How hot is too hot

upsetter.

Active Member
Wondering how best to check temperature of cobs? Mine are running on passive sinks. I have an infrared thermometer, but heard you can't get good readings from bare aluminum. How about anodized pin sinks... where do I check and what is the danger zone? Running citis if it matters. Just finished the build and would like to avoid melting cobs if I made any mistakes along the way.
 
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sanjuan

Well-Known Member
I'm sure it's not recommended but I scan the COB from a couple inches away and grab the max reading. I installed a thermocouple on one luminaire and results were similar.

I want things below 85C; I'm running CBX3590's.
 

upsetter.

Active Member
measure voltage at startup and steady state

less than 3% voltage drop = no sweat
3-5% voltage drop = check your datasheet or manufacturer-provided product simulator

in general if you can put your hand on the heatsink no worries
Awesome. I was worried about messing up thermal paste and having poor transfer. Ill checl em out tonight. Thanks!
 

Abiqua

Well-Known Member
A little context helps too...for instance, i personally would never run a 80C Tc but that is perfectly acceptable from the manufacturer.

imho 50c is too high as well, but more an enough compromise off the manufactures max Tc rating.....
 

sanjuan

Well-Known Member
I use the pain test. I grab the heatsink with my uncalloused fingers. If it hurts before a second has elapsed, things are too hot. (Of course, if the COB is incorrectly seated the heat will not be transferred to the sink.)
 

Organic Miner

Well-Known Member
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