DIY Grow Lights with high-efficiency LED strips

I see a lot of folks still trying to grow with off-the-shelf “blurple” LED lights. This discussion thread will explore a vastly better alternative, using mid-power LED strips to build your own lights that will deliver better spectrum and far more lumens per sq. meter, at 50% better energy efficiency, for less than half the cost per watt of commercial fixtures.

The key to pulling this off is using recently introduced high-efficiency mid-power LEDs mounted on rigid PCB strips, mounted on simple aluminum sheets or bar stock.

Because the LEDS are only around 3 watts, are spread out across the PCB strip, and are highly efficient, they generate less heat than COBs, and far less heat than HID lights. They generally need no large heatsinks like COBs, and their thin profiles allow the DIYer to employ them in tents, cabinets and micro grows where HIDs, COBs and even CFLs are not tenable due to their heat load and/or vertical space requirements.

This technology is so new that most grow light manufacturers aren’t aware of it, and almost none are employing it in their products. The manufacturers of these mid-power LEDs and strips, Samsung, Phillips, Bridgelux, are focused on the big market for commercial lighting retrofits and so aren’t producing strips designed specifically for the horticultural market yet, so finding the right LED chips, mounted in the right configuration, on the right sized strip, in non-wholesale quantities can be challenging.

So I decided to design my own strips. I’m calling them SolStrips.

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My SolStrip samples arrived last week. So far, they are testing well. Highest diode density of any strip or board around using the Samsung LM561C chips, 1.25 cm2 per diode. But the real value is their flexibility in DIY builds, allowing me to choose the density and arrangement that I need for the space I want to light.

Three to five of these fit nicely in a half-size commercial baking sheet. I’m working on a DIY design based on the baking sheets - best aluminum sheet value out there, and the 1 inch rim makes an effective reflector for redirecting stray photons.

Cheap-o lux meter gives 8980 lux at 12" on one strip at 24v, 2A. Almost 19,000 lux at 12" on the 3-strip sheet at 24v, 6A.

Specs:

Size: 400 mm x 30 mm (15.75” x 1.2”)
Power: 48 watts, constant current, no resistors
Output: 9000 lumens

LEDs: 96 diodes Samsung LM561C top bin
CRI: 80 (S6 bin), 90 (S3 bin)
LED Color Temperature: 3000°K, 4000°K, 5000°K (2700°K and 5700°K tba)
Efficacy: 161 – 212 lm/w

Power Consumption: 36.8 to 48.4 W
Operating Current (If): 2000 mA
Operating Voltage (Vf): 18.4 to 24.2 Vdc

Luminous Flux: 7200 – 9000 lm based on Samsung spec
$10 lux meter test: 8980 lm2 @ 12”

PCB: Aluminum on 2 oz. of RA copper core
PCB thickness: 1.6mm
Thermal conductivity coefficient: 1.5
Mounting Options: M3 screw holes, thermal tape
Electrical Connectors: 2 x 18-20 AWG push-in 2061-2-2P

Application Environment:
• Lumen Maintenance: L70 = 7 Years
• Min. Ambient Operation Temp: -40˚C
• Max. Board Temp. (at tc): + 85˚C
• Max. Board Temp. for life rating: + 65˚C
• Max. Current Rating: 2.8 Amps

Compare to:

  • Samsung H Series H22D x 2
  • Samsung H Series HB562D x 4
  • HLG Quantum 288 chip board (3 Q-Strips)
  • Photon Fantom 240 chip Sunboard (3 Q-Strips)
  • Cutter Sol-Skin 594 chip board (6 Q-Strips)

The Mean Well HLG-***-24 line will work well with these strips in builds - just pick the wattage you need, 48w per strip.

Will test these 4000k 90 cri samples before placing a full order. If they check out they should be very competitive to existing Samsung rigid PCB options.

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Nice! Might have to pick up a power supply and give this a shot – I’d like to replace my blurple+T5 combo I’m running in my veg tent, and this looks like an excellent way to go!

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Keep up the good work mate

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Cant wait to see the result on a real grow :smiley:
Stay safe grow hard

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I see that you are liking led strips as much as I am… :slight_smile:
I find them much better than cob, honestly…
Light more diffused, lower distance attainable, less hotspot probs…
DS

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Sounds great. Would like to be involved in a group buy if that ends up happening.
Can you advise on what would be required/recommended for a 2x2 (possibly a little bigger in the future) scrog grow (2-4 plants) that would work all the way from veg -> harvest? Also what drivers?
Thanks very much

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Oh damn. Im ready to buy quantum boards for a veg room. Maybe ill consider these. What are your prices?

