Hi Florin, I liked your PCB experiments. May I suggest you place more vias when you want to use both sides of copper pours as a heat sink. I conducted some tests about 10 years ago and found that the vias acted like smoke stacks and pulled air through them which provided about 10% more cooling, compared to the vias filled with solder. The bare pours (without solder mask), is more efficient as you can imagine, with the added benefit of being able to solder copper fins or copper heat sinks, to act as heat sinks. I've used a $2 variable voltage boost converter from AliExpress on my 12V 10W COB LEDs, and adjusted the output of the converter to about 9.7V, because they are too bright for mood lighting. They hardly get warm, but I've attached the LEDs to 30mmx30mm heat sinks just in case I wanted to crank them up. It provides a constant voltage of 9.7 from a junk 7.2V power supply. No current limiting resistors were harmed in this project. Thought I share that with you and your viewers.
It would be interesting to see further tests with that AL8805 board and heat sinks. Of course it is easy to keep them cool with over-sized heat sink and huge fan, but tests with different kind of small heat sinks would be _cool_ . One that have fins with fine spacing and one with coarse spacing, for example.
One tip I've heard about old solder paste is it realy just loses the liquid flux and you can revitalize the paste by adding more liquid flux or maybe just some IPA back into the mix. Of course you have to mix it somehow so squirt it out to a dish and mix and then use the paste.
Yes you can do that but results will vary, I once tried it and it turned out I added too much flux and after using that paste to assemble some boards it left too much flux residue on each solder joint. Since paste is not really that expensive I prefer getting new paste every 6 months or so.
Couldn't you use copper tubing soldered on the back of that red board or even heat conductive silicone and a heatsink of some sort on any of these? Good deal all in all so I would just make it work.
There are plenty of things that can be used as a heatsink but the application usually dictates a space constraint and in this particular case, I only have a few millimeters of space available, I am currently searching for a small heatsink.
There are plenty of things that can be used as a heatsink but the application usually dictates a space constraint and in this particular case, I only have a few millimeters of space available, I am currently searching for a small heatsink.
Great video. If you need led's to be cooled by pcb, you need mcpcb. If you find some place with descent price where you can order custom pcb. I tried sinkpad, al and cu, and works great, but price is problem. If you can compare efficiency MP24893 vs AL8805 at higher current.
MCPCB helps suck the heat away from the LEDs but you need to get rid of that heat someway. My application has a tight space constraint so I would be using a very small heatsink. I'm not convinced the MCPCB will make a huge difference because I will have limited heat dissipation capability anyway.
I tried AL and CU. CU MCPCB spread heat perfectly. Cree XP-G2 @ about 0.5W mounted on 20mm copper star was enough cooling in open air. With CU star there is no temp. difference between center and borders, heat is evenly spread, but that is not case when AL star is used. If you are limited with space, use most efficient led you can find. For example Cree XP-G3 S5 bin would have 110lm light output @0.5W, same as Cree XB-D Q4 bin @1W @@voltlog
For efficient cooling I would glue the pcb on a cheap small cooling fan which is also 12V, same as your power, and consumes only 100mA of current, or less if you regulate it. The 40x40mm one costs only less than 1€50, see fr.aliexpress.com/item/2Pin-DC-12-V-40-40mm-Ordinateurs-Portables-Ventilateurs-De-Refroidissement-Pour-Ordinateur-Portable-Refroidisseur-Fans/32854459773.html?spm=a2g0s.9042311.0.0.27426c37ceR06w
Hi Florin,
I liked your PCB experiments. May I suggest you place more vias when you want to use both sides of copper pours as a heat sink.
I conducted some tests about 10 years ago and found that the vias acted like smoke stacks and pulled air through them which provided about 10% more cooling, compared to the vias filled with solder.
The bare pours (without solder mask), is more efficient as you can imagine, with the added benefit of being able to solder copper fins or copper heat sinks, to act as heat sinks.
I've used a $2 variable voltage boost converter from AliExpress on my 12V 10W COB LEDs, and adjusted the output of the converter to about 9.7V, because they are too bright for mood lighting.
