As mentioned above, there is no practical way to deal with 4000 lumens in such a small light - unless it is some kind of water cooled frankenlight project. It is not meant to be used above 600 lumen for any extended period of time. But it’s nice to have such power just a double click away… be it for a few seconds.
The coming 26650 D4S will have a little more mass, but not nearly enough to sustain turbo very long either - especially with so few and short fins.
Turn it on, put it in the Freezer. Problem solved … 
Don’t think its possible, sorry.
Maybe wear an oven glove.
Peltier cooler?
How about a hydration bladder filled with ice water?
Put it in a backpack, run the tube down your shirt sleeve, and leave it on a slow drip right onto the D4 head.
Would totally work for night hiking. Kinda messy for indoor use. 
OK IAMLUCKY.
Ammendments.
Those torches “on max” are for wow factor.
My A41 I use a lot round house.garden and walking. On 4 or 5 from 7 settings.
Imalent DN35 the same (450 fine, 1500 for scanning. NEVER used the 2200).
Outside walks I use along with a XM-L2 headlight .
Serious light. It’s the BLF L6 for my requirements. (Can’t SEE any further chuckle)
The max on those tiny torches is. realistically a novelty though,
S2 or late model C8 do 90% of what’s required. Or more exxy ones.
No argument from me on the second part. I’ll go even further. An S2 will cover 99% of my actual use, and 100% of my flashlight requirements.
But I’ve found that, even though I also initially scoffed at such briefly sustainable outputs, I do from time to time appreciate having the feature.
As a result, I no longer think of it as a novelty.
I haven’t checked out the Imalent DN35. I’ll have to look it up.
Any tube light with more than 3A of drain can’t realistically be used for long period.
It’s physics. There’s nothing more to say that was not discussed for years here.
Add some mass to make the Turbo timer a bit longer…
Add some fins? Nope, that doesn’t make a huge difference.
Add some magic cooling fluid ? Well you’ve got to cool that fluid with a radiator and some air flow now…
Peltier ? Even hardkor gamerz don’t use them…
Add some copper ? Now your light weights more than you like and isn’t cooler anyway…
1000 lumens in a tube light for 1h is already an impressive performance IMHO 
3000 lumens is what an Olight SR mini II can sustain for 1h, but again it gets scorching hot and weights 300g… Not really a pocket light :person_facepalming:
I don’t use my D4 as much as I would like, I might try to flash Anduril so I’m not tempted to use the turbo mode
Most realistical and doable thing from an industrial point of view is maybe design the flashlight body with a slot to carry a tiny fan somewhere. With a dust air filter, it would be usable.
Cheers :-)
How about not using a high amp battery
I’ve learned to not turn it all the way up (yes it is possible, just resist the temptation)
Wait until winter. Seriously. Using pocket-rockets outside in winter is fun; no step-downs needed.
The other thing you can try, if you can’t wait, is use it as a bicycle light. I find that my 2300 lumen Zebralight will maintain max output for several minutes if I’m riding (and indefinitely if it’s a cool night). The D4 is brighter and hotter, so won’t last as long, but you might get a couple of minutes out of it?
Speak for yourself. Winter lasts a few weeks here, and it’ll get below freezing only a couple times during winter. Hi from Florida!
Highly recommended. :+1:
Unofficial Warning Label: Use responsibly, the state of Crowdyfornia has determined that this is not a toy for young children ;-), can cause burns and fires if left on turbo unattended. There will be an initiative on the next ballot to ban Pocket Rockets, buy now, before the Ban!
How do you that?
Posted here, by ToyKeeper, about thermal configuration mode: TK's Emisar D4 review !
When you feel you have reached the temperature you can hold, you release the button, the it will blink N+N time, in my case 5+2, indicating 52º. If you go up or down it will be the same way. Hope it helps :+1:
thanks a lot
Freeze it into a block of ice before use.
You’ll want to de-gas the water somehow, for optical clarity.