200 X Cree XP-G3 on one board

[nevergoodenuf]

@Will-In-China I think you have the 400 watt heat sink? I have the 500 watt version and it looks bigger or at least more heat pipes. My issue with that design is that is has to much of a hot spot, even without the reflector on. If you switched to COB or square led board and mount them at the four corners of the heat sink, you would end up with a much more even light distibution. Then make square reflectors to reflect the extra light to the outer edges.
Something like this-

 

[nevergoodenuf]

Dam it, now you have me side tracked on building with old parts. The only thing I don't have is thermal Epoxy. How does 4 COB at the corners @ 125w each and the old XBD's will be ran @ 100 watts (.3 or well over 155 lumen per watt). And since I have a monster fan, that can be thrown in.
Didn't mean to hijack your thread, just my thoughts, since I have played around with one of them before.

 

[Will-In-China]

@Will-In-China I think you have the 400 watt heat sink? I have the 500 watt version and it looks bigger or at least more heat pipes. My issue with that design is that is has to much of a hot spot, even without the reflector on. If you switched to COB or square led board and mount them at the four corners of the heat sink, you would end up with a much more even light distibution. Then make square reflectors to reflect the extra light to the outer edges.
Something like this-View attachment 3767752

@nevergoodenuf wow yeah, great to find someone else tinkering with the same heatsink, I see you have 6 of the copper heat pipes, I need to grill the shop keeper and see if he's had me over for a 400w

The position of the cobs I totally get, maybe even more spacing would be even more optimal? Getting the back of the cobs in direct contact with the copper and then sealing it all up again to keep the IP rating would be a challenge, maybe an unnecessary one depending on the COB heat.

Where are you headed with your build, what are you aiming for? Was it the hotspot that made you give up on the board you mounted in the center?

 

[Will-In-China]

Dam it, now you have me side tracked on building with old parts. The only thing I don't have is thermal Epoxy. How does 4 COB at the corners @ 125w each and the old XBD's will be ran @ 100 watts (.3 or well over 155 lumen per watt). And since I have a monster fan, that can be thrown in.
Didn't mean to hijack your thread, just my thoughts, since I have played around with one of them before.View attachment 3767779

Dude I'm loving it go for it, let rip...

 

[nevergoodenuf]

Like I said, these are old parts, look in my sig to see the Luna's and CLU058. Diodes are for people with expensive machines

 

[frica]

I guess that's done with reflow soldering.

The thing that will probably always put SMDs above COBs when it comes to mass production.

 

[Will-In-China]

It just "Boggles" my mind the umol drop 4 ft. 885 umol to 5 ft. 64 umol...

Cool light though.

Phpatrick

Phpatrick you were right, it was me! For some unknown reason I left of the last number!

2ft = 2000 umol
3ft = 1267 umol
4ft = 885 umol
5ft = 640 umol
6ft = 471 umol

 

[Will-In-China]

well for example if you wanted to limit current you could dial voltage down so it cant rise over a certain point if that makes sense. most drivers are combination constant current/constant voltage depending on how you operate them

The drivers I'm using is 2x Mean Well HLG-240H-36A's and heres the dials labeled "Vo ADJ" and "Io ADJ"

 

[Will-In-China]

I need to get some red's ordered this week, should I stick with the cree XP-E or look at Osram? Is there anyone else with good efficiency I really should look at? How many reds should I swap out?

All opinions welcome!

 

[Colo MMJ]

I have 4 spectrum kings

Which model? Do you like them?

 

[CobKits]

Phpatrick you were right, it was me! For some unknown reason I left of the last number!

2ft = 2000 umol
3ft = 1267 umol
4ft = 885 umol
5ft = 640 umol
6ft = 471 umol

I just cant wrap my head around something that needs to be 4 feet from the canopy to get the right intensity. seems like working backwards, you must have some tall ceilings!

 

[Will-In-China]

I just cant wrap my head around something that needs to be 4 feet from the canopy to get the right intensity. seems like working backwards, you must have some tall ceilings!

@CobKits help me understand why 4ft away is the right intensity?
Remember a sunny day mid summer I measured at 1700 umol and the temp at 2ft was only 10 degrees over ambient

 

[CobKits]

How many hours per day in nature do plants get 115% of full sunlight?

 

[Will-In-China]

How many hours per day in nature do plants get 115% of full sunlight?

I see where you are going now.

I reference icmag below stated the University of Mississippi who recorded optimal growth at 1500 umol At 30 °C, granted they didn't state if the 1500 umol was given for 12 hours. https://www.icmag.com/ic/showthread.php?t=127379

Here are my umol readings for a bigger period of time during that same mid summer hot day.

10:00 = 1420 umol
11:00 = 1680 umol
11:45 = 1700 umol
12:30 = 1650 umol
13:00 = 1450 umol
14:00 = 1240 umol

These were taken with the correct SUN setting not the ELEC setting used for measuring electric light

But you are right it's hard to argue with mother nature, providing more than she does cant be good or better, right? Or could it?

Mwaa ha ha haaa!

 

[CobKits]

so your answer is zero hours per day then?


do two grows, one at 1000 umol and one at 2000 umol for 12 hours a day and get back to us

 

[CobKits]

reference icmag below stated the University of Mississippi who recorded optimal growth at 1500 umol At 30 °C, granted they didn't state if the 1500 umol was given for 12 hours. https://www.icmag.com/ic/showthread.php?t=127379

actually it said "WUE increased only up to 1500 μmol m-2s-1 PPFD at 30 oC and decreased thereafter at higher light levels." so im not sure why you would think 2000 umol would be a good target

while 1500 umol may be the "maximum" it is not the "ideal" if you understand the law of diminishing returns. in other words the same electrical energy used to light up 2 sq m at 750 umol will yield *a lot* more than 1 sq m at 1500 ppfd. like 1.6 times as much

from our buddy @Rahz :

 

[CobKits]

in theory, if electricity were free and everyone was a master grower we would all strive for 1500 ppfd

in practice, it gets increasingly difficult to maintain the ideal air/nute/water/temp balance the harder you push it. its really easy to grow between 700-900 ppfd and get excellent results very efficiently, and a very high quality crop as youre not pushing the envelope of plant stress.

Its not hard to run into heat stress/bleaching/nute deficiencies when you push it above 1200 ppfd and these factors alone could more than offset the 10% yield gain you just used 30% more energy to achieve, making it a wash in many cases

 

[CobKits]

But you are right it's hard to argue with mother nature, providing more than she does cant be good or better, right? Or could it?

i dunno, i have yet to get my bill for the sun :0

 

[Victor6634]

Which model? Do you like them?

I use the closet cases for vegging and I love them so do my plants will post some pics later

 

[Will-In-China]

in theory, if electricity were free and everyone was a master grower we would all strive for 1500 ppfd

in practice, it gets increasingly difficult to maintain the ideal air/nute/water/temp balance the harder you push it. its really easy to grow between 700-900 ppfd and get excellent results very efficiently, and a very high quality crop as youre not pushing the envelope of plant stress.

Its not hard to run into heat stress/bleaching/nute deficiencies when you push it above 1200 ppfd and these factors alone could more than offset the 10% yield gain you just used 30% more energy to achieve, making it a wash in many cases

So whats the deal with the 1000W HPS fixtures that kick out over 2000 umol are they actually stunting the plants growth as opposed to helping it?