LED Light Design and Build Diary

[NakedMonk]

are those last 2 photos of the fixture already made up waiting for the PCB to be mounted to them?

[putt4dough]

are those last 2 photos of the fixture already made up waiting for the PCB to be mounted to them?

Yes they are. I have been working on the design for a couple of weeks and during that time have been putting some work through local suppliers for my day job. I piggybacked some of the parts onto those jobs. The parts you see are aluminium extrusion (cut to length, machined) and some mild steel that has been laser cut and powder coated. I know from designing and prototyping many things over the years that the best way to test a design is to have it in your hands. It also stops buggering around with small/unnecessary tweaks as they're much harder to change in real life than in CAD.

[NakedMonk]

Yes they are. I have been working on the design for a couple of weeks and during that time have been putting some work through local suppliers for my day job. I piggybacked some of the parts onto those jobs. The parts you see are aluminium extrusion (cut to length, machined) and some mild steel that has been laser cut and powder coated. I know from designing and prototyping many things over the years that the best way to test a design is to have it in your hands. It also stops buggering around with small/unnecessary tweaks as they're much harder to change in real life than in CAD.

 

Very nice work. Have you experimented with or know if there is enough surface area on that extrusion to expel the heat from the lights without the addition of a heatsink? Also I have been wanting to get my hands on some extrusion, 2020 to be specific, does the mob that you get your supply from are they wholesale only or do they retail to the public?

[putt4dough]

Very nice work. Have you experimented with or know if there is enough surface area on that extrusion to expel the heat from the lights without the addition of a heatsink? Also I have been wanting to get my hands on some extrusion, 2020 to be specific, does the mob that you get your supply from are they wholesale only or do they retail to the public?

 

I haven't experimented with the heat sinking yet and it's the biggest unknown. It seems that it's calculable but I haven't been able to get reliable numbers from the methods I've found online. I think what I'll do is mock up a PCB using a piece of aluminium and some 10W resistors. I'll screw it to the extrusion and run some current through the resistors until the're consuming around 100W and then measure the temperature of everything. Those temperatures, the ambient temperature and the power running through the resistors should give me a good indication of the thermal resistance of the extrusion. I think!

 

Try Modular Components and Automation in Dandenong South, Victoria. They carry Item brand extrusions, which are German made and top notch. You'll pay more than the Chinese stuff but it's good quality.

[NakedMonk]

Thanks mate, just googled them. Definitely will be giving them a call

[NakedMonk]

Very curious on your results with the temperatures. Being the extrusion has such a massive profile, I would like to think that you wouldn't need an additional heatsink and the extrusion should expel enough to safely operate the lights with no issues and still be passively cooled by that alone.

[kloud9]

Yes, 3000k plus some blues around 450nm and reds around 650nm. I like the idea of having the blue and red spikes with an option to turn them on and off to inspect the grow without needing glasses to filter out the purple looking light. This might be a bit too much for a first design though.

No way not too much, run with those spectrums ..

 

Posted from the OZ Stoners mobile app

Edited July 9, 2019 by kloud9

[putt4dough]

No way not too much, run with those spectrums ..

 

Posted from the OZ Stoners mobile app

 

Ok, good advice!

[putt4dough]

Very curious on your results with the temperatures. Being the extrusion has such a massive profile, I would like to think that you wouldn't need an additional heatsink and the extrusion should expel enough to safely operate the lights with no issues and still be passively cooled by that alone.

 

I'm curious as well. I want the extrusion surface area to be enough to dissipate the heat but I'm not 100% certain. I'll setup a test in the next couple of days and we'll see.

[kloud9]

Cool

 

Posted from the OZ Stoners mobile app