How do you guys measure the temperatue on a heatsink?
And what temperatures are acceptable and why?
(I guess, I can use my QB288 heatsinks as a point of reference)
As I understand, the cheap IR thermometers are set to a threshold that doesn't necessarily work with polished aluminium at higher temperatures ???
Measuring temperature on heatsink
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- LED Wizard
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I never measured from the heat sink. Aluminium does not melt that easily. The temperature you need to follow is your led, the strips usually have tc points meant for measuring, not sure about cobs. If you don't have something to measure the tc point, you can use a lazer thermometer to measure the strip casing.
My strips can handle 80c, and they run at under 40c.
My strips can handle 80c, and they run at under 40c.
"Nothing is true, everything is permitted"
On higher-end IR thermometers, you can change the emissivity value to something that works better for anodized aluminum. I've read .77 is a good place to start.
Aside from that, taping a thermocouple on there would be a good way to do it.
Aside from that, taping a thermocouple on there would be a good way to do it.
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- LED Enthusiast
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Thanks for the feedbackunkle_psycho wrote: ↑Mon Jul 02, 2018 7:44 pmI never measured from the heat sink. Aluminium does not melt that easily. The temperature you need to follow is your led, the strips usually have tc points meant for measuring, not sure about cobs. If you don't have something to measure the tc point, you can use a lazer thermometer to measure the strip casing.
My strips can handle 80c, and they run at under 40c.
Melting point is like 600-700°C , so it's more about efficient cooling and dissapation.
I think the H inFlux strips are rated for 90°C.
I'm trying to figure out if tit's worthwhile getting a bigger heatsink.
I have 30x20x2mm U-channel, and I want to campare it to 30x30x3mm which is about twice as expensive
Thanks!
Great idea using a thermocouple
I think I'll use a cheap IR thermometer for the strips and a thermocouple for the heatsink.
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- LED Lover
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I use a DS18B20 probe on my heatsink that's hooked up to an Arduino. My heatsink usually reaches about 50°C when the light is cranked all the way up.
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- LED Wizard
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Sorry, just messing with you.PurpleGunRack wrote: ↑Tue Jul 03, 2018 4:28 amThanks for the feedbackunkle_psycho wrote: ↑Mon Jul 02, 2018 7:44 pmI never measured from the heat sink. Aluminium does not melt that easily. The temperature you need to follow is your led, the strips usually have tc points meant for measuring, not sure about cobs. If you don't have something to measure the tc point, you can use a lazer thermometer to measure the strip casing.
My strips can handle 80c, and they run at under 40c.
Melting point is like 600-700°C , so it's more about efficient cooling and dissapation.
I think the H inFlux strips are rated for 90°C.
I'm trying to figure out if tit's worthwhile getting a bigger heatsink.
I have 30x20x2mm U-channel, and I want to campare it to 30x30x3mm which is about twice as expensive
Thanks!
Great idea using a thermocouple
I think I'll use a cheap IR thermometer for the strips and a thermocouple for the heatsink.
Heatsinks have serious diminishing returns, so if you double your heatsink, you don't get anything like double cooling. In that sense it would be a pity to pay much more for a little bit more capacity.
"Nothing is true, everything is permitted"
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I would'nt expect anything like double coolling properties, but if it's what keeps the strips under the nominal performance temperature of 55°C it's well worth it
I found some tape you can put on glossy surfaces that adjusts to the standard emissivity value 0,95
I found some tape you can put on glossy surfaces that adjusts to the standard emissivity value 0,95
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- LED Wizard
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Here there is a calculator, which I imagine can calculate how much they differ in capacity. Don't know if this would be useful?
https://www.myheatsinks.com/calculate/t ... plate-fin/
https://www.myheatsinks.com/calculate/t ... plate-fin/
"Nothing is true, everything is permitted"
For heatsinks, a little bit of airflow goes a long way. So rather than increase the size of the heatsink, place a small fan somewhere nearby.PurpleGunRack wrote: ↑Sat Jul 07, 2018 5:38 pmI would'nt expect anything like double coolling properties, but if it's what keeps the strips under the nominal performance temperature of 55°C it's well worth it
I found some tape you can put on glossy surfaces that adjusts to the standard emissivity value 0,95
If you want to get into the weeds a bit, look up free convection vs. forced convection.
Here's a chart of typical convective heat transfer coefficients: https://www.engineersedge.com/heat_tran ... _13378.htm
The h of free convection of a plate is ~5 W/m2-K, while low speed airflow over a surface is ~10 W/m2-K. Basically, if all other things were constant, your heatsink will be twice as effective with just a bit of airflow.