Philips LED bulb teardown

[reagle]

If they were in the kitchen hood, that may be a bit warm environment for them to begin with?

E14 2W LED lamp[/url] with 36 5050 SMD LEDs and a promised average lifetime of 40,000 hours, for my kitchen extractor-hood. Well, the LED lamp failed in less than a month's time, with a couple of LEDs having fallen off their PCB(!) and clinking within the lamp bulb! I cracked the lamp open to solder the LEDs back in their position, only to find out that not even one component was properly soldered: All the PCB solder joints were unacceptable in terms of solder quality and quantity, already showing cracks, while the LEDs were only needed to be touched lightly in order for them to fall of the PCB... Of course, a reflow using regular 60/40 alloy solder-wire fixed the problem. I am sorry, though, I did not take any photos of the product and the procedure.

What a waste of the finite earth resources in the name of profiteering...


-George

[A Hellene]

Not only this; it was also mounted on a slightly vibrating appliance, due to the dual vacuum motor turbines that try to evacuate the cooking vapour and smell.

I understand that I may have used that specific LED lamp in a harsh environment; but its failure in less than a month's time is unacceptable. I neglected to mention that it was RoHS compatible, using the 'hard' tin solder alloy that does not forgive vibrations; now it does, by the removal of the RoHS compatible alloy and the use of the 60/40 one.

My criticism was not directed towards the lack of any restrictions of the product to be used as a fridge/oven lamp or to be working in a vibrating environment. It simply is a product that, in my opinion, would never reach the promised lifetime of 40,000 hours under any circumstances because of the unacceptable design/assembly quality.


-George

[reagle]

Right, I agree completely

[jahonen]

For me it seems that most lamp manufacturers seem to be just copying the lifetime promised for the LEDs themselves, completely ignoring that the el cheapo electronics will fail well before that. I think that there is no need or legal requirement for the manufacturer to proof that their statement is actually true for realistic operation conditions (near roof, closed armature etc.) I can't stop thinking that we need a special water cooled lightning armature for for those promised lifetimes

Regards,
Janne

[T4P]

I am pretty certain that the LED armature's driver outside my flat will die in 3 years ( It's switched on for 12 hours everyday )

[rollatorwieltje]

Has anybody tried some lower power LED bulbs? I'm looking into replacing some 12V 20W spots. I'm a bit worried about the electronic transformer, those things tend to output pure garbage. It's a 100W model with 4 bulbs connected. I'll probably need 4x 3 watt LED bulbs, that's very close to the minimum required for the transformer to turn on (I'm not sure about the exact value required since it's a pita to get to it).
It wouldn't be very economical to install 4x €17 LED bulbs only to see them die very fast, for the same amount of money I could buy a lifetime supply of halogen bulbs.

[SeanB]

The LED lamps are not happy with the crappy electronic transformer, as they literally can output 100V spikes and call it 12V. Best to replace the transformer with a 20W magnetic unit when you convert, and this will ensure best life from decent LED units, provided you allow them air flow to keep them cool.

[FenderBender]

So an electronic transformer is like a SMPS is it not?

[reagle]

There is also a thing called Acrich 2 LED from Seul Semi. They use two long strings of Leds on a single die, and just need a single resistor to run off AC. No Dc-Dc to break. Has anybody played with them yet?

[FenderBender]

There is also a thing called Acrich 2 LED from Seul Semi. They use two long strings of Leds on a single die, and just need a single resistor to run off AC. No Dc-Dc to break. Has anybody played with them yet?

Hmm they look cool. Transformerless converter?

[A Hellene]

Though I have been a fan of CREE for quite a long time with their XM-L series, I'll have to admit that Bridgelux has also drawn my attention with their high CRI and light output. Unfortunately, I have not yet found the time to play with the latter ones...


-George

[T4P]

There is also a thing called Acrich 2 LED from Seul Semi. They use two long strings of Leds on a single die, and just need a single resistor to run off AC. No Dc-Dc to break. Has anybody played with them yet?

Dangerous and risky for the LED's themselves

[T4P]

The LED lamps are not happy with the crappy electronic transformer, as they literally can output 100V spikes and call it 12V. Best to replace the transformer with a 20W magnetic unit when you convert, and this will ensure best life from decent LED units, provided you allow them air flow to keep them cool.

Magnetic? One does not simply use a big inductor for a LED ...

[reagle]

Actually, no converter. Just two really long strings of LEds in parallel but facing opposite ways so that each one is on during a half cycle, and a resistor to limit current. The whole thing is UL approved and pretty simple. Not sure what the failure modes are though

Hmm they look cool. Transformerless converter?

