Diy led

[Red2143]

Does anyone still build leds or is it not economical given the existing options?

 

[Pntbll687]

Haven't seen any DIY led lights in a long time. With options from amazon, and more options like reefi-labs uno pro 2.0 coming out, I don't think the juice is worth the squeeze for many at this point.

Let's take a 40 breeder for example. You could DIY a light, not exactly what the cost would be. Or you could by a 150w Hyper reef from amazon for $185, and two 3ft bars from AliExpress for $54ea and you've got an sps dominant tank covered for sub $300 before shipping. Gonna be real hard to compete with that going the DIY route.

 

[SteveMM62Reef]

Check out Chanzon COB LED’s and Matching Drivers on Amazon. The Heat Sinks, I ordered of off eBay. Waiting for all the parts to arrive. Want a Midday Sun, for my Reef Tank, plus a Nighttime RGB for my Refuge.

 

[Spicy Reef]

Definitely Cob for spread :)
I'm using the same 3watt leds found in black boxes for my Pico Reef Bowl however. It's been fun trying to drive them... I have some tricks using wifi led controllers and alexa for sun rise sunset effect

 

[SteveMM62Reef]

I finally received the Heat Sink. Used the Conductive Paste, Screwed the 30 Watt Blue COB to the Heat Sink, it’s running at 80 to 83 Celsius. This seems about right, for a COB, but Chanzon is saying 60 Celsius, which seems low. I know the cooler the COB the longer it will last, but still seems unrealistically low. BTW, I‘m checking the temperature with a Fluke Temperature Meter, with the Tiny Beaded probe, at the back of the COB LED. Light Washed out the iPhone Camer.

 

[oreo54]

80C is actually pretty high, depending on where you measured it
You said "at the back of the cob" so I assume the heatsink back?
I've used those heatsinks for "10 watt" cobs.
Cobs lasted years before being removed from service ( new design).
Obviously they never came close to those temps.
Those heatsinks I velive are not anodized making them a bit worse for passive cooling.
That said you do want the heat getting to the sink so hot sinks are better than cold in a sense.
Not sure of the alloy either. Does make a difference.


What size driver did you use?
I don't have any scientific proof but I'd not exceed 500mA for "30 w" cobs likely making them 15-ish watt cobs.
Quotes are because wattage is driver dependent and really only denotes " theoretical".

Soo use driver current and voltage measurement across the cob to see what your actual wattage is.
Would be best to check on the driver mA output as well.


90*40mm is the recommended size for 20-50w cob.
90*10 for 10w cobs.

You may want to thinly coat the heatsink with some Matt black spray paint.
This only applies to passive cooling.
It is roughly equiv. to anodizing.

As a practicing professional materials engineer, let me weigh in.

From a purely thermal point of view, best option is to apply a thin coat of a matte black paint. Stay away from glossy finishes.

Heatsinks are overwhelmingly convective as far as heat transfer goes, so it won’t make a big difference, but a matte black paint will have a much higher emissivity than the “silver” aluminum for radiative transfer. A thin coat of paint will only create a negligible effect in terms of insulating against conductive heat transfer.

Cheers,
Terry.....
( New quote)
Under natural convection conditions, the performance of a heatsink with a black surface will be 6% to 8% better than that with a plain or bright surface. However, this differential disappears under forced air conditions.

source:

http://robots.freehostia.com/Heatsinks/Heatsinks.html

or:

https://www.mouser.com/pdfDocs/Ohmite_Heatsink_Guide.pdf

Scott has right:
Heatsinks work more by convection than radiation so colour isn't such a large issue as surface area, orientation of fins and good air flow

The paint increases surface area as does anodizing.

The emissivity of clear anodized is 0.76 to 0.84, close to black (0.82-0.86)
and the plain is just 0.04?
Is that correct?

To paint or not to paint - Heatsink Question

I am going to experiment with this shortly - I have a few sinks that are natural aluminum and some of the same profile that are painted black vs brown. I am planning to use an upcoming **** build (most simple- single sink, single transistor to mount) to compare various types of mounting...

www.diyaudio.com

 

[SteveMM62Reef]

Thanks for the information. The Probe I used is a Fluke 80PK-1 Bead Probe. They are Tiny, and I can wedge it between the Heatsink fins, to touch the back of the COB. I was trying to avoid the Heatsink with the built in Fan, but may end up going that route. At the moment I’m experimenting. I placed a couple Aluminum blocks on the back center of the Heatsink, temperature went down, but it was temporary. I did use heat paste, will try flat black paint. Also may try doubling up on the Heatsink.