So I tried a N5 BC (Voltage: VH) in my M21A. My LD-A4 driver in the light was ordered with 8-12 Amp range so I set it to the bare minimum. Tail current was measured at 7.94A and voltage across the LED at 3.446V. It’s obviously bright AF, quite close to the sliced dome 3V XHP50.2 that it replaced.
The XHP50.2 measured 3.226V across the LED and the MOSFET probably took a hammering and caused the driver to overheat the whole time.
I will have to replace the LD-A4 with a LD-B4 driver and the corresponding PCB to combat the hot MOSFET. But I need some advice…….
Will it be OK to run the SST-40 at 8A? Or should I dial it down to 7A? The light is being used as a tactical light with high to low modes, no mode memory. So it always starts in turbo.
Where can I buy a copper spacer? I have silicone cubes and sheets that I can use to space it. Otherwise I’ll have to make my own… The MOSFET is definitely running cooler with higher Vf of SST-40, but more cooling will definitely help. It’s a pity my 7-9 Amp LD-B4 failed for some unknown reason.
Wow… Do I just tape it to the MOSFET?? Sounds risky. I thought about using 1mm silicone sheets on the driver side of a thick circular copper disk and insert silicone cubes on the shelf side to add some pressure as the driver is pressed down by the retaining ring.
Yeah I have some… I will then fill the cavity between the shelf and driver with silicone cubes to add pressure and that little bit extra heat conductivity.
Mosfet resistance is irrelevant in case when linear driver operates in linear mode, in that case power dissipation in mosfet is (V_batt - V_led)*I_led.
So switching to other mosfet won't change a thing. Improving thermal path between mosfet top side and pill does help a lot, but it's not easy to make very good thermal path for deep pills/driver cavities. Example how to do it is S2+ thermal kit:
Interesting results. I always thought dedoming this shifts the DUV higher which is the opposite of what you got. I wonder why the dedomed SST-40 NW in the Nightwatch NI40 is so horribly green +0.02x.
I might slice my FT03 SST-40 NW since there are now replacement LEDs available. I’ve never attempted a complete de-dome though and dont really want to get into doing that myself.
Have any one successfully dedomed SST40, Not slicing, i want to dedome it because i got a very cool white sst40 and i want it to shift color plus the throw
I just got 10 more SST-40 from KaiDomain. Do you want me to try one for you? What methods of de-dome do you have at your disposal? I would want to do what you could replicate, or it wouldn’t be much use to you. :innocent:
EDIT: Actually, just realized, I have some dead ones I burnt up. I’ll try those first!
Nope dedoming these is tricky i think heat might work best. I killed 2 in petrol trying to dedome them. One worked with heat then got killed by a reflector sliding.
I just had one dedome its self now lol the silicone burnt up months after a sliced it. I don’t think its the LED fault it was out of the light for ages i just put the sliced SST40 back in my FT03 last night. Could of had dirt on it from storage as i had no issues with it till now and i used it sliced for over a few weeks. I had a XHP50.2 in my FT03 for the past few months.
Luckily i noticed the smoke and turned the light of i cleaned the dome with some alcohol and it seems to work still.
So I got my 5000K SST-40 LED’s recently… DD bin from Kaidomain and DA bin from Convoy. At low current the DD is a lot greener than the DA from Convoy. At medium current the DD is yellow and DA more white. At high currents the DD is white, where the DA almost has this slight magenta tint to it… I then went ahead and put a DA in my S2R Baton II with a beaded optic. And I can live with it, seriously. I will actually use this light now. And I have recently used my FW3A 219B SW40…. Obviously the color rendering is not good. But it’s an acceptable tint compared to any other SST-40 or XM-L2 in any of my Olights. I’m gonna order some more!
No idea. I think people only came to that conclusion cause of the macro photos of the LED make it clear it wasn’t sliced and diced like some of the Kaidomain ones or otherwise.