Hi, during last year i bought some led lamps, and i can say that some are an very good replacement for CFL, incandescent and lower life halogen main bulbs.
I have
- 3x philips 9w, the color is quite reddish, but they work quite cool.   (one reached EOL on September 2015, the second, which i bought the same day of the previous, on 28/12/2015, i have calculated an total time of 800 hours, frequent switching, in both cases, led chip failure)
- 1x philips 9w, the color is quite reddish, will it last???

- pharox 400, well balanced color (looks more like 830 cfl) and don't have any problem.
- 2x philips 12.5w masterLed, some yellowish light, quite warm, but don' have any problem. (one have reached EOL@ 3000h, update: bad soldering on one led module, repaired)
(philips is sent me an replacement lamp before i could repair it   )
- 1x 8w century led lamp; a totally crap: the first lamp had an screw loose, so i replaced it; the second broke glass due thermal issue; runs very hot and aluminium heatsink can hurt (i hurted myself when i screw that lamp).   I gave it to an (now ex) gf, hoping she (won't) electrocute herself
- 1x philips gu10 4.5w halogen replacement: reddish light, but good quality. (gave to the same girl)
- 2x lexmann 4.5w halogen replacement: 0.5s delay, but well balanced colour. (gave to the same girl)
- 1x lexmann 2w 12v halogen replacement: quite cool, 20W replacement.
- 1x gu10 chinese unknow name: i use it rarely, the lamp is fully disassemblable; i added some heat grease. (update: i'm keeping it far from ac, because it's FUSELESS!)
- 7x mr16 12v chinese unknow name (aso) replacement, i replaced all my halogen in garden lighting, they works very well after an year.
- 5x mr16 12v chinese unknow name (aso) replacement, i replaced all my halogen in garden lighting, they works very well from 2011, but two ballast failed (one silently, the other burnt, all of them are fuseless).
- 3x Ikea LEDARE E14 old type led spot, they visibily flicker as 25/50Hz, they suffer of luxeon lottery.
- 3x Ikea LEDARE 400lm 6.5W, they work well
- 4x Ikea LEDARE 400lm 4W, Ikea improved efficiency and all of them works well.
- 1x Ikea LEDARE 600lm 10W, dimmable. I'm using it on an switch, it runs very hot, it give an beautiful light; heatsink seems to be some kind of painted metal.
- 1x Ikea LEDARE MR11 (not)dimmable, i'm using it in nativity scene with homemade dimmer, it works well (but flicker with low voltage, so i have to keep it at minimum voltage)
- 1x Philips E14 3W candle light, it works well as bed lamp. (update: after 4000 hours, it starts to have 100Hz flicker, bad cap?)
- 2X Philips E27 3W light, i'm using them as indicator. (update: due an accidental drop, one broken, the other suffered the same fate from an earthquake in 2014)
- 1X Osram Pharatom E14 1W red light, i'm using as darkroom safelight (it works better than old incandescent lamp)
- 1X Osram Pharatom E15 1W amber light, i'm using it as signal in automatic door (it's dim, i think due low efficiency of amber leds, but it's noticeable)
- 2X Lexmann 1W multi-led smd halogen replacement (they works well, but they are dim, due 50Hz AC transformer)
- 1X 10W Lexmann MR16 12V spot, i'm using in my homemade 12xAA NiMH rechargeable pipe-torch.
- 1X Philips 9.5W 806lm E27 (Philips kindly sent me an replacement lamp with an signed apology letter, because one lamp failed)
-6x Ikea Ledare 8W 400lm E14.

-6x  Lexmann 3W 12v double led lamps, they aren't dimmable, but they dim very well in nativity scene.

Some filament led lamps, various wattage, i hope they will last.

Fortunately, quality has increased from LOA selfdestructing led bulb.

LED light bulbs, willn't last for more than a year maximum, because of several reasons:
Even if the LED light bulb would contains regular 5mm low power LEDs, if these LEDs are crowded together and are fed by their rated current, they will overheat and fail prematurely.
Also, mains voltage LED light bulb, contains an integrated LED driver, that will fail before the LEDs themselves. The integrated driver of most LED lamps, fails within a few years average.
In short terms: LED lamps haven't a longer life than CFLs at all.
An israeli member, called Ash, said that CFLs and LED light bulbs, should be used as a temporary solution for the existing incandescent fixtures, until the fixture replaced with a real fluorescent or LED fixture.

