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Philips "L.E.D. Bar" lamp which failed after about 20 hours use

Philips "L.E.D. Bar" lamp which failed after about 20 hours use

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This Philips LED Bar lamp, made at Shanghai Bei-Lun K-Lite, (Bei Lun is the "suburb") in China with the "signpost" plant mark has 29 LEDS per bar and 8 bars in all. An impedance converter with a bridge rectifier and chopper chip are visible in the base. It is suspected that the base volume also contains a Buck inductor and some capacitors.

Wiegers_Tube_Gear_Corrected.JPG Wiegers_Tube_Gear.JPG Failed_Led_Bar_Lamp.jpg B2224-01r.jpg

Light Information

Light Information

Manufacturer:Brand, Philips. Manufacturer, Beilun, Company, Ningbo K-Lite Mfg.Ltd.
Model Reference:None as Such.
Lamp
Lamp Type:Helium Cooled LED Bar Solid State
Filament/Radiator Type:Eight Solid State "Bars" in Parallel
Base:B22-d/25x26 with White Polymer Insulation and Control Gear Inside
Shape/Finish:AE-60
Service Life:"Up To 15,000h" (This specific case, c20h)
Electrical
Wattage:7.5
Voltage:170-240v R.M.S. A.C.
Current:Not Measured, but calculated at 30mA R.M.S.
Optical
Lumen Output:806
Lumen Efficacy:107.4lm/w
Color Temperature:2700K
Color Rendering Index:>90
Physical/Production
Dimensions:60mm dia., 105mm high
Factory Location:Bei-Lun, South of Shanghai, 29.889811 121.783871
Fabrication Date:August 2015, Date Code 5H3
Application/Use:General Lighting Service

File information

File information

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Filename:Failed_Led_Bar_Lamp.jpg
Album name:Globe Collector / Miscelaneous Lamp related stuff
Keywords:Lamps
File Size:84 KB
Date added:Dec 11, 2015
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Silverliner
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GoL
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Dec 11, 2015 at 09:36 PM Author: Silverliner
All the "filaments" buckled. I can see the cloudy deposits on the inside of the envelope. I suspect it is somehow overheating. Maybe a faulty driver or atmosphere?

May all the great lighting technologies have their place in history.

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Dec 11, 2015 at 10:30 PM Author: dor123
Looks like a production defect, as many bars are broken, and there are no reasons for the LED bars to become broken if the lamp didn't dropped.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

James
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Dec 12, 2015 at 04:50 AM Author: James
This is not such an uncommon failure mode for LED filament lamps made by mediocre-quality suppliers. These lamps are filled with a helium-oxygen mixture which is needed for its thermal conductivity to cool the LEDs. Helium has very tiny atoms and will leak out through small imperfections in the glass-to-metal seals or even along the copper-NiFe interface within the dumet sealing wire if that is less than perfect. Although the traditional lampmakers know how to control such things, glassworking is a new domain for the LED companies and we start to see the return of old problems that were solved decades ago. They will learn, with time!

When enough of the gas has leaked out, the LED temperature rises hugely and causes the silicone-phosphor encapsulant to degrade. It shrinks somewhat and peels itself away from the sapphire substrate of the LED strip. Eventually this rips apart the wirebonds that interconnect the string of LED die on one filament, and that filament will burn out. Then the remaining LED filaments are overloaded, which accelerates the process for them until the circuit is finally broken and the lamp is dead. A kind of greasy-looking coating typically builds up on the inner surface of the bulb, originating from VOC's that are baked out of the plastic components.

Sometimes the LED die themselves are also damaged and since they usually fail in short-circuit mode, that explains the dark patches along some filaments. Since the ends of the filaments are cooled due to the weld to the leadwires of the stem, the ends usually stay lighted sometime after the die at the centre have been destroyed.

Andrew - the factory ID symbol you see here is that of K-Lite in China, who produces LED lamps for many different resale vendor companies.
Prismatic
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Dec 12, 2015 at 06:41 AM Author: Prismatic
Wow. Very interesting picture. I also think it lost the fill gas and the filament overheated. I think when a led filament lamp survives the first 50 hours it should stay fine.

Are you going to exchange it as this is a typical defect and should be covered by waranty?

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Dec 12, 2015 at 08:02 AM Author: Silverliner
James, you mentioned K-lite. That's a common brand of bulbs sold in the dollar stores here, incandescent, halogen, and CFL. Wonder if they are related. Interesting explanation, makes sense.

May all the great lighting technologies have their place in history.

