Author Topic: Dangerous LED lamps.  (Read 9563 times)
toomanybulbs
Member
****
Offline

View Posts
View Gallery


Re: Dangerous LED lamps. « Reply #15 on: October 18, 2014, 09:54:42 AM » Author: toomanybulbs
do post pics of these failed units.
i also suspect the led string opened up allowing the voltage to rise.
typical cheap and nasty film cap,bridge,and lytic to tone down the flicker.
probably pushed way too hard and died young as a result.add in cheap noname leds and the bomb is ticking....
Logged
Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #16 on: October 18, 2014, 10:23:17 AM » Author: Medved
Well, what I've already met (it was not lighting), were electrolytic assembled polarity reversed in a complete production batch. It have passed the "quality check", because it worked for that short time. But of course all burst short while after the customer plugged it in.

Now if this happens to the halogen ballast (there the only electrolytic is just in the overcurrent protection circuit), it may work for years seemingly OK. Only when a short circuit happens, it will just burst into flames, as the protection won't be working at all.
Same with certain designs of fluorescent ballasts (using such capacitor in the EOL protection), the thing will seemingly work well, but burst once the tube dies...


But regarding your case, what puzzles me: Most of them have failed at once, after serving for already some time. That means the trigger has been some external event, most likely the mains overvoltage spikes, yielding an overcurrent in the LED's. And that overcurrent then could cause the LED string to fail open circuit, with the electrolytic destruction as the final result.
So still remains the question, where that overcurrent came from: And occasional spike of "normal" peak voltage would not kill so many at once, it had to be really quite long burst...
« Last Edit: October 18, 2014, 10:37:55 AM by Medved » Logged

No more selfballasted c***

FrontSideBus
Member
***
Offline

Gender: Male
View Posts
View Gallery


FrontSideBus
Re: Dangerous LED lamps. « Reply #17 on: October 18, 2014, 11:26:21 AM » Author: FrontSideBus
More than likely they are all consistantly crap and all died at the same time from the same flaw...
Logged

Bulbs are for planting: Lamps are for lighting!
http://www.lighting-gallery.net/gallery/index.php?cat=11271

Liam
Member
**
Offline

Gender: Male
View Posts
View Gallery


Re: Dangerous LED lamps. « Reply #18 on: October 18, 2014, 08:40:24 PM » Author: Liam
Why i think they have all blown is because there is 8 Spot lights in my kitchen and each set of 4 is connected up to one live feed wire so one lamp popped triggering a spike to the other 3 remaining also exploding there Capacitors. It seems the LED chips failed before the capacitors exploded as they went out before the loud bangs, and if you see my video you can see the LED's failing before the capacitors did..

Ebay link to the pieces of evil here   http://www.ebay.co.uk/itm/4-6-10-X-SMD-Lamps-LED-Bulbs-Spot-Lights-GU10-Day-Warm-White-Lamps-High-Power-UK-/230809182924?pt=UK_Light_Bulbs&var=&hash=item35bd4ca2cc   Look at his negative feed back because of the same experience i had where they all failed in one night.
Logged

My gallery http://www.lighting-gallery.net/gallery/index.php?cat=11495

Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #19 on: October 19, 2014, 12:19:49 AM » Author: Medved
If the failing started as interruption of the LED and consequent popping of the electrolytic, it could not create any excess on the input. The reason is, all this is behind the current limiting capacitor. So that cascade of events you describe is not possible with this LED ballast concept regardless on how bad quality is all the workmanship and components.

Even when speaking about component overload: Statistically they do fail in similar age, but still the spread is always at least 10% (taht is when the aging mechanism is exceptionally well under control, that practically excludes bad manufacturing quality) of that age. So if the thing was even just a month old, the failing would be spread among at least three days, so not all within one single night.
So the only plausible explanation for all failing at once is some external event, at least acting as the "last nail"...

But that does not mean that even should be something the lamps should not tolerate well, it just means something had happened in the electrical system and and what I intended to point out, that "something" could well be a danger on it's own, regardless if consequently some cheepeese lamps blew or not... That is the reason, why to look for the source of that event.
« Last Edit: October 19, 2014, 12:50:20 AM by Medved » Logged

No more selfballasted c***

toomanybulbs
Member
****
Offline

View Posts
View Gallery


Re: Dangerous LED lamps. « Reply #20 on: October 29, 2014, 09:12:43 AM » Author: toomanybulbs
if the caps were reversed at the factory it wont work right for the short test either.everything the ballast cap can deliver would go into heating the lytic.
now if it didnt vent due to current being low enough it might actually reform in reverse.
so the most likely cause is the open led theory.
Logged
Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #21 on: October 29, 2014, 11:46:46 AM » Author: Medved
Definitely, the electrolyte reversal is very unlikely here, because it worked before.
But the thing is, why the LED's have come open circuit all at once. And there the most likely scenario is some mains disturbance from some problem in the mains, yielding an overcurrent from the capacitive ballast (so not handled well by that ballast design).

