Frequently Asked Questions

QUESTION:  Lifetime and reliability.  I have been told that LEDs work for 100,000 hours but I hear that some only last 50,000 hours.  What is the truth?

Answer:  The short answer is ‘both', it's all down to how you define lifetime of an LED and reliability.  One key difference between current lighting and LED's is in the definition of a failure.  LED's if driven correctly, are inherently reliable and do not stop working.  Their failure mode is decreasing light output, so it is the norm to specify the point in time when the light output drops to 50% of its initial output and even after this time, the LED is still working but it is not as bright.

Luxeon has taken a leaf out of the lighting industry and raised the bar to 75% of initial light output, which matches the lighting industries requirements for lumen maintenance targets.

So the claim for Luxeon LEDs is 50,000 hours before the light output drops to 75%.  However the LED is only one piece of the solution, so we design all our drivers and colour engines to match the lifetime of the Luxeon LED at 50,000 hours or more.

QUESTION:  All your LED boards are wired in series, why?

Answer:  For ease of wiring and flexibility, LED technology requires a constant current to power the LED and in the past, the control circuit to achieve this was very simple (resistor).  With the Luxeon LED, an electronic power control driver ensures the LED's are powered at the correct current under all circumstances.

By using a constant current controller and wiring the LEDs in series, we can ensure that any manufacturing variations in the LED (Vf) and volt drops in the cabling is overcome. This allows the driver to be remotely located and allow long cable between the driver and LED boards (30m) without loss of performance.

One offshoot from this approach is the ability to mix different colours of LED's together in a spring.

QUESTION:  I am writing regarding information about LED lighting.  I am trying to find out about LED light output.  What is a lumen and how does it compare to the way we measure conventional light bulbs?

Also could you advise me on a suitable LED product that could help a first timer get started and understand the general principles of LED's?

Answer:  Thank you for your email regarding LED's.  Your quest to compare current light sources against LED sources will be a tough one and you hear the phrase "it depends..." an awful lot!

Beware the claims of no heat, LED's do generate heat BUT in a very small space, so the key to successful designs is the heatsinking of the LED, which is why LEDs are blended in with the fixture and not stand alone, like a capsule or gls lamp.

Second key point is LED's require a driver and please make sure that the driver is the correct one for the LED you wish to use!  Also beware of electricians who think LED's are low voltage halogens, and can save money by using a cheap LV ballast.  (The LED works really bright for 0.5 milliseconds as one-shot flast bulb!!)

 QUESTION:  How long can the cable be between the ColourDriver and the LED fixture/board?

Answer:  The cable can be 20 to 30 metres long however longer runs can be achieved using a higher grade cable.

The reason for this, is that we use constant current techniques to drive the LEDs which compensates for the voltage drop losses in the cable.