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Scary CFLs - Habemus plus vis computatoris quam Deus
Ramblings of a Unix ronin
unixronin
unixronin
Scary CFLs
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mr_spock From: mr_spock Date: July 23rd, 2012 09:53 pm (UTC) (Link)
LED's don't have the same problems, because they don't build up the heat in the base the way a CFL does. Unixronin once posted that the big difference between incandescent bulbs and CFL's was what they did with the heat - incandescent bulbs radiate it out from the globe, where CFL's try to absorb it into the base and radiate it from there - which the sockets on standard light fixtures aren't designed to handle. LED's are superior to both because diodes (LED = light emitting diode) don't generate as much heat in the first place.
unixronin From: unixronin Date: July 23rd, 2012 10:06 pm (UTC) (Link)
And because the LED lamps come with proper heat-sinks built in to keep the emitter wafer cool.
mrmeval From: mrmeval Date: July 24th, 2012 01:04 am (UTC) (Link)
Don't count on that, some of the ones we've dissected have what appears to be enough metal but it is not. Estimated failure time was less than a year. The failure mode would be subtly decreased brightness. Several of the ones cut open had a tiny cap, diode and resistor to power the LED. Only one had a decent looking current regulator but the components used were of a suspect brand and it also had an anemic heat sink. If the regulator actually worked it would cut the light down when it gets too hot.
selfishgene From: selfishgene Date: July 25th, 2012 01:38 pm (UTC) (Link)
Its almost like the eco-loonie brigade is lying to us .. nah, couldn't happen.
hrrunka From: hrrunka Date: July 23rd, 2012 10:12 pm (UTC) (Link)
High power LEDs do get quite hot, and are prone to fail if not properly mounted on something that'll get rid of that heat. (We had a construction project involving them at my local ham radio club, and more than one of them popped its clogs because it got too hot.) Then there's the circuitry that turns the mains into something the LEDs can work on. The component count isn't huge, but it's definitely non-zero. There's quite a lot to go wrong. My experience so far suggests that the 20,000 hours sometimes claimed for them is more than a little optimistic, and in reality they'll last more like 2500 to 5000 hours. However, my sample size is, so far, still in single figures. I put 4 LEDs into a ceiling fitting. Two failed in under 1000 hours, and one is now showing signs of failing soon, at around the 2000 hour mark.
unixronin From: unixronin Date: July 24th, 2012 02:21 am (UTC) (Link)
Personally I'd like to see a house with dual wiring systems - regular AC for appliances, low-voltage DC for lighting.

We've actually had a pretty good record with the LED lamps we've bought. Aside from my first-ever LED flashlight that developed a thermal problem in its controller circuitry, I don't think we've had an LED lamp fail yet. I will note that I waited a long time before they reached an output-at-price level I considered acceptable, and I'm very picky about which ones I buy. The first ones we installed have been in service about two years now, I think.

Edited at 2012-07-24 02:24 am (UTC)
hrrunka From: hrrunka Date: July 24th, 2012 08:36 am (UTC) (Link)
These four high intensity LEDs were installed in April 2010, roughly 900 days ago. They get used, on average, maybe six hours a night (only 2 or 3 at this time of year, but 7 or 8 in the depths of winter), so that's 5400 hours or so of use so far. They were quite pricey, but would have been worth the price if they lasted even half of their projected 20,000 hours. However, two failed within a year (so under 3000 hours) and a third has started blinking, so will undoubtedly fail within days. As they've failed they've been replaced with slightly lower intensity but much cheaper LED lights. I've been on the look-out for higher intensity ones at a price that makes sense for somethinng that'll last only a couple of years.

And yes, sensible low-voltage lighting wiring would make a lot of sense in the LED lighting world.
mrmeval From: mrmeval Date: July 28th, 2012 12:02 am (UTC) (Link)
My company is building street and industrial LED lighting. We've went through all the low end players in that industry. We're now engineering our own power supply/controller though we did find two vendors for power supplies that actually worked but we will 100 percent test them as no vendor is ever stable. We're after street, highway and industrial building lighting and for the street/highway we must provide 50,000 hour life expectancy or we pay for the repair/replace which is around $12,000 for each bulb. We've gotten the efficiency up so high that we can crank out more lumens per watt than any of the competition so far. I believe we're up to 100 lumens per watt or better. The DOT does not really care about the power savings it's the longevity they're after but every kwh that is saved is a bonus.
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