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FAQs - Here are some answers to frequently asked questions.
The Right Light
Flashlight choice depends on intended use. Typically, there is no single light that works well in all situations. Consider your applications, then ask yourself the following questions.
Do I need a light for close-up or long range?
In general, lights with incandescent xenon or halogen bulbs give highest performance and are best for distances. Both xenon and halogen bulbs provide high output for their size. Halogen bulbs may have a longer life than xenon and both require replacement and can fail on extreme impact.
Low wattage LED (Light Emitting Diode) bulbs - less than 1 watt - have solid state construction and are very durable and long-lived - up to 100,000 hours for some lights. Normally, LED bulbs do not require replacement and are excellent for close-up work. Low wattage LED bulbs can give extremely long runtimes at low illumination levels.
High wattage LED bulbs (1 watt or more) give the reliability of an LED while rivaling the performance of an incandescent. For more info on LEDs,
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To search for LED flashlights, just use the green navigation bar on the left side of the page; and use the "Keyword Search" function. You can select "LED, Single Low Watt", "LED, Multi Low Watt", "LED 1-2 Watt" or "LED 3+ Watt."
What battery type do I prefer?
You can easily search the BrightGuy website by battery type. Just use the green navigation bar on the left side of the page. Select your battery choice from the "Battery Type" pull-down menu.
How long of a run time do I need?
The BrightGuy website lists the run time of each flashlight. Just be sure to "click through" to the final detail page for the flashlight you've selected.
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Light Measurement*
All light measurements can be traced back to the Candela, which is the unit of luminous intensity. The Candela is also sometimes called candlepower, and is similar to an older unit, the candle, which was based upon an actual candle of specified dimensions and construction.
There are two basic methods used by various flashlight manufacturers to rate the light output of their products.
Total Luminous Output may be expressed in candela or in lumens. This is a measure of the entire light output of the flashlight regardless of beam focus. It is almost solely a function of the lamp, and for practical purposes is equal to the lamp output which lamp manufacturers rate in Mean Spherical Candela (Sometimes called Mean Spherical Candlepower which is not the same as peak beam candlepower), or in lumens. Multiply candela by 12.57 to convert to lumens. For example, the 20 watt lamp used in the SL-35X™ is rated at 450 lumens or 35.8 Mean Spherical Candela.
Peak Beam Candlepower is a measure of the brightest spot in the focused beam. It is a function of both the output of the lamp and the efficiency of the reflector. The focused spot of light has the same intensity that a bare source of unfocused light of the same candlepower would produce on the same area from the same distance. For example, a flashlight of 20,000 beam candlepower would project, within its "hot spot," the same amount of light on a wall as would a bare lamp of 20,000 candela at the same distance. Typical values of beam candlepower will run into the tens of thousands for powerful rechargeable flashlights.
Since the Total Output system does not take into account the focusing efficiency of the reflector, there is no way to convert between peak beam candlepower and lumens.
Additionally, all light rating systems depend on the perception of the human eye and are therefore subjective. Another important factor besides absolute intensity is the whiteness (technically the Color Temperature) of the light source. If two equally intense light sources differ in color temperature, the eye will perceive the whiter source (higher color temperature) to be brighter than the more yellow one. Color temperature is expressed in degrees on the Kelvin scale. A very white flashlight lamp will be rated around 3200 K.*
*Streamlight, "Information about how the brightness of a light (luminosity) is measured.", http://www.streamlight.com/releases/light_measurement.htm (accessed January 25, 2005).
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LED
The BrightGuys believe an informed decision is the best one, so here is some basic information on LED flashlights to help you choose just the right LED flashlight for your needs (for specific information, please refer to individual product descriptions):
Low wattage LEDs
In general, low wattage LED's (less that 1 watt) are good for close range and walking (10 feet or less). More specifically, most low wattage LED flashlights do not give a "beam" of light; instead they give a volume of light - like turning on a lightbulb. In addition to eliminating the need for replacement bulbs, most low wattage LED flashlights offer extremely long run times - in some cases up to 30 days of continuous use.
High wattage LEDs
Most high wattage LED flashlights (1 watt or more) do give a beam of light. It is generally a smooth circle of light with no clearly defined edge and does not feature a true center "hot spot" when compared to a standard non-LED flashlight. Because of the increased brightness, the run times of high wattage LED flashlights are usually significantly shorter than low wattage LED flashlights. High wattage LED bulbs also offer a 10,000+ hour life eliminating the need for costly replacement bulbs. (LED bulb life varies depending on model.)
Color temperature of LEDs
The color temperature of white LED light can look noticeably whiter, closer to sunlight, when compared to the light from a standard non-LED flashlight. In fact, standard non-LED light often looks yellow in comparison. However, the color of white LED light will vary from flashlight to flashlight and sometimes has a slight blueish or greenish appearance.
To search for LED flashlights, just use the green navigation bar on the left side of the page; and use the "Keyword Search" function. You can select "LED, Single Low Watt", "LED, Multi Low Watt", "LED 1-2 Watt" or "LED 3+ Watt."
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Candlepower vs Lumens
Peak beam candlepower is the measure of the brightest spot in the beam and is a function of both the output of the lamp and the efficiency of the reflector. As a result, peak beam candlepower is a subjective measurement, and different flashlight manufacturers measure it differently. Therefore, comparing peak beam candlepower ratings of flashlights from various manufacturers will not give an accurate comparison of brightness.
On the other hand, lumens can be used when comparing brightness because it is a measurement of the entire light output regardless of beam focus.
Since peak beam candlepower is a measure of the reflected light, there is no way to convert peak beam candlepower into lumens.
The BrightGuy website shows light output in peak beam candlepower (referred to as candlepower or CP) and/or lumens. This information comes directly from the manufacturers.
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HID
HID or "High Intensity Discharge" is a type of bulb. Unlike a standard bulb that uses a glowing filament of tungsten for the light source, HID light is emitted from a very small glowing ball of ionized gas. As a result, you will get 3 times as much light from a set of batteries and the light output will be much whiter - closer to sunlight. An additional advantages of HID is increased bulb life - HID bulb life is up to 20 times longer than halogen or xenon.
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What is a hazardous location?
Hazardous locations are areas where fire or explosion hazards may exist due to the presence of ignitable concentrations of flammable gases, liquids, vapors, dusts or ignitable fibers or flyings. These locations are grouped according to the properties of the flammable materials that may be present and the likelihood of flammable concentrations.
The National Electric Code (NEC) defines hazardous locations by "class" and "division."
There are three classes as follows:
Class 1 locations are made hazardous by the presence of flammable gases, liquids or vapors.
Class 2 locations are described as hazardous because of the presence of combustible dusts.
Class 3 locations contain easily ignitable fibers or flyings.
"Division" refers to the likelihood that ignitable concentrations of flammable materials are present.
Division 1 designates an environment where ignitable concentrations of flammable gases, liquids, vapors or dusts can exist some of the time or all of the time under normal operationg conditions or where easily ignitable fibers and flyings are manufactured, handled or used.
Divison 2 locations are areas where ignitable concentrations are not likely to exist under normal operating conditions or where Class 3 materials are stored or handled.
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Finding safety-rated flashlights
It's easy to find safety-rated flashlights on the BrightGuy website. Just use the keyword search in the green navigation bar on the left side of the page, and select either "Safety Rated, Div 1" or "Safety Rated, Div 2."
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