What is an LED
A Light Emitting Diode is a semiconductor light source. They are a SSL (Solid State Lighting) device, which means there are no bulbs , no pressurised gases, no chemicals and no burning filaments. In simple terms they work by electrical energy flowing through a semi-conductor.
Very few would argue over the effectiveness of LED technology v’s traditional incandescent lighting. With up to eight time the efficiencies over the traditional incandescent lamps, it’s hard to argue there superiority.
LED light colour
Whilst it may sound strange white light does not exist. The perception of white light is actually a combination of Red, Blue and Green. White LED’s can be created in different ways, with the most common way being the use of a Blue LED and a phosphorous coating. Different phosphorus coatings will produce different hues of white colour, such as Warm White, natural White, Cool white
Without getting into the physics behind light, Colour temperature of a light source is effectively the hue that is radiated from the light source. To explain, a ‘red hot’ object has a temperature close to 600 degrees centigrade. By comparison, a ‘white hot’ object may have a temperature of 7000 degrees or more. By example If you have seen a glowing ember (600 centigrade) it has very little light output. So at lower temp temperatures almost all the energy is converted into heat. Conversely, at higher temperatures, the production of light improves.
Light lux and lumens
Lamps used for lighting are commonly labeled with their light output in lumens. In many countries this is required by law. Most manufactures however of LED technology are now using this as the standard measure of light. (You can find the output of the Off-road Scene Light Bars listed in our specifications).
A 23 watt compact fluorescent lamp emits about 1500–1600 lm
The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square meter, lights up that square meter with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square meters, produces a dimmer illuminance of only 100 lux. Mathematically, 1 lx = 1 lm/m2.
A source radiating a power of one watt of light in the color for which the eye is most efficient (green region of the optical spectrum) has luminous flux of 683 lumens. So a lumen represents at least 1/683 watts of visible light power, depending on the spectral distribution.
Light output Raw lumens v's Effective lumens
Often when retailers quote light output of a product in lumens they fail to mention the quoted number is actually the Raw Lumens (or Theoretical Lumens), as opposed to the Effective Lumens. Raw Lumens is a theoretical number rather than the actual measure of light output itself, and is calculated by simply multiplying the number of LED’s on the light by their maximum output rating. For example, if a light uses 20 LED’s each with a maximum output rating of 50 lumens, the raw or theoretical output would be 1000 lumens (20x50=1000), and no laboratory photometric testing is required to come up with this number. The problem with the raw or theoretical output is that it doesn’t take into account factors out in the real world that can decrease the light output considerably.
Like all lamps, LED’s suffer light quality loses due to several factors. The three main reasons being
Quality of the LED light components and the manufacturing:
It is important to purchase a product that is using a quality manufactured chip. However, as important is the actual “packaging” of the chip set. You can have a high quality chip but if the packaging is second rate so will the end result in terms of light output and longevity of the product. In general terms “packaging” refers to the process of selecting and combining the lens, substrate, electrodes and encapsulation resin of the LED. In some instances packaging can amount to 50% of the cost of the product, so has a large impact on the end pricing point.
Quality & manufacturing losses
The optical clarity of the lens will dictate the loss of light intensity as it passes through the lens and the surrounding air. There are studies that show this loss can be as much as 10 - 20%.
There is a common misconception that LED’s produce no heat. They produce little if any heat in front of the light source. They do however produce considerable heat at the rear of the diode. Thus the reason for the heat sink built into the back of the work lights and LED light bars. If the heat produced by the diode is not dissipated away from the diode, the longevity and the light performance will be greatly diminished.
Calculating the difference between Raw and Effective lumens:
The Raw Lumen output is calculated by simply multiplying the number of LEDs in a lamp and their rated output.
Example: Raw Lumen output of 20 LEDs rated at 50 Lumens per watt is 24 x 50 = 1000 Lumen
Effective Lumen output is calculated by taking the Raw Lumen value and subtracting the Thermal, Optical and Manufacturing Losses.
Example: If thermal, optical and material loses for say 40% the effective lumen output in the above example would be 1000 Raw Lumens 40% loses = 600 effective lumens.
In summary: You will never achieve the same amount on light out in the real world as what the raw lumen number indicates, and this is why the raw number is so subjective as it in no way indicates the light output quality from one light to the next. To effectively compare light output between light you need to compare the Effective Lumens
Advantages of LED lighting
Long life - Long life time is one of the key benefits of LED’s with Off-road Scene LED light Bars rated to 30000+ hrs of life.
Energy efficiency - LED’s operate at 80 to 90% efficiency meaning they convert 80 to 90% of electrical energy to light compared to traditional lights that are only around 20% efficient.
Ecologically friendly - LED lights contain no toxic materials and are 100% recyclable,
Durable quality - LEDs are extremely durable and built with sturdy components that are highly rugged and can withstand even the roughest conditions. They are resistant to shock, vibrations and external impacts, making them ideal for the harsh environments of the outdoors.
Infrared - LED’s produce very little infrared light. Because of this, LED lighting is highly suitable not only for goods and materials that are sensitive to heat due to the benefit of little radiated heat emission, but also for illumination of UV sensitive objects or materials such a in museums, art galleries, archeological sites etc.
Operational in hot or cold environments - LED’s operate in both extreme hot and cold environments, making them ideal for the temperature extremes of the Australian outback or colder regions like the snow.
Instant lighting & frequent switching - LED’s provide instant start up meaning there is no warm up period. They can also be switched on and off regularly without affecting the LED’s lifetime or light emission.
Using the B series as an example. They come in the 12 degree (spot), 60 degree (flood), and combo. The below diagram depicts the beam pattern of each one. The most popular and the one we recommend is the combo. It has the 12 degree beam angle LED’s on the outer edge to provide lengthy distance projection and 60 degree beam angle LED’s in the centre of the bar which provides a large degree of spread projection. The combo is the best seller and the one we highly recommend for all round performance.
Distance and lx levels are for reference only