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Dec 12, 2015 at 08:38 PM Author: Globe Collector
Your description fits this lamp's failure mode exactly, James. What is the purpose of the oxygen additive to the gas mix? Would it not be more logical to use Hydrogen. Helium is only in finite supply here on Earth and it is becoming rather rare at the rate we are (AB)using it!

The substrate upon which the LED dies are mounted looks just like PRE-PREG, that fiberglass renforced resin printed circuit boards are made from. Can you tell us more of the structure of the sapphire substrate....it certainly makes more sense as it contains no valatiles to outgas.

I initially thought that outgassing had contaminated the bulb atmosphere, reducing its thermal conductivity. It is quite obvious that heat was an issue just prior to failure.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Dec 13, 2015 at 03:12 AM Author: James
Its slightly better for LED lumen maintenance to be in a very dry but slightly oxidising atmosphere to prevent blackening - same as many metal halide lamps are filled with nitrogen-oxygen in the outer bulb.

Hydrogen is indeed better for heat dissipation but brings safety issues during dosing into the bulb. Moreover at least at the present time Helium is exceptionally cheap, in part due to the US Govt selling off the vast reserves it stockpiled during previous decades. One day though that will change - unless we find new natural gas wells! (Helium availability is linked to the rate of methane extraction from the earth).

The thermal conductivity of expoxy FR4 / CEM1 type PCBs is not good enough for these LED filaments, even with a thick layer of copper. Most manufacturers use artificial sapphire plate. Recently many are switching to PCA, same material as ceramic arc tubes since its a lit cheaper with similar thermal and optical performance. Some other Chinese use glass which looks the same, and even call these kind of LEDs Chip-on-Glass or COG, but due to the poor heat conductivity, lamps made with those are usually dead within a couple of thousand hours (even though the packaging of course claims 10-20x longer life than they actually achieve!).
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Dec 13, 2015 at 03:37 AM Author: tony88
hydrogen so it is an led bomb have you ever herd the BOOM when some one ignites a balloon filled with hydrogen I have one of these lamps for about 12 months and still working well , I might move it to an outside light now
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Dec 13, 2015 at 07:09 AM Author: Globe Collector
Oh, there aint much hydrogen, and it aint a stoiciometric mixture with oxygen, so even if it was ignited at would just be a small pop!

Interesting about the slightly oxidizing atmosphere, I know a Nernst rod won't light at all without oxygen. I did not realize that some metal halides had a slightly oxidizing atmosphere too. Can you cite a few specific examples? I have some metal halides with sintered copper or compacted copper wire getters which I suspect are a lot less active than Zirconium-Aluminium getters.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Dec 13, 2015 at 05:32 PM Author: rjluna2
Wow, what a failure you have found here Andrew

Pretty, please no more Chinese failure.

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Dec 13, 2015 at 09:51 PM Author: Globe Collector
Yes, Robert...it was an expensive one too, least we are all getting something out of it.

As James told me of the plant, I have edited the database to include this information.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Martin Lelle resr1286
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Jun 07, 2016 at 07:08 AM Author: ResR
That is interesting failure, I have never seen anything like this before. It does look like the LED filaments overheated and shorted out from center to the edge in this specimen. Even my 4,69€ Henske 4-filament is still working fine.
Also I heard somewhere that the LED filament bulbs are made in old incandescent light bulb factories to reuse the existing machinery after the ridiculous light bulb ban put a gag on the incandescent bulb market.
Thanks for sharing.

http://www.lighting-gallery.net/gallery/index.php?cat=11837

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Jun 07, 2016 at 07:56 AM Author: Globe Collector
Martin, this damn thing cost me AU$18.00...(that's 11.88 Euros!). I think I will have to come to Estonia to get them cheaper!

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Sep 28, 2017 at 09:36 AM Author: Lampenfreak
I guess the filaments were only overloaded. So they got to hot & that's the result. I have some cheap Chinese filament lamps in use (from factory supply and from Hornbach), which work very good and produce no heat. For every new stuff I make a 3 days (72h) test run to see how hot they get. If the lamps stay cold they are good enough for daily use.
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Sep 28, 2017 at 11:26 AM Author: Lightingguy1994
I had this happen to an orange Feit LED , thought i fried it with misuse but it turned out it had no gas fill, the lamp glass was also slightly deformed from factory
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Sep 28, 2017 at 04:23 PM Author: Globe Collector
It is possible the Feit, (based in California) may well source from manufacturers like K-Lite too. Dave would know more than me on the specifics though. Containing helium in any container for any significant duration is a real challenge, wehat with its high atomic velocity, inertness and the lowest boiling and melting points of any element.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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