ebay COB LED's......anyone use them

[Lousybreed]

I was looking at the ebay COB's...you can get everything from 365nm on up in wattages from 10-100 watts....so I was wondering if anyone has built a lighting system for a successful reef tank with these? Seems like you could cluster some 400nm, 420nm, 455nm, and 470nm for a nice blue channel....throw in some whites and maybe have a nice light? Thoughts? Has anyone done this?

 

[Lousybreed]

and the prices are sooooooo cheap it is tempting!

 

[oreo54]

Freshwater..saltwater..people have used them...more than one wants to admit..:)
https://www.ebay.com/itm/45W-LUXEON...567829?hash=item3d11702755:g:FXYAAOSwXshWtI~T

These were popular for a bit..Some sort of overstock. Quality chips and boards. Odd plug..
As to whites, one can get "real" CREE 10W COB's for a few bucks from like digikey.. 1-$2..
Though real high k like 10000 don't exist..

Only real problem is consistency of quality and inferior eficiency.
So one shouldn't generally drive them hard (no more than 500mA) which means one might use 2 or 3 to equal one"quality" chip...

 

[naoki]

My experience is with white COB LEDs (not monochromatic ones). It depends on the cost of electricity. The electricity cost in Fairbanks, Alaska is one of most expensive (about 20 cents /kWh) in the US, so even if these inefficient COBs are free, it becomes more expensive to run than modern COBs like Bridgelux Vero 29 within 1-2 years (about 12h/day). I tested them more than 3 years ago (here is a a link to my blog post), but I'm guessing that they haven't improved the quality that much. If your electricity is cheap (and if you don't care too much about the environment), it could be ok for a couple years. It is pretty easy to calculate the total cost of ownership and make a comparison. I was curious how long it will last, so I've left one running, and I think it lasted at least 4 years ('100W' COB driven at 50W with a CPU heatsink) in my grow tent for orchids.

I'm using Bridgelux EB Strip Gen 2 (it's a linear module) for my tank. These mid-powered LEDs (also Samsung F-series) appear to be more efficient than COBs at this moment. I don't have the exact number at this moment, but Photosynthetic Photon Efficacy is > 2.5 micromol/J. I think Gen 3 is coming out soon. It is 5700K, so I'm going to supplement them with blue Citizen CLU048-1212 (COB with no phosphor layer).

 

[Kampo]

and the prices are sooooooo cheap it is tempting!

I use a LED board I got off Ebay (see the radeon clone thread in DIY) yes there is money savings, but it isn't as cheap as you may be thinking, the LEDs are not the highest cost. Heatsinks are not cheap if you want a nice looking light. need drivers, need a controller, need to have tools, and factor in your time. I'm about 180 dollars invested into my light so far.

 

[garbled]

I built a system with them years ago, there is a post by me on that other forum about my build.

Short answer, they are *amazing*. I love them. I am also currently repairing mine, because trying to run them off computer CPU heatsinks was a terrible idea. I run them off meanwell ballasts, and was super happy with them for years until I blew them up. Right now I'm waiting for a shipment of 4 new oversized passive heatsinks for them. I feel like I went overboard, but we will see once I finish testing. As I wire them up I'll probably either post about it in detail on my build thread, or make an article.

If you do go COB, here are my 3 big tips:

1. Passive heatsink. Your cheap fan will die and your LEDs will follow.
2. Get the lenses. Get big lenses. I used 77mm lenses, and they are awesome.
3. Figure out how to secure the lens to the LED. They are more or less supposed to be glued on. This doesn't work. I'm going to 3d print a bracket to hold them on, but a little chunk of aluminum with a 77mm hole in it would be fine.

 

[garbled]

Oh, also should note.. I currently run 5 20 (or was it 30?) watt ones over my 125G softy tank. Those have been running on passive sinks for 6+ years with no problems other than two of the stupid lenses falling off.

 

[naoki]

Yes, there are pros and cons of active vs passive heatsinks (especially once you start to pay attention to the efficiency). With active cooling, you should include the thermal switch. But the large passive pin-fin heatsinks (133-140mm diameter) with 0.79-0.85C/W of thermal resistance are quite cheap now (e.g. something like these), they would be simpler and easier. That would be my choice, too, although I would prefer linear modules for dispersion and better efficiency. With efficient LEDs (up to 50W or so), the sacrifice in the efficiency isn't too bad.
With the aquarium application, well-designed silicone lens would be nice (especially those square beam pattern) since 3-4 sides are open (unlike reflective grow tents).

 

[garbled]

There are a few COB LED's on ebay with a mix of 15k and 430nm blue in the same chip. If you used 2 separate ballasts to power one of these, you could easily dim each set separately. Those pin sinks are pretty nice. I see the big one is good up to 75W, and cheap too.

 

[Kampo]

I wounder wherre Rapid LED gets the enclosure that goes on top of the pin heatsinks they sell to make these grow lights. seems like you could pretty easily get a few ldd drivers in it and a raspberry pi to make an enclosedlight

 

[garbled]

That's a Mechatronix pin heat sink with the optional Meanwell driver kit. The thing at the top is meant to hold some sort of puck-style Meanwell driver. If you dig around for Mechatronix (yes, spelled like that) you can find them.. They have some pretty high end heatsinks. I've actually ordered a few for my system.

From what I understand, the little top mounted bit comes empty, and you are meant to supply your own driver. So probably perfect for your idea. It's supposed to have a cooling gap so the LED sink doesn't heat up the driver sink.

 

[garbled]

Also worth noting, if you want to be cheaper, you could always get a 100W COB, run it at 75 watts and use one of those pin sinks. You would probably be more than fine doing something like that if you don't need the full power of a 100.

 

[User1]

I've not used them before. I use Blue Acro's and have been happy.

 

[Lousybreed]

Guys thank you for the replies and info. WHAT A MIXED BAG. I just finished my first DIY LED build. The time it takes to do right, you might as well just buy the good stuff up front! I will probably build a cheap one just for the heck of it however. But not for the big tank.

 

[Reefbildr]

I built this, t5/led hybrid
Driverless cob led 50w

 

[Lousybreed]

I built this, t5/led hybrid
Driverless cob led 50w

So that thing runs on AC 110V?

 

[Reefbildr]

Yes sir , plug and play

So that thing runs on AC 110V?

sir

 

[Lousybreed]

That is amazing

 

[Reefbildr]

Best alternative,They are great leds but to my understanding they are designed more for plant growing as these ac leds mostly come in RBG.

I’m love building things and so wanted to see what’s i could come up with and found great results. Haven’t posted it yet but on a 24” deep tank running LED’s at full power wot has t5 I got 1300 par 6” above the water and 250-500 at the bottom. Needless to say I’m glad I don’t have to run them in full no more then 30% without heatsink with no heat issues. Also will last longer.
These ac led run at 350ma 30-36v


But if I had the money I would get multi channel Cree LED’s with meanwell 5 channel controller with WiFi dimmer.

Speaking of I have list of kits on what’s type of LED’s your wanting to build.