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Thread: DIY Cree Eave Lighting

  1. #61

    Default Re: DIY Cree Eave Lighting

    Quote Originally Posted by thumblessprimate View Post
    I'm hoping that there will be an update from Mike on his outdoor LED setup. I'm in the midst of have something similar completed. I'm still a little concerned about the lights handling moisture and other outdoor conditions.

    A person mentioned using LED sealant. Is that something one would spray on the entire surface of the PCB except for the emitter or would one spray on the the PCB plus the emitter?

    I've got some liquid electrical tape lying around the house, is that something that might work as well? I was going to use some to cover any exposed copper wire at the solder joints to prevent oxidation of the metal anyways. Thanks.
    I guess it's really going to depend on environmental specifics. I did something similar using 3x rebel boards and took what seemed like pretty basic precautions:
    • Fixtures themselves are under the eaves of the roof, thus can't be rained on under normal conditions
    • Enclosed the LED's using a sample jar with a glass lid
    • Used RTV silicone on the wiring penetration to seal it
    • Ran a half-bead of RTV silicon along the backside of the sample jar lid just to ensure it didn't fall off


    The fixtures won't get rained on under normal circumstances and are reasonably splash-resistant. Any moisture that does penetrate can diffuse out through the unsealed half of the lid. Insects can't get into the fixture.

    I did nothing for the solder joints - those will likely be the major weakness of the fixtures.

    My 4-fixture installation has been going strong on a >75% duty cycle (I typically turn them off during the day in the summer) for more than 18 months now. They survived the brutally hot summer of 2011 and don't seem to mind the occasionally-horizontal rain from the spring storms around here. Dallas is kind of humid, but has nothing on locations closer to the gulf where relative humidity generally stays 80% or more ... not sure if more moisture ingress protection would be called for in such locations.
    Last edited by idleprocess; 07-14-2012 at 01:00 PM.
    I apologize that this letter is so long; I did not have time to write a short letter

  2. #62

    Default Re: DIY Cree Eave Lighting

    Quote Originally Posted by cdrake261 View Post
    I see...if you could do it over again, would you still go with xr-e? Or go with one of the other two? Also, do you have an idea how much it cost you every month to run those for 12 hours a day, all month long?
    In my application I probably would stick with the XR-Es. Primarily because I like the soft light level I have now--if they were much brighter they would probably start to become annoying since there are eave lights over bedroom windows.

    If my memory serves me correctly (and my math is approximately correct), an XR-E at 350mA is around 1.1 watts and I have 10 of them, so ~11 watts of light and add a bit for the driver, so let's assume 12.5 watts of load. 12.5 watts/1000 watts/kwh x 11 cents/kwh x 12 hrs = 1.6 cents per day or $6 a year. That's one coffee at Starbucks.

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