LED lamps dont have many of the problems that CFLs have. If they are built well (thermal design, ....) they will last many years

Dor : I say that about CFL's, but unlike them, LEDs can be good lamp either as E27/26/B22/Gxx/GUxx lamp for existing fixtures, or as part of a complete fixture. It all depends on quality of the LED lamp (which can be way higher than CFLs), and using it in the correct applications and not just anywhere

Ash: LED light bulbs have a LED driver that may fail before the LEDs.
Also as chinese LED lamps are much more expensive than chinese CFLs of similar quality, this will eventually result in a low quality LEDs that will don't last for long. Kev already had an experience with LED fixtures that lasted few months.

What I use:
- 1x SSC P7 driven by ~9W: Already serve twice as long as previous CFL's. Even with that large heatsink insufficient cooling - used in quite tight enclosed bowl, the driver IC goes to Thermal shut down mode after about 1/2..1 hour (and then it cycle). Not as a big issue for the application (in the toilet), but as a concept trial of screw-in LED it failed.
- On the kitchen ceiling I have 4x 4W ACRICHE modules behind common bowl (fixture converted from 2x60W to 4x4W LED). A ~30nF capacitor connected parallel to the wall switch made quite nice ~0.3W nightlight from that fixture, up to my knowledge only feasible with the ACRICHE's concept (~180V long string of back-to-back parallel LED pairs with resistive ballast). Very satisfied with that, mainly with the very simple nightlight mode
- Hand lantern used occasionally, installed as a "emergency" light. From the total 30 LED's 4 are already dead, I have impression one other is following. LED's are HP "Auto LED's" sold by "GM Electronic", driven at 30mA each (900mA total, rated 50mA), no brightness difference between individual chips (so no current redistribution problem of the parallel connection), they start to flash when it warm up a bit and then die. After it completely cool down, they start to work again. But the board operating temperature did not exceed 32degC. All that after no more then 30..40 hours.
- 2x IKEA 3W "goose neck" bed reading lights: Very poor quality switches, I had to replace them after about half a year. Then work well for already 4 years. Wife's one is used quite heavily, no difference to the occasionally used one on my side.


"2x lexmann 4.5w halogen replacement: 0.5s delay, but well balanced colour"
This is very strange ballast - I would like to know, where the 0.5second came from.

"2x lexmann 4.5w halogen replacement: 0.5s delay, but well balanced colour"
This is very strange ballast - I would like to know, where the 0.5second came from.

as philips master led 12w (or endura led), i think it is an soft start.

this delay isn't much uncommon in led lamps: depends about driver used.

The heating-flashing LEDs are as far as i know bad connection between the chip and the thin wire that connects to it, then disturbed by thermal expansion

Then, there are all those circuits with LEDs in parallel on a common resistor. Some led go open due to the wire issue, others are now overpowered. Another one fails, now others are more overpowered and so on

It is either electomigration of the too thin metal layer around the bondwire ball on the die, or thermal expansion crack, to determine that, it would be necessary to FIB-cut out the bond and look at it with an electron microscope.
In both cases it mean bad design of the LED package, 25mA is not that much.

The LED's are fed by constant current source made of a buck DCDC converter (using MC34063, so no even tiny current overshoot).
The brightness was always exactly the same among all chips, so I could rule out the problem of few dies overloaded.
Temperature of the LED board stay below the 40degC, so way below the LED power rating
So the only remaining cause are the bad LED's alone. And as it is more then single or two led's, it is clearly either whole batch problem, or poor LED design. And I'm convinced the second would be the case.

With one or two LED's died in the whole group the current difference for the other won't change so much to explain other LED's failing so soon. I would rather expect all LED's degraded to the point of failure at about the same time.

Now I have 100 pieces of SMD 1210 LED's, I have to find the time to make the board and replace it. I'm curious, how that would work...

today i replaced the light in my bedroom, i replaced 2x 23w cfl with 3x ikea ledare E14 spot.

50hz flicker is very noticeable (i'm thinking about replace all with lexmann led bulbs).

now i can see in my wardrobe, but the rest of room is dark.
fortunately i have also some other lights.

i replaced ledare lamps, lexman are brighter and flicker free.

