My Plan For A Cree Cxb3590 Light Bar

[Marxconha]

Man, you think in what i think before i think! Are you Jesus? Hahahaha! With this information i am secure that i can build something fine with security. Thanks very much seaslug you make me happy!

 

[seaslug]

You're welcome, Marxconha.

I'm putting more work than I expected making the heatsinkUSA extrusion as flat as I want. It is dished 0.0105 inches across the 3.945 width. SupraSPL no longer makes the effort to flatten and polish heatsinks but he advocates underpowering COBs. He likes 72Vf running at 750mA (50W), I believe. I don't care about polishing but a surface as large as a COB deserves a flat place to transfer its heat.

Edit: you would think a pair of 72V COBs could be driven in parallel by a 1400mA (for 700mA each) but this is discouraged by Cree. An imbalance of the Vf between the two COBs could result in too much current going through one of them.

 

[seaslug]

. . , But, if i build a small panel with 10 XP-E R3 Red and 10 XP-E R3 Royal Blue, for one plant or two in max, it will work? The wavelength of Red is 620-630nm and the Royal Blue 465-485.

I don't think this would be worth doing, it seems like too little power for flowering. And the 630nm is not what you want for flowering. I have an early LED luminaire called Procyon 100 that uses 630nm (not 660nm) and people were not happy with it for making buds. A mix of 630nm and 660nm would work well.

 

[Marxconha]

Yeah, it's a lot of work! But the reward gonna be great! Patience you must have! About the heatsink, you are polishing them? I don't understand that part. I know that the COB need a flat place and i saw that SupraSL polish the heatsink... That means were the COB will be must be flat? And rest can be polish? That applies for the XPE?
About the lenses, i was reading that they are not really necessary, because of the angle that the led light produce. Why are you putting them?

If multiple CX family LEDs are being used, connect them in series" :(

I will need some time to think in my project.. Maybe i do something stealth with the small LED and put other's for flowering.. need time and money to put my thoughts in order...

There are some words of Descartes that i wanna share with you, when you think you are tired about building this panel you can think in them, and smoke one or two :) (i will translate do português para o inglês, so if you don't understand a shit, sorry. The book is Meditation Métaphysiques from Descartes and this paragraph is the first from the second meditation. Everybody should read!)
"The meditation that i made yesterday filled my spirit of so many doubts that is not in my power to forget them. Otherwise, i don't see another way to solve them. Is like i had fall from deep waters. I am so surprise, that i can put my foot on the deep and i can swing for the top. I will do my best and get forward, entering in the same way that i was last night, getting away of everything that i can doubt; and i will continue in this way until i have found something right or, at least, have learn that certainly there is nothing right in this world."

"

 

[testiclees]

hey seaslug, ive been observing your project for a lil bit but just signed up today.

I ve got a pair of hlg h120 c700 drivers to power 4 cxb 3590 cd bin 3500k, 72v. I grabbed a scraped massive heat sink on ebay and cut it in half (passive cooling). Im strapping those halves onto an optic 360.

So your project was interesting and helpful to me thanks!

Also cant go wrong with a lil descartes.

T

 

[seaslug]

We have been having a heat wave in Seattle or else I would try stress relieving my aluminum heatsinks in the kitchen oven. It looks like 350 to 400F might work without destroying the existing T6 heat treat (but I don't need the strength, anyway).

I'm flat filing the heatsinks but even a 12 inch double cut bastard is slow going, too slow and I'm rounding the shoulders without getting down to the bottom of the "dip". Next I'll try 50 or 60 grit on an electric palm sander.

SupraSPL used to polish his heatsinks (like the CPU overclockers used to) but his tests showed flattening and polishing heatsinkUSA product wasn't necessary. He is down at the lower levels of current, though. I have to believe a thinner layer of thermal grease is better than thick. The heatsinkUSA extrusion has the amount of warp I expect to see coming from the aluminum mill but I was hoping it might be 0.005 inches across four inches. I've never polished heatsinks myself, just flattened as much as practical and it feels smooth to the touch.

If you want to run 1400mA through a 72V COB and give it long life, make sure the mating heatsink surface is flat, is my advice. The stars probably don't matter. I have thermocouples to epoxy to my CXB3590 so I'll see how things are under the glass. The heat is removed from the back of the COB, of course, but someone said photons will start heating the glass at around 75W.

The lense question is a good one. The COBs will run a little warmer, I expect, but the lenses come with a neoprene seal and will really protect the light emitting surface. I ran a seed crop last time with two big males that I shook with my Lumigrow lights on--and watched a ton of pollen get sucked into the luminaires, LOL. People like 80 to 90 degree lenses for plant penetration but I was happy getting the COB 110 degree viewing angle for good overlap between luminaires and bouncing off walls. So there is a trade-off. The lenses look good, IMO, and they were less than six dollars each from Kingbrite (minimum order of 10).

Unfortunately, I need to put this project on hold will I attend to family matters. I'm a young senior citizen and people are starting to leave at an accelerated rate.

Edit to that: I'm spending my money on COB stuff instead of my retirement account. :D

 

[Toaster79]

I used these ;)

Surface grinded to the point I made some scratches with a paper towel wipong off thermal paste. A spit of polishing compound and a rub is all they need.

