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  • Author Author: Gough Lui
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Click MR16 LED Globe Failure Post-Mortem

Gough Lui

One of my regular blog readers submitted an LED globe for post-mortem analysis, having failed well before the expected lifetime. I take a look inside, determine the configuration and analyze the relatively "anonymous" product which seems to show several design shortcomings which I discuss and think might be relevant to other readers at the element14 community.

 

The article is posted at http://goughlui.com/2016/06/01/failed-click-ltmr5w3k-5w-led-mr16-replacement-globe/

 

What really gets me is that many products are still designed using multiple-parallel LEDs without any current balancing mechanisms (e.g. remember emitter feedback resistors when paralleling BJTs?) and that leads to potential for a single string to be overstressed continually, fail early, and begin the cascade of failure as other LEDs are forced to soak up current in excess of their ratings, and operate in less efficient regimes resulting in greater heat production and degradation of the semiconductor material. Of course, if you went all-series, you would have an all or nothing situation and require higher voltage driver electronics, but I personally would gravitate to this arrangement for reliability reasons, or go with multiple independent channels if reliability is demanded.

 

Any comments, or stories related to LED globes or LED light designs are very much welcome.

 

- Gough

  • in reply to Gough Lui

    I used halogens in my house, and regret the five or six downlights I used.

    Good planning allows the use of minimal lights and in our case we have two 10 deg ones on in the lounge at 50w each, with two 36 deg in the kitchen at 50w, and three 35w in the hall on a dimmer.

    In all most nights we use 290-300w of light total.

     

    I'm sure some electricians did make good money, and sadly many consumers still buy the cheap lamps and wonder why they don't last ... like the LED one.

    I use either Phillips or Osram lamps and would be lucky if I replace 1 per year (total 33)

     

    As you can see I'm in no hurry to change to LED.

     

    mark

  • in reply to mcb1

    Yeah, I never really understood the whole fascination with downlights. The old halogens were rated for something like 36 degree or 60 degree beam spread and really were more suited for spot and accent lighting, and somehow it became vogue to light up a whole room with 10-20 of them - at a lot of installation effort, I might add. All that heat ... and all that wasted energy. I'm sure some electricians probably earned a good living putting them in image.

     

    - Gough

  • Nice breakdown of the fault.

    Unfortunately LED technology is rather pricey and the alternatives like this give the consumer a bad taste.

     

    I still believe the LED lamps for domestic use have a long way to go before they are equal to what they are replacing in most applications.

    The biggest waste was downlights which were designed to not throw light across the ceiling and show the lower quality finish.

    Unfortunately it requires twice as many lights, hence is a power waster.

     

     

    I think your links are fine as the item is not an element14 sold product.

    Mark

  • in reply to jw0752

    Love the humour - although I am still trying to find the right level of balance. I find that when I post them around the community, I get the valuable discussion and feedback that I don't otherwise get when it's just sitting on my site, but at the same point in time, I feel a bit guilty of spamming links and I'm sure some people might not appreciate it as much as if the content was posted here directly. But since the content itself is not "directly" involved with element14 equipment, I'm a bit torn between the two, but I suspect if I just use my own "blog" area here, I might not cop as much scorn image.

     

    - Gough

  • Hi Gough,

    I am hoping that they do as good of a job figuring out what went wrong with me when I stop ticking as you performed on the LED globe. This is a great learning experience to follow your dis-assembly and analysis of the light.

    I am glad that you are bringing some of these links to your web site onto the Forum.

    John