The delivery charges in UK take the piss, you could order 2 veros and have delivered or pay 3quid more and have 3 delivered lolI ran 1400 & 1200 about 12" above canopy no problem.
you will be sweet with those drivers, best of luck with your build. Have you considered heatsinks yet btw?
http://pages.ebay.com/link/?nav=item.view&id=271924953294&alt=webjust go ahead and use i5/i7 heatsinks with fans, about 6pounds each.
That would be awesome if you could mateyep. and you can use wood screws, because theres already holes in them so you dont have to tap em. ill post example how i did it in the evening
To give you and others a better perspective, I went ahead and turned on the fixture for about 15 minutes before testing from 24" to 12". I took and wrote down multiple readings from different locations and averaged the highs and lows for each of those displaced sectors, with the fixture within a reflective tent rather than an open space. Keep in mind I was taking tests with the doors wide open, so realistically the overall PAR in each sector would be slightly higher if the door was closed. I didn't account for this but the difference between the back side and the open front wasn't too significant. Also, I swabbed down my sensor for each series of testing with isoprophyl alcohol.Dang huge boost from the reflectors great data! Was the system fuly warmed up and was it done inside a reflective tent or in the open? This makes me want to do more extensive testing of lenses vs reflectors vs bare because I am still running most of mine bare at 6-10" from canopy. I did put reflectors in the veg tent and it has increased intensity significantly.
So you calculated the expectation of ~800PPFD average and from this data it looks to me that your actual actual measurements were pretty close to that? The PAR meter cannot see above 650nm so your measured PPFD should be a bit lower than calculated especially for the warmer color temps.
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One suggestion I would have would be to calculate the PPFD of the calculated space an individual cob will actually cover and plotting this out one by one with graph paper. With optics this is relatively easily, but very difficult with bare reflectors. This will account for height and position, but won't take into account reflective surfaces.To give you and others a better perspective, I went ahead and turned on the fixture for about 15 minutes before testing from 24" to 12". I took and wrote down multiple readings from different locations and averaged the highs and lows for each of those displaced sectors, with the fixture within a reflective tent rather than an open space. Keep in mind I was taking tests with the doors wide open, so realistically the overall PAR in each sector would be slightly higher if the door was closed. I didn't account for this but the difference between the back side and the open front wasn't too significant. Also, I swabbed down my sensor for each series of testing with isoprophyl alcohol.
The problem I see with the calculated ~800PPFD is that it doesn't signify where the fixture lays with relation to the intended area. In other words, is that 800PPFD at 12" or 24"? Is that with or without reflectors? My understanding of PPFD could be half filled but I suspected that the calculated 800PPFD would be an average of the area, which in this case is substantially higher than the best, actual readings. From this revelation, I question the PPFD calculation method of determining how many COBS should be placed in a given space and ponder whether or not we are supplying our gals (and gents) with proper levels of light.
Damon, over at Apogee, supplied me with the supposed correction factors that apply to the Vero lineup (version 2) and surprisingly the boost wasn't very significant for the 5000K (- 3.6% loss) - those numbers in the sectors above have indeed been corrected.
My mates just given me one of them heatsinks. Will be ordering the veros next week. Might stick one on eBay as I won't need it
Curious as to why you didn't spread the outer COBs further out to more evenly distribute the light? Might get you closer to that theoretical 800 PPFD.One thing I haven't seen a lot of here in this thread, nor in any others, is PAR charting. It's apparent to me from my own results, as well as others, that these Vero COBS are highly capable of producing the outcomes that a lot of us here seek within the garden. I personally would like to see more PAR testing from the community under both commercial and DIY lighting fixtures, as I find it fascinating to compare numbers and data, in order to see where and how different factors stack up against one another in various scenarios.
Here's some data that I did in my free time over the past few days:
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^ To provide a better perspective of how the COBS were placed and aligned in the tent.
As most of you might tell, there's a huge difference in how well the reflectors perform from 12~18 inches in comparison to not using reflectors. I should mention that these reflectors are some of the best of the best and are from an actual licensed optic company, rather than from some unknown source (yeah I believe it makes a difference in where the parts come from, hence reliability).
Now to top off this demonstration, I'd like to compare the actual readings from operating these COBS to the calculations that I and a bunch of others sometimes use when determining their light setup.
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Even when I calculate the average for the best scenario (reflectors @ ~12"), that average falls below the calculated PPFD for that temperature (5000K). Now there are multiple factors that could influence this discrepancy but I believe it will take readings from the other temperatures in order to conclude on the theory that calculating PPFD gives too generous of readings in relation to what is really taking place under the COB.
@alesh - Thank you again for your past support with respect to this material; I hope this demonstration appeals to you in some manner or another.
@Greengenes707 - Thank you for demonstrating your knowledge of this matter in other threads and kindly debuffing some of the ambiguity that follows with this research. I know we've had are quarrels in the past, mostly thanks to me, but I've grown accustom to your personality over a short period of time and respect what you stand for here in the community. I've been waiting to mention this for some time but I apologize for verbally and publicly undermining your product in the past. You have a terrific product and I personally hope you come out on top of this COB-lighting market (if I don't), as I believe you've worked hard enough and have provided the public with a great deal of wisdom and data.
@stardustsailor - I thought you once said 'hell with reflectors' ?!? ;P
@SupraSPL - If it weren't for your intuitive excel sheets, I don't think I could have gotten this far. Thank you Soupdawg!
Well first off I need to apologize for the typos I can no longer edit....The reflectors are 94% efficient, designed for Vero 18, 90 degree, no lenses.
One suggestion I would have would be to calculate the PPFD of the calculated space an individual cob will actually cover and plotting this out one by one with graph paper. With optics this is relatively easily, but very difficult with bare emitters. This will account for height and position, but won't take into account reflective surfaces.
Only hypothetical, let me see if this works out on paper. What sort of reflector were you using in the test?
Well I'm not as far along in my mathematics as some on this board. So forgive any mistakes, but my line of thinking is that we can use trig to calculate the area that a cob will cover at a given height. Then we can calculate the PPFD of the individual cob over that area. Then by plotting the cobs position in the grow room we can calculate how much the light footprints of each cob will overlap and hopefully predict the increased intensity at a given position within the grow space.Would you care to elaborate your understanding of your proposition, as I'm not familiar with the approach.
Hmm I'll look on overclockers. What's kb?overclockers sell AC A11 fo £6.
KB sell cobs cheaper than everywhere else
@AP. - Great stuff mate, nice write up. I've been thinking about reflectors for a while... I'm thinking about them seriously know!