Around 155ºF. Pretty much have to turn it off and put it on a heat sink at that point. (~68 - 70 C)
50c/55c (120F-130F) is a good temp for me.
I bought more shockli 26650 from rmm last night. Thanks.
My two “early edition” D4S’s. 
Making 5685 lumens and 5171 lumens, respectively. Both from Sony VTC5A cells.
For clarification, both of these are made with the MCPCB and Optic that Hank designed/chose for use with the Emisar D4S. Both of these are running Bistro from an FET+1 driver.
Thought I would drop in and share this holster solution for the D4s.
I had an old Olight M21 Warrior holster and it ain`t too bad re-purposed for the D4s.
Depends how long you hold it. Slow burn is a thing. And it’s insidious as you don’t feel it until long after it’s done. There are people who got burns to their legs from using car seat heaters in warm weather. I once burned myself lightly (no damage but skin was sensitive) by holding a warm soup bowl that never actually felt painfully hot. I just held it for a fairly long time.
Okay, in that case it stabilized at a higher output than I would expect. With no cooling or heat sinking, I figured it would settle lower.
During tests I generally have a fan blowing at the light, from 1m away, at the fan’s lowest speed. I’m not sure if this is a good way to simulate the heat-sinking of a hand, but it does at least make a pretty measurable difference compared to stale air. My thermal testing is pretty imprecise though.
It is kinda useful when they do. Otherwise I think they are called flash cubes. (If you know what they are you are really old…)
Know what they are? I probably have some in a desk drawer somewhere. 
I just moved for the second time in 7 years, so I am sure there are none in the box of photography stuff I have hidden in the garage. LOL
This may have already been discussed earlier. But is it possible to mod the light to a different aux led? I don’t love the blue. Would much rather green or even red. Is this doable?
Here’s what the AUX LEDs look like on the meter. This is with the optics and a slight Zircon minus green on top so on the CIE graph the LEDs would actually sit just a bit higher.
Regarding the step-down rate. Keep in mind that if you don’t start on turbo, you should have longer before the light steps down from your initial output levels.
The floor is N clicks, to set it to level N, or 0 clicks to leave the current value unchanged.
The ceiling is 151 - N clicks, so 1 click for 150, 11 clicks for 140, 21 clicks for 130, etc… or 0 to leave the current value unchanged.
The ceiling is basically off by one to make it possible to set the ceiling to turbo.
Are there any good beamshot pictures for this yet?
Do I see what the die/phosfor of the ice-blue aux leds produce or is some of it also the main leds excited by the blue aux leds?
There are 150 levels.
When setting the ceiling, 1 click sets it to 150. 2 clicks set it to 149. 3 clicks for 148. And so on.
I’m still not sure I understand the question, but this is how I recommend configuring that:
- Look at a thermometer. Mine says 22 C, so we’ll use this value.
- Go to thermal config mode.
- Calibrate the sensor: At the first “buzz”, click 22 times to tell the light it is now 22 C.
- Wait until the light shuts itself off. If you haven’t changed the value already, this should leave the temperature limit at the default value of 45 C. Otherwise, you could click 15 times at the second “buzz” to set the limit to 45 C. (limit = 30 C plus N clicks)
I received my D4S from Hank today. XPL hi equals on happy fat guy in a wheelchair. Civil twilight at 8:24 pm EST. Toykeeper and all involved THANK YOU VERY MUCH!!! All caps very intentional
So, is the XML HI worth the $18 upgrade and is that how you get the 4K lumen?
I’m not worried about throw. There is nowhere in my yard that is further than roughly 500 feet before the treeline.
If I need more throw than that, I’ll grab the D1S or the BLF GT.
I definitely think so. Again THANKS to all who developed this!!!