HLG-550 vs PLC-6

Stephenj37826

Stephenj37826

Well-Known Member
wietefras said:
Having the right total photon count doesn't mean you can simply ignore uniformity. If you give some of the plants 1400umol/s/m2 while most get around 450umol/s/m2, then you will still end up losing yield at the highest intensity part and the low end gives relatively more fluff. You'd be much better off if all of them get around 650umol/s/m2 instead while taking a small loss in photon count.

It's not just yield, but also quality that gets affected by unequal lighting.

Besides, maximum photon count on the plants would be if you lay the lights right on top of them. That's clearly not an option, so in the end you will always need to compromise to find the optimum height. You will need to go high enough where uniformity becomes "adequate", but not so high that your are wasting too much photons on the walls in the chase of "perfect" uniformity.

Are you talking about putting those white plastic reflector cones on COBs? Do people still use those? I though by know everybody understood that's really the worst thing you can use on COBs. Apart from absorbing much of the photons that they are supposed to reflect (between 30% and 50%), they narrow down the beam angle so they do exactly the opposite of what you suggest would better.

Although it's good that you agree with my point that it's better to have multiple light points close to the canopy. This can be obtained best by well distributed (ie relatively small) bare COBs or led strips (reasonably) close to the plants. This is indeed better for photon count, light penetration and it gives you much better uniformity at close distance. That's why I'd say you should have at most one light source for each sqft and not just one big COB, HPS or board in the middle of a 2'x2' area.

However, I would not agree that only PPF produced by the fixture matters. A sphere value does not say it all. Just like it didn't with the bare bulb PPF values we got for HPS. You need to know how much light actually reaches the plants. A light that needs to hang at 22" away from the plants will waste much more light on the walls than one which can be at 8" for the same uniformity. Apart from obvious problems with grow room height when you use fixtures which need that much distance.
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Im not saying PPF is all that matters. I am saying in an overlapping light pattern (larger multiple fixture room) ppf is a very clear indicator. Also I said goniophotometer which gives you light distribution in professional fashion. Moving forward if you don't use these standard tests you won't be taken seriously. Par meters have a big place in lighting for the end user but it's not the end all be all when comparing fixtures.... Not even close.


And by penetration (still a common term) I mean less shadows in the inner canopy due to more point light sources ( incident angles)...
 
Stephenj37826

Stephenj37826

Well-Known Member
Also to make things clear when getting a IES file generated from a goniophotometer test it is better to have a single light engine done for a more accurate simulation in near field applications. For 100% accuracy the fixture needs to be simulated no less than 3X the distance of the largest measurement Length or Width of the light source.
 
pirg420

pirg420

Well-Known Member
Olive Drab Green said:
I use the 29Cs. They’re a little over 1000 PPFD, for what it’s worth. I dunno what DB is?
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When you quote ppfd you need to state the height and the coverage area, as well as reflective walls or not. There’s other things too but those are the big ones.
 
K

key4

Well-Known Member
pirg420 said:
When you quote ppfd you need to state the height and the coverage area, as well as reflective walls or not. There’s other things too but those are the big ones.
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I do think people who just state a single number are missing the point. Full map at atleast 3 different heights (otherwise you just have a 2d view and are plants aint 2d) using the relevant size tent with the extractor going too. What about temps shouldn't we be recording the temps too? air temps/heatsink temps.

New to this still but i know i can never afford to put all 8 lights i do in a sphear and with mine being open frame with commonly used chips, Par maps and test diarys from trusted growers will get me by.


Most growers (including me before myled journey) dont have a clue what all these measurements are any way and when they do learn a bit they use them incorrectly and just confuse others even more "1000ppfd" "600 par" etc

e2a yea i will be paying for advertising before anybody moans.
 
Stephenj37826

Stephenj37826

Well-Known Member
key4 said:
I do think people who just state a single number are missing the point. Full map at atleast 3 different heights (otherwise you just have a 2d view and are plants aint 2d) using the relevant size tent with the extractor going too. What about temps shouldn't we be recording the temps too? air temps/heatsink temps.

New to this still but i know i can never afford to put all 8 lights i do in a sphear and with mine being open frame with commonly used chips, Par maps and test diarys from trusted growers will get me by.



Most growers (including me before myled journey) dont have a clue what all these measurements are any way and when they do learn a bit they use them incorrectly and just confuse others even more "1000ppfd" "600 par" etc

e2a yea i will be paying for advertising before anybody moans.
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If you have a 4x4 solution I suggest to send it. If you are running most of your light engines the same with the same cooling the biggest variable will be driver efficiency differences.
 
pirg420

pirg420

Well-Known Member
pirg420 said:
When you quote ppfd you need to state the height and the coverage area, as well as reflective walls or not. There’s other things too but those are the big ones.
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To actually answer your question, the 29c’s are one of the best chips and beat the db at every wattage. Sounds like you have a very nice rig
 
K

key4

Well-Known Member
Stephenj37826 said:
If you have a 4x4 solution I suggest to send it. If you are running most of your light engines the same with the same cooling the biggest variable will be driver efficiency differences.
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Appreciate the advise thanks.
I deleted part of that post that sed i could just send in a single engine for each of the 3 chips i do but i diddnt think that was ok to do. I do have a light designed for a 4x4 with each chip using 6 on each light.So I can just get them tested then divide it for the lower wattage lights?
 
