Features December 2007 Issue

Practical Sailor Sheds Some Light on LED Flashlights

In a search for the perfect, energy-efficient flashlight, testers evaluate brightness, beam quality, and utility.

Testers evaluated 25 different flashlights. Among these were products from Inova, Underwater Kinetics, Tektite, Sea Fit, Streamlight, Garrity, Pelican, Dr. LED, and IQ Lights. The goal of this test was to find a flashlight that was compact, light, and provided superior spotlight and wide angle illumination for objects in close range. Unfortunately, no light we tested answered all of these requirements. The winners proved to be units that excelled at one. We also discovered that size still matters, and more batteries means more power, more light, and more life. The best marine flashlight is one that suits your needs. A well-equipped sailor needs a few different flashlights to cover all the bases: one that’s a dedicated spotlight, one that lights up the lockers, one that serves the needs of bright, wide angle floodlight, and lastly a tiny pocket light used for in-the-cockpit chart reading or other instances when you need a quick light but want to preserve your night vision.

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Underwater Flashlights
Ralph Naranjo

When Underwater Kinetics’ SL4 Sunlight with Xenon bulb (right hand) and the nearly identical SL4 with LED were compared side-by-side, the “warmer” color temperature and higher intensity of the Xenon bulb was obvious.

A technological evolution has made flashlights smaller, lighter in weight and brighter, allowing them to be easily carried in a pocket or attached to an inflatable PFD. They range in mission from micro-size devices that give momentary illumination to insert a key or check a chart, to compact, waterproof spotlights that will illuminate a mark a quarter-mile away and keep on working no matter how wet they get. With the rapid growth of light emitting diode (LED) technology, the range of alternatives has become even greater.

What We Tested

For this test, Practical Sailor focused primarily on smaller LED flashlights, although some Xenon and conventional incandescent bulbs were included for comparison. Eight manufacturers submitted products for review. Some, like Pelican, are familiar brands from past tests. Others, like Dr. LED are relative newcomers riding the technology wave. Ultimately, testers found that although the new generation of LED flashlights are bright and low in power demand, when it comes to spotting buoys at a distance and focusing a tight, bright beam, Xenon bulbs—like those found in the tested mini dive lights from Underwater Kinetics—couldn’t be beat.

How We Tested

In our comparison, testers looked at spot versus flood lighting, beam focus, brightness, the color of the light, and how power consumption affected battery life. Baseline evaluations included light meter bench tests (see "How We Tested"), reflected light luminosity readings (measured in lumens), a navigation-mark illumination evaluation, and a series of tests that simulated onboard light usage. Testers also inspected the construction quality and measured the battery life of each light. Products that carried a water-resistant rating were splash-tested and units deemed waterproof were immersed. We evaluated each light’s ease of operation and scrutinized disassembly and battery replacement.

Color Temperature

Photographers refer to color temperature as the hue conveyed by a beam of light. Mid-day sunlight is around 5500 degrees Kelvin while more amber afternoon sunlight is approximately 3500 degrees. An incandescent light bulb measures in at about 3500 degrees, consequently white paper looks a little more yellow under a typical lamplight. These examples of color temperature relate to what a "black body" object would look like at a specific extreme temperature. Because LED lights are cool, and have no heated, glowing filaments, they are rated according to the color that they produce. LED chips emit blue light and bits of phosphor are added to reradiate a more natural color. Recent advances in LED technology are allowing these lights to produce more lumens per watt, with better beam focus and a more eye-appealing color, so it will be interesting to see what the future holds for LED flashlights.

Batteries

As expected, the LEDs in this test produced a usable amount of light for a much longer period than other types tested. Battery type varied among the units. Size AA was the most popular, although there was a notable number of size CR123A 3-volt lithium cells. Testers measured no-load voltage at the start and finish of each test. On average, when LED devices and Xenon bulb lights of similar initial brightness were compared, the LED unit’s length of useful light was often three to four times that of the power-hungry Xenon light. Alkaline batteries provided the longest life, but rechargeable batteries make sense for a sailor who uses his flashlight frequently.

Underwater Flashlights


After a little more than an hour of battery use, the LED light on the Underwater Kinetics SL4 LED rivaled its Xenon twin in brightness.

Powerful Spotlights

One of the most valuable functions of a flashlight is its spotlight function or ability to tightly focus a light beam and illuminate a distant target. Our principal field test of this function was the illumination of a fixed navigation mark approximately 200 yards away.

Underwater Kinetic’s SL4 Sunlight was the hands-down winner of this test. The Xenon bulb/reflector combination sent out a piercing beam of warm light that cut through haze and allowed the navigation aid to stand out brightly. It’s interesting to note that Underwater Kinetic’s SL4 eLED version of the same power pack was not as effective in this test. Designed primarily as small dive lights, both of these units should appeal to sailors.

Also showing strong performances in this category were Pelican’s Recoil 2410 Submersible Stealthlite, an LED light with a proprietary element in the reflector path that does a superior job of eliminating glare. It produces almost no flood effect at all and keeps its beam collimated (parallel) over its entire range. The Pelican light is uniformly bright and even, showing no sign of concentric rings or distortion. Underwater Kinetic’s smaller AA cell-powered Xenon Mini Q 40 was also a bright spot illuminator, although its beam was irregular in shape. Other bright, compact, lightweight (123A cell) performers included Inova’s well-made XO3 and Dr. LED’s finely machined compact MI6 flashlight.

