Cree R2 heat question

[trout]

Has any one here tested the heat output of the cree Q5 and R2 leds.
The reason I ask is I did a basic test a while ago with a triple Q5 and a Bflex , in a light housing I made with the Bflex set to trip at 50 degrees
in my house with an ambient temp of 16 degrees
with the leds running at 1000ma the light heated up to trip temp in 5 mins 30 seconds and after tripping to low power it was a further 1min 30 secs until it would allow full power again .

Now I have put 3 R2 leds in the same housing with the same optic and bflex , and running the same test it took 3mins and 20 seconds to heat up to trip the bflex . with the same 1min 30 secs to full power again .

I know this is a basic test but it does say to me that the R2 makes more heat at 1000ma than the Q5 so may need more heatsinking .

 

[SemiMan]

The difference in efficiency between the two bins is not that great so the reduction in energy converted to heat versus light is not that great. Remember that the Vf could be anywhere in the range on the data sheet so no guarentees that any particular Q5 is going to be more efficient than any particular R2. On average they should be, but any one in particular may not be.

Semiman