Stephenj37826

Stephenj37826

Well-Known Member
key4 said:
Appreciate the advise thanks.
I deleted part of that post that sed i could just send in a single engine for each of the 3 chips i do but i diddnt think that was ok to do. I do have a light designed for a 4x4 with each chip using 6 on each light.So I can just get them tested then divide it for the lower wattage lights?
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Yeah if you are using the same drive current.
 
wietefras

wietefras

Well-Known Member
Stephenj37826 said:
I am saying in an overlapping light pattern (larger multiple fixture room) ppf is a very clear indicator.
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Which is not what most people here are using. PPF is nice of course, but we like to see what it actually does in a standard sized tent too. More so than say a fixture which produces a stellar PPF measurement in a sphere and then loses say 20% more of it's light on the walls than other fixtures since it needs to be so high above the plants.

Of course I understand you don't like PAR matrices because the quantum boards (or other fixtures with "concentrated light sources") come out rather poorly in tests like that, but for the buyers that's exactly the info to have. In a huge grow room those wall losses will be much smaller and indeed PPF is all they will need, but for smaller grows the wall losses do end up that high. I've seen even drop down to less than half of the average of what PPF/m2 would be at 18". So you can end up with only half the light you expected to be getting. Or alternatively you need to drop the fixture down further and struggle with unequal lighting.
 
Stephenj37826

Stephenj37826

Well-Known Member
wietefras said:
Which is not what most people here are using. PPF is nice of course, but we like to see what it actually does in a standard sized tent too. More so than say a fixture which produces a stellar PPF measurement in a sphere and then loses say 20% more of it's light on the walls than other fixtures since it needs to be so high above the plants.

Of course I understand you don't like PAR matrices because the quantum boards (or other fixtures with "concentrated light sources") come out rather poorly in tests like that, but for the buyers that's exactly the info to have. In a huge grow room those wall losses will be much smaller and indeed PPF is all they will need, but for smaller grows the wall losses do end up that high. I've seen even drop down to less than half of the average of what PPF/m2 would be at 18". So you can end up with only half the light you expected to be getting. Or alternatively you need to drop the fixture down further and struggle with unequal lighting.
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Sure. As stated though I'm petty sure I can buy an orca tent and show much better numbers /less wall loss than an ebay special sub 100 dollar tent.

I'll buy an orca 4x4 and redo our test vs the cheapo tent we used. Also was the meter left flat in all measurements every time? My gut says no. Our tests in a tent the meter is always set level.


Also we need 3+ charts as stated to understand how the light spreads as you go farther away from the light as stated previously we are growing in a 3D world.
 
nfhiggs

nfhiggs

Well-Known Member
Stephenj37826 said:
Some meters have that function but I can't be sure what each person testing his or her light with a par meter is doing/using. With an accredited independent lab using a sphere /goniophotometer I can be sure that the measurements im seeing are unbiased and 99+% accurate with no variables like I mentioned above.

Standardized 3rd party testing is how the rest of the lighting industry rolls.

Just saying it's a small price to pay to have certified results.
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Fair enough.
 
pirg420

pirg420

Well-Known Member
key4 said:
I do think people who just state a single number are missing the point. Full map at atleast 3 different heights (otherwise you just have a 2d view and are plants aint 2d) using the relevant size tent with the extractor going too. What about temps shouldn't we be recording the temps too? air temps/heatsink temps.

New to this still but i know i can never afford to put all 8 lights i do in a sphear and with mine being open frame with commonly used chips, Par maps and test diarys from trusted growers will get me by.


Most growers (including me before myled journey) dont have a clue what all these measurements are any way and when they do learn a bit they use them incorrectly and just confuse others even more "1000ppfd" "600 par" etc

e2a yea i will be paying for advertising before anybody moans.
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Good points. Temperature, and voltage come into play as well, I use and test my lights on 230, it’s about 1-2% more efficient than 115volt.

Also warmup time.
nfhiggs said:
Well, that begs the question - since they are considerably less expensive why are you not using them?
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Vero c’s are less expensive? Not from my suppliers. The Db’s are very close to the b’s.

Also you need to realize I’ve been selling that fixture for 3 years. It’s outdated but still very viable.
 
wietefras

wietefras

Well-Known Member
Stephenj37826 said:
I'll buy an orca 4x4 and redo our test vs the cheapo tent we used. Also was the meter left flat in all measurements every time? My gut says no. Our tests in a tent the meter is always set level.
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Agreed, that's a clear issue with many of those tests (done by individuals). The issue being more that the lamp isn't level or not centered correctly. The PAR values often clearly show a movement of the light off center.

Another issue is that people often keep the front flap open during testing to have have access to the PAR meter. That mostly hurts the measurements only on that side, but some fixtures might be affected more than others.
 
nfhiggs

nfhiggs

Well-Known Member
pirg420 said:
Vero c’s are less expensive? Not from my suppliers. The Db’s are very close to the b’s.

Also you need to realize I’ve been selling that fixture for 3 years. It’s outdated but still very viable.
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OK, I'll take your word for that. I just keep hearing how the Veros cost less than the Crees.
 
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