COB efficiency Spreadsheets

churchhaze

Well-Known Member
Wondering the same thing. Would anything above 700nm actually be able to contribute to photosynthesis though?

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Very little, but like blue, some is good. A small amount of 730nm is also good. The 3000k 80cri SPD has something like a 6:1 R:FR ratio. HPS has more like 2:1. That lower R:FR ratio of HPS could have something to do with why it makes such a good flowering lamp, as well as the high rate of photons.

Too bad it would be hard to have 2 values for everything if we want to represent both 380-750 and 400-700 individually. We'd either have to name them 2 things (like PAR[380-750] and PAR[400-700], or compromise and just decide on one, knowing we lose valuable information with one, and mislead with the other.
 

AquariusPanta

Well-Known Member
Very little, but like blue, some is good. A small amount of 730nm is also good. The 3000k 80cri SPD has something like a 6:1 R:FR ratio. HPS has more like 2:1. That lower R:FR ratio of HPS could have something to do with why it makes such a good flowering lamp, as well as the high rate of photons.

Too bad it would be hard to have 2 values for everything if we want to represent both 380-750 and 400-700 individually. We'd either have to name them 2 things (like PAR[380-750] and PAR[400-700], or compromise and just decide on one, knowing we lose valuable information with one, and mislead with the other.
Whichever one helps us grow better should be taken into consideration.
 

Greengenes707

Well-Known Member
Hard to say. I can't find anything useful about Gavita (their website AND spec sheets are seriously PITA).

Regarding the range -- I don't know. But PAR range is often referred to as being 400-700 nm.
RQE is what is scientifically used not just the term PAR. RQE was established by McCree who is credited with defining PAR and shows activity beyond/below 400-700. 720nm being 25%...to some people that is how well green is used.

So to me it is only logical to include all active radiation. As per definition of PAR should be included anyways.


I'm not arguing or questioning anything you've done. I would like to thank you fornit all and your new thread. Just voicing my opinion/understanding of what PAR really is, openly for discussion.
 

alesh

Well-Known Member
[...]
I'm not arguing or questioning anything you've done. I would like to thank you fornit all and your new thread. Just voicing my opinion/understanding of what PAR really is, openly for discussion.
Oh please do!
I really don't know whether we should use 400-700nm range or any other. TBH main reason why I posted this range is the Wiki article about PAR. Not a reliable source, I know.

It is also true that that if the rate is below 25% outside of that range it is more accurate not to include it.
 
Could someone add in an explanation to what these numbers mean? :(

It looks like lumens per watt is higher at lower volts, but per PAR is cheaper at higher volts?

Do LEDS operate more efficiently at lower or higher voltages?
 

churchhaze

Well-Known Member
Could someone add in an explanation to what these numbers mean? :(

It looks like lumens per watt is higher at lower volts, but per PAR is cheaper at higher volts?

Do LEDS operate more efficiently at lower or higher voltages?
It's cheaper at higher current, but less efficient. That means you'd need fewer of them to fulfill your lighting requirement.

It's more expensive to run at lower current because you need more of them to fulfill your lighting requirement, but then it's more efficient.

Efficiency is the column next to startup cost per watt. It says how much output power (in watts) are produced for 1W of input power. So 50% efficiency would produce 0.5W PAR power for every 1W electric power input..
 
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