Not sure if this has been asked before, when one uses a linear driver to drive the 12V XHP-35 emitter, wouldn’t the 4S batteries kill the XHP-35 immediately due to the extra 4V?
Yes I did read your test graph (thank you for that!), and yes I do realize that the Vf of the LED would increase as the current increase, but how about when the LED is in low mode (i.e. 0.1A or lower) while the Vf is still around 12V only?
Anyone has tried to mod the Acebeam K50 with this XHP 35 emitter? The K50 does look like a good candidate for it as it has 4S batteries configuration and comes with a big reflector.
3000 lumens, possibly 250+kcd, and that really sounds like a HID flashlight.
The only change I had to make from the 2S board was to upgrade my 10uf cap from a 10v to a 16V. All my other components were already 16V or more.
Initially I ordered the 16v caps from Richard, but since you asked about the other components I updated my bom with a 16v cap. Here is the list. I have not tried the 16v cap in this bom yet, but it has exactly the values as the ones I got from RMM so it should work.
Its been my experience that XHP-70s on a 12V board can be driven directly on about any 4 cells. The XHP-35 I have found in some cases you need to dial the PWM back just a hair or use a small resistor.
In some setups like when I used 4 x 26650s I changed the PWM value from 255 to like 225 to take the current down a hair. With perfect heat sinking 2.5A is really the max for this emitter.
IIRC using 4x 18350s I think I ran it wide open at 255. The lower powered cell in combination with the tail spring/switch was enough to keep the current where it was need.
All of the above info assumes direct bond thermal path ( sinkpad/noctigon) and good thermal path etc from there.