To make it clear: I never said that disturbance was something the lamps (whatever technology) should not tolerate in the first place.
Definitely a usable quality product should tolerate all disturbances not only from normal mains operation (switching,...), but even coming from most of the faiure events (include short circuits, resulting into circuit breaker disconnection caused overshoots in the rest of the installation,...), there is nothing to argue too much about.

What I said: Just use those c***py LED's as an indicator of the mains prolem: They failed multiple at once (very unlikely on a clean sinewave) => there something should have happened. Isn't that "something" the thing to really worry about?

Logged

No more selfballasted c***

toomanybulbs
Member
****
Offline

View Posts
View Gallery


Re: Dangerous LED lamps. « Reply #22 on: October 30, 2014, 08:03:43 AM » Author: toomanybulbs
probably just junk leds run too hot.
even samsung had a bad batch on their led tv's.
fun to replace 200 5630 led's to save a 55" tv.
i have done this twice.once on a 50 and once on a 55.
seems 1 shorts and overheats the rest in the string.then a few more give up till 1 opens.
i guess i can hit bulb recycling bins in search of some to autopsy.
as much of this garbage as folks buy they should be easy to find!
Logged
Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #23 on: November 03, 2014, 02:05:52 PM » Author: Medved
This is a good example how far the Chinese designers are willing to go when asked to reduce the selling price:
"Was the low cost in our contract? Yes, so there it is. Was the CE mark required by the contract? Yes, so there it is. Was something about the safety standard conformance in the contract? No? So where is the problem?"
Logged

No more selfballasted c***

Medved
Member
*****
Offline

Gender: Male
View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #24 on: November 07, 2014, 01:32:33 PM » Author: Medved
That is the difference between "western" and Chinese engineer: The "western" just says "NO" when he knows the customer requirement could not be fulfilled safely and with reasonable quality.
The Chinese one provides just the minimum required by the contract. So if the contract does not list any requirements related to safety, he just skip that when such skipping means cost savings. Even the Chinese tend to do the things safely, but only when it does not mean any conflict with the customers specification. And he treats the budget as one of the requirements, so if the safety is not listed in the specification, the price in the contract has a higher priority.
Most of them do explain the consequences during the negotiations, but if the customer insist on the lower cost, in China he get that on that lower cost even when that means unsafe product.

And the thing is, if one refuses, some other one does not.

And here I was talking about B2B relationship, so the "customer" means a distributor or retailer, who orders quantity for sale in his home country. Because he is then the one responsible for the quality, the makers expect that customer is a professional, who knows what he wants and who is the one responsible to make the specification compliant with his target market (that is, what the law says in all the civilized countries anyway).
Not an end user of that product...

Logged

No more selfballasted c***

Solanaceae
Member
*****
Offline

Gender: Male
View Posts
View Gallery

All photos are brought to you by Bubby industries.


GoL Solanaceae.Keif.Fitz Keif Fitz bubby_keif
Re: Dangerous LED lamps. « Reply #25 on: May 24, 2015, 06:07:14 PM » Author: Solanaceae
Wow. I wish people would realize they are playing with fire (literally!) when they use LEDs.
Logged

Me💡Irl
My LG Gallery
My GoL Gallery

tolivac
Member
*****
Offline

View Posts
View Gallery

Re: Dangerous LED lamps. « Reply #26 on: May 25, 2015, 12:35:46 AM » Author: tolivac
The LED lighting at our transmitter plant hasn't erupted with fire yet.At home I use LED portable lights powered by rechargeable batteries.So far,so good with those.OLIGHT SR90,50,51,and many others from Kobalt and Streamlight.Another LED light from WalMart-this one has worked really well in my collection-one of my favorite "maintenance" lights for seeing into the dark corners of our transmitters.Have a well used JetBeamRRT LED light that is now several years old-a gun show find.And a Powertac Chameleon multicolor LED portable light.
Logged
Solanaceae
Member
*****
Offline

Gender: Male
View Posts
View Gallery

All photos are brought to you by Bubby industries.


GoL Solanaceae.Keif.Fitz Keif Fitz bubby_keif
Re: Dangerous LED lamps. « Reply #27 on: May 25, 2015, 01:00:32 PM » Author: Solanaceae
Just keep your eyes out for any suspicious buzzing or flickering- that may be a sign of impending EOL.
Logged

Me💡Irl
My LG Gallery
My GoL Gallery

Print 
© 2005-2024 Lighting-Gallery.net | SMF 2.0.19 | SMF © 2021, Simple Machines | Terms and Policies