nice work @Baudelaire consider me interested! Already purchased 4x QB304 but would consider building with these for my 2nd tent! Was looking in to making my own PCB design with LM302B chips as they are considerably more wattage per diode, what are your thoughts on that chip?
5H Club • Craft Time
Over a month gathering parts, running a drill press like an old time slot machine waiting on the payout…
This is my version of Bridgelux EB strips and Vero 18 cobs. Still testing but first indication is that I’ve over lit and don’t need the cobs, or perhaps turn on late flower. These strips are a tight fit (2 inches around fixture) and take up full ceiling so trying to incorporate circulation into the design.
Just a sneak peek…
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That’s a nice rig, good example of mixing strips and COBs. Those are the 2 ft EB strips? The tight fit in a 2 ft width tent or cabinet is one of the issues I tried to deal with in designing the SolStrips. They are 40cm, about 16.5 inches, which leaves room for mounting on a frame and/or sink. What are you mounting the strips to? Looks like aluminum sheet? How thick? How’s the heat management going?
-b420
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The LM302B has twice the watts but is around 30% less efficient based on my back of envelope math using Samsung’s flux ratings at the test current (about 133 lm/w) versus 187-200 lm/w with the LM561C chips in the SolStrips. That’s a pretty big hit, which will create more heat to manage, which is already elevated due to the higher wattage chip. But that 1-2 watt range is the area to watch in mid-power chip technology, I expect to see very efficient (200 lm/w) chips in that range in the next year or two. Right now, the sweet spot in efficiency, price and availability is the LM561C chip, imo.
-b420
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thanks for your analysis! i’m still new to the LED game (got tricked by the blurple “equivalent wattage” on my first purchase)
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Well… I went with PC board standoffs for the EB strips so they ‘float’ for air flow.
The perforated plate was too thick but what I wanted for the original design so I could
just mount the EB to it and use the perf holes for mounting. What I ended up with was
marked .063 and the other number am not sure what it stands for.
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Forgot about heat management… The EB strips have no heat issues at 700mA.
They don’t even get warm. The COBs on the other hand, they run warmer than
I’d like at the moment. Am still working on the space itself, and once the panda
is put in place and circulation set up they will be under more thermal control.
Am trying to track down a par meter so I know where to hang the light and if
the COBs even need to be run (perhaps one or 2 in late flower?)
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Interesting design @HalfBee. If you ever want to run those EBs harder you’ll want to mount them directly on the ally plate - aluminum conducts heat much better than air, even moving air. Thermal mounting tape works great, no drilling or screws. Even 10mm Klapton tape will work and is easily removable, while you are dialing in your design. The other number on the ally sheet refers to the type of aluminum alloy.
Harder to see your COB design - seems like they are mounted to some plywood housing with a case fan? That could work, but if not I’d look at your heatsinks - MechaTronix? If you got the right size sinks, they should be all you need there. If not, there are mounting holes in the sinks to mount PC fans right on top. I’d probably lose the plywood and just mount a $5 fan on each COB. Should do the trick in a much cleaner way. I’d also arrange the COBs out in a simple rectangle to spread out their light as evenly as possible, and use the strips as fill-in lighting.
All in all a nice rig and great example of a COB/strip combo design.
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LOL… the ‘plywood’ you see is the ceiling of the box through the fixture
that particular picture is not complete. Yeah, they are MechaTronix and
rated properly for my Vero18s as am running them at 30 wattish range.
It’s more a time of year issue as they are affected by ambient temps,
usually run my flower lights at night. Have a plant ready to force sex
with 12/12 and will see how it handles just the EBs at first.
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Running the EB strips alone let me continue while the heat was on
and sex the plant. Have since added back the 80CRI cobs for veg.
This was a veg light thrown together - 3 Vero13 5000K 70CRI gen7 @350mA • Vero18 3000K 80CRI gen7 @700mA - the interesting part is the beams. You can see both the color and intensity difference.
This is the same situation with the 6 EB strips running. The individual LEDs throw a shadow in
common with others they align with, but the arrows show the offset between the strips.
Am wondering @Baudelaire if you rotate every other led 90 degrees (or row) if it would
produce a more even coverage. These shine like a long pencil thin COB when diodes aligned
in same direction.
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What about putting the cobs in the corners of the fixture?
That was a temp light that was ZipTied to the frame before the EBs went on.
Only used it a couple days, but it’s the type of footprint being illustrated.
4 bright beams replaced by not as intense but more distributed beams.
Final fixture was pictured higher in the thread. Those cobs also give a beam
but it’s melded well with the EB footprint.
Inside the light is more on the white side than the yellow of running the cobs alone.
Am still experimenting and liking it so far.
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So that’s the light that comes through the crack in your door? Interesting, I haven’t see that with my strip rigs. I wonder if the EB strip’s optics are very narrow beam? I haven’t used the EBs before to know, but some 5630 SMDs have very narrow beam angles - I’ve seen as narrow as 20 degrees. The Samsungs in SolStrips have a more typical 120 degree spread.
Not sure how you would rotate the strips 90 degrees and maintain even coverage. Given you have multiple emitters, including COBs, I’m not sure I’d worry about it. There are optical lens available for many of the commercial strips like EBs, that might help but you’d sacrifice some lumens, 3-7% depending.
-b420
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Talking about the layout on board placement like this where they alternate
orientation and thereby the way they spread the light. Just a notion…
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I see. Hmmm. Complicates the PCB design, but I’d have to check with my engineer as to whether it’s feasible.
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The diodes on the EB strips are square and not sure if optics is the
word to describe their beam angle.
The shadowing is partly the spacing of the diodes but is also that
all the panels were drilled in one pass and once mounted they align
with the strips on the next panel. If I offset a couple mm it would
probably blend much closer to what I’m seeing on the <–> ends.
LM301B is the new efficiency king. 5% or so over the 561C. And Samsung already has them on a new strip, the Q series.
Not to take away from your success here, but it seems to me this is just re-inventing the wheel. Both Samsung and Bridgelux both have good efficient strips already available. in 11", 22" and 44" length and different densities. The 44" double row F-series from Samsung has 288 top bin LM561C diodes.
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I’m aware of the LM301B, 5% increase in efficiency, 30% increase in cost. @legalcanada asked about the LM302B. Different diode.
If a 44 inch Q strip works for your needs, and you can afford it, go for it. Horses for courses.
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I hear ya on the 301B price - wish they would have followed the same layout and pricing structure as they used with the F strips. A 288 diode strip using 301B’s for ~50 bucks would be a heck of a deal.
The 44 inch Q strips are not terribly expensive, Digikey already has them in stock for $23 each, but they only have 80 diodes in them. I like the big 44 inch F series - 288 diodes for under $50
Like I said, if a 44-inch format suits your needs, go for it. I look at Samsung as a supplier, not a competitor. I designed the SolStrip to work well in smaller formats where stringing out 80 chips along a four-foot strip isn’t practical or desired. SolStrips have 96 diodes, 48 watts, 9,000 lumens, on a 40 cm strip that can be combined to create any spectrum, or series of spectrums, the grower wants. And for $20 a strip - as good a value or better than the commercial strips.
Samsung produces strips for commercial fluorescent retro-fits. As they should be, they are a multi-billion-dollar conglomerate looking for billion-dollar business opportunities. Designing for the indoor horticulture market isn’t even on their radar. That’s where producers like SolStrip, HLG, Photon Phantom and ChilLED come in. Dedicated designs for the DIY LED gardener.
-b420
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