Thanks. The central solder pad of the Osram Black Flat has an area of 3.06mm2.
So the thermal resistance of the insulating layer when using this LED is: 35μm / (10W/m*K * 3,06mm2) = 1,144°C/W
Add this to the 0.027°C/W of the aluminium PCB (1.6mm thick, 210W/mK) you get 1.171°C/W.
With 22W (maximum measured by Köf3, can vary quite a bit, I assume 80% efficiency) it thus adds ~20.6°C to the temperature of the LED.
Assuming perfectly even solder pad height a 20mm copper Sinkpad PCB would add less than 1°C (0,0147°C/W).
So while you're PCBs are a great idea, I agree with you in not reccomending them specifically for the Black Flat (most people use this LED at close to maximum power). Does your supplier offer other insulation materials?
Added soldered Luxeon Vs on various mosX boards, also variants without mosfet/NTC for direct replacement in many lights like Convoy triples and Emisar D4 quad :
I want to make a correction on something I’ve said in the past about thermal protection triggering too soon on my E2L.
Yesterday I rebuilt it with new leds and in the process I noticed because a crumb of dirt got under the mosled pcb during reassembly, the board wasn’t making good thermal contact on the side of the thermistor.
So that explains why thermal protection triggered almost instantly (always less than 15s), and the driver heat management was working as intended all this time .
After a more careful reassembly it takes something above 30s at 9A before stepdown with factory settings, which is in line with what I had expected in the first place.
I also melted the lighted tailswitch :person_facepalming: , but it’s not the switches fault, I think I might have damaged it during soldering of the spring as it always felt a bit too easy to click, and during a runtime test at 9A it just melted in place :weary:
That is good example why is good to have temp. sensor on MCPCB instead on driver PCB - in other case driver don't see that something is wrong with PCB contact and LED would probably de-solder itself together with wires which would cause havoc inside of light.
OMTEN switches are unfortunately made from low melting point plastic, so soldering everything around switch is more challenging.
As led4power said, it is an aluminium spacer I didn’t put the silicone pads as this was for “demonstration” purposes only, when the products arrived!
But this is top notch! Super well made
BTW, I’m using one of the the Luxeon V (with pebbled TIR lens) …and, honestly, it is the best tint I ever seen!!! Honestly!
So thank you I guess now I’ll have to try the triple with those leds :person_facepalming: :sunglasses:
Can you make silicone pads like this? Never liked hacking up the silicone cubes, never got them to fit precisely. I always thought there had to be something better!
BTW, this only works for LD-A4 driver because mosfet is highest component.
Even better would be if Simon or Kiriba-ru can make solid pill with ~1.2mm depth (LD-A4 has 0.9-1.0mm height), in that case only one silicone sheet would be needed and thermal transfer would be better (but not by much).
When building up a switch assembly, I start with desoldering the switch, when everything is done (spring, bypass etc.) I resolder the switch in place, touching the solder with the iron as short as possible. And still, every third switch that I solder in is destroyed and has to be replaced.