What happens to Spectrum when we dim our lights?

MichiganMedGrower

Well-Known Member
interesting topic. has anyone looked into the question of spectral shift with age.seems red output would drop as the phosphor ages and degrades with use but I have been unable to find any data on this
I would like to see the data too.

I can sure see the plants response worsen after 9-10 months under the same Hortilux super hps.

My cheap lumen meter shows some loss but that could account for plant growth. Although if hortilux shows that dimming changes spectrum so would a weaker older bulb I guess.
 

MichiganMedGrower

Well-Known Member
It's a chart dated 2011 and Whazzup posted it end of 2011 on Opengrow when they were introducing their DE fixture.

The first line is the DE bulb.

I remember reading whazzups findings a few years ago but I was saying the Hortilux charts and blog and a past video were for dimming single ended hps.

The blog says 2016.
 

CobKits

Well-Known Member
As stated drive current is based upon maximum umoles as the subject of my comment. Find someone else to fight with not me.
not "fighting"

when you post incorrect info on a public message board expect to be called out

700 mA is neither 'maximum umoles' or maximum PPFD/watt for that chip
 

jarvild

Well-Known Member
interesting topic. has anyone looked into the question of spectral shift with age.seems red output would drop as the phosphor ages and degrades with use but I have been unable to find any data on this
No phosphor coating on MH or HPS bulbs. Type of gasses contained render the color. Now with a monochromatic light source as with LED's , they use it for color rendering.
 

VegasWinner

Well-Known Member
not "fighting"

when you post incorrect info on a public message board expect to be called out

700 mA is neither 'maximum umoles' or maximum PPFD/watt for that chip
Go away expect to be called. Yes you are fighting. You never noticed I never stated an exact drive current on purpose so no wrong information was given. You are just looking for a reason to fight so go away you are misinformed as usual. Now you have been called out BG. Make it personal I put you back on ignore because you do ignorant so well.
Go shadow box
randori
 

CobKits

Well-Known Member
Go away expect to be called. Yes you are fighting.
give it up. you say people are "picking on you" every time you get corrected. i dont care who the user that posted that was, i would have corrected it. it is 0% about you.

You never noticed I never stated an exact drive current on purpose
except that you did. you said it was "about 700mA", when in fact there is NO current that is 'optimum':
With 36v cxb3590 I believe the optimum drive current is 700mA or so, not sure the exact number
I put you back on ignore
feel free, no love lost. I'll still correct your misinformation
 

VegasWinner

Well-Known Member
Lots of good conversation guys let's keep on topic and keep the ideas and relevant info flowing
I agree. calling people out as always wrong is WRONG.

Every diode has a sweet spot or drive current that delivers the highest umoles per watt, that is the point of pcb design. Anyone can drive a diode hard and make it bright, but to make the diode most luminous is the goal.

No WRONG in that understanding. Review the data sheets for various diodes and they give you the drive current, usually too low to be real, but they also give real drive current as targets for designers. normal method of doing business.
 

CobKits

Well-Known Member
Every diode has a sweet spot or drive current that delivers the highest umoles per watt
Yes it is less than 1% of nominal current and is typically out of the practicality of design.

your "Sweet spot" analogy suggests that there is a practical current where there is a maximum in efficacy, when in fact, efficacy continues to rise as current drops. due to thermal limitations, *every* led looks like this when efficacy is plotted vs wattage in absence of other factors


upload_2017-10-3_3-36-36.png


something that had a "sweet spot" (or as you previously called "optimum drive current to get the highest umoles per watt" or "maximum umoles" would look something more like this with a defined maximum current below which only incremental gains are seen as opposed to going pseudo-asymptotic on the Y-axis:

upload_2017-10-3_3-41-17.png

so for LEDs the "optimum" current is always the lowest you can afford to run, and is different for each user. its an economic decision (payback of efficiency/yield gains vs available capital) - there is no inherent "sweet spot" in LED current

even in that second graph we are still seeing maximum efficacy at lower current, but are experiencing diminishing returns. a true "optimum current" would generally be driven by multiple variables (like crowding of diodes to maintain a certain level of flux at canopy, and would look more like this

upload_2017-10-3_3-47-39.png
 

VegasWinner

Well-Known Member
I am just going to put this out there. Thinking you have the RIGHT to TROLL someone and demand YOU have ALL the RIGHT answers and THEY have ALL the WRONG answers is truly the EGO at work, as well as making PERSONAL Attacks under the guise of something else. I do NOT need to be RIGHT at the expense of Others, that is self-serving. However I can be RIGHT without offending others unless the TRUTH offends them.
 

Abiqua

Well-Known Member
I am just going to put this out there. Thinking you have the RIGHT to TROLL someone and demand YOU have ALL the RIGHT answers and THEY have ALL the WRONG answers is truly the EGO at work, as well as making PERSONAL Attacks under the guise of something else. I do NOT need to be RIGHT at the expense of Others, that is self-serving. However I can be RIGHT without offending others unless the TRUTH offends them.
Answer the question, there was not a SINGLE personal attack....All I see is deflection for the original question, and then surprise a personal attack by you....YOU FUCKING HYPROCRITE

Answer the question. Maybe the truth does offend, but no so long as you are incapable of providing it......

Furthermore ALL your posts will be flagged for Advertising TOS violations. Take your big smo/mongo frog, atttitude back to the weeds.....
 

wietefras

Well-Known Member
Yet again Vegaswiner doesn't get it and gets upset that he was wrong and got corrected by someone who does understand the matter.

I have already explained already that there is no single "optimum" and that at best you could go for an "optimal" current which is "optimal" only for a certain situation (depending on other parameters as well).

COBkit actually put a lot of effort in trying to explain this to you again and he even included charts to demonstrate the facts. How on earth does this not sink in?
 

Abiqua

Well-Known Member
What's your fucken problem it's my thread go piss off you do nothing to contribute in this section you don't like what I have to say stay out of the thread it's really simple :)
Fascist...take yo ass back to the flea market with your buddy. Funny how you resort to personal attacks rather than substance.....the stink y'all make is ringing a little too close to home.......

Leads obviously don't grow great cannabis, suckers.
 

Abiqua

Well-Known Member
What's your fucken problem it's my thread go piss off you do nothing to contribute in this section you don't like what I have to say stay out of the thread it's really simple :)
so what, you didn't comment on Cobkits posts, which is succint and sums it up perfectly. Fuck off please, I don't have a personal beef, but I can....
 

Abiqua

Well-Known Member
Real classy, come into a thread and talk like a real Asshat to the OP???:roll:
Ya, your really lifting this section up......NOT
More like fueling the Fire :fire:
what is your point.....that you are bandwagonning for no reason? .....please explain the optimum then?
 
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