color temperature control

[tazztone]

Good work!

well the drivers only deliver 50% max like this, wouldn't they? still better to use 2 potentiometers.

Just got a 200watt COB fixture (20x 20watt cobs, run at half power), and it puts out a fair amount of heat, even at 160lm/w. Thinking anything I can do to up the efficiency will make for happier plants.

with any strip light you will have the advantage of having a spread out rather than a point light source. that may be enough of an advantage.
the vestas are only 7% less efficient than lm561c CRI80 in terms of PPF/W if i remember correctly.

[ATPinMotion]

Depends on the driver - I think I know what you mean though. Each side of the vesta is rated for 1 amp, and if each driver delivers 1 amp, you'll only ever have 1 amp total through the strip, or only .5A through each when balanced.

You could just use larger drivers, but I agree, discrete dimmers offer the greatest flexibility.

The strips I'm favoring are Samsung LT-Q22

80 CRI only, but just over (or under) 200lm/w depending on CCT

Compared to a Vesta, they have only half the power handling which means Vesta is still ahead in lumens/dollar but with a claimed efficiency of ~130lm/w it's not a small difference. Vestas will be more costly to operate. Running 18h/day in the Veg tent, efficiency has its advantages.

Still, CRI 90 and tunability offered by the Vesta are very attractive for interior lighting and photography.

[tazztone]

Vesta is still ahead in lumens/dollar but with a claimed efficiency of ~130lm/w it's not a small difference.

yeah lumen per watt of vesta are lower than cri80 sammies. however lumen only tell half the story.
in terms of PPF/W they are more equally matched.

i posted this comparison at RIU:
"if you run one F564B at 1.8A u would make 204 umol/s (at an efficiency of 2.35). *assumed 50°C.
comparing this to two vestas: they would emit 224 umol/s (at efficiency of 2.27)
in this scenario two Vestas give you 10% more photons at 3.5% lower efficiency while saving you 6$ compared to one F564B.
plus you would probably damage your F-strips faster because they run hotter."

also check out this post i made comparing lm561C and LM301B (Fseries vs Qseries): viewtopic.php?f=11&t=943&p=6042#p6002
if you get a F-series instead of Qseries you pay 1.23x more per strip.
but you also get 1.8x more light (more LEDs)
and only lose 2.5lm/W efficiency (F562B vs Q562A at same Total wattage)

[ATPinMotion]

Thanks for the link. Really appreciate the data you have shared!

Sorry to pollute your thread here - I thought about starting one of my own, but it seems we have resolved your question.

Can you go a little further into PPF vs Lumens?

I come from an audio engineering background, so I'm quite familiar with FFT's and spectral distribution curves if you will. I understand how blurple lights can have high PPF with very few lumens, but if we are comparing two LED's with the same macadam's 3-step CCT, and CRI, wouldn't the lumen : PPF ratio remain constant and thus have the same conversion factor? I see from your graphs that is not strictly true, and the 90CRI models have a bit more 'sideband'(?) Not sure if that's the right term but i mean energy outside the 'lumens' band. On the charts this seems pretty subtle, am I missing something here? In your example (vesta vs 564) I just don't understand how Vesta's are ~25% less efficient in lm/w but only 5% less efficient in umol/w.

After much deliberation (and a few pricing changes) Bridgelux EB gen 2 seems to be the 'holistic' choice, in my location, at this moment. Criteria being 'lumens per dollar per watt'.

Unfortunately only 3500K and 5000K are available. I want to get 1x 4000k strip for seedlings/clones, 2x 3500K's from veg and 3x 3000k's for flower. But availability for the 3000K and 4000K 4000lm strips is March 1 (I'm in Canada)

So I think I'm just going to order 6x 3500k strips to get started and suppliment or swap out down the road. At $15/strip I'm not likely to regret such a decision am I? Have you compared umol/w of the Vesta's to EB gen 2?

[tazztone]

I understand how blurple lights can have high PPF with very few lumens, but if we are comparing two LED's with the same macadam's 3-step CCT, and CRI, wouldn't the lumen : PPF ratio remain constant and thus have the same conversion factor? In your example (vesta vs 564) I just don't understand how Vesta's are ~25% less efficient in lm/w but only 5% less efficient in umol/w.

concerning lumens vs PPFD check out this by induluxtech.com:

a little shift away from the green towards the red wavelengths (what you get from CRI80 to CRI90) drastically reduces lumen count (1951 CIE curve) but has little effect on YPFD values (mccree).

EB gen2 is a common choice. the vestas probably use the same LEDs but higher CRI.
higher CRI is done at expense of efficiency (you lose some photons because of the phosphor layer that's doing the "conversion").
these graphs were made by the user livinglight and can be found in the thread about the Vestas i started

with the vesta you pretty much get more LED's for the money. driving them softer means you gain efficiency (that you lost by going CRI90).
if you buy enough of them you end up close to F564B, but also closer to it's price.
if the vestas were CRI 80 you'd probably end up beating everything in terms of photons per W per $

[ATPinMotion]

Damn do I love learning stuff, thank you for indulging me! This rabbit hole goes deep! I'll give your Vesta thread another read through - I understand a lot better now what I am looking at. Lots to sink in on this subject. Thanks again my friend.