|Robin Graham||04/07/2020 23:45:28|
|728 forum posts|
Has anyone found a brand of LED GLS bulbs which last anything like the the 25 - 30,000 hours burn time which is commonly advertised? I think my record is about 9 months, so I must burn them for over 100 hours a day.
I've bought cheapo Wilko bulbs, mid range from Screwfix, pricier Phillips and Osram but they all fail well before the advertised MTBF. The only advantage I've noticed with the 'big name' brands is that they seem brighter than the cheapos with the same advertised lumens / colour temperature. In all the brands I've tried there is quite a big spread (in the same brand/model) between lamps which fail very early and those which last longer.
I'm not really complaining - still saving money, but I'd like to know more. Does anyone know how these lamps typically fail? The LEDs themselves, or the drivers?
Edited By Robin Graham on 04/07/2020 23:46:15
|Michael Gilligan||05/07/2020 00:00:43|
15886 forum posts
Swapped the switch for a good MK one with a nice crisp action, and all has been well.
|John Olsen||05/07/2020 00:41:29|
|1049 forum posts|
My experience suggests that it is usually the little power supply that fails. I suppose they would argue that the light itself is still fine....
3738 forum posts
It's maybe the voltage that kills them
I've been running a little 3xAA battery camping light 24/7 for 4 years as a night light in the hall, batteries get done about every 5 months
240v LED Bulbs in use a lot go from 3 months to a few years
|Sam Stones||05/07/2020 01:13:21|
762 forum posts
No promises that you'll get your answer directly, although I'm sure you'll find Big Clive both informative and entertaining. He specialises in using reverse engineering and many other ways to reveal faults.
Lighting and associated electronics is one of his particular skills.
However, you might have to wade through his many videos.
Edited By Sam Stones on 05/07/2020 01:14:08
|Harry Wilkes||05/07/2020 07:12:57|
928 forum posts
3738 forum posts
So is that the startup surge killing the driver?
and is it the power supply or the led that fails?
So the light filament (the LED) is fine and nowadays the power pack/driver fails, lol, they always find a way to gouge the customer
So if you want a "forever" system get a low voltage lighting system
What about a 12v boat or car LED system, are they more reliable
Edited By Ady1 on 05/07/2020 08:07:26
|Michael Gilligan||05/07/2020 08:27:49|
15886 forum posts
No ... The driver seems to survive, but I think the bad switch contacts are acting as a diode for a few mains-cyles: de-stabilising the driver and over-driving the LEDs.
To quote my previous post: ... a recent failure resulted in two visibly burnt LEDs in the array [one of which went open-circuit].
For the avoidance of doubt; that’s two LED chips in the array within a single ‘mains light bulb’
Edited By Michael Gilligan on 05/07/2020 08:31:12
940 forum posts
Have no problems with led life but changed all our light switches for MK a few years ago as we redecorated each room, I always go for the quality option where electrics are concerned, I got fed up with cheapo switches arcing when switched, you can’t put a price on safety.
|Peter G. Shaw||05/07/2020 09:26:09|
1121 forum posts
My experience of both LED's & CFL's is, to say the least, poor.
We have a Philips CFL in the hall which was a "free" gift dating back to when we had wall insulation installed back in 1995. That light is still working ok. I can't comment on its light output after all these years.
We have had some Osram CFL's which seem ok, but on the other hand, we have had Megaman or whatever which frankly don't last.
Lately, we bought three of the highest power LED's that we could find for use in our back room which due to the kitchen extension is a dark room at the best of times. These LED's, plus two replacements, failed by flashing (no, not by us, the electronics started flashing). Replacement by a slightly lower power set by Crompton and they now seem ok. We still have one of the original higher power LED working ok, but I do have a spare Crompton waiting for use.
Light Switches. All of ours were changed at the same time back in 1995 for Volex switches. As some lights are satisfactory, then in general, I would tend to rule out switching problems. My personal thoughts are that the "cheaper", ie lesser known brands, have problems with the heat generated by the electronics whilst the better known brands, Osram, Phillips, Crompton can cope with this heat. Very subjective, I know, but those are my thoughts.
