Reply
Thread Tools Display Modes
#1
Old 02-23-2015, 05:33 PM
Charter Member
Join Date: Mar 1999
Location: Southcoast Massachusetts
Posts: 884
Cold weather = flashing outside LED flood light?

I installed an outdoor, two-lamp LED, motion activated flood light above my garage a year or so ago. I purchased it from an orange-branded home improvement chain store, cost about $80 or so. Works fine.

When the outside air temperature is -4 F or less, the light doesn't stay on, it goes into a sort of strobe mode, where the light flashes about 100 times per minute. Both lamps flash together. At -3 is doesn't do it, only -4 or lower. It's happened twice this season, and a small handful of times last year. We have insanely low temperatures predicted for tomorrow morning, and I expect to see the flashing light again.

My Google-fu seems to be failing me - finding only how to make LED flashers - what's going on with this light?
#2
Old 02-23-2015, 05:56 PM
Member
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,613
Frozen capacitors, probably.
#3
Old 02-23-2015, 08:52 PM
Charter Member
Join Date: Jun 1999
Location: The snow is gone!
Posts: 26,850
Neither LEDs nor CFLs work as well in cold weather as old fashioned incadescents. I've seen the flashing strobe effect on an LED, and also found that CFLs take forever to warm up and give light in cold weather.
#4
Old 02-23-2015, 10:41 PM
Guest
Join Date: Jul 2014
Location: Appalachia
Posts: 824
Quote:
Originally Posted by Northern Piper View Post
Neither LEDs nor CFLs work as well in cold weather as old fashioned incadescents.
All manner of explanations for CFL cold temperature failure is available, but I've yet to be able to locate any inference to the same for LEDs. To the contrary, any info related to LED function indicates that LED semiconductor performance increases at lower temperatures.

My guess would be that the OP's strobing LED problem is caused by inadequate circuit design in the infra red motion detection aspect, or, perhaps in the power supply (ballast) for the fixture... Not in some imagined inability of the LED itself to operate at low temperatures.
#5
Old 02-23-2015, 11:13 PM
Guest
Join Date: Jul 2014
Location: Appalachia
Posts: 824
Quote:
Originally Posted by beowulff View Post
Frozen capacitors, probably.
I think the cap most prone to freeze problems (at approximately -40 degrees Celsius) is an oil cap... not commonly used in this type of circuitry, but nonetheless, well below the temperature discussed here.
#6
Old 02-24-2015, 12:33 AM
Guest
Join Date: Dec 2010
Posts: 6,884
Quote:
Originally Posted by gogogophers View Post
I think the cap most prone to freeze problems (at approximately -40 degrees Celsius) is an oil cap... not commonly used in this type of circuitry, but nonetheless, well below the temperature discussed here.
I'm not so sure. Ordinary electrolytic caps--used in pretty much everything--often only have a minimum temperature range of -25 Cish. Example. That's -13 F; not too far below the OP's temperature. I can imagine cheapy caps crapping out at even higher temperatures, or a poorly designed circuit not handling the change in capacitance over that range.
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:13 PM.

Send questions for Cecil Adams to: [email protected]

Send comments about this website to:

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2018 STM Reader, LLC.

Copyright © 2017
Best Topics: learn neuroanatomy dry humor examples porn remakes ferret kills cat battery dehumidifier maggie gyllenhaal breasts bifurcated needle hostess expiration date cdn abbreviation pinch a loaf deliver phone books for money carousel or merry go round western illinois university election prediction 65 pence to usd how often replace clutch robert heinlein best books if you could have dinner with anyone dead or alive who would it be denver broncos fan chant how to steam open a sealed envelope how does unemployment work for the employer honey this one's eating my popcorn