LH351D emitters reflowed on 20mm copper 3535 DTP boards but other than that no idea, found no figures. They should be pretty close to XP-L or XP-L2 ones.
Ok then we can assume ~2.5°C/W junction-to-heatsink (2.2 junction-to-solder point from datasheet, + a generous 0.3 for DTP and thermal interface), so at ~5W each junction will sit at ~12.5°C above ambient (“ambient” in this case is the heatsink temperature).
So even the smallest fan will work without overheating (Tjmax is 150°C) but you’ll get less output than what they’re binned at (at 85°C) and you’ll have to derate your output calculations accordingly.
Thanks for adding some light kikkoman. Will buy a set of six thick 12V 6cm fans and make 'em work at 5V for super silent cooling, two at the wings leaning into the main, and 4 at the main. That should keep the stuff cool enough while being silent and reliable.
if 50w is the input your heatsink will be fine.
as not all 50w is dissipated as heat.
and using newer tech leds like you have it just gets better.
might be able to run passive.
better for efficiency and reliability.
no fans to fail.
Right on cue snakebite. But this stuff got cancelled after my friend spoke with me about the mandatory “product specifications”. See: Flush ceiling light overhaul heatsink calculations. Will right now update the thread for the sake of it.