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Got mine built and on test, I built 1 x 2 strip board and 1 x 3 strip board with the option to turn the 3rd strip on or off. I am comparing them to a 2 x 55w tube T5 flouro lamp and a 4 x 23w tube T5 flouro at the moment, running in 2 strip mode. I will keep youupdated on my results.

Thanks :wink:

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@MadScientist @Baudelaire

Here we go some pics of the strip lights I think they are 23 watts per strip not exactly sure I think Mr B knows more about them than me.

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Those look really good to me. What do you think Mr. B?

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Where did you buy the LEDs and PCB strips?

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I went with the Bridgelux EB strrips - can get them at Digikey or Arrow for $7-8 on the 22"
and $15 for the 4 foot. Similar but not the same as above.

I’ve planned and planned and redesigned - waiting to drill my brains out.
Ended up with twice as much metal as wanted so a second set will get
drilled for future revisions. Doing 2 and 3 strip panels for module design.
Seeds are in the soil as of yesterday… so deadline is approaching…

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Interested in pricing I’m looking for a good strip product that emits light horizontally like hanging a large CFL would.

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My thinking browsing the Bridgelux site is they promote these in:
> Pendants and Troffers

Box them up - some sort of deflector for side light spillage downward
and tent sides a good substitute. 2x2 and 4x4 these stretch from side
to side and coverage directly under them is more concentrated than
a flouro tube would give.

So far only experimenting and running at test current (700mA) but
1000 and 1200 mA options available (1400 mA max, but why, just add more)

Their main advantages being, cost, 22v, and no heatsinking (except upper currents)
In doing the math… running 6 at 700mA gives about same as 4 mixed Vero18 at 1A.

That’s the 2 foot strips… the 4 foot are double the voltage 44v range and the figures
match up to using two of the 2 foot in series.

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Lots of interest in LED strips, that’s great.

I’m a proponent of COB LEDs too. I’ll put up a couple of my COB bar projects on another thread. I think COBs still have starring role in the modern indoor grow room of a certain size, ranging from medium sized cabinets (>12 s.f.) to about the 75-100 s.f. range. I use Citizen CLU048s in my flower room and love them.

But below that PCB-mounted mid-powered LED chips, in strip or board formats, are coming into their own as the premier technology for tent and micro-grow environments.

This is due to:

  • Their tremendous efficiency at turning watts into lumens
  • The massive reduction in waste heat that comes from that efficiency
  • The even distribution and high quality of light produced
  • The longevity of the chips, staying at 90% of initial output specifications for 40-50,000 hours

Most especially, the PCBs’ ultra-thin profile allows for design formats that solve some of the small tent and micro-space growers’ everyday issues dealing with vertical height limitations, canopy-to-light zone limitations, heat exhaustion and temperature maintenance. In these areas, mid-power LED strips and boards really shine (pun intended).

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You can, until I get some lab testing completed and have PFFD data, figure about 30-40 watts/s.f. for a flower space, 20-30 w/s.f. in veg. At 48 watts per strip, each SolStrip should easily cover 1-1.5 s.f. at bloom intensity, or 2 s.f. at veg levels.

In your 2x2 space I’d use two strips and a dimmable constant current driver like the Mean Well HLG-100-24B so you could adjust the light intensity to dial it in to your space and requirements. Mean Well makes the HLG line in a 24v series that steps up in 50 watt increments (HLG-150-24, HLG-200-24, etc.) that pairs nicely with the SolStrips, allowing for a lot of DIY options.

I hope to have a mechanism available this weekend for folks who’d like to reserve some strips from the next shipment. The Shenzen fabricator has a large minimum order requirement, but with enough interest from the members here I think I can get these delivered for under $20 a strip. The easiest apples-to-apples comparison would be to the quantum boards made by HLG, with 3 SolStrips @ $60 matching the output of one 288-chip quantum board at $75.

Comparing to other LED strips, the SolStrips are twice the chip density per centimeter of the H-Series Samsung strips with the same LED chip, and twice the density and better efficiency than the Bridgelux EB strips - both of which are 24 watt strips, like the TCI/Estonia strips @Herbie is using.

I think once a few of you start playing around with these strips, and seeing the potential for using the various color ranges to build your own spectrums and life-cycle circuits using different combinations of 2700K, 3500K, 4000K, 5700K and deep red/blue strips, you’ll start to see these as “light Legos” to use as building blocks to create your own custom lights with top-line diodes delivering twice the lumens from half the watts as HID, and at far less cost than Chinese “blurple” lights.

-b420

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Very interesting @Baudelaire :+1:

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Just got a luxmeter from my growshop owner friend and finally got to properly check my LEDs…
Holy cow…
It’s roughly 30.000 @ 18cm , getting to 5cm it jumps to 53.000, that is 400hps level…
From 55$ of LEDs and half hour of work I’m Astonished…
DS


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Looking good. How are you heatsinking those boards?

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