Max temp for electronics

[shoutingsteve]

So, a little background: I am a lighting designer for theater and events, and occasionally opera.  I bought some fixtures and got a really great price on them, but the specs didn't say they had integrated fans.  These fans are too loud for opera, and are not adjustable.  I opened one of the units up and found that the fans are just plugged into the board.  I disconnected the plug and now am using a thermometer probe to measure the temperature of the heatsinks.  The unit with e disconnected fan is about 200 F (measured after running an hour), and the  one with the active fan is about 150 F (measured after running an hour).  Is this enough for me to worry about?  How hot can  LEDs and circuit boards get before they start to be damaged?

Note: these are cheap lights off AliExpress, so I doubt they have a "safety off if overheating" feature.

[mariushm]

I may be wrong, but I think the temperature of the heatsinks on leds should be up to around 60-80c , ideally lower than 80c

 

You will want some fans to move the air... you don't want pockets of air trapped and overheating the leds. You'll get reduced life out of the leds or they'll start to flicker or die on you

[Hackentosher]

Generally ICs are good to around 100C +/- 15C, but that's at the silicon junction. If you're measuring 93C at the heatsink, the device is almost certainly 15C higher than that. In my research on LEDs, I've found that generally they are rated to 85C and burn irreparably if they go much higher, so yeah that fan is necessary. I've noticed LEDs tend to dramatically change color when they overheat, in my experience their white balance goes very cold right before they go dim and die. Honestly if you can't get nice lights, I think the right move is to ghetto water cool them, or find a bigger quieter fan. 

[shoutingsteve]

42 minutes ago, Hackentosher said:

Generally ICs are good to around 100C +/- 15C, but that's at the silicon junction. If you're measuring 93C at the heatsink, the device is almost certainly 15C higher than that. In my research on LEDs, I've found that generally they are rated to 85C and burn irreparably if they go much higher, so yeah that fan is necessary. I've noticed LEDs tend to dramatically change color when they overheat, in my experience their white balance goes very cold right before they go dim and die. Honestly if you can't get nice lights, I think the right move is to ghetto water cool them, or find a bigger quieter fan. 

Can you recommend a way for me to water cool them?

[shoutingsteve]

5 hours ago, James Evens said:

What is 200 F? What is 150 F?

Max temp. always depends. There are ICs which are build to withstands over 300 °C for years while most LEDs like it cold so wouldn't go above 70 °C if you don't know anything (cooler is better for longevity) .

 

For the power delivery it depends again. Constant current driver can easily take 100 °C while electrolyte capacitors while die very quickly if run that hot. So again 70 °C isn't ideal but would be the limit I am comfortable with as higher means even more downtime due to repairs.

 

If you can't fit a larger heatstink to the LED lamps water cool them.

Can you recommend how I could water cool them?

[Hackentosher]

14 minutes ago, shoutingsteve said:

Can you recommend a way for me to water cool them?

I'd pick a generic waterblock from here and find the cheapest rad and pump that doesn't look horrible. https://www.aliexpress.com/wholesale?trafficChannel=main&d=y&CatId=0&SearchText=waterblock&ltype=wholesale&SortType=default&page=2

 

This actually might work, but I'd probably upgrade the pump and radiator so you could cool multiple lights on the same cooling loop https://www.aliexpress.com/item/4000009594241.html?spm=a2g0o.productlist.0.0.23a9d0098Qz62v&algo_pvid=e64e43cb-6164-4ece-8d91-0eadea4188ea&algo_expid=e64e43cb-6164-4ece-8d91-0eadea4188ea-12&btsid=0bb0624516038620021642181e86ad&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_