Led Lights... How Much Heat?

PerroVerde

Well-Known Member
So im guessing about 600 watts of cob can replace 1000 watts of hps?
It can...

15 CXB 3590 3500k @ 37w (1050ma) = 555w x .61 ( 61% efficiency) = 338.5 initial PAR watts x .9 for reflector/wall loss = 304.6
Now divided by let's say 4 x 4 so 16sf = 19.04 PAR watts per st.
Now multiply that times 4.65 umol = 88.55
Now multiply that times 10.7 ( feet in a meter squared) = PPFD of 947.5...

Not to shabby for 600 watts and those 15 cobs can be evenly spread over your area and even can be passively cooled. This is what's been showed me by many here (Supra, GreenGenes, Growmou5e) and many more. The main reason I'm building my own light...
 

hotshotisdashit

Well-Known Member
It can...

15 CXB 3590 3500k @ 37w (1050ma) = 555w x .61 ( 61% efficiency) = 338.5 initial PAR watts x .9 for reflector/wall loss = 304.6
Now divided by let's say 4 x 4 so 16sf = 19.04 PAR watts per st.
Now multiply that times 4.65 umol = 88.55
Now multiply that times 10.7 ( feet in a meter squared) = PPFD of 947.5...

Not to shabby for 600 watts and those 15 cobs can be evenly spread over your area and even can be passively cooled. This is what's been showed me by many here (Supra, GreenGenes, Growmou5e) and many more. The main reason I'm building my own light...
Nice break down.
 

eastcoastled

Well-Known Member
I built my first cob fixture. 4 cxb3590 cd bin @ 50 watts each, passively cooled on two 5.88"x20" heatsink us profiles. Each cob is centered 5" from the ends with 80 degree lenses, so they have 10" of heatsink. The two heatsinks are spaced evenly on aluminum angle so each cob covers 1 sq ft In a 75 degree room, my heatsink comes in at 85 degrees on the edges closest to the cobs. The metal lens holder measures 95 degrees. The canopy temperature measures 78 degrees 8" from the lenses(which is probably closer than anyone would want). These readings were taken with a quality laser thermometer, not a $15 piece of shit. I have a desktop thermometer sitting on top of the heatsink, and it reads 77 degrees. I know this isn't scientific, but these things run cool, and the light is very similar to hid in that it lights up the whole room.
 

bassman999

Well-Known Member
I built my first cob fixture. 4 cxb3590 cd bin @ 50 watts each, passively cooled on two 5.88"x20" heatsink us profiles. Each cob is centered 5" from the ends with 80 degree lenses, so they have 10" of heatsink. The two heatsinks are spaced evenly on aluminum angle so each cob covers 1 sq ft In a 75 degree room, my heatsink comes in at 85 degrees on the edges closest to the cobs. The metal lens holder measures 95 degrees. The canopy temperature measures 78 degrees 8" from the lenses(which is probably closer than anyone would want). These readings were taken with a quality laser thermometer, not a $15 piece of shit. I have a desktop thermometer sitting on top of the heatsink, and it reads 77 degrees. I know this isn't scientific, but these things run cool, and the light is very similar to hid in that it lights up the whole room.
Only the light spread is much more uniform
 

HockeyBeard

Well-Known Member
It can...

15 CXB 3590 3500k @ 37w (1050ma) = 555w x .61 ( 61% efficiency) = 338.5 initial PAR watts x .9 for reflector/wall loss = 304.6
Now divided by let's say 4 x 4 so 16sf = 19.04 PAR watts per st.
Now multiply that times 4.65 umol = 88.55
Now multiply that times 10.7 ( feet in a meter squared) = PPFD of 947.5...

Not to shabby for 600 watts and those 15 cobs can be evenly spread over your area and even can be passively cooled. This is what's been showed me by many here (Supra, GreenGenes, Growmou5e) and many more. The main reason I'm building my own light...
Isn't the hotspot of HID 2000K bulbs @ about 3ft 1100ish? I can't find a PPFD chart for HPS off hand. It probably varies by reflector. Maybe it's more, but my understanding was that I was getting really really close to HID numbers on a third of the energy and a fraction of the heat.

