OTR i3 project [was: Need advice: Thermal paste between pill and body?]

You’re right, the middle of the threads wil make good contact.
But because of tolerances there will be air gaps at the top and bottom of the threads.
I don’t know if you gain a lot, but I think it won’t hurt to apply some thermal paste.
Downside, if that hardens (cures) it will be more work to get the pill out again.
So use thermal paste that stays soft and mushy.

PS, I don’t use thermal paste but I clean the threads very thorough after removing the pill.
That way I hope radiation will compensate for part of the missing contact area.
When assembling the light I re-apply some lubricant on the (outside) threads of the tube.

Ok, Gentleman, thanks!

I’ll do it. Will measure and report back, but takes sometime until I have a proper cell.

I tried it once and it was too messy. Would not do it again personally.

If you ever have to adjust or remove the pill paste will get places you don’t want, even places where ground contact might be made. Nightmare to clean and requires a ton to “fill gaps” in something like threads. Dont bother.

I tried it Once… 6 years ago… :person_facepalming:

The 502b had a poor heat dissipation design. You might look there to find a few different ways people tried to improve it.

From some of the test on here I have seen about adding thermal paste, it seems when to much is added it doesn’t help that much.
A thin layer was tested as the best, in this situation for fill it should help but I would guess to say not alot.

Not good?

Ok :+1:

Won’t - can’t. Difficult enough w/o the paste. But I had already in mind that it likely will be a mess.

First impression of temperature regulation of Crescendo:

Will repeat with new cell.

Very rough lumen estimation: max. 900lm

I messed it up. Ordered a 1x2mm Osram since I wasn’t aware the 2mm^2 LEDs are not square :person_facepalming:

Also, it is not centered. Had no fitting gasket, and it is really difficult to do it this way.

But: It sucks 3,9 amps out of that old NL166 now and makes 51560 cd / 454 m.

Of course, the beam is full of artifacts. Looks terrible.

The result looks fine to be honest, you can black out some stuff to clean up the artifacts and call it a day. On the much larger Z821 I was not able to break 7x kcd so your result looks good on paper. I tried a 1mm2 NM1 and the result was single digit throw increase, for sure not worth it and ultimately went back to 2mm2 LED.

I’ll keep the LED :+1:

Sorry if there’s an obvious answer: Any way to switch off temperature regulation except just adjusting temperature in Crescendo (where it gets as hot as possible)?

And one remark on the performance in the wilderness ( :smiley: ): Breathtakening. Never thought a zoomie could be that impressive.

Simons 7mm gaskets fit perfectly :slight_smile:

I went to see the crescendo cheatsheet and it seems that taking it to the limit of temperature configuration is the only option :zipper_mouth_face:

I may need some of those gaskets, for the Z821 in this case :stuck_out_tongue:

I’m glad you also like this light!

I’m tempted to get that Z821 too.

It is a nice light! I’ve been carrying it (after modded) in my night walks. I also alternate with the OTR i5 (just with high mode configured and after putting a Luxeon V 4000K instead of the CW XML2 U3-1A).

BTW, can you show us a beamshot with that gasket latter, please? I am curious to see how it looks like once it seems “tighter” (between led and the metal “reflector”, or whatever it is called ) :stuck_out_tongue:
Thanks in advance :beer:

I may take pictures later, but the corona is still not as even as I would wish. No wonder, there are two threads, the retainer and imperfections of the lens as potential contributors to a tilted optical system. I’m still happy since I know I did everything I could.

I broke the o-ring between lens and bezel. The new one makes it nearly air-tight :weary: . I’m about cutting it up again.

Also, it is not perfectly in focus. The LED should be raised or the retainer lowered. Don’t think it has a great effect on brightness tho.

I applied a small amount of thermal paste.

After 60 s:

With thermal paste: 36,5 °C (initially 23 °C)
Without thermal paste: 33 °C (initially 22.3 °C)

50 °C are reached after 2’34’’ now (in temp limit adjustment mode).

Brightness [a.u.] vs. time [s]

Temperature regulation (50 °C max.) kicked in early but was off by +9 K. I couldn’t comfortably touch the light. Nearly 80% brightness for the first 100 seconds is quite good imo. The cell had more than 3.7 V left after 6 minutes.

I think this is all ok somehow. Toy is in its final state.