COB efficiency Spreadsheets

Darth Vapour

Darth Vapour

Well-Known Member
Meinolf said:
Unfortunately you cannot put the sun into a tent.

Besides: Have you read a single line in this forum?
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Actually i have read and posted lots in this forum lol as for this thread first post i am just curious on percentage of light and percentage of heat as per cob units is all which i think is relative
also with CRI ratings this also can determine efficiency most of the time higer CRI rated lamps or what have you have less lumen out put so with all this said
I think we cannot truly believe manufactures said efficiency on what ever
Tests need to be done by out side sources ,, We could be very well shocked at actual efficiency.
Something i learned long ago don't believe everything a company says while trying to boast there products
for instance The LUXIM plasma lighting system was measured in base-up and 90° orientations at full power. NLPIP found that the light output in the base-up orientation was 18,378 lm, which is 20% lower than the rated light output. LUXIM’s LiFi STA 41 01 Data and Reliability Package claims that the light output in the 90° orientation is 4% lower than in the base-up orientation (LUXIM 2010c). In the 90° orientation, NLPIP measured a light output of 17,013 lm, 23% less than the rated light output in this orientation and 7% lower than the measured light output in the base-up orientation.
 
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PurpleBuz

Well-Known Member
Meinolf said:
"light with a wavelength greater than 680nm is much less efficient [in driving oxygen evolution] than light of shorter wavelengths" (Taiz et. al. 2015: 179)

So most of that deep-/far-red light will become tissue heat, but that's not necessarily a bad thing, because the heat is driving transpiration, therefore gas exchange and nutrient uptake (Sometimes with led only my temperatures are too low). The high 730 proportion may also give a lot more stretch, but might as well be somewhat beneficial to multidirectional cob lighting (Some LED buds get extremely dense to the point of bud rot menace).

The results would have to be compared to give an educated guess on the efficacy of such high CRI spectra, and the aligning efficiencys make it possible to do so. I suppose a lot of people will try. What's the price of a unit anyway?
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I thought cree whites or vero whites emit an insignificant amount of 700+nm light. Is that not true ?
 
Meinolf

Meinolf

Well-Known Member
PurpleBuz said:
I thought cree whites or vero whites emit an insignificant amount of 700+nm light. Is that not true ?
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Well, I based that 730 claim on a single look on Alesh's new graph, where it appears the amount of far red light to be higher than at 80CRI. This is inuitive to me as the phosphor "shifts" the blue light towards red. Would you please overlap the other graphs for comparison, @alesh? :)
 
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Greengenes707

Greengenes707

Well-Known Member
Darth Vapour said:
the upside of Higher CRI is full spectrum and nothing beats the sun @ 100 CRI

Anyways i been doing some reading about light Efficiency One of the basic laws of physics is the law of the Conservation of Energy. This simply states that energy cannot be created or destroyed, it can only be transferred from one form to another. So when a 100watt lamp is switched on, 100 watts of electrical energy is converted to 100watts of light and heat; a 50watt lamp produces a total 50 watts of light and heat, and so on.* However, some lamps are more efficient at producing light than others; this determines how much of that 100 watts is transformed into light, and how much is "wasted" and comes out as heat
An incandescent lamp is an extremely inefficient light source. According to the Wikipedia online encyclopaedia, a 100 watt bulb is 2.1% efficient. In other words, it produces about 2 watts of light and 98 watts of heat.

A halogen lamp is a bit better. For every 100 watts you put in, you get about 3.5 watts of light and 96.5 watts of heat.

Fluorescent lamps are said to be about 8.2% efficient, and although there were no figures on Wikipedia for mercury vapour lamps, I found one reference saying they were about as efficient as fluorescent lamps, and another that said they were three times as efficient as incandescent lamps... so we're looking at 6 - 8% efficiency here. 100 watts of electricity will be converted to, at most 8 watts of light (including UV light) and 92% will still come out as heat.

So the main factors which determine how much heat a lamp puts out, are what type of lamp it is, and its wattage.

However, the heat and light from a lamp can be emitted in all directions, or focused on a small area (consider the heat and light you might experience sitting 2ft below a 60 watt frosted "globe" lamp as opposed to a 60 watt narrow beam spot lamp) hence the shape of the lamp, the type of glass surface and the presence or absence of reflectors, such are found inside spot lamps, will also play a major part in determining how hot a basking spot gets directly under any lamp, of whatever wattage.

So has anyone actually figured out how much light percentage to heat percentage on the Cobs
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We told you months ago...you know...all the efficiency numbers we have told you multiple times for months...
But you didn't want to listen then. It was hogwash to you.

Also the high CRI has a lower LER. So no matter what it will have a low efficacy(not the same as efficiency). But the photons pumped out are the same.
EX for concepts, numbers are abstract...
100lm/w of 90cri is equal to 140lm/w of 80cri in photons...which is what plants care about.
 
ttystikk

ttystikk

Well-Known Member
Here's my justification for using Cree CXB3590 COB LED 80 CRI chips @3500 Kelvin...

Because I really like the results I saw from y'all using them. Seriously!

Theory is all very well but if the results are weak, something's wrong.

I have hung back from LED for a decade, until I saw respectable results coming from real people with the chips I want to use.

Again, CRI is based on how HUMANS see things, not on how well plants respond. I'm reluctant to say that high CRI automatically correlates to ideal lighting for plants.

My bet is that the overall spectrum quality combined with the chip's lighting efficiency now commonly achieved will return the results I'm looking for.

I'm betting a lot... so I sure hope I'm right!
 
SupraSPL

SupraSPL

Well-Known Member
Darth Vapour said:
i am just curious on percentage of light and percentage of heat as per cob units is all which i think is relative

I think we cannot truly believe manufactures said efficiency on what ever
Tests need to be done by out side sources ,, We could be very well shocked at actual efficiency.
Something i learned long ago don't believe everything a company says while trying to boast there products
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I agree we should be very skeptical about any claims initially. For a long time CREE has been the go-to for the LED flashlight guys which are much more numerous and focused than us and have had many lights tested. Stardustsailor had a Cree CXA3070 top bin and Vero29 tested in a university lab and verified that they emit above their minimum values. CREE does not stand to gain in the medium to long term by overtstating the light capabilities, they tend to be conservative to avoid overpromising.

Once you have reliable lumen figures the next step to figuring efficiency is finding LER. CREE provided the LER for CXA 2700K (321) and 3000K (325) and this matches up with their published SPD curves. So we have a pretty solid idea where were are regarding actual efficiency of LEDs.

You can verify this further with a caloric test. Run a COB at 100W+ on a small heatsink and monitor the temperature increase/time in the heatsink. You could then estimate the amount of heat energy that was pumped into the heatsink.
 
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dionysus4

dionysus4

Well-Known Member
did i miss the LER spreadsheet for cxb3590 and cxb3070?
what about info for driving them lower than 50w?
 
littlejacob

littlejacob

Well-Known Member
PurpleBuz said:
does this chart tell us that the two monos (Philips deep red and osram hyper red) for deep red are significantly more efficient than any of the phosphor chips ?
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Bonjour
It is what I have understood too!
It is not clear...it should be mentioned somewhere!
Thanks alesh for the info!
Have a great day ★
 
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