 

[testiclees]

Good luck!

This is my first try I learned so much reading the DIY threads that I've been eager to put one together

For the cxb 3590's I'm using the ideal holders and driving the cobs at .700mA. As far as prep for the cob I wasn't gonna do anything more than rub the contact locations with the 0000 steel wool and then clean it up again with alcohol. I might try pads AND paste and see which seems best match for the holder. The holder directions say either is fine.

This cob will be about 56% efficient at .700mA (72v). The heatsink is 31" x 12", it weighs 29#. 200 dissipated watts should be easy to passively cool with this heatsink in a breezy 70-82 degree room.

I have an optic luminaire that runs vero29's at 90 watts a cob around 2mA. It comes with magnetic lenses. These are 90degree (pretty sure) and they have a gap between the lens frame and the light case so cooling air passes through. Supra tested to see if the lenses effected the cob temp and found that it was negligible. I put the lenses on a cob when plants are at different heights so that plants growing close to the lamp get a naked cob while shorter gals get the lens. I think it helps.
I aree with you and prefer to use abundant par, reflective surfaces and not use lenses.

 

[testiclees]

Yo, SS whats going on?

Im nearly complete just waiting on the cobs.

 

[seaslug]

There has been a death in the family so this project is on hold right now.

The Apogee PAR meter isn't all that good, I've read. I got a quote for a Li-cor sensor at $580 with standardized millivolt output. Might hook up to a Fluke 87 with a 0.1mV resolution.

 

[testiclees]

There has been a death in the family so this project is on hold right now.

The Apogee PAR meter isn't all that good, I've read. I got a quote for a Li-cor sensor at $580 with standardized millivolt output. Might hook up to a Fluke 87 with a 0.1mV resolution.

Sorry to hear SS, my condolences and a prayer.

Do you need to own a meter? I believe they can be rented.

 

[REALSTYLES]

@seaslug SupraSpl warned me about the apogee it can't read the far red or blue spectrum. It's better to convert lux to umols and the all you do is divide the lux by 66 I think warm whites and 69 cool whites to get your umols. As for lumens it's lumens = 0.09290304×lux × (square feet) hope that helps

 

[testiclees]

@seaslug SupraSpl warned me about the apogee it can't read the far red or blue spectrum. It's better to convert lux to umols and the all you do is divide the lux by 66 I think warm whites and 69 cool whites to get your umols. As for lumens it's lumens = 0.09290304×lux × (square feet) hope that helps

SHOW OFF!

 

[seaslug]

My cheap lux meter is probably enough for what I need. The $580 quote includes a leveling mount for $55. The cosine performance is good so I'd skip the special mount. You have to sign a non-export agreement to even get a quote directly from Li-Cor. The Li-Cor meter with a BNC connected sensor was $1100 a couple years ago.

The response curve of Apogee sensor vs Li-Cor:
http://ledgrowlightsoutlet.com/par-and-led-grow-lights.html

 

[502dude]

Hey seaslug, I'm looking for professional help with LED's for my 502 grow here in WA. Are you in a position to consult for me? I got 21,000sf I need to light up.

 

[Junk]

Hey seaslug, I'm looking for professional help with LED's for my 502 grow here in WA. Are you in a position to consult for me? I got 21,000sf I need to light up.

DAMN that's a lot of light

 

[502dude]

DAMN that's a lot of light

Yessir! Gonna need a whole bunch of LED's - thousands actually. Don't wanna do HID. Its old news. We r just starting to fit out our warehouse now. So exciting!

 

[seaslug]

Hey seaslug, I'm looking for professional help with LED's for my 502 grow here in WA. Are you in a position to consult for me? I got 21,000sf I need to light up.

I'm flattered but I'm just a retired maintenance tech that hasn't held a real job in many years. :rolleyes:

 

[seaslug]

I flattened the surface of the first heatsink using 50, 60, 80, 100 grit (wet and dry 3M brand) abrasive sheets held by "Time Shaver Tools P10 Preppin' Weapon"

The surface is flat within a thousandth of an inch, measured across the 3.945 width. I'll sand it smoother but I honestly think the "brushed satin" finish of the 100 grit (even used dry) is enough. This is where thermal grease can fill the "grain" of the surface--without being depended upon to fill up the space of an unflattened heatsink.

I considered using my kitchen oven as a stress-relief furnace but it is still too darn hot in Seattle (record setting June and July). I was going to use 350 to 400F for twenty minutes or a half hour and let cool at room temperature. This shouldn't hurt the T6 heat treat (but I don't need the strength, anyway). The goal would be to unwarp the extrusion before flattening it mechanically.

 

[502dude]

I'm flattered but I'm just a retired maintenance tech that hasn't held a real job in many years. :rolleyes:

Nice! I'm looking for help in designing an efficacious grow light. I'm reasonably up to speed but could do with some tech help to finalize the design. Can either yourself or someone you may recommend help me out? Its not a full-time gig, just some consult work that I'm happy to pay for accordingly dude. I'm also the owner of Dutch Master Nutrients too.