What causes all of this heat?

[Busse]

I use my Surefire Kroma K2 alot, usually at least a set of battaries per day. After a short time (15-25 mins) the body gets super hot. I find myself trading hands alot with it because it gets so hot.

My question is... is all of the heat from the light itself or just the over all system working to create light? I dont really know how a flashlight works so hopefully someone can explain.

 

[nerdgineer]

mostly from the light itself, which is inefficient and creates heat as a waste product of making light. Some also from inefficiencies in the circuitry here and there.

PS. It's not necessarily a sign of a bad design. There is no perfect efficiency, in anything...

 

[BB]

If the batteries are lasting you ~1 hour 15 minutes (main beam on high--from FlashligtReviews.com), then the heating is probably to be expected--both from the "light engine" and the batteries themselves (that is a lot of power to drain in a short amount of time).

If you are getting heating when running the other LEDs--then probably something is not right (batteries should last 20 hours or more--depending on light level used).

-Bill

 

[Busse]

Its only from the high beam for around an hour and twenty mins.

 

[jbosman1013]

sounds like you need a new flashlight

 

[Empath]

With incandescents, the heat is deliberately created, since the heat is what makes the light. With the LED, the heat is unwanted, but is a by-product and a manifestations of the inefficiencies.

Beyond being unwanted as a manifestation of inefficiency, it's also unwanted because it's damaging to the LED. The heat you're feeling is a demonstration of how effective the heat is being diverted away from the LED.

 

[Busse]

sounds like you need a new flashlight

Hows that? This 300 dollar flashlight works great it just burns my hand :sick2:

 

[jbosman1013]

just saying you might want to look into a light with more runtime like a fenix

 

[BB]

From LED Museum Kroma review:

[FONT=Verdana, Arial Black][FONT=Verdana, Arial][/FONT][/FONT]Approximately one hour into the test, the bezel temperature was measured at 109°F (42.8°C).

I used a noncontact IR thermometer for this measurement, so I had zero chance of bumping something and queering the test.

Ambient temperature in the testing area at this time was 80°F (26.7°C).[FONT=Verdana, Arial Black][FONT=Verdana, Arial][/FONT][/FONT]

Sounds similar to your experience (although, possibly not as hot as you are feeling).

Really sounds like the nature of this beast. (I am not a SureFire person--so take this with a grain of salt).

-Bill

 

[ledprof]

As the other members said, heat is an unwanted output of the LED systems. However, if your only choice is passive cooling (no forced convection, no liquid cycling cooling etc), there is only one solution for that problem: increase the surface area. Probably there is 3W or more heat is generated in a handful area, plus it is difficult to remove heat while you are holding. it may be an expensive device but it is for sure there is a design problem with thermal part of the flashlight.

 

[wintermute]

With incandescents, the heat is deliberately created, since the heat is what makes the light. With the LED, the heat is unwanted, but is a by-product and a manifestations of the inefficiencies.

Beyond being unwanted as a manifestation of inefficiency, it's also unwanted because it's damaging to the LED. The heat you're feeling is a demonstration of how effective the heat is being diverted away from the LED.

How eloquently put.