Project New COB Veg Light, planning thread

AtterStiga

Well-Known Member
Hi guys, I'm AtterStiga, and this is a combination of planning and getting through the wait for my cxb3590 kits to arrive. With what will replace one of my 600w hps in the flower room on the way, and nothing to do atm with that project, I'll just turn to the next. I have never had the space for a veg room before, but that has changed now. I'm tired of the boom and bust cycles in this availability of ganja, so now it's awn.

Since I don't yet have a dedicated veg light, I'll attempt to build a cob light for targeted frequencies and dimmable modularity. The Cree cxb2530 @350 or 500mA is probably my favourite contender right now, but I'm definitely open for suggestions. I've seen them built with single heatsinks, but I think I'd rather build with separate pin heatsinks like the Cutter kits, only smaller, obviously. After gaining a deep albeit theoretical understanding of the workings of cob lights, I predict the sourcing and gauging of heatsinks to be the biggest problem.

First questions: when dealing with thermal resistance, are we looking for a lowest possible number? I suspect it is, but the Wikipedia page looks kinda like something that should be on the walls inside a pyramid in Egypt.

Does anyone know if somebody already made a list of of bins on the different Cree cxbs? Like a spreadsheet? I can find out by looking at spreadsheets, but it's always good to get the opportunity to love somebody else's work lol.

I realize that the individual heatsinks might be cost prohibitive in the numbers we're speaking of here. In that case I would be grateful if somebody knows about a good source for extruded heatsink bars, preferably in Europe. I can imagine those babies rack up the shipping cost.

I might just go for a cxb3590 kit in whatever K is best suited for vegging, but it's a bit of an overkill. And I do believe that the cxb2530 or something like it would be great for the culinary herbs I've been planning to grow for ages.

If I end up doing this I will definitely post the build. I'm just assuming that the factors influencing a big cob light are the same with a small one. Of course, small as in smaller cobs, I'm one of those people who believe the babies love plenty light in veg as well. If anyone has information regarding ill effects of radically changed spectrum at the switch, pls shout out.

Just realized I have built a wall of text here, so it's a good time to end it here. Link me to some heatsinks if you know about any, all constructive input is appreciated. English is not my first language, so sometimes it's a bit hard to google effectively. So please bear with me.

Come on, lets explore the possibilities together. Gonna be sweet.
 

AtterStiga

Well-Known Member
Ok, so as my two orders for the flower light build is on a trip I'm honestly a little bit jealous about, I have been doing some more reading. The cxb2530 seems like an elusive fish to find in stock. Did find a heatsink http://www.cutter.com.au/proddetail.php?prod=cut2988
That can run some 48w dissipation for $12. The specsheet has information about how to attach Vero 13/18 and a lot of other chips, but no Cree. Some you can just screw on, some need a cob holder and some you can choose. Self drilling 3M screws, length varies. No drilling needed.

So now it's time to study some other cobs than Cree, can't believe they're so far ahead of the rest. LG makes 2 billion chips a month, wonder if they're priced accordingly and if you can veg some plants with them. I think I will try to find out who has products of a predictable satisfactory quality.

Anyone know anything about non-Cree brands, I'd be much obliged if you pass the info on.

If anyone has got a link to an explanation of thermal resistance for dummies, pls give it to me. I intuitively understand how heat behaves, but going from there to actually doing the math seems to be harder.

I assume that a heatsink that is a little bit bigger than absolutely necessary is better than the minimum size.
 

AtterStiga

Well-Known Member
I can't believe I didn't find this earlier

http://www.led-heatsink.com

Seems to be located in Taiwan. Anyone has any experience with them? MechaTronix. Shipping times and such. This could be a lot easier than I feared.

Edit: the ModuLED 9980 heatsinks was actually almost €3 more at the Taiwanese place than at Cutter. Those guys down unda look pretty good right now.
Edit 2: ModuLED xtra 9980 seems to be designed for Cree cxb 13/15/18 @$10ish. Depending on cost of cobs this modular system might just become reality.

Peace to whoever follows my ramblings.
 
