LED and overheating

Singapore 21st September 2011

Learning something new about LED’s every day it seems! While it is nice from public relations point of view to have a 100% LED project with a short ROI (Return on Investment), we keep having little problems with the place in full operation for a couple of months now. First we had some humming issues in the decorative pendants, now we have some of the LED down lights flickering and going on and off impromptu without any clear indication why…

I have to state that we did our due diligence before specifying the down lights, LED source and dimming system. Considering we are using the latest 10W Philips MR16 Master LED, we had the luminaire manufacturer test the combination of LED lamp, transformer and luminaire before confirming the specifications to make sure it was all working well together. We then had the whole system tested (including the recommended transformer) with the proposed dimming system. All came back positive so we went ahead with the installation. Now after a few months operation we start having some issues with LED down lights flickering and going on-off.

We investigated the situation and narrowed down the probable causes. As not all LED donwlights in the same circuit are affected with the “symptoms, we can say that the dimmer is not at fault. This narrowed down the probable causes to either the lamp itself (it is a new lamp), the way it is connected in the lamp holder or the transformer. However after talking to Philips a new possiblity came up…over heating! The LED lamps have a built in “thermostat” regulating the lamp if it gets too hot. Philips is now saying this affects the lamp performance and issues like flickering or going off can occur. Apparently this seems to happen a frequently in new installations but was not brought up during testing by Philips. It seems now a consistent issue with these lamps…Tomorrow we we will meet to see if indeed this could be the fault causing our flickering and going off problems…

In Light Watch today some mega LED lighting point installations realised (mostly by artists Leo Villareal, Erwin Redl, Jenny Holtzer) to contrast with the relative simple issue I am facing with just a few down lights. Imagine having to fault find in installation with more than 40,000 point like the underground tunnel from Villareal. Pictures from Google.

Light Watch 167: LED installations from Leo Villareal, Erwin Redl, Toshiba and Jenny Holtzer

21. September 2011 by Martin Klaasen
Categories: light watch, lighting applications, lighting of the future | 5 comments

Comments (5)

  1. Martin, we have experienced something similar with newly fitted lights when we originally had halogen lamps.

    We were advised by a lighting shop that the new LED bulbs would give a very good light and last a long time (guaranteed for 3 years).

    However, having very recently changed to LED bulbs, we are now getting the same problem of them going off and on.

    I wonder if this will affect the life of the bulbs and if the guarantee will still stand?

    I note your blog was dated September last year and wonder if there is an update?

    Look forward to hearing from you.

  2. Dear Ann
    I have received many enquiries of the same nature with people experiencing similar problems. It seems to be a common problem that many people face in the retrofit market. I don’t know the environment and the lighting system that ths has happened in and what brand of LED lamps you are using. Heat is one of the key issues with LED lamps. Unknown to many in the general public about 75% of the lamps energy prodution is heat, compared to only 10-20% for halogen lamps. So cooling of the LED lamps is crucial for it to work well and overheating will generally cause the flickering or on-off effects. Some LED lamps have a build in fan and when this stops working it triggers a switch off when the heat limit is reached. Some lights need proper airspace to allow the lamp colling to be effective. Retro fit LED lamps placed in a very enclosed housing may encounter this situation. It is hard for me to say whether you can claim on the warranty without knowing the specific details and warranty conditions but there are certainly cases were the manufacturer should take responsibility and replace the lamps free of charge. I would certainly contact the vendor to establish the root cause of your situation. Hope this helps :)
    Martin

  3. i am doing tests with LED beads.LED with 200 Lumen.my batteries were charged with solar panels.as we did not have much sunlight for the past 3 days, I charged it with normal power.from then I see the LED started flickering after working for approx 3 min.I found the back of the LED was getting very hot.I added a small heat zinc to it.the LED started flickering after 8 minutes.when charging on solar the batteries got charged till 3.85v.when charged with normal power the battery charged to 4.2.so to conclude higher voltage caused the LED to over heat,and then it starts flickering.the cause of flickering is over heating,which was caused by over voltage.regards

  4. This is really nice information and I really did not knew this can even be possible. No one think on this side.
    Thankyou keep posting good content

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