On 16/11/2017 12:34, Dave Liquorice wrote:
On Thu, 16 Nov 2017 11:57:22 +0000, Martin Brown wrote:

The 300Lm/W was achieved on a near infinite heatsink under perfect
laboratory conditions with a fabrication technique that doesn't easily
scale up - basically a one off research device made of unobtanium.

Around 130Lm/W is the current production device which is still
impressive and better than HPS (but still short of 220Lm/W LPS).

As far as what is on the shelves you're hard pushed to get over
100lm/Watt. I quite like the newer stick filament type, in standard
sort of clear envelopes not the fancy "period" ones. You have to
watch the power and lm numbers as not all are 100lm/W. The warm
white colour temperature is good, and light dispersion very similar
to perl tungsten. They don't appear to have any electronics either.
Not had this type long enough to comment on life.

By the time you include the control electronics and practical derating
to achieve lifetime that is about par for the course. They don't last as
long when run at absolute maximum ratings and a bit on the hot side.

The LED failures I've had have been the chips falling off the
board/heatsink...

I have had single LEDs in a chain fail and PSUs expire so far. None had
dropped off the board though - they just stopped conducting electricity.

--
Regards,
Martin Brown