General DIY LED thread

[oreo54]

Is it acceptable to solder connection wiring to led star pcb after being torqued to heatsink with thermal paste? I am planning to try one to see how hot the heatsink gets from the solder process.

Generally that is how it is done

To attach the LEDs to the heatsink, use the Arctic Alumina heatsink epoxy. As the packaging states, the bond is PERMANENT so make sure you have the LEDs aligned before attaching them. It’s best to save the wiring job until the LEDs are mounted and the epoxy has cured.

DIY LED Reef Tank Light

 

[Matt Carden]

I am using a thermal paste which I would assume should hold up under the short duration high temperature of soldering.

 

[dantimdad]

Is it acceptable to solder connection wiring to led star pcb after being torqued to heatsink with thermal paste? I am planning to try one to see how hot the heatsink gets from the solder process.

That’s how I do mine. It helps prevent overheating during soldering. Done it for years

 

[TDEcoral]

Does anyone know or have an educated guess which diodes ReeFi is using in their lights? The site says Cree XP-E2 and Lumileds Luxeon Rebel, but their 435nm, 420nm, and 395/400nm diodes are what appears to be a quad-die LED and I can't find a product from either manufacturer that has those specifications. The Cree XHP50 or 70 and Luxeon M would be closest as far as I can tell? Maybe he's having them custom made? I'm mostly interested in the 435nm violet which is what Radion uses in their lights according to his spreadsheet on the ReeFi Uno page. 435nm seems to be an uncommon offering and I'm guessing must be a specific bin?

ReeFi® LED Uno – ReeFi Lab

www.reefi-lab.com

 

[Matt Carden]

I didn't think Cree made led under 440nm. I bought some UV off AliExpress that said they were Cree but I didn't believe it. The dies look the same as Cree 440 and up. I paid less than $.50 each.

 

[oreo54]

I didn't think Cree made led under 440nm. I bought some UV off AliExpress that said they were Cree but I didn't believe it. The dies look the same as Cree 440 and up. I paid less than $.50 each.

Once upon a time, there was an LED and lighting company called Cree. As much as any LED provider, Cree innovated. It was known for advances in brightness, in efficiency, and for an impressive collection of patents.

Then one day a Bay Area engineering “solutions” outfit with a 32-year history of going in and out of public ownership as a computer-memory products firm, and which had recently entered the high-performance computing services business, acquired the Cree group that made LED chips.

The strains of the LED business had become such that Durham, NC-based Cree Inc. agreed in October 2020 to sell its Cree LED unit to Milpitas, CA-based SGH (previously Smart Global Holdings) for around $300 million. The sale closed last March. It was Cree Inc.’s second big move out of LED illumination, as it had previously sold its LED lighting and bulb division, Cree Lighting, to Sycamore, IL-based Ideal Industries.............The company is moving toward what Adams calls a “fab-lite” model, outsourcing much of its LED production.

Cree LED sales ‘up substantially,’ says parent CEO (UPDATED)

New owner SGH is revamping manufacturing and developing new products aimed at architectural, horticultural, medical, and other markets.

www.ledsmagazine.com

Just thought it was interesting and frankly not uncommon.

 

[HarryC]

Hey guys! I'm in the planning stages of my first DIY fixture build. I'm wondering if anyone in here is familiar with the Luxeon Rubix line? They have excellent flux ratings on paper (almost double the Rebels in some cases). Just curious if anyone has used or seen these diodes yet. They're cheaper than Rebel line so I'm skeptical that they're actually better.

https://lumileds.com/wp-content/uploads/DS309-luxeon-rubix-datasheet.pdf

*VS*

https://lumileds.com/wp-content/uploads/files/DS68.pdf

 

[HarryC]

Input appreciated on which of these layouts is better. Tank dimensions are 24"x24"x33". The first one I'd run side to side, second front to back.

 

[oreo54]

Think most would favor the left one.
And unless you are going for a light island effect the led pucks should be spaced differently.
The center gap is more like the 2 side gap spacing should be. And the center sort of as wide as one if the current side gaps.

