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Discussion Starter · #1 ·
First a disclaimer, this has nothing to do with specific lights nor any plant growing characteristics.
It is just a really nice compilation of a bunch of led related qualities based on multiple metrics.
Obviously based on "normal" i.e like house lighting, galleries ect.
Synopsis for those that don't want to waste time.
4 competing "looks"
Ways to use tri-chromic leds to maximize one or all of the "looks".
Uses broader phosphors than narrow band rgb emitters so no direct comparison
Bibliography alone is rich in areas of interest.

1026986
 

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Discussion Starter · #3 · (Edited)
Do you mean that the suggested nm in the graph will provide the most “pleasing” color spectrum?
If referring to "color preference" that appears to be what they are saying.
Average psychological preference to tone basically.

Remember these are phosphors so doesn't directly apply to RGB or any other colored LED.
"Fidelity" composite w/ Chihiros background. 6500K for the phosphor mix.
10000K for the Chihiros
1026990


One thing though if you look at color dulling it is no wonder standard or poor whites alone are not err punchy.
Blue pump plus yellow phosphor.
Once one sees the difference between high CRI whites and normal the science makes sense..
Since some also add a cyan phosphor (high CRI) you can see the 3 catagories it affects.
 

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There's a bunch of COB Leds out there now on Amazon that are touted as having "sun like" and "full spectrum sun" spectrums. That have very similar spectrum graphs. I bought a few of the 3 watt bead COBs LC makes in the 4000K range of white light. They are pretty effective for plant growth when used with generic quality 8mm X 60mm 6500K 3 watt COBs. I can run a pair of the beads and a 8X60 strip off a 5 volt switching phone charger, all in parallel over my 10 gallon shrimp tank. It seems to be a good. low-mid light level for low tech.
 

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Discussion Starter · #5 · (Edited)
There's a bunch of COB Leds out there now on Amazon that are touted as having "sun like" and "full spectrum sun" spectrums. That have very similar spectrum graphs. I bought a few of the 3 watt bead COBs LC makes in the 4000K range of white light. They are pretty effective for plant growth when used with generic quality 8mm X 60mm 6500K 3 watt COBs. I can run a pair of the beads and a 8X60 strip off a 5 volt switching phone charger, all in parallel over my 10 gallon shrimp tank. It seems to be a good. low-mid light level for low tech.
Keep in mind, technically, each branch should have a terminating resistor for current control.
Not much a problem at 5 v since you only are getting 2.5 v per cob. Current draw should be low .

I' d be curious as to the exact parts you used.

Reread it are you running one bead on a parallel branch?
5V is technically too much.
Should add a 2.7Ohm resistor. 1W or greater. If "3W" beads.
Should be or they'd probably have fried by now.

Your current may be limited by the charger

Above paper doesn't really deal with plant vision or preference.
Different needs.
 

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Keep in mind, technically, each branch should have a terminating resistor for current control.
Not much a problem at 5 v since you only are getting 2.5 v per cob. Current draw should be low .

I' d be curious as to the exact parts you used.

Reread it are you running one bead on a parallel branch?
5V is technically too much.
Should add a 2.7Ohm resistor. 1W or greater. If "3W" beads.
Should be or they'd probably have fried by now.

Your current may be limited by the charger

Above paper doesn't really deal with plant vision or preference.
Different needs.
I should said that there's a big 5 watt 3 ohm resistor for current limiting but it never gets above the heatsink's temperature. I've been running this pair of DIY LEDs for almost a year now and the slight overvoltage I believe is is handled by the limits of the 1.2 amp rating of the charger, as it's about 3.3 volts at the terminals. Can't say I see any change in the brightness.
 

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Discussion Starter · #7 ·
I should said that there's a big 5 watt 3 ohm resistor for current limiting but it never gets above the heatsink's temperature. I've been running this pair of DIY LEDs for almost a year now and the slight overvoltage I believe is is handled by the limits of the 1.2 amp rating of the charger, as it's about 3.3 volts at the terminals. Can't say I see any change in the brightness.
Resistor drops the voltage.
If you have 3.3 across the diode that's probably the V(f) at the current current draw.
Rough guess is the one diodes pulling about 1/2A.
Don't know about your strip but the 2 are well within the power supply rating 2 x .5.. 1A

You are consuming 1/3 of your power with the resistors
Can't figure (w/ the calculator) the % Ohm but it just drops more voltage/watts and diodes pull less current than below but it
should be close enough for a sort of snapshot of whats happening
At 3.3v you reaaly have 1.8A on the power supply (6 Watt supply) .

  • [*]each 3.9 ohm resistor dissipates 879.9375 mW
    [*]the wizard thinks the power dissipated in your resistor is a concern
    [*]
    [*]together, all resistors dissipate 1759.875 mW
    [*]
    [*]together, the diodes dissipate 3135 mW
    [*]
    [*]total power dissipated by the array is 4894.875 mW
    [*]
    [*]the array draws current of 950 mA from the source.
 
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