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 Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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 Re: Best LED light for 4x4 tent  [Re: Rockahaus]
#771444 - 03/09/15 11:55 PM (10 years, 24 days ago) |
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The spectrum king might be a decent option provided you have the lamp 2-3 feet above the canopy... although 25 watts per foot is a bit on the light side. I will say though that it's comparable to other offerings as far as price goes. The main consideration if you're okay with the wattage is whether the lamp is quality, and that's something I can't comment on.
Another forum I frequent raves about Area51 lamps, also uses Cree emitters and assembly in the states. Two of their 190s (which I think they're out of at the moment) would be about the same cost and would provide a better footprint while getting the lamps closer to the canopy.
Although... even the panel LEDs available on the market tend to provide conical coverage meaning the space below the lamp receives much more light than the space to the side. It's kinda irksome because the main potential advantage of LED over HPS currently is the ability to spread the emitters out and provide even coverage over the entire grow space. (LED and HPS are neck and neck in efficiency at the moment, though that will be changing in the next couple years) Retail LED lamps tend to be compact because it's less expensive to build them that way. The retail LED grow light market is difficult because they tend to push the emitters hard and use cheaper parts. One of the cool things about LED is that the efficiency goes up the softer you drive them.
My solution was to build my own lamps. I've been using under driven VERO COBs cooled with radial heatsinks mounted to aluminum frames, no fans. I just recently completed a 350 watt lamp for a 2x4 tent providing about 140 LPW. It provides about 43 watts per foot and got 1.2 GPW (actual wattage) on the first run (1.35 GPW by lamp output). The parts for the lamp ran about $800, so for $1600 you could build a lamp that would likely yield almost 2 lbs in that 4x4 tent from 700 watts. You would need to spend at least $2000 for the same results with retail lamps. For the same cost as that Spectrum King you could DIY a 525 watt lamp that would provide about 33 watts per foot over every foot in your tent.
So something like that might be worth considering. DIY LED can seem daunting, but with the advent of COBs the workload is dramatically reduced... and using Bridgelux Vero series with molex connectors mean no soldering whatsoever. Drill, hacksaw, screwdriver, wire stripper/pliers, tap bit and handle and you're in business, although I would highly recommend a small drill press which can be bought for under $100.
There is an even cheaper way to go about things, and that's DIYing a lamp with fans. I was attracted to the fanless option and it still came out less than retail so I was sold. Having not priced things out for fan cooled DIY LEDs I can't really comment on how much cheaper it would be.
I don't usually post here but I'll check back and if you're interested in the DIY option I will be glad to provide more info if you like.
Edited by Rahz (03/10/15 12:17 AM)
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: Rockahaus]
#771512 - 03/10/15 01:05 PM (10 years, 24 days ago) |
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If you're not into DIY, fair enough. I'm not much of an electrician either. Took me several weeks of research and asking lots of questions before I felt confident enough to start pricing parts.
As far as efficiency, it's true COBs were less efficient when they were first introduced but that margin has disappeared. My lamp is running about 140 LPW and the yield per watt speaks for itself... but datasheets for comparison are available for all the emitters in the Cree and Bridgelux lineup.
I've also heard good things about Advanced LED, and another company called Apachetech (though those are a bit pricey).
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: Rockahaus]
#771573 - 03/10/15 09:09 PM (10 years, 23 days ago) |
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It's just providing a current to an emitter and keeping it cool.
The Vero datasheets show the LPW for various drive currents.
For non-typical currents the datasheets have charts, one showing current -vs- voltage. It can be used to find the voltage for a particular current. Voltage X current = watts. Another chart shows luminous flux (lumens) as a percentage of the standard currents output -vs- current. Standard output X (percentage) = lumens @ your chosen drive current. Standard output X (the percentage) / watts = LPW.
Using that info I can see that a Vero 29 wired to a 700mA driver will use about 25-26 watts and produce 140-142 lumens per watt.
