[RFI] Cree LED Light Bulb

Charlie Gallo Charlie at TheGallos.com
Mon Aug 11 14:05:18 EDT 2014

On 8/11/2014 Peter Laws wrote:

> On Mon, Aug 11, 2014 at 10:25 AM, Kim Elmore <cw_de_n5op at sbcglobal.net> wrote:
>> That's interesting as in their on-line FAQ, Cree says they approve of installation in can fixtures. We've had 42 W CFLs in there for the last 8 years and never seen evidence of overheating. However, the light is cycled a lot and I suspect the failures we've seen are related to that. Cree again states that power cycling is harmless to their LED bulb. I guess I'll get to find out!

> Lumens, gentlemen, please!  IMHO, bulbs should also receive a rating
> based on how much heat they generate.  Clearly, there is a difference
> in the heat output of an Edison bulb that consumes 60 W of power and a
> CFL that puts out the equivalent light (at considerably less power
> consumption).

Actually, we know this:
The TYPICAL 60 Watt soft white edison bulb generates 800 lumens.  Now,
if  there  was  100% luminous efficiency, you get 683 lm/W, so you are
getting 1.17 watts of actual light, and 58.83 watts of heat

The cree bulb I have sitting here, which claims 75 watt equivalent and
800 lumens..(Interesting, eh) draws 14 watts

Again,  you're  looking  at  1.17  watts of light, and therefore 12.83
watts as heat

Pretty  much,  if  you  think  about  any lightbulb, assuming it isn't
giving  off  massive RF, or sound, anything not out the front as light
is going to be heat

73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)

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