Maximum Lumens Over Time Via Liquid Cooling of Hand-Held Lights (Flashlights)

[Enderman]

@Agro

Said a man in the process of building a water cooled flashlight.
Yes, WC makes sense for recoil as you can hardly find another way to cool the LED (well, OK, there’s another option). Otherwise, not really.

Haha yeah it’s a bit ironic.
Of course in this thread we are talking about regular tube or compact flashlights, my large searchlight is a bit of an exception

@danallen

Enderman, The reason liquid cooling systems are used for cooling CPUs instead of air-cooled is they are more powerful when space is constrained. The liquid cooling is more expensive than air cooling, but in cases where air cooling cannot do the job, liquid cooling is used. In flashlights, space is constrained. Why would that lead to liquid cooling being impractical in a flashlight but not in a computer?

Enderman, Very sensible and solid, but then you miss out on the brightest possible light. My goal is bright and long run time.

No.
Liquid cooling is used for CPUs because there is only so much mass that you can attach to the CPU mounting bracket before you risk damaging the motherboard.
Also the area for a heatsink to fit is limited due to other components around the CPU socket such as ram and GPUs.
By using liquid cooling you can move the heat dissipation area elsewhere in the case, where there is a lot more room allowing you to use multiple large radiators.
Of course this depends on the case’s radiator support.
If the case is compact, such as mitx with only one or two fan spots, there is literally 0 improvement by using liquid cooling instead of a heatsink.
The heat dissipation depends on the area only, not where the area is in relation to the heat-producing component.
Liquid cooling just allows you to move the area elsewhere, where there may be more space, allowing for better temps.

So no, liquid cooling is only better than heatsinks when you can actually have more space to place radiators.
Unless you want a giant radiator stuck to a flashlight, so you need to carry a backpack around to move the flashlight, liquid cooling isn’t really useful for flashlights.
.
.
If you want the brightest possible light and long runtime you will have to find a compromise in the middle, because LEDs have limited efficiency, so you cannot get both long runtime and tens of thousands of lumens at the same time unless you want to carry around a backpack full of batteries.

One of the lights I’m modding will be ~10k lumens and have a few hours of runtime on max, the batteries cost hundreds of dollars and weight like 15 lbs.
If you want stuff like this you have to build it yourself because no manufacturer is really building this kind of stuff yet.