Kevin Stubbs (FSLL) - Technical Sales Manager at Llumarlite, illuminates an issue that many rarely think about
People nowadays think “LED’s don’t fail”, seeing another example this week reminds us they can fail, or they might not be providing what we expect for as long as we might have wanted….
All or Nothing? At a quick glance many LED luminaires seem OK, but take a closer look and they might not be as good as you think, wasting energy or giving insufficient light
This luminaire was typical of all those recently spotted installed as under canopy lighting for a garage forecourt, the luminaires looked virtually new from a distance
On closer inspection a huge proportion of LED’s were way below their expected output. Every one of the luminaires had significant failures.
Most of those are still dim, which means they are probably still drawing full power but giving very little light, probably due to the phosphor or substrate degrading.
What Maintenance factor had been allowed on this scheme? Probably 0.9 (90%) because “they’re LED” and not allowing anything for dirt or maintenance
What was the lifetime claimed? Probably L70 B50 50,000 Hours
What is the actual performance?
140 of these 315 LED’s are visibly below their anticipated performance.
44.4% below par – i.e 55.6% still appear to be burning OK.
If we assume that the bright ones are giving at least 70% of their anticipated output, i.e L70
If 44.4% are below that 70% output of L70, that’s B45, lets say L70 B50
How many hours – they looked fairly new, they were on all day, so being generous we said 2 years that would be 17,000 hours (let’s hope they get turned off sometimes?)
Therefore it looks like these luminaires have a system lifetime worse than L70 B50 15,000H!
* That could be worse than the discharge lamps they replaced!
I wonder how much light you’ll get should they ever last for 50,000 hours? Even then they may still be “surviving” (i.e. not failed),
Also remember – all of the LED’s are probably still drawing the same power, whether dimmed or not, if you have a constant illuminance driver or control system you could be increasing the power consumption by 30% to compensate, accelerating the failure rate too!
That’s just one small project, one more lot of precious materials wasted, unnecessary recycling due, - even if the boards are replaceable the problem (if heat related) will probably recur.
Where can I get help? – Llumarlite has a team of experts. We can help you discover the root of your lighting problem, help you do a lighting health-check, and help you to specify and responsibly choose lighting and controls systems to resolve your problems or help you save energy and improve your working environments.
To find out more about LED System reliability or quantifying your LED needs
* read our blog introducing colour quality
* or download our free 16 page guide; What do i need from a light source - guide to colour flicker lifetime