*Edit:
You are at the Budget Light/CandlePower Forums Convention in Alaska, held during January when it always is dark. Your flashlight is as bright as anyone’s, but there is some dude or dudette whose light stays bright way longer than yours. You can say a liquid cooled light is ridiculous, you can say anything you want. All the other dude/dudette has to do is keep pumping batteries into their light without saying a word. I guess you could switch to a replica of your brightest light. So which is more ridiculous, the liquid-cooled light or the set of 4 lights your need to keep pace with the power output of the one that is liquid cooled?*
Oh, I don’t know what the #1 problem with high-powered flashlights is, but to me, the biggest problem is the limit on runtime at max output imposed by heat that cannot be pulled away fast enough. I don’t have a shop or the experiences to put together a nice implementation of a water-cooled flashlight, but I bet Lumintop could do it (mentioning Lumintop because I can see their work on the BLF GT). I bet there are a lot of manufacturers that could do it. I am thinking it is one of the most obvious projects for BFL to make happen.
I also figure I am completely wrong, because no one else is bringing this up.
I’d ask for people to post their interest in a water-cooled 30,000+ lumen light, but I am not connected or qualified to make a project like that happen.
Why aren’t we going for a water cooled crazy light that can have long run times at high output?
For current available high power lights. The MT09R seems to do very well in maintaining max output. However, there’s debates going on about how the thermal regulation works or if it even works. For active cooling, I’m really looking forward to the Astrolux MF05 and Acebeam X70. Acebeam replied to my email saying that there will be NW 5000k version of the X70 this time too!
bad news for you: you lost the bet
for example, look at acebeam x80, a soda can light, now how can you add pump, fan, water to such a small light, even if you can, where is the rad to cooldown water
another problem is durable, more components, more things to broke, especiall things with water
the problem is not about water or air cooling, but about the size and led technology, no matter what you add to acebeam x80, it can’t run on max turbo for 5 minutes
the bigger the light, the longer it can run on turbo
Personally, I use flashlights every day in my occupation and I could care less if there is a 30,000 plus lumen water cooled light and don’t consider this to be in the top ten flashlight problems . If you really feel there is a demand for this type of light, I’d suggest you design one and put it on the market.
Water is not cooler. It just transfers heat to external heatsink. Which usually have to be equipped with fan.
Both new elements (water pump and fan) were widely tested with big stationary lights and both were not able to work long in real life. Flashlight working conditions are ways more hard. Shockproof waterproof fan can cost more than Q8.
30000+ lumens=300+W. Four 30q cells=38Wh. (38/300)×60=7.6 minutes.
You could make a water-cooled light where water actually IS the cooler. :sunglasses:
Think of those battery powered fans with water bottles with pump attached. You could build a flashlight with one of those installed. Fill the bottle up with water, then as you run your flashlight, give the pump a squeeze to spray water aerosol all over your heatsink. As the water evaporates it should pull heat out of the heatsink. Repeat as necessary (or until you run out of water).
“The first trustworthy lighting device was the flashlight, invented about 1896. Portable electric lights were called ”flash lights” since they would not give a long steady stream of light.”
Not a problem for me… we use the highest mode for like 2 minutes to check for the large surrounding area… then we step down to medium or 70% mode. Runtime ? No problem. 8x 18650 will do the job.
Big head, big tailcap with fins and heatpipes integrated to the tube to transfer heat from head to tail. On big lights like L6 the tailcap side always stay cool. Let it do the heat shredding too.
A water-cooled light seems way too impractical. It would add a ton of weight and many (comparably) fragile parts that wouldn’t survive a good drop (pump and fan especially).
I think a good solution to the heat problem is to use heat pipes, as Zozz already mentioned. You can get rid of a lot of heat if you transfer it in a spot that you aren’t touching. A well sized heat pipe going straight down the center of a soda-can light (in between the batteries) could lead to a big fin array inside or on the tailcap where your hands won’t be holding it. This could also reduce the outer temperature of the light at a given power level, as you could isolate the shell from the driver/LEDs instead of thermally linking them. If you really want to shed even more heat, a fan inside the tailcap blowing on the fins would help and I guess it would be easy enough to replace there if it broken during a drop.
Watercooling in a flashlight is pretty useless because
water just transfers heat, it does not cool, so you would still need a radiator
a pump not only takes up room but also adds an additional point of failure
watercooling also increases the risk of failure due to a leak
the size of a flashlight is fairly limited so there really isn’t a need to carry heat far away, which is the main point of watercooling
another main point of watercooling is being able to use much larger radiators than a heatsink that can be stuck on a CPU. Again the size of the flashlight is a limitation unless you want to carry around an external radiator box with tubing running to your flashlight
With size being the limitation you can get equal or better performance than watercooling by using a large heatsink or heatsink+fan.
There are lights that can do several thousand lumens without dropping down due to a larger heatsink.
It is definitely possible to get 30k+ lumens using a COB LED and a large CPU heatsink with fan.
The only problem is that few people would want to spend $500+ on a large flashlight that only gets 5 minutes of total runtime due to power draw.
Even if you could design a flashlight that can keep cool at that kind of power, how about runtime?
For 30,000+ lumen you could use 4 XHP-70-2 at 12.5A each (8000lmn x 4) ~6.85v.
Using IMR35000mah cells in 2s5p config you would get 15 minute runtime, probably less depends on voltage drop.
Sure you could use more cells, but I would call 4s5p a portable light with a backpack power supply, not a flashlight.
Cheers David
Edit :- for those that want to work out the cooling required that is 342.5w
. . . . vvvv
I think that’s a neat idea. Based just on the enthalpy of evaporation, 100mL of water has about 3800 W*min of cooling capacity. So it could remove, for example, 300W of heat for 12.5 min, or 50W for 76 min. Of course you would need forced air to effectively evaporate the water.
To boil water the LED would need to be much higher than 100*C which is horrible.
It is possible to do without boiling the water, by spraying it into mist and cooling it with air.
Again, not a compact solution for a flashlight.
