A few years back I replaced the GU10s in the kitchen ceiling with LED ones. These have 20 or so bright LEDs in them behind a diffuser, but you can still see each LED. Other evening, I noticed that about half those LEDS were out. Tonight, those LEDs are back on again.
Anyone know anything about failure modes for the jobbies?
When you say half, do you mean half in each lamp or half the lamps themselves? Most LEDs just die, so if some work and then fail then come back it sounds more likely to be a low voltage issue or some other weird problem. Not all leds seem to work efficiently at the same voltage and current, well not quite anyway. I guess it depends on how each is driven in this case. Brian
I will repeat what a charming sales assistant said in Homebase
"LED bulbs are a work in progress, aren't they?"
Ther is some terrible far east shit out there, and I dont think anyone has found the 'best' solution yet.
Seems as if they're the 'encapsulated' LEDs - horrible things that are OK for single indicators. You'd be better off with COB or SMD - at least they aren't 'wrapped up' ready to cook. The cheap 3-AA-cell torches have 9 LEDs and these do the same. I have a torch in a fixed location in each room, they're hardly used and yet most of them have one or more LEDs out. If yo want to replace them, a lamp with the old 5050 chips is one option - nice big SMDs that aren't over-driven.
Yes, sorry, I wasn't clear. I meant that in one particular LED GU10 lamp, of its 20 or so LEDs, only about 10 were working. The other LED GU10s in the kitchen were all working normally. Then a day or so later, that one GU10 has magically fixed itself.
They're probably wired as two series strings, and one LED in one half is close to burning out for good, when it overheats it isolates all the others in that half, cools down and they come back on with it ...
Hmm, interesting, thanks. I'll keep an eye on that one and see how it develops. It was OK this morning when I went down to get the fresh loaf out of the breadmaker.
Fairly typical of mains LEDS. The LED itself may be very long lasting, but the internal PS, not. It's the price you pay for doing it in an all in one unit so it is a simply plug in replacement for tungsten. No different from CFLs - although they did tend to last their quoted life rather better.
In my experience they are better now than they were. The 'good' ones that I got from LED Hut were always blowing. Replaced them with some cheap alternatives obtained from an Amazon vendor, a never-heard-of brand, a couple of years ago and none of them have gone.
About 10 years ago I replaced 18 GU10 bulbs with LED ones bought on eBay. Some started failing within a few months. The seller replaced them all and we?ve not had a single failure since (which surprises me!).
Tim
And a warm up time of how long and a half brightness after 12 months.
CFLs were and still are shit.
My GU10 is tending to flicker a bit now. With half the LEDs going off and then coming on again.
Likely just a cracked pcb trace.
One failed lamp. Swap it for a new one
I had a similar experience with some "high power" 12V LED lamps from TLC. They all started flickering after a time varying between about 3 months and 6 months. Bright and dark spots would develop where some LEDs were unlit and others were over-bright and then they would fail completely. As they had a 3 year guarantee they were all replaced - about three times each on average. The final replacements have now been working fine for a couple of years. I dismantled one to try and find the cause. The switching power supply was nicely made and was working fine. The LEDs were "chip on a square of alumina" with the usual yellow phosphor gel on top. They were in a series/parallel array driven by a constant current power supply. The COB LED array was definitely the problem. Possibly failures of the junction between the bond wires and the surface metallisation which would open and close as the chips heated up and cooled down thereby causing flickering. As some of the series chains went open circuit the constant-current power supply would then overdrive the remaining chains, accelerating the final failure. John
Gotta be a cracked pcb trace or dry joint for half the leds.
Only if run at the specs they can handle. This is why some only quote a long life if they are on for less than about 4 hours per day, the heat buildup is the problem.
The caps can heat up making the thinbg get even hotter.
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