COB efficiency Spreadsheets

EfficientWatt said:
Lower current => higher lumens/W but less light per cob.
Higher current => less lumens/W but more light per cob.

Therefore, for a target amount of light:
=> lower current, means more cobs are needed, so more upfront $$$, but higher efficiency and electric savings.
=> higher current, less cobs needed, less upfront $$$ needed, less electrical efficiency/savings too.

(Voltage drops a little at lower currents, and rises a little at higher currents, but it is thru current that we drive them (underdrive/overdrive))

EDIT : Churchhaze was quicker :oops:
Click to expand...
I am new to LEDs and I have a few lights I bought at an auction locally.
I plan to build some after this grow is over.
I have a few hundred questions, but Ill start with one...

I understand the info I quoted, but what about life expectancy of the LEDs when driver harder as opposed to driven softer?
More lumen/par loss more quickly, and/or burn out faster?
 
In most cases, yes. But I beleive it's more tied to actual operating temperature, and how well you cool.

Of course it's easier to cool an underdriven led, but :
An underdriven led with poor heat dissipation (running at +90°C) will probably die before a hard run led with extreme cooling (running at ~35°C).


bassman999 said:
I am new to LEDs and I have a few lights I bought at an auction locally.
I plan to build some after this grow is over.
I have a few hundred questions, but Ill start with one...

I understand the info I quoted, but what about life expectancy of the LEDs when driver harder as opposed to driven softer?
More lumen/par loss more quickly, and/or burn out faster?
Click to expand...
 
bassman999 said:
I am new to LEDs and I have a few lights I bought at an auction locally.
I plan to build some after this grow is over.
I have a few hundred questions, but Ill start with one...

I understand the info I quoted, but what about life expectancy of the LEDs when driver harder as opposed to driven softer?
More lumen/par loss more quickly, and/or burn out faster?
Click to expand...
Bonjour
What kind of led?
Have a nice day!
 
EfficientWatt said:
In most cases, yes. But I beleive it's more tied to actual operating temperature, and how well you cool.

Of course it's easier to cool an underdriven led, but :
An underdriven led with poor heat dissipation (running at +90°C) will probably die before a hard run led with extreme cooling (running at ~35°C).
Click to expand...
I was thinking of buying a few and adding more when the I could afford it, and then running them softer at that point for better spread.
 
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littlejacob said:
Bonjour
What kind of led?
Have a nice day!
Click to expand...
I havent decided yet, Theren are so many choices, and I dont fully understand the pairing to drivers yet.
I dont understand the BIN thing either. I know what cri is, but not sure how that relates to plants and or lumens/par.
 
I also have some questions about heatsinks.
Is there a formula for spreadsheet for in^2 per watt dissipation or something?
There is a local place that sells sheet metal and heatsinks that they machine on premesis.
Or is thee somewhere really cheap online?
 
bassman999 said:
I also have some questions about heatsinks.
Is there a formula for spreadsheet for in^2 per watt dissipation or something?
There is a local place that sells sheet metal and heatsinks that they machine on premesis.
Or is thee somewhere really cheap online?
Click to expand...
Bonjour
There is a formula in the thread heatsink for diy or in heatsink in Europe!
Online solution for US is heatsinkusa and for EU it is TME.com...if you want a very safe build...but some use cpu cooler but if the fan fail it could fry your cob (but if you choose small cheap and underdriven cob it is a good option imo)
Cree bin their cob if you aim for cxb 3590 the scale go like this (from lower to highest bin):AB.AD.BB.BD.CB.CD.DB.DD.
But not all the bins are available for each temperature (for ex CD is the highest bin in 3500ºk and I guess DD is only and rarely available in 6500ºk...)
And for driver compatibility you need to know the vf of the cob you want(36V for cxb 3590 @1400mA) and the driver output (4 cxb 3590 X 36V= 144V so you will need a driver who put out 144V minimum)
I have an hlg-185-1400b to run my 4x cxb 3590 3500ºk 36V CD and it work very well...I am so happy with it!
Have a great day ★
 
bassman999 said:
Is there still no way to multi-quote here?
I hate to reply one at a time
Click to expand...
sure there is, look :
bassman999 said:
I also have some questions about heatsinks.
Is there a formula for spreadsheet for in^2 per watt dissipation or something?
There is a local place that sells sheet metal and heatsinks that they machine on premesis.
Or is thee somewhere really cheap online?
Click to expand...
=> first page, my first post has Heatsinkusa cm²surface area per inch length.
accepetd values here are 120cm² per W of heat dissipated for passive, and 40cm² for active cooling.
 
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littlejacob said:
Bonjour
There is a formula in the thread heatsink for diy or in heatsink in Europe!
Online solution for US is heatsinkusa and for EU it is TME.com...if you want a very safe build...but some use cpu cooler but if the fan fail it could fry your cob (but if you choose small cheap and underdriven cob it is a good option imo)
Cree bin their cob if you aim for cxb 3590 the scale go like this (from lower to highest bin):AB.AD.BB.BD.CB.CD.DB.DD.
But not all the bins are available for each temperature (for ex CD is the highest bin in 3500ºk and I guess DD is only and rarely available in 6500ºk...)
And for driver compatibility you need to know the vf of the cob you want(36V for cxb 3590 @1400mA) and the driver output (4 cxb 3590 X 36V= 144V so you will need a driver who put out 144V minimum)
I have an hlg-185-1400b to run my 4x cxb 3590 3500ºk 36V CD and it work very well...I am so happy with it!
Have a great day ★
Click to expand...
I am going to look for a thread about drivers, and try to understand them better, and what to look for with wiring options.
Series, parallel, or a combination of the 2 to get amperage or voltage where you want it
 
EfficientWatt said:
sure there is, look :

=> first page, my first post has Heatsinkusa cm²surface area per inch length.
accepetd values here are 120cm² per W of heat dissipated for passive, and 40cm² for active cooling.
Click to expand...
I saw that, but I dont understand it at all unfortunately.
It seems like 120-150 in^2 per 100 watt, but that was a guess based on looking at some specific recommendations I saw listed
 
bggrass said:
I looked through the thread but can't find the cxb3590 DD 72v sheet. Does anybody have it?
Click to expand...

The DD is only available in 6500K so far. We do not have the SPD or the LER for the 6500K Cree so it would be tricky to determine efficiency and PAR W but I am trying to get that information from Cree.

You can see an example of a 6500K curve from Citizens COBs
Citizen CLU SPD.png

Since the 6500 is higher in blue, and blue photons require more energy to emit, there will be less photons per PAR W (a lower PPF).

The data we do have, 5000K CXA3590 DB and 5000K CXB3590 CD:
CXA3590 5K DB 2.png CXB3590 5K CD Verical.png
 
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Hi everybody. Please excuse me for my probably very stupid question. Everywhere on the forum I read "check the efficiency spreadsheet thread". Here I'm, but I didn't find any spreadsheet to download or use. I mean, is there an actual spreadsheet (excel or like?) file to download, or do you mean the PNG file image of a spreadsheet shared here?

Also, where can I find a thread explaning the header abreviations used such as factor 50c, lm85c, lm50c, vf50, 50c dissW, 50c lm/watt, 50c %, etc?

Thanks
 
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