Pressed to replace working lighting with so-called ‘energy efficient’ lighting by well-meaning but narrow sighted conservationists, I recently replace about 25 CFL lamps with 12W LED MR16 lamps.
They have started failing now after a couple of years of service, perhaps a few thousand hours of service. So much for the claims of 100,000 hours… clearly preposterous.
In an effort to identify which of the switched mode power supply or LED assembly was the problem, I tried to substitute LEDs to different power supplied.
That was not a good idea, lets look at the anatomy of your typical Chinese junk MR16 LED.
Above is the complete 12W MR16 lamp with GU5.3 bipin connector on the back.
Problem is that having removed the socket from some of these lamps that have had about 4,000 hours of service, trying to reinstall the socket pushes the pins into the interior of the lamp.
Above is the internals of the back of the lamp, the white cap and the LED driver PCB assembly with pins soldered to the PCB, and held in place with silicone adhesive… which fails with age and so the whole thing is pushed inwards.
Incidentally, it is the driver that is the most common cause of failure, though of course the yellow phosphor that gives warmer light than the native blue LED fades from day one. Again something that clearly will not last 100,000 hours.
Above, it is possible to re-engage the socket by removing the white cap carefully from the heatsink, maintaining the wires twisted, and pressing the driver into the cap with thumb whilst locating and pressing on the socket, then carefully spinning the heatsink back onto the white cap until tight.
Life statistics: with say 4,000 hours of service, we have lost 20% of the MR16 lamps, and 0% of the power supplies. The replacement and labour cost of failures has been much greater than the electricity saved, and of course there is the energy cost embodied in the manufactured product, transport etc going into the waste that is conveniently ignored.
But, this procedure might help to reduce otherwise working lamps going into the waste due to shabby design, materials and manufacture.