Hands on with the Philips 75 Watt equivalent LED bulb
- Thread starter ratsbew
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Good review but you didn't light it up for us?
blasterman
Flashlight Enthusiast
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Ok, somebody (please) tell me if I'm wrong on this.
I've also noticed that other Phillips LED bulbs tend to run too hot to touch. Thinking about this for a moment (no, I won't strain myself) if we measure the outside of the sink at 70C, is it pretty safe to assume that on die or junction temp is likely up 50% higher?
The remote phosphor design obviously keeps that aspect of the design away from the furnance, but how is Phillips getting their longevity numbers when the base LED is baking?
Oh yeah....kudos for the review.
I've also noticed that other Phillips LED bulbs tend to run too hot to touch. Thinking about this for a moment (no, I won't strain myself) if we measure the outside of the sink at 70C, is it pretty safe to assume that on die or junction temp is likely up 50% higher?
The remote phosphor design obviously keeps that aspect of the design away from the furnance, but how is Phillips getting their longevity numbers when the base LED is baking?
Oh yeah....kudos for the review.
Thanks for doing the 2nd part!
SciGuy
Newly Enlightened
I'd have reservations in regards to your temperature measurements with the infrared thermometer. The silver heat sink will certainly have a lower emissivity than the .95 that most infrared thermometers are set for so the actual temperature of the metal parts is probably even higher than indicated.
Hugh
Hugh
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Good point. I need to get myself one of those nice multimeters with a thermal probe.
I bought a 60w and 75w led Philips bulbs 2 weeks ago to replace the few incans left in the house, everything else is cfl, these are on the special dimmers for cfl/led lights.
The only thing I miss the the real low glow you can get from an incan, these dim down and at a certain point just turn off, this is normal.
The only thing I miss the the real low glow you can get from an incan, these dim down and at a certain point just turn off, this is normal.
I wonder if the heatsink has a coating. Most seem to have it to improve emissivity to help get rid of some of the heat. Color don't matter much as white coatings can be .97 or more emissive.
Here is a very interesting read on how coatings affect emissivity and therefore temperature: http://www.molalla.net/members/leeper/coatbar.htm
SciGuy
Newly Enlightened
It certainly looks like it's way better than a polished aluminum surface but since it still "looks significantly metallically reflective" it probably isn't too terribly high an emissivity. Perhaps it has a super coating of some sort that emits infrared extremely well.
Hugh
I can say I would like to try this bulb, but the length & heat issue is going to be a concern for some fixture applications, and safety may be a concern with children grabbing it with that heatsink base sticking out so far. I would like to see some more objective tests on longevity and how the plastic holds up to see if the life estimate is realistic...although I don't know how to test that with results coming any time soon. It is great that it is dimmable. I will wait for prices to lower...but this is the type of thing I have been waiting to see, and they should have had this as a proven, ripe, affordable technology before issuing the incandescent light bulb bans. I can't use something like this in my many built in recessed lighting fixtures. Not even the CFL will fit unless I go down to lower watt outputs. I also need dimming in a number of banks of lights which rules out CFL's. In any case, this is a very cool development that I will follow and likely try to use in certain fixtures.
There is no issue. The lamp shade/paper probably don't get much over 80-90º.
