The Chinese Quantum Board Knock Off Builds

[MidnightSun72]

Do you know of any sellers who can guarantee top bin 281B's?

I think Meiji or Kingbrite can't remember which use the SK bin for the LM281B. So I just use that bin or whatever bin they claim to check their posted efficacy numbers based on diodes counts and compare to the Samsung calculator for the claimed led binning. But the numbers almost never match and the alibubbers over state 100% of the time.

In my extensive use of the Samsung led calculator I can say on average a fixture with 281bs will need to have around 1.5-2X more diodes to achieve similar efficiency as the Lm301bs.

 

[mannitu77]

i highly doubt theire using that bin. If you have some data/claims/website from them, would be nice to link it for me. With the exeption of the Migro Lights, ive not seen a single light so far with LM281B+, which had a testresult that good that it indicates such good diodes. His efficiency numbers/claims of 2.7 umol/J system efficiency would require a bin like that. He doesnt tell though.

Maxisun still likes to use LM281B+s and makes really nice lights. They top out at 2.3-2.4 umol/j.

 

[Hoverjet]

I agree with mannitu, the lm281 is a very viable option for grow lights at the moment. While the 301h is undoubtedly the top light, it is in high demand so the prices are high. Less efficient, but still very efficient in relative to history, lights like Bridgelux, Nichon and the lm281 provide a really nice $/wattage ratio.

I have 2 Kingbrite qb style lights, both 240w but 1 with 301h and the other with 281's. The 301h board also has Cree IR and FR as well as LG UV while the lm281 board has Epistar FR and no name IR and UV. Also the 301h has a Meanwell driver and the lm281 has a no name. I got the lm281 light second because I wanted better coverage after getting a new tent and I am cheap. The lm281 was only 75$ + shipping.

I was expecting a significant difference and figured I would have to run the lm281 a little harder to compensate. The reality is they are very close is output. The plants don't favor either one with both at 100w. Using an app on my iPhone gets similar readings with the 301h having a slight advantage.

The only difference is the plants under the lm281 are more squat and bushy while the ones under the 301h stretched out more. The 301h board has 3000k and 3500k diodes and the lm281 board has 5000k and 2700k diodes, so the difference in color temp was likely responsible for the plant differences.

That's my experience with the diodes and I'm happy with the lm281 light. My biggest complaint is the no name driver, I just don't trust it like I do Meanwell. The no name driver runs hotter but not by much. One of my rules of diy over the years has been to never skimp on the power supply part of anything so I hope that doesn't bite me in the butt on day.

TLDR: The less expensive diodes, like lm281, Brideglux, etc, are great alternatives right now with 301h in high demand. It's all about the flower in the end.

 

[mannitu77]

@Hoverjet
are these the "QB288" ripoff boards with LM301s and Cree FR? How expensive were they? At least here from europe i was suprised theyre not really a good deal, not as good as you would think they are. Compared to HLG.

 

[Hoverjet]

@Hoverjet
are these the "QB288" ripoff boards with LM301s and Cree FR? How expensive were they? At least here from europe i was suprised theyre not really a good deal, not as good as you would think they are. Compared to HLG.

The 301h/cree was $183 + $30 shipping (I think) back in 2020. They are the qb288 "style". I also have a HLG b-spec qb in my veg tent. I suspect the 301h on that are a better bin because it is brighter given same wattage. HLG is more expensive here because they are better lights.

 

[mannitu77]

yeah but the Diablo Board isnt really more expensive than the knockoffs. Its 666 diodes, while 2 knockoff QB288 have 576 diodes. 129 dollar. And you know exactly what you get. Sure smaller surface area, but you can hang it a little higher. Its only the fixtures that i think are overprized. Or lets say, not really effective for that money. Just a ton of aluminium.

I was surprised to see, 2 of these diablo boards with heatsink are only 289 dollar. If you buy an ELG-300 with it, you basically have a HLG 350R for 360 instaed of 599 dollar. And if you fit a 140mm fan on the back, you even have better temps.

Im really waiting for someone like Migro or LED Gardener to finally test a view of these QB-knockoffs. Sure they are knockoffs, but given how popular they are...both the old LM281 and the newer Lm301 Versions...and Shane already tested all kinds of cheap LED-gimmicks.

 

[growkingky69]

Good stuff. I was stuck between LM281B and LM301H because for some products the price is literally double. I think I'll go get LM281B and buy 1 more just in case one fails

 

[Moflow]

I don't suppose anyone is offering the Samsung 561C s6 led lights anymore?
Mine are 4.5 years old now and still grow great weed.

