HighlanderNorth
Flashlight Enthusiast
There seem to be 2 schools of thought when it comes to figuring out whether a certain LED flashlight is doing a good job of keeping the internals of the light cool, and dissipating heat. I'll call them theory #1 and #2. Theory number #1 seems to be a popular one. Theory #1's idea is that if a light is getting and staying HOT, then that proves that the flashlight's design is good, and the light is removing heat away from the internals like it should be doing, and the heat itself is proof that it is working properly. I agree with this about 20%.
Theory #2 is that if a light is getting and staying HOT, that means the opposite of Theory #1. If the light is getting and staying HOT, then it isnt doing its job of removing heat away from the internals and dissipating it like it should be. I agree with this theory 80%. Its not so cut and dry either way.
Most lights are made of aluminum, and I learned early on at my 1st job at a machine shop that aluminum does a GREAT job of dissipating heat. It does a MUCH better job of it then steel, titanium, magnesium, etc. Heat flows through and out of it quickly, which is probably one of, if not the biggest reasons it is used for LED flashlights. But aluminum alone isnt always enough, you need a good heat sink, but you also need as much aluminum surface area as possible. Thats why manufacturers machine cooling fins into their higher lumen lights, to increase surface area, so that more heat is able to dissipate out and away from the light.
Here's a parallel analogy. Lets say you built up a '69 Chevelle with a big block, high horsepower V-8, but you installed an aluminum radiator from a 600cc motorcycle, instead of the large aluminum aftermarket high performance car radiator you should have installed. That little radiator IS made of aluminum, and it will dissipate SOME heat, but its not large enough, and doesnt have enough surface area to handle the large amount of heat, so the engine will overheat.
Well, according to theory #1^, it's a good thing thats its so hot, because that shows its keeping heat away from the internals(engine in this case). Well, thats not true here. Its NOT dissipating heat fast enough, and the high heat is proof of it....
I used that analogy^ to explain the same basic problem with some of the smaller, but high lumen lights on the market now, like the ZL SC600, or the Jetbeam PA-10 with a 14500 Li Ion battery on turbo. These lights are small, have small diameter heads, and they dont have cooling fins, so there is a lack of surface area to adequately extract and dissipate enough heat to keep the internals cool when running at the highest setting. But if you take another larger light that runs at 650-750 lumens, and it has a larger head with cooling fins, it will do a better job of keeping the internals cooler. The larger light with the cooling fins WONT get as hot as the ZL SC600 or the JB PA-10. But since the larger lights arent getting as hot, does that mean the larger lights arent doing as as good a job at dissipating heat? No.... They are doing a better job, which is proven by the fact that they ARE NOT as hot as the smaller lights.
I said I agreed with theory #1 20%. Well, to some degree, if you can feel heat in the head of the light, that does mean its pulling heat away from the internals, but only to a certain point. If it gets really hot, and keeps getting hotter, then its NOT doing a good job, as its not properly dissipating that heat.
I just compared my ET G25C2 and SWM T20CS on turbo recently, as I was trying to lower the voltage of the 2 18650's I was using in the 2 lights so I could safely store those 2 batteries. I turned both on turbo and left them on my nightstand. The T20CS was getting hot quickly, whereas the G25C2 was slower. The SWM after 25 minutes was probably 140 degrees F, and still getting hotter minute by minute, whereas the ET was only about 95 degrees F after 25 minutes, and wasnt getting any hotter. I removed the battery tubes and felt deep inside to see which one was hotter, and clearly the SWM was the hotter one. The ET was only warm. They both have similar size heads, but the ET has larger cooling fins, and a thicker body(more aluminum).
Whats your opinion on this subject?
Theory #2 is that if a light is getting and staying HOT, that means the opposite of Theory #1. If the light is getting and staying HOT, then it isnt doing its job of removing heat away from the internals and dissipating it like it should be. I agree with this theory 80%. Its not so cut and dry either way.
Most lights are made of aluminum, and I learned early on at my 1st job at a machine shop that aluminum does a GREAT job of dissipating heat. It does a MUCH better job of it then steel, titanium, magnesium, etc. Heat flows through and out of it quickly, which is probably one of, if not the biggest reasons it is used for LED flashlights. But aluminum alone isnt always enough, you need a good heat sink, but you also need as much aluminum surface area as possible. Thats why manufacturers machine cooling fins into their higher lumen lights, to increase surface area, so that more heat is able to dissipate out and away from the light.
Here's a parallel analogy. Lets say you built up a '69 Chevelle with a big block, high horsepower V-8, but you installed an aluminum radiator from a 600cc motorcycle, instead of the large aluminum aftermarket high performance car radiator you should have installed. That little radiator IS made of aluminum, and it will dissipate SOME heat, but its not large enough, and doesnt have enough surface area to handle the large amount of heat, so the engine will overheat.
Well, according to theory #1^, it's a good thing thats its so hot, because that shows its keeping heat away from the internals(engine in this case). Well, thats not true here. Its NOT dissipating heat fast enough, and the high heat is proof of it....
I used that analogy^ to explain the same basic problem with some of the smaller, but high lumen lights on the market now, like the ZL SC600, or the Jetbeam PA-10 with a 14500 Li Ion battery on turbo. These lights are small, have small diameter heads, and they dont have cooling fins, so there is a lack of surface area to adequately extract and dissipate enough heat to keep the internals cool when running at the highest setting. But if you take another larger light that runs at 650-750 lumens, and it has a larger head with cooling fins, it will do a better job of keeping the internals cooler. The larger light with the cooling fins WONT get as hot as the ZL SC600 or the JB PA-10. But since the larger lights arent getting as hot, does that mean the larger lights arent doing as as good a job at dissipating heat? No.... They are doing a better job, which is proven by the fact that they ARE NOT as hot as the smaller lights.
I said I agreed with theory #1 20%. Well, to some degree, if you can feel heat in the head of the light, that does mean its pulling heat away from the internals, but only to a certain point. If it gets really hot, and keeps getting hotter, then its NOT doing a good job, as its not properly dissipating that heat.
I just compared my ET G25C2 and SWM T20CS on turbo recently, as I was trying to lower the voltage of the 2 18650's I was using in the 2 lights so I could safely store those 2 batteries. I turned both on turbo and left them on my nightstand. The T20CS was getting hot quickly, whereas the G25C2 was slower. The SWM after 25 minutes was probably 140 degrees F, and still getting hotter minute by minute, whereas the ET was only about 95 degrees F after 25 minutes, and wasnt getting any hotter. I removed the battery tubes and felt deep inside to see which one was hotter, and clearly the SWM was the hotter one. The ET was only warm. They both have similar size heads, but the ET has larger cooling fins, and a thicker body(more aluminum).
Whats your opinion on this subject?
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