was wondering if you have been able to compare your projected ppfd numbers to the actual measured numbers....
now that you have a decent par meter ?
Top bin COB comparison
- Thread starter SupraSPL
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now that you have a decent par meter ?
Greengenes707
Well-Known Member
That's not what a par meter shows. Average PPFD(calculated confinement of PPF) vs instantaneous PPFD(meter extrapolated figure)
that's true but at some point one needs to validate estimated ppfd.
Greengenes707
Well-Known Member
Again...a sphere is needed!!!
robincnn
Well-Known Member
@Greengenes707
We may not need a sphere for this. I think @PurpleBuz is asking for comparison of calculated projected PPFD for a given power and sqft using the calculators posted around here and the actual PPFD measured in a reflective tent of the same power and sqft. The PPFD of tent would be a fancy averages of values at diffrent points on a grid. Only question is what height.
Do you think PPFD in sphere is more relavent to our growing than averages in a tent. After all we growing in tents and need a calculator to predict PPFD in tent.
I have done this test before and the projected numbers were very close to what I measured. Will share results when I test next time.
The projected PPFD may be diffrent from actual scenario incase of non reflective sides. Also there could be a deviation if cobs not spread evenly
We may not need a sphere for this. I think @PurpleBuz is asking for comparison of calculated projected PPFD for a given power and sqft using the calculators posted around here and the actual PPFD measured in a reflective tent of the same power and sqft. The PPFD of tent would be a fancy averages of values at diffrent points on a grid. Only question is what height.
Do you think PPFD in sphere is more relavent to our growing than averages in a tent. After all we growing in tents and need a calculator to predict PPFD in tent.
I have done this test before and the projected numbers were very close to what I measured. Will share results when I test next time.
The projected PPFD may be diffrent from actual scenario incase of non reflective sides. Also there could be a deviation if cobs not spread evenly
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nevergoodenuf
Well-Known Member
I am wondering what the differences are @30". Does one have better throw than the other?
captainmorgan
Well-Known Member
I've ordered twice from KB and the 3590s arrived in what appears to be Cree packaging with labeling that looks correct,even has two different lot numbers. And it doesn't say sample,thought I saw a pic with labeling before saying "sample" somewhere.
Stephenj37826
Well-Known Member
First of the year I'll try and test them all in sphere for everyone. I'll get PPF at ~50 and ~75 watts if that will help
nogod_
Well-Known Member
+35w & 25w if you can
Obviously useless to your company but for the medium scale grower often the volume discount for 50 chips vs. 25 chips is significant. In my case it didn't add much to the materials cost to purchase twice as many chips and drive them half as hard because the break got me a great deal. In your case I'm sure the break for 500ct vs 1000ct + added labor is not enough to justify make a 700mA lamp.
But I'd love to see some hard data to be able to put the issue to bed!
Obviously useless to your company but for the medium scale grower often the volume discount for 50 chips vs. 25 chips is significant. In my case it didn't add much to the materials cost to purchase twice as many chips and drive them half as hard because the break got me a great deal. In your case I'm sure the break for 500ct vs 1000ct + added labor is not enough to justify make a 700mA lamp.
But I'd love to see some hard data to be able to put the issue to bed!
Stephenj37826
Well-Known Member
You talked me into it lol.
bassman999
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That is a big difference
robincnn
Well-Known Member
good idea. but heat will not be easy to measure in my active cooled test with fan. I will have to run passive cooled and check compare heatsink temperatures. No more tests for a while now.
SupraSPL
Well-Known Member
I have some 3000K Vero 10, 13, 18 and 29s on order, will be interesting to do caloric testing to get some idea of efficiency comparison. Ill put each COB on identical small heatsinks, passive cooled in a large still room, then make a PAR map with pulsed measurements, and then let them thermally stabilize to compare temps. I have a much better digital probe thermometer now so we hopefully get some useful data.
AquariusPanta
Well-Known Member
I'm very happy to see that someone else has taken the initiative to investigate the legitimacy of calculated data and compare it with real world numbers. That is science at it's absolute best and something that I find highly honorable.
My data taken from an Apogee PAR meter, which I take seriously and enthusiastically, shares similarities with your data, in that the difference in output between a Vero 29 and a top-bin Cree CXB3070/3590 is not as great as what we've been led to believe from our trusty datasheets.
Now before I went on hiatus a few months back, I sprung some data on you all on how these cobs compared against one another and much to my surprise, the Cree cobs DID NOT perform as greatly as expected when compared to their Vero counterparts. My final conclusions at that time were that either Cree was giving us exaggerated projections, Bridgelux was giving us deflated projections, the Cree COBS from Jerry were NOT genuinely binned as advertised, or that somewhere along the lines I goofed up and made considerable errors. Since then I've compared all of my data, plus some with the latest Mothership, and it's now evident through what you've provided, Robinccn, that there's something off with these Cree cobs that most, if not all of us are obtaining through Jerry Kingbrite.
I suspect ordering straight from Cree would serve as a hopeful yet costly attempt at restoring faith to the Cree CXB namesake but how practical is that for the DIY squad? And how do we, as consumers, differentiate between Jerry and other dealers of Cree cobs?
As far as the sphere test goes, I really don't see how taking that route is going to change anything that has already been established mainly because if someone has a PAR meter that measures X to Y wavelengths and also have a correction factor that takes into account W to X and Y to Z wavelengths, then it's simply a matter of light output and determining which lighting source puts more of it out. I'd suspect the blend of spectral discharge would vary between the Cree and Vero cobs, as well as between two of the same kind, but that's not something a bunch of us find indicative at this time when choosing between the two considering both cobs have similar spectral charts and are obviously kicking ass in the grow scene.
In conclusion, I'd like to see an in-depth analysis of how a low-bin Cree CXB3590/3070 cob fairs against a top-bin Cree CXB3590/3070 cob. If those numbers are similar, then it's should be apparent to all that someone or something is falsely advertising their product.
Insufficient data to substantiate that claim or even to suspect. don't spread rumors unless you can prove it.
AquariusPanta
Well-Known Member
Lol you're so adorable. I have data, lots of it too. Would you like me to upload it here or would it be more suitable for me to direct traffic to the resource page at heavenbright.com?
if you can prove it do so. I have seen robin's data and while one may suspect cause its the only common thread (kingbrite) it certainly doesn't prove anything.
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