They hardly get warm, but I've attached the LEDs to 30mmx30mm heat sinks just in case I wanted to crank them up. It provides a constant voltage of 9.7 from a junk 7.2V power supply.
No current limiting resistors were harmed in this project.
Thought I share that with you and your viewers.
Thanks for the info, I never thought about using thermal vias for convection cooling.
It would be interesting to see further tests with that AL8805 board and heat sinks. Of course it is easy to keep them cool with over-sized heat sink and huge fan, but tests with different kind of small heat sinks would be _cool_ . One that have fins with fine spacing and one with coarse spacing, for example.
Yes I will experiment in a future video with some small heatsinks.
One tip I've heard about old solder paste is it realy just loses the liquid flux and you can revitalize the paste by adding more liquid flux or maybe just some IPA back into the mix. Of course you have to mix it somehow so squirt it out to a dish and mix and then use the paste.
Yes you can do that but results will vary, I once tried it and it turned out I added too much flux and after using that paste to assemble some boards it left too much flux residue on each solder joint. Since paste is not really that expensive I prefer getting new paste every 6 months or so.
4:41 LED datasheet
5:29 NSI 45025AT1G
6:26 Infineon BCR 402U
7:17 thermal tests
9:43 AL8805 & MP24893
Excellent video 👍
Thanks for the video, I really like some of the parts on LCSC
Exactly, I can find parts in their catalog that are otherwise hard to get from the usual suppliers.
Couldn't you use copper tubing soldered on the back of that red board or even heat conductive silicone and a heatsink of some sort on any of these? Good deal all in all so I would just make it work.
There are plenty of things that can be used as a heatsink but the application usually dictates a space constraint and in this particular case, I only have a few millimeters of space available, I am currently searching for a small heatsink.
Thanks for sharing :-)
why not add some bigger thermal pads or vias to the LEDs? It should help them last longer right?
....... I don't care what INTERPOL Says, I think your cool man !
Good video ! 👍
Dissipation problem :
Use smd components only and have your pcb on ( anodized ) aluminium ?
There are plenty of things that can be used as a heatsink but the application usually dictates a space constraint and in this particular case, I only have a few millimeters of space available, I am currently searching for a small heatsink.
Great video. If you need led's to be cooled by pcb, you need mcpcb. If you find some place with descent price where you can order custom pcb. I tried sinkpad, al and cu, and works great, but price is problem.
If you can compare efficiency MP24893 vs AL8805 at higher current.
MCPCB helps suck the heat away from the LEDs but you need to get rid of that heat someway. My application has a tight space constraint so I would be using a very small heatsink. I'm not convinced the MCPCB will make a huge difference because I will have limited heat dissipation capability anyway.
I tried AL and CU. CU MCPCB spread heat perfectly. Cree XP-G2 @ about 0.5W mounted on 20mm copper star was enough cooling in open air. With CU star there is no temp. difference between center and borders, heat is evenly spread, but that is not case when AL star is used.
If you are limited with space, use most efficient led you can find. For example Cree XP-G3 S5 bin would have 110lm light output @0.5W, same as Cree XB-D Q4 bin @1W
@@voltlog
Miloš Arsić thank you for sharing your experience 👍
2:54 Hi friend, could you tell me why you have used kapton tape?
To keep the hot plate clean.
Nice videooo quality, which one camera used?
Thank you. The camera is iPhone 8.
VoltLog, I don't want to buy iPhone 😭
For efficient cooling I would glue the pcb on a cheap small cooling fan which is also 12V, same as your power, and consumes only 100mA of current, or less if you regulate it. The 40x40mm one costs only less than 1€50, see fr.aliexpress.com/item/2Pin-DC-12-V-40-40mm-Ordinateurs-Portables-Ventilateurs-De-Refroidissement-Pour-Ordinateur-Portable-Refroidisseur-Fans/32854459773.html?spm=a2g0s.9042311.0.0.27426c37ceR06w