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Anyone out there know if LED outdoor

2012-12-25 21:01:09.83163+00 by Dan Lyke 11 comments

Anyone out there know if LED outdoor floods turn on instantly in < 50F weather? Hate that CFLs take 10 minutes to warm up and turn on...

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comments in descending chronological order (reverse):

#Comment Re: made: 2012-12-31 16:25:08.157876+00 by: Dan Lyke

Yeah, when you put it that way... Okay, back to the 150 watt glowing filament.

#Comment Re: made: 2012-12-30 20:58:12.509208+00 by: TheSHAD0W

And come to think of it, if those flood lights are only on for an average of a few minutes per night, you probably ought to stick with incandescents. You're not going to save any money, and the environmental costs of producing the LED lights are not trivial, so you're not benefiting the world either.

#Comment Re: made: 2012-12-30 19:59:38.197633+00 by: TheSHAD0W

LEDs are about twice as efficient as CFLs, which, considering the cost difference, IMO isn't enough to justify switching in most circumstances. I've replaced two lights at my house which are on constantly, and more for convenience than for efficiency; the CFLs were needing to be replaced too often, and one of the lights was in an awkward spot. Low-temperature issues like Dan's are a valid reason to consider switching also.

In a few years LEDs will certainly surpass CFLs, but they're too much money right now.

#Comment Re: made: 2012-12-30 15:57:27.759854+00 by: Dan Lyke [edit history]

The issue with LEDs I've seen isn't so much lumens per watt, the current devices seem to be on par with CFLs, it's overall output of the device: we can get a 2k lumen CFL outdoor flood that screws into a stanard socket, but the LEDs seem to top out at <1k. Which probably means we'll be replacing that single-socket fixture with a 2 socket fixture.

And, yeah, lighting in our house is dwarfed by the refrigerator, though when I've got the shop lighting fully cranked up we are sucking 300 watts with it (heat is gas). The application where it's worth going beyond the 70 or so lumens per watt fluorescents are giving is commercial lighting.

#Comment Re: made: 2012-12-30 15:10:11.851742+00 by: meuon


Cree announces 200 lumen per watt LED's coming..

I foresee DC lighting circuits in homes in the future.

(note: Lighting is a very low percentage of actual home electricity use for North America.. Heating and Cooling is the highest)

#Comment Re: made: 2012-12-27 15:58:51.658464+00 by: Dan Lyke

Hmmm... prices are non-linear, we may have to replace that fixture with one that can take two bulbs...

#Comment Re: made: 2012-12-27 02:46:37.187173+00 by: TheSHAD0W

The new LED lamps I've seen are very well designed, have aluminum heat sinks which should limit any potential issues with thermal shock, and should be electronically stable at low temperatures. If only they weren't so expensive... :-P

#Comment Re: made: 2012-12-27 01:00:12.817769+00 by: meuon

The ones I have (unknown brand from Lowes) work at near freezing instantly, it hasn't gotten colder than that yet.

#Comment Re: made: 2012-12-26 17:01:23.634095+00 by: Dan Lyke [edit history]

I should also note that the answer to this question seems obvious: You can simply pulse even super cheap LEDs fast enough to do really high bandwidth data communications.

However, I also know that driving LEDs really efficiently is non-trivial (as any search for "joule thief" and "LED charge pump" will tell you...), and that heat dissipation is a big part of high output LED engineering, and driving circuits can often be heat sensitive. Whence my Q.

#Comment Re: made: 2012-12-26 05:04:31.781505+00 by: Dan Lyke

Warm weather it's dark late enough it mostly isn't an issue. Okay, time to open the wallet and try one...

#Comment Re: made: 2012-12-26 00:24:49.358845+00 by: TheSHAD0W

Yeah, they do. Shouldn't be affected by cold weather at all. Very hot weather, they might overheat and step down or turn off.