[nukie]

Do you still have the batch no of the Rebels that failed? There was a recall early 2008.

MCPCB thermal performance varies from different manufacturers. Best is stick to FR4 PCB and lots of vias as a mounting platform for these smd power LEDs. PCB with vias have better thermal performance vs MCPCB.

Finally, dehumifying or ovening is required to drive all moisture from the clear dome before solder reflow, moisture in the dome can cause premature LED failure. Follow the datasheet regarding the reflow instructions. A lot of people choose to ignore the steps and end up with a short lived LED.

The Acrich are high voltage *LED modules*, that includes a high voltage IC controller which makes fitting very easy and straight forward.

The Rebels are tough units, how are you testing them and not making 3000 hours. How are they mounted? Are you using the recommended layout and have you included vias in your board for better thermal performance?

The leds are bonded onto  aluminium PCB which are then mounted onto aluminium extrusion, all with silver thermal epoxy bonding. They operate at 40 deg C above ambient temperature. Design spec is in excess of manufacturer requirements. All led lamps are manufactured identically using modern pick and place machines and reflow.

So why do some last up to 3000 hours and some fail long before that ?
Is this a led quality control issue ?

All leds were purchased in the UK from Future electronics so I would be extremely surprised if they are fakes.

Show me a rebel led that's survived over 10,000 hours running 24/7/365, ambitious specs, yet to be proven, similar to hard disk drive manufacturers quoting in excess of 150,000 power on hours.

tapatalk

[reagle]

Another cool company is http://www.luminus.com
Had their rep in, and he showed some really huge LEDs. Some are used in projectors, some in cars and even in UV curing.
http://www.luminus.com/products/CSM-360_11_1694759754.pdfl 40W input power , 6000 Lumen
These are mostly designed to be very concentrated light source, but pretty cool nevertheless

[T4P]

6000lm ? Wow .... WOW
150lm/W 

but my favorite XM-L U2 (which is nowhere to be found ...) does 129.8lm/W @700mA
Or the T6 which does 121.2lm/W @700mA

[SeanB]

An electronic transformer is a SMPS without feedback, so the output voltage is dependant on both load and input voltage. Most output AC direct from the secondary, and rely on the lamp being a resistive load with high thermal inertia to integrate the pulse waveform applied into a RMS approximation of 12V. Unloaded or low load they can have very high voltage spikes, and this will not be liked by a LED lamp that has a bridge rectifier and capacitor on the input, which will be charged up to the peaks. They are designed for an input after the bridge that is from 11 to 16V DC for the non dimmable ones, the dimmable ones work from 5-16VDC. This is often not shown on the package, but is often in fine print in the catalogue.

[nukie]

No where to be found??? There's plenty of U2 bin available since their release never a shortage! I just bought 7pcs like 1 hour ago!!!

6000lm ? Wow .... WOW
150lm/W 

but my favorite XM-L U2 (which is nowhere to be found ...) does 129.8lm/W @700mA
Or the T6 which does 121.2lm/W @700mA

[T4P]

At least on major suppliers 

[M. András]

Another cool company is http://www.luminus.com
Had their rep in, and he showed some really huge LEDs. Some are used in projectors, some in cars and even in UV curing.
http://www.luminus.com/products/CSM-360_11_1694759754.pdfl 40W input power , 6000 Lumen
These are mostly designed to be very concentrated light source, but pretty cool nevertheless

their sst50/sst90 leds are used in flashlights suchs as the olight sr50/sr90/91 series pretty nice beast

[reagle]

their sst50/sst90 leds are used in flashlights suchs as the olight sr50/sr90/91 series pretty nice beast

Wow, they are more of a weapon at that light intensity levels.. 2,250 Lumens 10-30W.

[T4P]

their sst50/sst90 leds are used in flashlights suchs as the olight sr50/sr90/91 series pretty nice beast

Wow, they are more of a weapon at that light intensity levels.. 2,250 Lumens 10-30W.

The flashlights they are in usually have a assault crown ... They are INDEED a weapon
But the LED alone is quite expensive ... about 20-30 bucks

[M. András]

i have an sr50 here with lithium-ion cells inside it, its pretty powerful for that 700 lumen, the big brother lumen value is only for the led itself what comes out of it around 1800 but still pretty high. for that 400bucks it must deliver it all the time btw however its thin aluminium on most of parts its pretty strong and looks nice

[reagle]

Just saw a news release about 3M making a new cool lamp:
http://ledsmagazine.com/news/9/8/21?cmpid=EnliifSeptember62012
The driver is in the dome, and the light is is shaped by the reflective light guides.