My glass lenses arrived early.. now this is happening [3DCOB] 70watt

Olive Drab Green said:

I don’t have a PAR spectrometer because I’m not rich, but I don’t think so? My plants are actually really tightly noded, and I almost thought I stunted them in yhe beginning, because the nodes were stacked less than a quarter inch directly on top of each other.

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You would probably see the same stacking without reflector. It's more because of the blue part of the spectrum. When a plant recieve at least 10% blue light the nodes will be tightly spaced to each other. For this reason you can veg with 3000°k COB's and still see good results.
This has nothing to do with the reflector or the increased centerbeam.
Without reflector you could decrease the distance, which gives you two advantages. More efficient use of light and at least a few percent more light, because even good Ledil reflectors come only on 92-94% as far as I know, a good part is lost by the redirection!

Randomblame said:

You would probably see the same stacking without reflector. It's more because of the blue part of the spectrum. When a plant recieve at least 10% blue light the nodes will be tightly spaced to each other. For this reason you can veg with 3000°k COB's and still see good results.
This has nothing to do with the reflector or the increased centerbeam.
Without reflector you could decrease the distance, which gives you two advantages. More efficient use of light and at least a few percent more light, because even good Ledil reflectors come only on 92-94% as far as I know, a good part is lost by the redirection!

View attachment 4093665

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92-94% isn’t too bad. Got info on the Angelinas? And, thanks for the info.

Look for the datasheet! But I'm preety sure it's the same 94% in the best case. So at least 6% light loss..

dandyrandy said:

Closer and more cobs. No lens for me.

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to use these cobs @ high or max. current is not recommended.
the silicone layer of denser red/yellow phosphors (logically)will get much hotter
than any other cool, warmwhite chips.
Once you see the silicone above the led die visibly changed - you will have a "thermal runaway"
as loosing transparency means - more (and more) light is converted to heat inside the layer.

Olive Drab Green said:

Which would you recommend

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with a lense and reflector you always will lose 3% - up to 10% of light flux

[]D[][]\/[][]D said:

I think it would be better to go with 40 5 watt chips over say four 50 watt

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These ~1800K chips are rated with 80lm/w - and if you add the rule of 10% more flux / @half current you can reach a min. of 117lm/w with 12,5% current, wich is a lot
(i estimate, that its even more)
- to compare these chips with high quality chips - you have to buy lots more chips and drive them at low current as close to canopy as you can.

(the above + the blue graph is 1800K full spec. chinise)


from left to right 5 x 100W chip + 1 x 50W chip in paralell @ 30,4Vf / 315mA / 10W driver
(10 x 1w in series // 55 parallel)


100W / 50W each 1w led is driven @ 5,7mA (~1,8 % of max. current(300mA)
and should reach incredible ~160lm/w (without any heatsink they reach only 40°C)



with 300mm x 15mm chip platine /12 x 3W in series / 32-36Vf -700mA / same spectrum
you can spread even better and cheaper per watt.