New style Samsung LM561C Board

burnpile

Well-Known Member
picked up one of these (just to see if its enough to keep a small mother plant alive) ... ~US$3. There's a lot of variations and different styles/qualities/wattages/etc of this on ebay etc



It was marketed as 18W but it only draws 6W according to my power meter. Marketed as 500-800 lumen output depending on the seller. I get about 5000 lux from it @ 8" from my light meter. Haven't had the chance to properly test it apart from that though, and I'm not saying it's good or bad or other, just putting this info in case anyone else is curious.

28 diodes total (avg 0.21W each):
  • 4 x white (seems to be Samsung LM561C's for these four?, guessing ~3K and ~6.5K)
  • 1 x ultraviolet
  • 1 x infrared
  • 11 x red (630nm)
  • 11 x blue (460nm)
Two homemade fixtures with these bulbs plus a couple 15w 5000k and 3000k mixed in, also what they look like today. These are blue cheese, swiss cheese, tangerine dream, and an 8 ball kush.
 

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estooki

Member
So these ebay boards

https://www.ebay.com/itm/Horticultural-Lighting-288pcs-LED-Board-3000K-Full-Spectrum-Quantum-LM561C-S6/192509696799?hash=item2cd278db1f:g:nbwAAOSwM91aZYsY


Is this exactly the same as the QB288 QUANTUM BOARD from https://horticulturelightinggroup.com/collections/all/products/qb288-quantum-board?variant=5508760141851
Just without the Brand stamped onto it ?

They are constantly sold out and i cannot finish my projects, would love to have another source.

Anyways are these the same product ?
I bought mine from that listing. Having talked to the company behind these boards, my understanding is that the diodes are connected 16 in parallel then 18 groups in series (rather than 18 in series then 16 groups in parallel) which makes it more fault-tolerant (i.e. if one diode goes out, it doesn’t take out any other). Kind of a minor point, but it’s nice to know they were thinking about it.

They were also pretty responsive to my questions, gave me driver recommendations and general advice on setup. So there’s that.

The boards have a nice weight to them, and the aluminum backing is a bit thicker than the HLG QB120’s I have. Diodes do not have a prominent black dot, and are bright AF lol. Overall a pretty well-constructed board. These are working just fine for me especially given the price point.

I don’t think there’s anything magical about HLG boards, but that’s just my $0.02.
 

sixixix

Well-Known Member
Something seems off.
You should be pulling circa 45.8 to 46V ish at that current.
I don't understand either. I tried communicating with the seller about this, but I feel that he didn't fully understand what I was trying to say, or maybe it was the other way around. I should probably give it another shot.

Might be a silly question, but have you checked that your voltage adjustment on your drivers isn't turned down? The forward voltages do seem low...
Yeah, that is not the problem :)
 

nfhiggs

Well-Known Member
I don't understand either. I tried communicating with the seller about this, but I feel that he didn't fully understand what I was trying to say, or maybe it was the other way around. I should probably give it another shot.



Yeah, that is not the problem :)
If all of the diodes are lighting up, and its pulling the full current from the driver, this would seem to me to be a non-problem. Seems to me you got boards made with diodes from the low Vf (AY) bin, which is a good thing, they are more efficient.

Do you know the series/parallel configuration?
 

sixixix

Well-Known Member
If all of the diodes are lighting up, and its pulling the full current from the driver, this would seem to me to be a non-problem. Seems to me you got boards made with diodes from the low Vf (AY) bin, which is a good thing, they are more efficient.

Do you know the series/parallel configuration?
Thanks for your feedback. It's 16S32P. Not all the diodes are Samsung, only the 3000K ones.

 

The Loafter

Well-Known Member
Not cheaper, and no verdict on how much better they are.
hlg has the specs up for qb324.

they seam less efficient than the qb 304 going off ppfd conversion at 1050ma. If I did my math right , a few nights ago.

Wonder why there wasnt a big announcement eh?
 

PhenoMenal

Well-Known Member
QB cooling ... a lot of ppl say "no need for active cooling, passive is fine" ... so far I've found that to be true but only at around ~22°C/71°F and under (ambient/day temps) :)

As i slip here from summer into winter, it seems that if it's ~22°C/71°F outside (or less), then i don't need any cooling, I can run a 2xQB304 @ 100% no problems, with just the passive heatsink doing its job, and the grow chamber never gets about 28°C/82°F. Anything warmer though and supplemental cooling IS required.
 
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