I don’t think building lights with this power level that can run continuous full power is ridiculous at all, in fact that is exactly what I like to do with things like the Storm of Ra. But if you are putting an LED like this in a host without active cooling you can always limit the current down a bit (that is I suppose after you figure out how the hell to drive it) and you will only sacrifice a small amount of lumens for a larger reduction in heat, there is no need to run an LED flat out into the range of diminishing returns if you can’t cool it at that level.
Also I think a water cooler would have no problem cooling this, at least if you are aiming for reasonable temperatures and not room temperature, you need some temp gradient in there. I was just the other day running two XHP70.2 flat out on a 240mm water cooler and it wasn’t even trying, I didn’t run it for very long since I wasn’t testing for that but from previous runs with water coolers they just don’t seem to care if you put several hundred watts into them.
This wattage would increase the junction temperature to 60C within a few seconds, maybe even less than one.
You 100% need active cooling to run this anywhere near full power.
I think maybe 1/4 of full power, like 50W, could run at a reasonable temp.
It’s certainly on my short list for future designs, although probably with even more extreme cooling and the cost of the LED, better cooling and the probably massive buck converter to drive it will significantly increase the price over the storm so will probably be a totally different light. But with these numbers my rough theoretical calculations for optical systems to pair it with are looking like it would have some serious throw, and I like serious throw.
Anyone here buy one of these yet? I was really close to buying one to mod something like the haikelite MT02, but didn’t pull the trigger.
In the meantime I’m planning mods using the dedomed SST-40. Three of these driven at 8A each will get you ~6300 emitter lumens and ~185-190 cd/mm^2, which is great. But then you must have multiple reflectors which adds difficulty to the mod and your beam intensity for a given head diameter will be reduced by the reflectors’ fill factor.
But only with their fans working at full power. CPUs almost never run at full power. Most PCs are only quiet when the CPU isn’t doing much. A quiet CPU and fan combo will be rather large for a flashlight.
Well as The_Driver pointed out in his first post it’s a lot closer to 200W but it depends a lot on the CPU cooler, a large and powerful one, designed for CPU use to be able to move heat very efficient to keep a lower temperature gradient and a cool CPU can probably move way more heat with a higher temperature gradient (running an LED close to what we normally run them) assuming you don’t saturate the heatpipes. Which I don’t actually know at what point most heat pipes will saturate (the point at which the cold side is hot enough to not condense the vapor) but I bet that would a massive amount of heat to do that given some of these coolers with 6+ heat pipes.
The size and noise issue concerns I’m in the camp they are not an issue for the right light, if you use a midsize heatsink that will need full turbo fan speed on max LED power is that really that bad? I mean a little noise to make it sound powerful and match it’s powerful output may be cool. If you want a quiet and tranquil light experience, waiving around a massive column of light with tons of lumens and Kcd is not that. On lower modes the fan will be quiet and you’ll have a nice tame light.
You should keep in mind, that a CPU runs a lot cooler than an LED
CPU core temp at 100% load stress test with a good cooler 45dC at 20dC ambient temp. DeltaT 25K
LED MCPCB 80-90dC deltaT 60-70K
So a good 100W CPU cooler can can cool a 250W LED at the same noise
First CPU cooler test I looked at was 49dC with a 4GHz overclocked I7530K
That is a 140W CPU, likely overclocked at 200W power, run with a programm that makes it run at 100% all cores
Noticeable is that best water cooling system was only 47dC 2K better
I have no idea where you’re getting that info from, because a high end CPU with a “good cooler” runs at 60-70C, while a typical heatsink can get up to 80C.
If you have an i9 or a highly overclocked i7, you need a very good cooler (at least 280 or 360mm rad) or else you will be hitting 90-100C and throttling.
The only way to get 45C on a CPU is if you’re using a custom loop with a massive amount of radiators, or phase change.
I think the tricky part here is CPUs can have wildly different power use based on conditions. No modern CPU is going to run full tilt all the time and depending how you test the CPU you’ll get very different results. The heat generated from a hard core stress test vs any normal conditions maxing (gaming, video editing, etc) the CPU is quite a bit different, stress tests are designed to do exactly that, stress the CPU, often to levels only the stress test and raw computation conditions can achieve. Also I wonder how out comparison stacks up if you consider how much power in vs heat out compared in an LED vs CPU. The LED is designed of course to put out as much energy in light and while not super efficient the only power out from a CPU is back into the other components which seems fairly little comparably.
I’m talking about normal workloads that use the full CPU.
Video rendering is one of them.
It will pin any CPU at 100%.
Stress tests like prim95 will obviously make temps even higher.
But no, there is no mid/high end CPU that will run at 45 degrees under load with any heatsink or AIO.
PS - a CPU turns 100% of the power it consumes into heat.
Yeah I agree 45 is way cooler than you’re going to get at load, we may be off in the weeds here a little here but I think with a decent cooler, the higher temperature differential we can use with LEDs (many are binned at 85C after all) and the say 10-15% (this is just a guess) less heat out over wattage in from light out the front and thermal radiation I think we can cool the 200 or so watts from this LED just fine. Too much more than that we might get a little toasty, if you want a super cool LED you’re going to need something more extreme but 200W at reasonable heat levels I think we can do. And from the pictures in sma’s test his heatsink looked OK but probably less capable than other options, so maybe we could get even a little more than his numbers. I’m quite excited!
The heatsink SMA used is horrible, one of the cheapest stock CPU heatsinks.
The MCPCB was also not contacting fully the copper core, and the thermal paste he used looked very bad.
Stick the CFT90 on an NH-D15 or a 280mm AIO and you should be able to get a peak at about 50-60A or even more.
Liquid metal TIM helps too
Well since I’m really only looking for DC-DC I’m not sure, just glancing at their DC-DC converters it seems they maybe can be set for constant current? But the lowest voltage output is only listed at 4.5V, they seem to be more for fixed voltage outputs…
Yeah, I haven’t found any constant current power supplies that can do 50-60A, but if you read the speds it does say on the meanwell PSUs that they limit current at their rated maximum (so 50A or 60A) so maybe it would work even though you can only manually reduce the voltage to 4.5v.
The first two I linked would be great for a stationary searchlight though.
