This morning, I turned on a LED lamp. It lit normally for half a second and then went out. This kind of failure seems to happen when the weather first turns cold.
I am curious about your experiences. I don't feel like tearing down a $2 bulb. 😉
Ed
I am curious about your experiences. I don't feel like tearing down a $2 bulb. 😉
Ed
That is good to know.
ETA: An open LED string is also consistent with the absence of a bang or burning smell (like CFLs used to do on failure).
Ed
ETA: An open LED string is also consistent with the absence of a bang or burning smell (like CFLs used to do on failure).
Ed
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I put it in the box of failed LED bulbs to take to the hazardous waste facility. These things were designed to become junk.
ETA: They're not hazardous, but have no value to e-waste recyclers.
Ed
ETA: They're not hazardous, but have no value to e-waste recyclers.
Ed
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Yeah, there's usually one LED with a black spot on it. Just for interest's sake I've bridge the burned out LED in the string on one of these, but the lamp doesn't seem to last much longer in my experience. I guess it depends how many LED's are in the string to share the additional current. Strangely, you can buy the same brightness of LED bulb from the same manufacturer but a few months apart and there might be 9 LED's or 15 on the MCPCB. I assume those with more might survive a 'bypass operation' better than those with fewer. I guess the less established manufacturers might shop around different factories.
I am impressed by our failure analysis team. 🙂
The replacement bulb has a noticeable strobe effect on the PC fan. I am wondering if the manufacturer left out the filter capacitor.
Ed
The replacement bulb has a noticeable strobe effect on the PC fan. I am wondering if the manufacturer left out the filter capacitor.
Ed
For a time, the dollar store sold "Sunbeam" LED lamps very cheap, possibly subsidized. They are more reliable than LEDs from Ikea. I bought shares in Cree when they started making LED lamps but that has not turned out well. The Sunbeam are just a rectifier and linear regulator and the LEDs, no capacitors. Which made them dimmable. Ironically, LEDs and CFLs that use inverters are expensive and generally not dimmable. This also means that you cannot use them with a TRIAC based photo switch for yard lights. Here in the US (vs Canada), there are only streetlamps where the HOA requests them, so people leave yards lights on at night, especially now that we have low power LEDs instead of incandescent. I have kitchen LED pot-lights that use 60Hz power transformers that have a slight ~hum. 😕 So I recommend simple and cheap, much the same as audio, no Rube Goldberg designs please.
The switching regulator is necessary for efficiency. The temperature regulation eliminates the heatsink.
The manufacturer could have designed a bulb that lasts forever, but they won't.
Ed
The manufacturer could have designed a bulb that lasts forever, but they won't.
Ed
Maybe. Switching regulators are about 90% efficient, maybe. Can be like 80%. That means if you drop less than 12V (to 24V) in a linear regulator, it is more efficient that a switcher. And there are places that the EMI generated by switchers is prohibitive.
A 60Hz transformer won't fit in the base. The LEDs drop 3-4 volts each. A linear regulator running from the line would be ~20% efficient.
Ed
Ed
And there are 25 or 30 LEDs in series, for a LED drop of about 100V, leaving the regulator to drop 20V, ie about 80% efficient.
Similarly I just took one apart that had 9 LED's, and we run 240v here, so I'm assuming the MCPCB runs on about 30v. It was a dud and only lasted a few weeks, with the switching PSU PCB turning very black indicating high heat. As I alluded to above, I bought a new one of the same brand which has 15 LED's for the same output and colour temperature. Yet again, I opened up the same brand months ago and that one had something like 20 + LED's. Being a cheap chinese brand OEM'd for a local hardware chain, I assume they have a number of suppliers under that brand hence the variation.
(The reason I know about the new one having 15 LED's is that I have to remove the plastic dome 'bulb' for it to fit into the cramped light fitting it's in, the enclosed volume not helping thermal issues).
(The reason I know about the new one having 15 LED's is that I have to remove the plastic dome 'bulb' for it to fit into the cramped light fitting it's in, the enclosed volume not helping thermal issues).
Bought RGB / white light bulbs at dollar store.
fun came with remote.
can be white or change colors.
has few color change sequences built in.
both died in 3 or 4 days.
Switch turd or whatever power supply dies in base.
cut it open and applied power to board.
leds are fine remote works fine.
power supply is garbage.
fun came with remote.
can be white or change colors.
has few color change sequences built in.
both died in 3 or 4 days.
Switch turd or whatever power supply dies in base.
cut it open and applied power to board.
leds are fine remote works fine.
power supply is garbage.
A contributing factor may be the electric company running the line voltage high (123.5V here).
Ed
Ed