode turns on the LEDs with a programmed self-timer, meaning that if the light is accidentally clicked on, it will gradually turn itself off at a rate of one LED each 2.5 minutes.

Golight Epoch 4. Light and stealthy (gray/black color), it has four LEDs in chambers that look like torpedo tubes on a submarine's hull, powered by two 123 lithium batteries. The housing lacks an effective means to prevent roll. One light level is provided, and that is weak within this group. Twist to turn on/off. A detent is provided as a lockout on the switch, but we consider it somewhat weak. The sealing O-ring was thin and didn't inspire confidence. Given this light's claim of being an "ultimate LED floodlight" we were disappointed.

Inova X5. Emissive Energy Corporation makes a small number of LED lights, of which the X5 is top of the line. It's a 4.75"-long aluminum tube, faceted along most of its length, with a 5-LED array on one end and a hybrid switch on the other. For protection and beam-shaping the LEDs are individually recessed into the housing. The 8 facets provide reasonably good grip. Press the tailcap switch for intermittent activation, or twist to toggle between continuous on and lockout. It's knurled to make turning easier, and has a lanyard attachment.

Overall the design is clean, spare, and well-executed as though from Scandinavia, and would not be out of place in the Museum of Modern Art. The X5 comes with a ballistic-cloth belt holster that retains it with elastic pressure, but requires two hands for removal.

Given its small size and weight, the X5 offers reasonable light in a good beam pattern. We'd like to see a lot more, and sharper, knurling on the housing, as well as a design feature to prevent rolling on smooth surfaces.

Inova 24/7. This friendly little R2D2 look-alike from Emissive Energy has eight (4 white, 2 red, 2 yellow) recessed LEDs arranged evenly around a turnable bezel. In addition to two levels of white light, it provides four attention-getting emergency/distress modes, a night-vision red light, and a self-locator beacon that can be left on for long periods. It runs on a single 123 lithium cell. The case is stable in two positions, has a spring attachment clip, and is yellow. An optional accessory kit contains a magnetic mount, a wall mount, and an adjustable headband to free your hands.

The rotary switch lacks a lockout feature and, since the 24/7 arrived in the "on" position we consider accidental activation likely. With its accessory kit the 24/7 seems quite useful for a great many tasks.

Streamlight 3C. As its name implies, this traditionally shaped light operates on three alkaline C cells. It combines 10 LEDs in a symmetrical array, activated by a thumb switch on the rear. Press for intermittent light, click for toggle on/off. No lockout is provided, although perhaps Streamlight is depending on the switch's heavy return spring to prevent accidents. Both lanyard attachment and spring-loaded belt clip are provided, the latter also functioning to inhibit rolling.

Streamlight Twin–Task 2D. It offers three light modes in a heavy-duty police-style housing. Ten LEDs are arranged in a circle around a xenon–filled incandescent bulb, and two alkaline D cells provide power. A traditional button switch toggles from one mode to the next, then off. The modes are: 5 LEDs on, 10 LEDs on, and xenon bulb alone on. The black aluminum housing is knurled for grip, although we'd like to see the cuts a bit deeper.

Beam quality is fairly good in LED mode, but in xenon mode it suffers from typical tungsten-filament shadows despite a crinkle-surface reflector design. The switch has no lockout feature but is probably less likely than most to be switched on accidentally. Resistance to rolling is low. A lanyard is supplied.

SureFire L1 Lumamax. Much of this description applies to all three SureFire models evaluated; for the other two we will only mention what's different. Known for its tactical flashlights and laser sights supplied to police and military users, SureFire specializes in high-power applications featuring minimum weight and bulk—as our results validate. LED lights were first introduced as conversion heads for existing incandescent models. The L1 is its first LED-only model, described as a "general-purpose illumination tool with a relatively long-running flood-type beam." It uses a Luxeon Star LED, claimed to be the highest-power family of LEDs on the market. An onboard microprocessor provides digital current regulation to ensure a consistent output of LED light throughout the single 123 lithium cell's life. Two light output levels are provided.

