Ok. Now it's all clear. While I was waiting your answers I was looking for more stuff, and I could understand almost everything.N8thaniel said:
Thank you again!
Paolo
Ok. Now it's all clear. While I was waiting your answers I was looking for more stuff, and I could understand almost everything.N8thaniel said:
ÂLet's Try said:As per a suggestion earlier in the thread, I'll be dimming these considerably. I have done the heat sink calculations to be able to run them passively without any form of active cooling (you need 17 square inches of heatsink per dissipated heat watt vs. 6 square inches of heatsink per heat watt when using a fan) and will have my heatsinks and thermal paste in a couple days. The pieces of aluminum are pretty big.
I think I'll still use fans to cool the heatsinks but I'm happy I'll have enough passive heat transfer capability in the event that any of the fans or power supply dies. Since I'll run the COBs at 700mA each and they are 64% efficient at that current, I won't have a lot of power wasted to heat to deal with either.
ÂLet's Try said:Do you get these spreadsheets from RIU?
Wow, very nice! Almost identical...flexy123 said:Hey, nice thread!
Â
I JUST happen to get me pretty much a similar light w/ 4x CREE CXB3590 36V 3500K CD bin although I got me the 1750mA Meanwell driver. I have the A version with the small internal dimmer, I am driving the lights currently estimated at 1600mA, about 80% using the dimmer.
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I am a little freaked now with you guys saying this is "more than mid-day in summer on the equator".
My grow space is 4x2 (120x60cm).
Â
But isn't the intensity of the lights also highly dependent on the height over canopy (mine are about 2' above plants) plus I have lenses too!
Â
Now I am freaking, should I dim the lights right away?
Â
What would be the PAR values for my 4x2' space? I looked at the formulas but all this is confusing although I know that my fixture right now should have about 36,000-38,000 lumens. Awesome lights.
Â
Edit: I also have seedlings under those lights
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I am growing certain things, along with Cilantro, Jalapeno and Seranos. Before, that stuff was under two cheap "300W" (aka: 120 real draw) MarsHydro LED lights.
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Edit: Mild - cool heat sinks, ah I see those lights are passive, otherwise I'd have sad overkillNice!
ÂLet's Try said:Wow, very nice! Almost identical...
I'm trying to figure out proper height as well. I have a row of seedlings under mine that just popped out (reaper and scorpion) and I think they're probably good where they are for now but we'll see...
Â
Âflexy123 said:Hey, nice thread!
Â
I JUST happen to get me pretty much a similar light w/ 4x CREE CXB3590 36V 3500K CD bin although I got me the 1750mA Meanwell driver. I have the A version with the small internal dimmer, I am driving the lights currently estimated at 1600mA, about 80% using the dimmer.
Â
![]()
Â
I am a little freaked now with you guys saying this is "more than mid-day in summer on the equator".
My grow space is 4x2 (120x60cm).
Â
But isn't the intensity of the lights also highly dependent on the height over canopy (mine are about 2' above plants) plus I have lenses too!
Â
Now I am freaking, should I dim the lights right away?
Â
What would be the PAR values for my 4x2' space? I looked at the formulas but all this is confusing although I know that my fixture right now should have about 36,000-38,000 lumens. Awesome lights.
Â
Edit: I also have seedlings under those lights
Â
I am growing certain things, along with Cilantro, Jalapeno and Seranos. Before, that stuff was under two cheap "300W" (aka: 120 real draw) MarsHydro LED lights.
Â
Edit: Mild - cool heat sinks, ah I see those lights are passive, otherwise I'd have sad overkillNice!
ÂN8thaniel said:Â
Â
what driver did you get? the 240 1750A?
Âflexy123 said:Â
Yup, one of the four mouser had. I am sorta regretting it since it was €82, but then again it's good to know I could run them at 1750mA.
Â
Now I am in the "bizarre" situation that I have a) not enough and b) too much light all at the same time.
Â
From what I researched, the 653-700 PPFD is too much for herbs and peppers, but then it's still below the optimal 1000PFD for some other plants.
I might move the herbs and tomatoes further away in my growing area I guess.
Â
By the way, your posts here, especially the one with the formula, PURE GOLD. Extremely helpful.
Did you ever happen to calculate PPFD for the old Marshydro 300W lights, just wondering?
Great news, hoping the costs will fall down!N8thaniel said:...
will be selling lights in europe soon
Âgrispa72 said:Great news, hoping the costs will fall down!