From there you just need a way to keep it cool. You can get more complex wiring up the emitters in series or in parallel, but you can also just buy a power supply for each emitter like I did. Emitters are wired to the power supplies, power supplies are wired to a positive and negative terminal, terminals are wired to a power cord. Plug it in and it is on. People have been using CPU coolers and getting really good results. My plan was to use passive cooling so I took a chance on cheap radial heat sinks I found on ebay that were advertised as 50 watt heatsinks. My first lamp I paired them up with Vero 18 pushing 31 watts. They ran a little hot so I use a couple fans blowing air across the lamp and they stay reasonably cool. That lamp has produced 1.1 GPW. The new lamp uses the same heatsinks but I'm only driving the Vero 29s at 25 watts and the heatsinks stay nice and cool without fans and has produced 1.2 GPW.
It hasn't been an exact science for me since I haven't been measuring temps with a temperature probe. Without knowing the exact temp of the thermal junction it's not possible to know the exact LPW the emitter is putting out. 140 LPW is probably a good guess for my new lamp. At any rate, 1.2 GPW is the figure I like and makes me feel like I built a lamp that out produces retail offerings of any brand. Engineers can build lamps, but they're also trying to build something as cheaply as possible and tack on as much profit as they can. I'm getting more output for the money and the light takes up the whole tent rather than a small group of emitters hanging in the center. This lamp sits about 6 inches above the canopy during flower.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: Rockahaus]
#771657 - 03/11/15 01:02 PM (10 years, 23 days ago) |
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Quote:
Rockahaus said:
Dude, that is a wild looking light. It looks like you used all white lights too. I may be over thinking it, just seems real confusing to know you are getting the right spectrum of light. like do you really need uv and ir, or even green light which I think Blackdog is using for photosynthesis.
There is some science behind uv and ir supplements, but it's also a flashy selling point. To keep things in perspective you can see the spectrum distribution for white emitters on the datasheets. Compare that to a spectrum distribution chart for HPS. White LEDs are obviously superior to HPS with or without supplements.
I used all 3000K emitters on that lamp. Plenty of blue for veg.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: phychotron]
#771659 - 03/11/15 01:06 PM (10 years, 23 days ago) |
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Quote:
phychotron said:
That is pretty sweet looking for a home made fixture. Do you have any photos of it in action?
Sorry I do not, but it was pretty.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: Rockahaus]
#771668 - 03/11/15 02:42 PM (10 years, 23 days ago) |
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Bridgelux emitters are a little less expensive than Cree. The Cree can run a little more efficient, so you could get by with fewer emitters nullifying the price difference. I'm specifically referring to Bridgelux Vero29 and Cree 3070.
For a general price gauge, here are the parts I used:
http://www.digikey.com/product-search/en?mpart=BXRC-30E10K0-L-03&vendor=976
http://www.powergatellc.com/mean-well-plm-40-power-supply.html
The Heatsinks can be found on ebay for $12-13 (make offer) if you do a search for "50 watt led heat sink" They may arrive needing some sanding.
So that's 28+16+12 ($56) for each unit. I used 14, plus the cost of hardware: aluminum frame, nuts, bolts, washers, screws, terminal posts, wire, power cord, thermal paste, which is around $100.
It's the expensive way to DIY LED (my lamp was about $900). It can be much cheaper if you use fans.
Vero29 @ 1.05A = 39 watts, 5160 lumens, 132 LPW paired with a CPU cooler would run really cool. 16 of those in a grid would be 1 emitter over every foot of space in a 4x4 tent, 82,500 lumens total. The cost for it assuming the CPU cooler was about the same price as the passive heat sinks I used would be about $1000-1100. You could of course choose to use less emitters and run them harder. The Vero 29 running at recommend specs (2100mA) is an 80 watt unit. 9 of them in a grid would supply 720 watts at about 120 LPW for a cost of maybe $700!
