Okay, well it is time to put this one to rest.
The LED's light output has dropped by 20 times it's peak value in the begining.
Thus it has reached only 5% of its original light output level.
The final chart is below, as well as the actual data source file, if you'd like to download it and play with it a bit yourself.
Source data for download:
http://www.molalla.net/~leeper/smjled2.xls
Here you can see how the phosphor is now really dark over the die:
Contrast that to this:
I took a Royal Blue LED, to excite the phosphor, and notice how the phosphor is no longer excited by the blue light over the die area:
Here is the die lit up, notice how there is very little yellow being produced above and near the die, and it is darkish over the die:
Oh, and before I forget:
- The current draw by the bulb was 0.2A @ 2.8V, the same as it was at the beginning of the test.
And finally, we have the comparision beamshots against some low output flashlights I dug up, after ArcMania's SMJLED2 PR SS has had ~245 hours on it (fyi, it doesn't really show up in photos against the beamshots of the earlier lights now):