The L1 is not much larger than a roll of nickels—the slimmest model in our test group. Its housing is Type III hard-anodized aluminum in a military gray/green finish. Deep knurling of the barrel sets the standard for a non-slip surface. The scalloped front bezel prevents a turned-on flashlight from going unnoticed even if set down on its front end. A hybrid switch provides the two light levels—press soft or hard on the two-stage intermittent rubber tailcap button to get the low or high beam, respectively. Twist the tailcap one revolution to toggle between continuous low or high beam, or the lockout position, safe from accidental activation. A spring-type pocket clip with integral lanyard hole completes the external features list. Resistance to rolling is excellent.

We appreciated the low-power setting for uses where maximum power isn't needed—in our case a significant portion of total use. At full power this tiny but rugged one-battery light produced an amazing 231 footcandles. Beam quality was excellent; the term "creamy" comes to mind.

SureFire E2o Outdoorsman w/KL1 LED Conversion Head. The E2 is part of SureFire's modular Executive series, available in two configurations of incandescent lamps, either of which is interchangeable with a KL1 LED head, tested here. The E2 model is like a two-battery, single light-level variant of the above L1 model, with a tailcap switch that can be clicked to toggle between on and off. Intermittent and lockout features are the same.

If purchased as the E2e Executive this model comes with a 60-lumen xenon head offering, by adding the KL1 head, the versatility of the long run time of an LED, plus the intensity and features of a police tactical light. The heads can be interchanged in well under 30 seconds.

SureFire L4 Lumamax. Although marketed as a separate model, the L4 is essentially an E2 body with the new KL4 high-power (5 watt) LED head, producing an astounding 522 footcandles of light. Instead of the clear reflector used in the above two lights, it has an "orange-peel" surface.

Producing light at above the level of a police tactical light consumes batteries rapidly: in about 80 minutes the L4 declines to the light level of the other two, but without their staying power. Although for the moment something of a special-use light, the L4 amply demonstrates that a tiny, pocketable device can produce gobs of brilliant white light.

Tektite Expedition Star. One in a large line of LED lights, this is the only model here featuring an optically focused beam: the majority of its power is concentrated into a claimed 10° angle. It boasts a Luxeon Star LED , the greatest claimed waterproof depth (1,000 ft.), and is said to run at full power for 15 hours on three alkaline C cells. Its switch is a simple toggle operated by twisting. It comes with a well-designed wrist lanyard. We liked its high light intensity and good beam.

Even if it's set down vertically, covering up its beam, a glow from the rear of its cap warns you it's still on.

Our only dislikes are that has no resistance to rolling, and it's the only light in the evaluation that needs two hands to turn on/off.

The Tektite Expedition was rated Best Value in our March 2000 report, as well, by different testers, so it's a good light.

Conclusions
The "size rule" is no longer in effect, for batteries or flashlights. Think in terms of energy density and pocketability.

For maximum light intensity, pick any of the SureFires (the L4 was the highest by quite a margin), the Expedition Star, or either of the Streamlights.

Best beam quality, as well as greatest light intensity per unit of weight, is offered by the SureFires and the Expedition Star.

Light intensity per dollar of purchase cost was a pretty even distribution. The top half are the Expedition Star, the SureFires and the Streamlights. For economy in operation, and for suiting the light to the task, these lights offer more than one light level: SureFire L1, Streamlight Twin-Task 2D, Inova 24/7 and EternaLight 3M. If all-round versatility of function is key, consider the EternaLight 3M or Inova 24/7.

For their high marks in the first four criteria, we consider as Best Buys the SureFire L1 Lumamax and the Tektite Expedition Star.

 

Also With This Article
Click here to view "Value Guide: LED Flashlights."
Click here to view "Small Pocket Lights."
Click here to view "Performance Guide: LED Flashlights."

Contacts
• Browning, 800/333-3504; www.browning.com.
• Emissive Energy Corp., (Inova), 401/541-9001; www.inovalight.com.
• Golight (Epoch 4), 800/557-0098; www.golight.com.
• Pelican, 800/473-5422; www.pelican.com.
• Sailor's Solutions, www.sailorssolutions.com.
• Streamlight, 800/523-7488; www.streamlight.com.
• SureFire, 800/828-8809; www.surefire.com.
• Technology Associates (EternaLight), 775/331-3330; www.techass.com.
• Tektite Industries, 800/540-2814; www.tek-tite.com.

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