For a space that size, a single lamp probably isn't the best idea, though the 9 emitter configuration over a 4x4 would weigh less than my lamp. For a 16 emitter setup, 4 strip lamps with 4 emitters @39 watts might make sense. Find the right power supply for the fans and you could wire them in series, or you could create an air conduit for the heat sinks and you might get by with a single beefy fan for each lamp (1 fan for each 4 emitters) though there would be some guess work involved in that setup. The advantage to using CPU coolers for each emitter is that it has been done many times and there are plenty of examples.
Or... you could spend the extra money and build two of the passive 2x4 units similar to mine. It would be 700 watts and cost around $1700-1800.
As you can see, there are lots of design considerations. Spending less entails getting more creative and complex... but you don't need to be a engineer to figure it out.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: phychotron]
#771696 - 03/11/15 08:03 PM (10 years, 22 days ago) |
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Quote:
Not sure I'd go with the larger watt diodes, maybe sticking with 10w maximum to spread the light out as much as possible over the canopy.
I agree with that principal. Vero 10s are 9 watt units at nominal current (4.4 watts and 132 LPW at 175mA) and cost less than $5 so I'm sure something interesting could be done with them wired in series. 
Larger COBs do have advantages though, efficiency for one if you were trying to reach 140-150 LPW, though 130 LPW is nothing to shake a stick at. Also to be taken into consideration is that COBs are naturally wide angle emitters. The datasheets for a particular emitter will have an angle -vs- light intensity chart that can help in planning emitter spacing.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: Magash]
#771732 - 03/12/15 02:26 AM (10 years, 22 days ago) |
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There are a lot of shoddy companies out there but DIY avoids that along with the premiums that come from buying from a company that sells quality products. As I said, 1.35 GWP from a 350 watt lamp in a 2x4 tent equals your 4 lbs in a 4x8. That I don't have pics might bother you, but 140 LPW is 140 LPW and can be verified by looking at the datasheets for the emitters I used. There's a bit of a learning curve in understanding them, but it's not that difficult. I'm driving the Vero 29s at 700mA.
For non-typical currents the datasheets have charts, one showing current -vs- voltage. It can be used to find the voltage for a particular current. Voltage X current = watts. Another chart shows luminous flux (lumens) as a percentage of the standard currents output -vs- current. Standard output X (percentage) = lumens @ your chosen drive current. Standard output X (the percentage) / watts = LPW.
http://www.bridgelux.com/wp-content/uploads/2014/02/DS33%C2%A0Bridgelux-Vero%C2%A029%C2%A0LED-Array-Data-Sheet%C2%A02014.02.03.pdf
Not having a lot of money to spend up front, a 600 or 1000 watt HPS might be the smart thing to do in a 4x4, but I do think a 600 watt DIY LED lamp in that space would pull 2 lbs. and as I mentioned and provided some details for, I could build that lamp for about $700.
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: phychotron]
#771733 - 03/12/15 02:38 AM (10 years, 22 days ago) |
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I've heard Apache Tech is the bomb, but $2500 for the lamp? 
How about DIY for $700? Or $1800 for the fanless version. I actually have two fanless lamps now, the 350 and a 720 watt I first built. 17Oz and 28Oz last two harvests. Almost 3 lbs. from 1070 watts.
And yea, I make left hand finger hash handling stems. 
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Rahz
Stranger
Registered: 01/17/13
Posts: 22
Last seen: 9 years, 9 months
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Re: Best LED light for 4x4 tent [Re: ashfiken]
#772934 - 03/19/15 10:18 PM (10 years, 14 days ago) |
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I'd be glad to give input on your project, but you'll have to become familiar with COB emitter and constant current driver data sheets so you can decide which emitters to use, how hard to drive them, whether to run drivers for each emitter or run them in series or parallel, then choose appropriate drivers and figure out how to keep it all cool, either passive or with individual fans on a frame, or fewer fans venting an enclosure. Come up with a design and wire it up.
Recommended brands for COBS: Cree (CXA and the new CXB series) and Bridgelux (Vero series) and drivers: Meanwell (they have a comprehensive LED section on their website).
Start a thread and I'll answer whatever questions you have. Look around at other forums too. Some of them have very active DIY LED sections and some of those guys are much more electrically inclined than me.
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