I don't know what would cause a LED lamp to flicker 50hz. LED lamps should flicker 100hz in normal use (If they haven't a mains frequency filtering).

It was December 2010 when I dived into LED. I've started with LEDON 10W - 600 lumen lamps.

Following lamps are now in use in my flat:

3x LEDON 10W 600 lumen E27
3x PHILIPS 9W 470 lumen E27 dimmable
1x Toshiba Ecore 5,5W E27
2x Ikea Ledare 8,1W 400 lumen E27 clear
4x Ikea Ledare 8,1W 400 lumen E27 opal
5x PHILIPS 11W 810 lumen E27
2x PHILIPS 5,5W 250 lumen E14 candle
4x Ikea Ledare 5W 210 lumen E14 candle

So I have now 24 LED lamps in use and some of them (the early ones) must have already about 2000h+ on them. Not one single lamp failed till now and there was also no recognizable drop in light output.

I know it is "only" 2 years but from my point of view these lamps do their work really good.

When I was a kid, incandescent bulbs were standard and I was mad after clf (Philips SL). I wanted to use them and play around with them and we know that these lamps weren't very popular at that time.
Today cfls are standard (thanks to the incandescent ban  ) and led lamps are a big topic for me. I think it is good that I kept my interests in "new" things and I try to keep it that way.

I don't know what would cause a LED lamp to flicker 50hz. LED lamps should flicker 100hz in normal use (If they haven't a mains frequency filtering).

uhm, can it be 100Hz?
it flicker more than F18 in magnetic ballast...

Quote from: dor123 on September 19, 2012, 06:17:01 AM

I don't know what would cause a LED lamp to flicker 50hz. LED lamps should flicker 100hz in normal use (If they haven't a mains frequency filtering).

uhm, can it be 100Hz?
it flicker more than F18 in magnetic ballast...

It is twice the mains frequency for both. For LEDs the power would normally be rectfied, so you end up with a waveform that is the absolute value of a sine function, which is periodic with half the period of the original sine function. For fluorescents, the tube will flash once for each half-period of the mains, so the light is periodic with twice the mains frequency (ignoring any afterglow from the usually slightly phosphorescent phosphor).

LEDs are usually stringed up in a long string in those lamps

Now there can be basically 4 types of ballasts for LEDs :



Resistor from 120/240V
If used alone, the LEDs will light only in 1/2 wave and only when the momentary voltage is above Vf*num of LEDs. So we get harsh 50 Hz flicker with duty cycle < 0.5

If used on a bridge rectifier, the LEDs will light for the same period (-1.4V on the rectifier) in both 1/2 cycles. So we get 100 Hz flicker. If a capacitor on the DC side is added, there won't be any flicker (depends on capacitor size)

If split in half and used as 2 antiparallel strings, the duty cycle is higher (as each string has 1/2 the num of LEDs so needs lower momentary voltage) but each string is lighting on its own 1/2 cycle



Capacitor from 120/240V
The capacitor cannot be used alone - If it would be, the LEDs would flash once in power on (untill the capacitor charges), then stay off (untill powered off and wait untill capacitor bleeds off). However it is possible to put a diode antiparallel to the LED string to discharge it each time, and get harsh 50Hz flicker. Perhaps only the cheapest LEDs would use this option

If used on a bridge rectifier, the LEDs will light about the same as if there would be just resistor. However the capacitor stays charged somewhat between the 1/2 cycles which means that it will "strike" earlier each time, and perhaps "go off" earlier as well. This may affect the duty cycle of the flicker. Or if there is DC capacitor, no flicker

If split in half and used as 2 antiparallel strings, about the same as with the resistor will happen



Magnetic transformer
This won't be found in 120/240V LED retrofit lamps but in 12V halogen systems where the LEDs are running on the 12V halogen transformer. A capacitor ballast won't be found here, Instead plain resistor (with or without rectifier), linear driver, or PWM driver can be used. In the case with resistor or linear driver, it is possible to get 50, 100 Hz or no flicker at all depending on whether no rectifier, 4 diode rectifier, or antiparallel strings are used, and whether a DC capacitor is there. PWM driver will usually have DC capacitor so have no flicker



Electronic ballast
This will usually have DC capacitor right away on the rectified mains (whether by 1 or 4 diodes), so have no flicker (unless it is failing). If the electronic ballast is going on and off with the 50Hz cycle, the LEDs will flicker accordingly