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AtterStiga

Well-Known Member
Enter the cxb2540... mouser has X2 bin 6500K at something like 4/9th of the cxb3590 CD 6500K there. But Cutter has DB 3590 6500K for like €3 more than mouser's 2540... haven't made any progress in understanding the non-Crees yet.
 

Ryante55

Well-Known Member
Do a little research on the citizen clu048 1212 its alot cheaper than Cree and not to hard to find now. For heatsinks the next thing I'm going to try is mounting 2 chips per 140mm heatsink at 500ma I have not tried it yet but I think it should work an would cut heatsink cost in half
 

verticalgrow

Well-Known Member
Do a little research on the citizen clu048 1212 its alot cheaper than Cree and not to hard to find now. For heatsinks the next thing I'm going to try is mounting 2 chips per 140mm heatsink at 500ma I have not tried it yet but I think it should work an would cut heatsink cost in half
Cobby put 3 1212's on a 140mm HS so it should work.

@AtterStiga Dont know if u got ur answer yesty but the screw holes for the 111mm HS are 5.5mm from base plate
but ur prolly getting the 140mm HS which could be different so best to wait b4 drilling holes in frames.

:peace:VG:eyesmoke:
 
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AtterStiga

Well-Known Member
@verticalgrow
Thank you, was beginning to feel a bit lonely lol. The video reminded me of one of the reasons I'm interested in cob led technology. I want to go totally modular in the end, boxes instead of rooms. Boxes on limited axis wheels to maximize space efficiency and minimize any impact on the room.
Yeah, I'm getting the 140s. Do you drive the cobs at 1400mA on the 111s? And the heatsinks does the job? Probably lower shipping on the smaller hs.

@Ryante55
I looked at the datasheet, and if I'm not mistaken it's comparable to the 2530/40? The English in it made my head hurt, and it's not even my first language lol. Do you have a lot of experience with them? If I go all in with 3590s (after the 12 I've got en route) I might just go with 3590s for vegging as well. But ideally I would love a lower driven veg light so I can have tiers of plants, as many as possible.
 

verticalgrow

Well-Known Member
@verticalgrow
Thank you, was beginning to feel a bit lonely lol. The video reminded me of one of the reasons I'm interested in cob led technology. I want to go totally modular in the end, boxes instead of rooms. Boxes on limited axis wheels to maximize space efficiency and minimize any impact on the room.
Yeah, I'm getting the 140s. Do you drive the cobs at 1400mA on the 111s? And the heatsinks does the job? Probably lower shipping on the smaller hs.
Yes Atter,
111mm HS is warm to touch @ 1400ma, 50W 3590's & yes they
only weigh 500grams compared to 140mm HS @ 800grams
:peace:VG:eyesmoke:
 

AtterStiga

Well-Known Member
@Ryante55
I found the citizen cob @$21, while digikey has 5600K Lumen Vero 18s @$16.30. Not to bitch, if you got a cheaper source I'd love to know. Citizen just feels so Alibaba, if you get me :-)
 

AtterStiga

Well-Known Member
Yes Atter,
111mm HS is warm to touch @ 1400ma, 50W 3590's & yes they
only weigh 500grams compared to 140mm HS @ 800grams
:peace:VG:eyesmoke:
Lol, what's 4kgs extra around the world? Gonna go check out the difference now. Maybe one day aluminum will replace gold again, and then the joke will be on you. Hmm, and now I'm wondering if my messed up brain will accept a different hs later...
 

Ryante55

Well-Known Member
Bookmarked, ty. Is the first numerals the chip physics size and the 1212 etc wattage model?
Ya the 1818 will be higher watt. Haven't done a grow with them yet they recently became more available and there's more data I'll be doing my next grow with them I don't think they bin.
 

AtterStiga

Well-Known Member
Ya the 1818 will be higher watt. Haven't done a grow with them yet they recently became more available and there's more data I'll be doing my next grow with them I don't think they bin.
Just found @CobKits 28 page thread, seems there is interest at least. What kind of distance from lights do you envision with them@500 mA?
 

AtterStiga

Well-Known Member
I'm trying to pin down the point of diminishing returns on ppfd in veg. I'm planning to start keeping mother plants, and control over light intensity would help with keeping the number of mothers down. Theoretically.
 
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