Locker Lookers

Effective close-range illumination requires less light and a wide-angle beam for a flood effect. High-power spotlights reflect off shiny, gelcoated surfaces, impairing night vision, and can be harmful to retinas exposed by dilated pupils. Inova’s very handy 24/7 has a rotary switch that lets you select either a red or low-intensity, white light. Further rotation in the white light direction increases brightness. The light’s additional selections include emergency flashing light combinations, one of which is a handy, automated repeating S-O-S signal. The low intensity light on the new MI-6 from Dr. LED makes for a good locker looker, but unfortunately for sailors, the first click of the switch selects the spotlight. Bouncing this light off a white cockpit bulkhead is like firing a flash.

The multi-diode Streamlight proved to be an easy-to-handle utility light with a convenient pushbutton switch. It provides a bluish, but useful, floodlight for close-up work. Flashlights with a bright, narrow central beam and uneven secondary halos cause too much reflected glare on reflective surfaces and the lighting is too uneven for illuminating onboard targets (See "Shedding Light on Flashlights").

Housing and Switches

Simple switches tend to be the most reliable, and it can’t get much simpler than one O-ring-sealed screw cap that both opens the battery port and also functions as the on/off switch. Most of the aluminum and plastic flashlights we tested used this type of switch, while the Inova units also incorporated an push-button in the end cap that allowed intermittent light or signaling. Dr. LED, Streamlight, Sea Fit LED and Underwater Kinetics’ LED zoom all incorporated push-to-click switches into their housings. One switch, the UK zoom light switch, malfunctioned during testing, although UK’s other light switches—including the twist-on switches on the MiniQ lights—functioned flawlessly. The toggle switches built into the waterproof Pelican Light and UK’s SL4 models served well during initial testing.

Underwater Flashlights


The top picks overall from left: UK SL4 Xenon, Tektite Expedition Star, Pelican Recoil 2410, Inova X03, Dr. LED MI6, Inova X5, and Inova 24/7.

Dive Lights

Underwater Technologies, Tektite, and Pelican target divers, but their lights are as useful above the water as they are below. These lights tend to offer bright beams, rugged housings, and are as at home on a sailboat as they are in a diver’s gloved hand.

Though its brightness was less than inspiring, Tektite’s Trek 400 did offer one unique characteristic that could prove to be a real winner in a search-and-rescue situation: The light floats with the beam vertical, where it might be visible in a search-and-rescue operation.

Findings

At the onset of our testing, we were looking for a flashlight that was compact, light, and provided superior spotlight and wide angle illumination for objects in close range. Unfortunately, no light we tested answered all of these requirements. The winners proved to be units that excelled at one task and weren’t designed to cover all bases. We also discovered that size still matters, and more batteries means more power, more light, and more life.

When it comes to the brightest light in the pack, the honors went to Underwater Kinetics’ SL-4 Sun Light with a power-hungry Xenon bulb that provides four hours of usable light per set of four alkaline C-cells. This rugged ABS molded dive light does double duty as a handy mini spotlight that’s great for checking marks and what’s going on at the masthead. Although the light is not an LED, it’s superior spotlight, waterproofness and price deserve earned testers’ recommendation.

Not far behind in the spotlight category was the Pelican’s Recoil Stealthlite 2410, the testers’ favorite light overall. This lightweight, ergonomic four AA-cell LED is submersible and comes with a unique focusing technology that nicely collimates the beam. It also has a useful light span of over 24 hours, and a glow-in-the-dark lens lip that makes it easy to find in the dark.

Tied in the mini metal light category were Inova’s powerful XO3 and Dr. LED’s MI-6, both bright, well-crafted lights. Both projected a bright spot beam but also produced a slight flood halo that decreased spotlight performance in moist marine conditions.

Our close-up, wide-angle needs were best served by Tektite’s Expedition Star, a triple C-cell dive light with an ABS housing. This powerful, and long-lived LED light source can brighten up a locker or light up the darkest recesses of an engine room.

When it came to close-up work and chart reading, our testers favored the compact, lower-power Inova multi-diode X5. The flashlight produced a very even clean disk of slightly blue light. Inova also scored another hit with its clip-on 24/7 convertible headlamp flashlight that allows a user to scroll through a range of useful white and colored options. If you’ve only got $10 to spend for this duty, the IQ Lights SP-3 is handy.

Conclusion

LED designs are taking over the industry thanks to their cool use of energy and resulting efficiency. However, focusing and color correction are still an issue. When it came to cutting through hazy marine air, a Xenon bulb, not an LED, was the right answer. Of the LED lights we tested, only Pelican provided a spot beam free from the effects of peripheral glare. Worth noting however, is that after about an hour’s worth of use, a comparable LED light could match the best Xenon bulb in performance.

A well-equipped sailor needs a few different flashlights to cover all the bases: one that’s a dedicated spotlight, one that lights up the lockers, one that serves the needs of bright, wide angle floodlight, and lastly, a tiny pocket light used for in-the-cockpit chart reading or other instances when you need a quick light but want to preserve your night vision. Our winners’ circle is a good round-up of the diverse capabilities we saw. These lights, and most of the others in the evaluation, show just how far the technology has come. Gone are the days when a good flashlight had to be the size of a shillelagh and the weight of lead pipe.

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