This breaks it down so so well.
 

littlejacob

Well-Known Member
Bonjour
You don't need cxb 3590 to get good results...Vero29(@1050) or Vero18(@700mA) would hit gpw for sure...
Even a 34/38% set up with multiple cob will give you better results than hid at same efficiency...because less light is loose and the light have more spread so a better light distribution! So imo it is possible to achieve gpw with around 40% efficiency and 1.5gpw with 56%! (In soil! Hydro should pull 2gpw or more! )
Try a small V29 panel with cpu cooler it will be cheaper than cxb 3590 with good results!
Have a great day ★
 

PerroVerde

Well-Known Member
Isn't the hotspot of HID 2000K bulbs @ about 3ft 1100ish? I can't find a PPFD chart for HPS off hand. It probably varies by reflector. Maybe it's more, but my understanding was that I was getting really really close to HID numbers on a third of the energy and a fraction of the heat.

This breaks it down so so well.
Here is a breakdown of hps 1000w systems done by Growershouse, great shop by the way... :)

http://growershouse.com/blog/best-indoor-grow-light-test/
 

wietefras

Well-Known Member
The trouble with those PPFD matrix measurements is that they don't use reflective walls. Especially with these big light that hang quite high, they lose a ton of light which is now not measured.
 

wietefras

Well-Known Member
My point is that those PPFD matrix tests are done without reflective walls. They hang a light over a piece of paper in a very large dark room. So every bit of light that would normally have reflected off the walls is not measured at all in those tests. That's a huge amount of light gone. Especially for 1000W HPS fixtures which are generally quite high above the canopy. I would guess they measure at best half the light coming from those fixtures.
 

dandyrandy

Well-Known Member
QUOTE="littlejacob, post: 12164638, member: 891850"]Bonjour
You don't need cxb 3590 to get good results...Vero29(@1050) or Vero18(@700mA) would hit gpw for sure...
Even a 34/38% set up with multiple cob will give you better results than hid at same efficiency...because less light is loose and the light have more spread so a better light distribution! So imo it is possible to achieve gpw with around 40% efficiency and 1.5gpw with 56%! (In soil! Hydro should pull 2gpw or more! )
Try a small V29 panel with cpu cooler it will be cheaper than cxb 3590 with good results!
Have a great day ★[/QUOTE]
You are correct! I hit a gpw plus with vero29's growing in soil. And I'm a novice.
 

littlejacob

Well-Known Member
Bonjour
Yes they are great too...!
And I know you are not the only one who pull more than gpw with those!
I guess it is possible at 38/40% efficiency with cob very well spaced!
So with more efficiency it will be more and more...
I on the way of my first more than gpw grow...I am sure because compare to hps it is much bigger.So now I guess all my grow would be in this range...even if I was sure to make "only"(only when talking gpw is weird!) Gpw I would have took cob...lol
When I grow I want quality and/or quantity now I will always have both!
Have a great day ★
 

PurpleBuz

Well-Known Member
My point is that those PPFD matrix tests are done without reflective walls. They hang a light over a piece of paper in a very large dark room. So every bit of light that would normally have reflected off the walls is not measured at all in those tests. That's a huge amount of light gone. Especially for 1000W HPS fixtures which are generally quite high above the canopy. I would guess they measure at best half the light coming from those fixtures.
that's the best way to do it. unbiased towards lamp systems that have better or worse light distribution.
any system that relies on reflective walls as a large proportion of its light loses a lot of that because of reflection losses.
 

bassman999

Well-Known Member
that's the best way to do it. unbiased towards lamp systems that have better or worse light distribution.
any system that relies on reflective walls as a large proportion of its light loses a lot of that because of reflection losses.
The problem I see with testing using walls is, what distance do you use to walls, and what type of wall?
Both of those will ad their own variables
 

hotshotisdashit

Well-Known Member
This question is for everyone. So what is the best cob light (outside of diy) available on the market?
1. Area 51
2. Optic Lighting
3. Go Green
4. Tasty
5.Heaven Bright
6. Another Panel (please list)
7. All about the same
 

hotshotisdashit

Well-Known Member
yes absolutely also...

Consider testing of a BML spyder versus an watt hps. BML spyder goes to extreme efforts to provide a nice uniform distribution without relying on walls\sides\reflective tents.
Ive seen people talking about the Bml. Any full grows on them? What were the results?
 

zep_lover

Well-Known Member
seen tastyled and johnson lights on here.looks like top quality parts like diy but buy off the shelf..it is not hard to diy your own cob lights.i bought ebay chinese cobs to try out and was very easy.i am almost done with my cxb3590 lights now.using vero is about double the cost of chinese cobs and almost half as much as cree cxb for a good test light.after building your own light, the pride factor is almost as good as your first crop of some good smoke!
 
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