Solid plan. Proven to work by many members here. 
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If you have drivers to play with @36v may i suggest citizen citiled cluo38’s. You can get solderless holders from radio shack. (At least ukrsonline my end I imagine they would be available where you are)
Each cluo38 is around £5 a piece. $6/7 depending on the current rates of exchange. If the idea interests you. Shout up and I’ll send a few links to get you started
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Thanks @anon58740919, yes, please shoot some links if you have them handy! We recently did a sample rotation of lighting fixtures at work, and before they went to recycling I pulled the drivers - just in case… would be good to use them. Same with aluminum extrusion left over from a job.
Anything I can use justifies my hoarding, so please help!!! 
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The seller is called ivo (export Estonia) and after me hunting for ages to find the royal blue he has just started stocking them 
no more dealing with marl international .
https://uk.rs-online.com/mobile/p/led-array-mounts/7750705/
These are my go to’s brother
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I second third and 4th this idea. This was my plan until I ran across the strips at a fair price. But I am in US so they are much easier to get my hands on.
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Try and take a look at my thread, I am testing a bunch of different cheap china strips.
The Dual row 12V strips, in series seems to work pretty well and they are cheap.
Still a week+ from harvest, but so far the results are looking good.
I have only heard bad things about the onboard driver COB’s, and didn’t go with SolStrip for the same reason as you.
Import tax and custom fee, will blow the budget.
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Thanks @Palindrome, I did read through. I think this is the way to go for me. I have the drivers and these look cheap as borsch. Besides this is not for high output gardening, im well set up with HID in that department. more experimental.
Do you have a preferred vendor for the 12v dual row? And I noticed you plucked all the resistors out - is that pretty much SOP for you on those? How hard are you driving them?
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Totally depends what “shoestring” means to you, but these are what I bought.
Perfect for your 36v drivers.
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I fell for the whole 117.2w capacity in the cluo48s but you’re practically paying double over cluo38’s. And solderless holders become more difficult to come by. how many of us are realistically going to push that from a single chip? I tend to run them between 25-40w a piece. Other than the royal blue which get pushed to 50
57.7w max on the cluo38’s iirc
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These COBs (like most) are at maximum efficiency below 50% rated power. I consider the 048-1212 to be 100w COBs, so running them below 50 watts is their sweet spot. I run mine at ~36 watts each (36v x ~1000mA) which is exactly their sweet spot according to the Citizen white paper. http://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/COB_5/CLU048-1212C4_P3708_0516.pdf
For the 038, I would run them at ~20-22 watts. No more. But that’s just me.
(The whitepaper for the 038 shows electro optical characteristics on page three, measured at about 19 watts - they chose those voltage and amperage values because that’s where the COBs perform best, regarding Lm/w) https://www.light.fi/assets/files/151210-CLU038-1206C4[Ra90-Below-B.B.L.]-DataSheet.pdf
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The thread is talking good wattage for cheap £ brother. That’s the information I was relaying. I understand the principles. But those stack up to costly principles 
those who know. Know. And you know bro 
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Costly in comparison to what, though?
My 5 COBs plus Meanwell driver cost less than my POS Meizhi Reflector 450 - they put out over double the lumens and use 10 watts less power. To me, that’s incredible value.
Not arguing, just very interested in all this, you know?
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Costly in comparison to buying twice as many chips to run the same wattage. So more holders. More screws. More heatsink. All stacks up. I’m not arguing either just stating my opinion on what I’ve learned so far in my own light building adventure. And the market research I’ve had to do when building for other members/customers ha
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Efficiency drops exponentially between 50% and 100% power, mate. Unless you get free electricity, this is something to consider. Not to mention longevity of the COBs.
Also, holders/screws aren’t a necessity (I used kapton tape) and the OP said he already has plenty of heat sink material.
Just my 2 Canadian cents worth. I’ll leave it at that.
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Evidently not grasping what I’m saying.
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Very fair point, here’s how I think about it:
- Use as much of the stuff I have on hand. This includes some drivers and lots of extrusion for heat sink. The more I use of the stuff I have, the less cluttered my storage is, and the more my wife likes me.
- Spending as little as possible, while maintaining levels of illumination/efficacy equivalent to about 8x 15W 1250lm LED screw-ins, because i have hoarded those too… But those i can keep guilt-free under the premise of “for the house”
- Evaluate and accept value propositions that allow me to better utilize existing material for nominal increase in cost. I’m willing to spend a little more to get a disproportional amount of “more” out, but definitely not hundreds of dollars.
The longer this thread goes, the less sure I am…
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You’ve got drivers and heat sink material, so COBs or strips make sense. For mounting COBs, a combination of heat sink compound (applied properly) and kapton tape is sufficient.
Totally up to you which design philosophy you decide to follow when choosing the COBs (if you do in fact decide to use COBs). I made it clear which philosophy guided my decisions, and doing so didn’t break the bank.
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If it makes your life any easier I’ve got a load of solstrip heatsinks remaining in my shed that never went with strips. I’ll send them to you no charge other than postage costs. You would need to order the strips themselves from baudelaire or find something suitable to take their place. But if they help. They’re yours
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Been thinking about this.
8 x 15w = 120w
8 x 1250lm = 10,000lm
Well, 2 of the COBs I mentioned (at ideal V and A) can do:
2 x 36w = 72w
2 x 4500lm = 9,000lm
60% of the power use gets you 90% of the lumens - AND a much better spectrum.
The COBs are only $17 each (including shipping), but unfortunately that source (which is very good, as cola said) only sells groups of 5. So you’d end up with 3 extra COBs (to do other things with?).
Just figured these numbers might be interesting to you.
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