cree P2, P4 etc, 350ma, star only, no external heatsink?

[VegasF6]

Hi, as title states, what would be the life of a cree xr-e lamp, or for that matter an ssc-p4 mounted on a star with no other heatsink, driven at 350ma? Let's assume that this would be on for several hours at a time, in a quasi enclosed housing like a dome lamp. I realize that many other dome light projects have been done, but I am just curious if the star itself is of any benefit as a heatsink?

This is taken from the xlamp pdf file:
Based on internal long-term reliability testing and standardized forecasting methods, Cree projects XLamp LEDs to maintain an average of 70% lumen maintenance after 50,000 hours, provided the LED junction temperature is main[FONT=Verdana,Verdana]tained at or below 80°C.
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So, if I could keep it at 176 farenheit or under, I could maintain the 50,000 hour life. I would be more than happy with a 2,000 hour life, but I don't want to lose 30% or more of my brightness.

 

[worldedit]

The star is better than nothing, but it wont be enough for 350mA. Especially using a lower bin. Try a small heatsink from a Computer or just a piece of aluminum. Unfortunately iron is not a very good heat sink.

 

[VidPro]

what he said, i think the balance point for the full sized star item (vrses the 15-17mm ones, is about 160ma or 1/2 that, in open air.
so just use 4 and run them low

or just drop an aluminum or copper plate down over the plastic of your dome, and run 2 at 350ma , that oughta do it, just spread the heat out enough so a slower transfer of heat doesnt effect the transfer needed at the hot spot.