Peter G. Shaw
|Oven Man||05/07/2020 10:13:27|
60 forum posts
My experience has been almost the exact opposite, the driver fails not the LED. Being the nerd that I am I usually pull failed items apart to see why they have failed. I have a collection of LED chips that work OK, just need to find a use for them. Some of them are series connected and need quite a few volts to drive them. About 20 years ago I replaced the filament lamp in our door bell push with an LED and it has worked perfectly ever since, still as bright as the day it was installed. As with a lot of consumer products the components are pushed right up to their design limits so it's probably not surprising that we see so many failures. Cost also dictates that high temperature rated components are a nono. As I mentioned in a previous thread it appears that manufactures guarantee the LED for x years but not the complete bulb. Has anyone tried getting them replaced under guarantee?
|Andrew Tinsley||05/07/2020 10:26:58|
|1150 forum posts|
For what it is worth. The lifetime of an LED is critically dependent on the ambient temperature. Get too many in a localised volume and the lifetime drops very rapidly Good LED bulbs have a very efficient heatsinks. As for drivers depends on the design and quality of components.
|Peter G. Shaw||05/07/2020 10:38:03|
1121 forum posts
As mentioned above, I bought 3 highpower LED's - these had a 5 year warranty. Two were changed under warranty - then the shop closed down! After that, another two failed again, same problem, flashing on/off. Of these, one was tested elsewhere and continued flashing so dumped, whilst the other appears ok (so far) in an open fitting, ie no lampshade to hold in the heat.
The replacement Cromptons have a 3 year warranty.
(Another) Peter G. Shaw
|3262 forum posts|
Standard old fashioned GLS lamps still working for me.
|1134 forum posts|
I'm banking on the driver. Have a 64 chip one in the bathroom which after about a minute, half go out. On switching off waiting a couple of minutes and back on again, same thing happens. Have rotated the lamp through 180 deg. in socket and original side goes out.
|Steve Skelton 1||05/07/2020 12:01:38|
|77 forum posts|
The thing that causes the most damage to an LED is running temperature. You will find most of the good quality high power units have a heatsink on the LED itself.
I have been on an Osram training course on the use and installation of LED's and they were very adamant that keeping the LED cool is critical and when they get hot they cook themselves and the light output is vastly reduced before they fail. Very similar to CFL's in that respect.
When you install LEDs consider where they are going and how to keep a flow of cooling air around them, otherwise LED's are a false economy.
By the same token drivers should be matched to the LED's they are powering for obvious reasons.
Ooops Andrew - missed your post!!
Edited By Steve Skelton 1 on 05/07/2020 12:02:30
|367 forum posts|
Robin, I suspect that the manufacturers would hide behind the 'M' in MTBF. As in "Yes, this one failed well before the mean time, but what about all the ones which go well beyond that time? Do you keep a record of them?"
I have had trouble with two Philips LED bulbs which emit an intrusive whistle, presumably from an internal switched-mode power supply. I have had to withdraw them from use because the whistle was irritating me beyond endurance.
|Michael Gilligan||05/07/2020 14:33:16|
15886 forum posts
Just to keep the conversation going ... here are some pictures of my failed ‘flying saucer’
The two burned LEDs are clearly identifiable:
|Robin Graham||06/07/2020 00:20:07|
|728 forum posts|
Thanks for replies. Reading MichaelG's and other respondents' suggestions that it may be the the switch that's the problem I remembered that I have a 4W LED bulb lighting the stairwell down to my cellar workshop. It's been burning 24/7 for over a year - I've become so used to it that I forget it's there. I installed it as a 'temporary' replacement for a PIR LED lamp which failed within 6 months, So maybe it is to do with switching - though obviously the switching in a PIR must be rather different from a normal light switch, presumably solid state. Hmm. The specs for the bulbs I've had claim 100,000 switching cycles, so I'd assumed that switching wasn't an issue.
Sam - thanks for the link to Big Clive - I'll have a wade.
George - I take your point, but in my (admittedly small) sample I haven't yet had a bulb to the right hand side of the mean.
Since my original post I have discovered that 12V (presumably DC) LED bulbs are available in GLS form. Is there any reason why I shouldn't disconnect the 240V house lighting circuit from the MCB and run the house lighting from a 12V power supply though existing wiring? The upstairs and downstairs have independent circuits wired with 1.5mm cable, which is good for 10A I believe.So 120W for each floor, which might be liveable with given LED efficiency.
Edited By Robin Graham on 06/07/2020 00:28:29
Edited By Robin Graham on 06/07/2020 00:29:11
|Michael Gilligan||06/07/2020 07:44:15|
15886 forum posts
That might be a good move, Robin
I will also just mention, in passing, that some 12V LED lamps have bridge rectifiers built-in, and can therefore be safely inserted either way round, or even used on low voltage AC [with the attendant risk of visible flicker].
Edit: this might be a useful place to start your investigation:
... Be sure to read the comments though ... it can be trickier than the advice suggests
Edited By Michael Gilligan on 06/07/2020 07:57:04
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