LED Technology Explained
Light Emitting Diode (LED) technology offers more than double the efficiency of the previous leading light technology, High Intensity Discharge (HID). Such advanced technology can be described as one of the most exciting and fast moving to hit automotive lighting. The efficiency gains can be harnessed to reduce power consumption of the lamp, or to deliver much greater light output for a similar power consumption.
Put into numbers, LED currently achieves approximately 100 lumens/Watt when driven at high drive currents, whereas Halogen lights run at around 10 – 12 lumens/Watt, with HID (High Intensity Discharge) operating at around 50 lumens/Watt. For a visual representation, take a look at the videos below. The first shows our Triple-R Long-Range LED lights side-by-side with a Piaa HID rally pod as used in world rally racing. Operating at 10% less power consumption, the Triple-R system still manages to outperform HID.
The second video pits the Halogen Lightforce Striker 170 (2 x 100W Xenophot bulb) against the Lazer ST-4 (44W LED) road legal spotlight. The Lightforce pencil beam achieves good range but the Lazer ST-4 hybrid beam pattern also throws additional light in to the near and midrange. With a theoretical efficiency limit of around 250 lumens/Watt, it's clear LED technology still has a long way to go over the coming years.
There is a clear distinction between lumens and lux when using as a unit of light measurement. Lumens can be defined as the measurement of how bright a bulb or a light source is. Whether you are 1 meter away or 100 meters away from a light source it is still emitting the same amount of lumens. On the other hand, lux is the measure of the intensity of the light hitting a surface at a given distance. Our recommendation is that you review the product photometric diagram and consider the spread of light that you want. Overall, lux is a good measurement for determining and comparing the brightness of a beam.
Selecting the right LED is important, and although this starts with choosing an LED capable of achieving the high performance requirements of an automotive headlight, the next step is choosing the right “bin”. LED manufacturers categorise their batches of the same LED in to those which are tested at the end of the production line to give high light output, versus those which have a relatively low light output. There can be a variation of light output (and component price) within the same product group of up to 30% from the low output bin to the high output bin devices.
A powerful LED with a high output bin, provides a solid foundation to achieve higher levels of illumination, but there are a number of other factors driving both the performance and the cost of the unit. Consider the materials used in the product: the cooler you can keep the LEDs, the more efficient they’ll be and therefore the more light you’ll get on the road. For example, Lazer products use ceramic coated metal substrate circuit boards with high thermal conductivity and a thick copper layer to help spread the heat away from the LED and to the lamp body as quickly as possible.
The “LED Driver” is also a crucial component inside the unit, this is the device which manages the drive current through the LED, ensuring an even and stable light output regardless of input voltage. The performance of the driver also influences the efficiency of the unit, and contributes towards the performance of the product to reduce EMC (Electro Magnetic Compatability) radiation.
The capacitors used within the product also contribute towards cost of manufacture and longevity of the product, where cheaper electrolytic capacitors might run for 1000 – 2000 hours, while ceramic capacitors can have a run time of tens of thousands of hours.