I was curious about the relationship between the size of the heatsink and the brightness of the flashlight and the temperature.
So I added a heatsink to the flashlight.
The right side is the basic product, and the left side is the modified product with heat sink added.
After modification, temperature and brightness tests were conducted in the same turbo mode.
Results were less than expected.
Although the area of the heat sink was tripled, there was little difference in temperature and brightness.
Temperature: increase at the same rate up to 45 degrees Celsius
(Small heatsink: up to 49 degrees)
(Large heat sink: up to 47 degrees)
Brightness: All the same (feeling)
The maximum temperature only differs by about 2 degrees. As for the brightness, I compared the lights side by side, but I didn’t notice a difference at all. The rate of decrease in brightness with temperature is also about the same. Why is the difference so small despite a 200% increase in heatsink area?
Bummer. I really wish some genius would make a breakthrough in heat management on a scale and level of simplicity that could be useful for small lights. It would change the whole game for us.
Thank you for posting the experiment! You taught me something.
I guess the limiting factor is the heat transfer inside the flashlight and the capacity of the surrounding substance (air, water). A while ago I’ve read somewhere about the effect of fins and the result was that you need a lot of them. Look at CPU coolers, hundreds of thin and large plates with enormous airflow.
Someone calculated the effect of fins on flashlights in a simulation and came to the conclusion that they don’t change the thermal properties of a flashlight.
Useless “experiment” and info. You just measured host temp of two no name lights . What is output power ? Maybe they have a holes under led and so on…
Yeh, I was also going to say this experiment is a little bit lackluster as well.
Direct thermal path stars do more for cooling the led than anything else.
Having said that, after the host is saturated with heat, when it comes to heat emission - airflow is king. If you’re walking outside with the light great! If you have it tail standing under the sink BOOO! …and according to kiriba-ru for passive cooling, the fins need 4mm space between the fins to be of any use (allow for natural convection).
200% increase in heat sink area would mean a flashlight twice as big. Adding a cooper piece inside the flashlight won’t necessarily improve heat performance. It may get worse, in fact.
To “add” heat sink you need to add mass. You can disperse what you sinked with fins but they have to be in addition to the mass.
So to truly conduct your experiment you could have doubled the length of aluminum behind the emitter AND widened it with cooling fins. Still, in a C8 sized light it will be difficult for air to flow between the fins and wick heat from the sink.
Yes, I frankenstein lights of all sizes, but without fail heat is the biggest problem.
The saving grace for most handheld flashlights is Turbo mode… use the modes up through high but Turbo is a short term emergency type level.
You are right. I turned on the fan and blew the wind at the flashlight. When measured again after 2 minutes, the temperature difference was close to 5 degrees. More detailed experiments are needed.
you’re right. I’ve experimented with a light standing still on a desk and it doesn’t have airflow. After blowing with a fan for 2 minutes, the temperature was tested again. The temperature difference was more than 5 degrees Celsius. In a real environment where you move with a flashlight and get winded, it will make a big difference.
