[Brandon Matsumoto]

My twinstar 300s gets super hot to the touch after running for 5+ hours. I just want to make sure this is normal, it would make sense given the output and thinness.

 

[jeffkrol]

My twinstar 300s gets super hot to the touch after running for 5+ hours. I just want to make sure this is normal, it would make sense given the output and thinness.

First is it in "free air" or in some sort of hood?
Second define "hot". Heatsinks at about 110F start to feel "hot", at least to me.
120F feels scorching which seems right.
It isn't ideal but up to about 120f for the leds "should" be fine.
You really need to measure it. Good thing is the heat sink is def. working well.

Google didn't come up with any complaints..

https://ewh.ieee.org/r4/chicago/pstc/content/Accessible-hot-surfaces-and-burn-hazards.pdf

I really don't like the "old school way" of measuring it..
120 F is the “safe” max temperature for human contact established by several regulating agencies around the world (UL, ISO, etc..)

Many years ago.. just out of school.. a electrician told me that “10 finger seconds was roughly equal to 140-145 F … the max safe operating temp of most industrial electric motor installations. Finger seconds? – just how long you could hold your finger tip to surface without pulling away (typ.. max pain threshold) … and without an actual burn occurring. With some personal experimenting.. I think he was correct.

https://www.edn.com/how-hot-is-too-hot-to-touch/

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