phosphor, how does it work?

Scenario: 2 leds from the same line at same draw. One is 5000k 70cri 160lm/w, the other 2700k 90cri 110lm/w.

From what I understand the only difference would be the phosphor. So, the phosphor does some sort of spectrum shift which I assume is not 100% efficient leading most of the difference in efficacy. I also imagine some of the efficacy to be lost due to the shift creating colors that may not contribute much to lumens.

How much though? Do low cct high cri benefit from extra cooling due to losses? How do you tell where in the 25-50w/sq a given light will perform best?

Yes exactly, there's an efficiency loss but not as much as lumen count might suggest. Warm K high CRI will put out a bit more waste heat but not generally enough to affect the cooling solution.

LED will always perform best at lower wattages. There's a price/performance relationship so dropping the current will have practical limitations. From a cost perspective it will depend on electrical rate, chip cost, efficiency gained, etc.It wouldn't be too crazy to drive Vero 29C at 30 watts for instance, but people generally run them at 70-95 watts and occasionally at 45 watts.

W/sqft will depend on desired intensity. Anything between 750 as 1250 PPFD is reasonable, wattage will depend on PPFD target and chip efficiency. If you can be more specific on how much light you want and what chip/current you're considering we can give more specific recommendations.

fjbudboy said:

I also imagine some of the efficacy to be lost due to the shift creating colors that may not contribute much to lumens.

Click to expand...

you def got it, just worth emphasing for noobs that just because lumen number goes down doesnt mean the new color created is outside of the PAR range we want, and in most cases its in a more usable red or blue wavelength

unrelated but thread title reminds me of