This softens the center hot spot and takes advantage of reflections off the side glass evening out the ppfd.
Suppose it would help with the light falloff on the ends of the t5's as well.

 

[Yodeling]

Hey guys! I'm in the planning stages of my first DIY fixture build. I'm wondering if anyone in here is familiar with the Luxeon Rubix line? They have excellent flux ratings on paper (almost double the Rebels in some cases). Just curious if anyone has used or seen these diodes yet. They're cheaper than Rebel line so I'm skeptical that they're actually better.

I haven’t tried the Rubix yet, but chances are they are better than the Rebels. The Rebels are pretty old now. One thing to keep in mind though that the Rebel specs are usually published at nominal current (usually 350mA), while the Rubix specs seem to be at 1500mA. So the Rebels (usually driven at 700-1000mA) are 2-3 times stronger than the published specs.

Edit: I just read the specs and they seem to be pretty even in performance assuming the Rebels are driven at 1,000 mA. Looks like the selling point of the Rubix is their small size. I might grab a few to try out.

 

[Yodeling]

Input appreciated on which of these layouts is better. Tank dimensions are 24"x24"x33". The first one I'd run side to side, second front to back.

Personally, I would try to spread them evenly over the tank, rather than clusters. This is obviously limited by your choice of heat sinks.

Also, I wouldn’t use so many limes. I don’t know about Rubix, but the Rebel limes are extremely strong to the eye.

 

[HarryC]

You have both been incredibly helpful through this planning process! This will be my last update until I have the PCB designed. @Yodeling I want these arrays to be almost like a stand alone unit that can be removed from the hybrid or used by themselves. Each of them will have it's own heatsink/drivers/power supply. I'm ordering 4 total heatsinks and PCB's so that I can add 2 more once I upgrade to a bigger tank. I think I'm going to custom design a 7"x7" liquid cooled heatsink similar to this one > https://www.lorithermal.com/aluminum-zip-fin-heat-sinks-with-soldering-heatpipe-lr00121.

 

[Lingwendil]

I am using a thermal paste which I would assume should hold up under the short duration high temperature of soldering.

Once bolted down to a heatsink they are much more difficult to solder for me.

 

[TDEcoral]

For anyone that has the Luxeon K16 in their builds, I think I've found the connector they use. I believe it's the Hirose DF57H-2P-2.4V and the connector housing would be the DF57H-3S-1.2C. I know it says it's a three position housing, but the datasheet says that the connector on the K16 is a three position with the middle blade removed. The housing crimp contact is the DF57-2830. For some reason r2r won't let me paste links into posts, but you can easily search these part numbers on digikey.

 

[dedragon]

any info on how 3030 leds like the samsung lm301b and lm301h would work for aquarium lighting. I really hope to see an led fixture using the samsung lm301 series leds, probably the 6500k and mint white lm301h chips mixed with some cree or other 460nm chips and a couple 380nm true uv leds. Hope it could maybe work.

 

[dedragon]

with how cheap some of these horticultural lights are it just seems like it may be applicable to reef tanks, diy led light is not my forte so i leave it with yall to ponder
example
Amazon product ASIN B08DFXZG55

 

[dedragon]

@oreo5457 maybe you know? Ati straton seems close but super expensive

 

[Matt Carden]

with how cheap some of these horticultural lights are it just seems like it may be applicable to reef tanks, diy led light is not my forte so i leave it with yall to ponder
example
Amazon product ASIN B08DFXZG55

These lights may not penetrate through water.

 

[oreo54]

with how cheap some of these horticultural lights are it just seems like it may be applicable to reef tanks, diy led light is not my forte so i leave it with yall to ponder
example
Amazon product ASIN B08DFXZG55

First these lights are not 1500W(atts)
Your link now goes to this one

LAYOND 600W​

Fine print

Actual Power Consumption:

70±4W

 

[oreo54]

These lights may not penetrate through water.

Red attenuates rather rapidly but the blue to yellow green content is fine.
Not seeing any secondary lensing so yea, spreads rapidly as well.

Then there would be the unacceptable color..