 

[mannitu77]

Good stuff. I was stuck between LM281B and LM301H because for some products the price is literally double. I think I'll go get LM281B and buy 1 more just in case one fails

what light are talking about? these QB288 boards? Or a complete light?

 

[mannitu77]

I don't suppose anyone is offering the Samsung 561C s6 led lights anymore?
Mine are 4.5 years old now and still grow great weed.

I looked them up after reading your post...these strips are still being sold. Interesting how good these LEDs are given their age. And still Samsung itself and many sellers keep writing "Lm301B" is the first LED to reach more than 200 lumen/ watt

LED Strips mit Samsung LM561C S6

Die High-Performance LED Strips mit Samsung LM561C S6 sind ideal geeignet für gleichmäßig dosierte Leistung. Mit seinen max. 12W und bis zu 204lm/W bietet er eine Vielzahl an Kombinationsmöglichkeiten auch für größere Flächen. Optimal geeignet für Anzucht, Wachstum und Blüte als Haupt- oder...

www.lientec-led.com

a strip with 48 costs 12eu---96 pcs. for 23eu..pretty interesting. Maybe you can get them even cheaper.

 

[UpstateRecGrower]

I don't suppose anyone is offering the Samsung 561C s6 led lights anymore?
Mine are 4.5 years old now and still grow great weed.

I would buy the F-series 144 or 288 strips from digikey

 

[Moflow]

https://www.digikey.co.uk/en/products/detail/samsung-semiconductor-inc/SI-B8V521560WW/6624005

These are decent budget strips as well.
Tunable too. Nice spectrum. @Rocket Soul made some great led fixtures with them.

https://www.digikey.co.uk/en/products/detail/bridgelux/BXEB-TL-2750G-3000-A-13/7899252

Their was a member here, @VegasWinner who got some 90 cri lm561c 2 channel boards made about 5 yrs ago.
He designed them and got Roget - R2THK Co. I think to build them and sold them at cost. A bargain.
I got 4 off him.
I had a HLG 288 QB Board that lost a string of leds and HLG promptly send me a replacement.
When vegaswinner heard about it he sent me another one of his Growgreen boards for free too!
What a guy!
He made a thread about them. It went a bit pear shaped. Some said it was a load of crap and they wouldn't work.... 5 years later and my Growgreen boards are still producing the goods lol lol.
The thread was quite funny.

DIY 4x12 3500K/5000k lm561c two channel board

revised gerber files for making the board can be found here ->https://github.com/AvidLerner/GrowGreenLM561CBoard Don't get me wrong, but you have no idea what you are doing. If you would like to know why this all is total crap, just take a look at how Samsung made their strips for example. There...

www.rollitup.org

 

[mannitu77]

im still looking for the right way or factor to convert these lumens/watt in the specs to umol/J....different sites/calculators spit out different numbers. Some websites only have 3500k/6500k for example...

yeah these 561 were the shit 5 years ago. Efficiency hasnt really progressed that much, if you go from the S6 with top voltage bin. I also wouldnt change them. Probably more efficient than my DIY-light with LM281B+ boards...allthough i dont know on how much current you run them.

 

[PJ Diaz]

Samsung itself and many sellers keep writing "Lm301B" is the first LED to reach more than 200 lumen/ watt

Link or I call BS

 

[MedicinalMyA$$]

im still looking for the right way or factor to convert these lumens/watt in the specs to umol/J....different sites/calculators spit out different numbers. Some websites only have 3500k/6500k for example...

yeah these 561 were the shit 5 years ago. Efficiency hasnt really progressed that much, if you go from the S6 with top voltage bin. I also wouldnt change them. Probably more efficient than my DIY-light with LM281B+ boards...allthough i dont know on how much current you run them.

Basic formula is total lumens x 0.015 = PPF
e.g. 25000 lm x 0.015 = 375 PPF

Divide by the Watts it takes to get there eg 150W / 375PPF = 2.5 for system efficiency

I think the actual PPF conversion numbers change per the color temp something like 3K = 0.016, 3.5K = 0.015, 4k = 0.014...

 

[PJ Diaz]

im still looking for the right way or factor to convert these lumens/watt in the specs to umol/J....different sites/calculators spit out different numbers. Some websites only have 3500k/6500k for example...

It will depend on the CRI of the specific diode.

Convert Lumens to PPF - Online Calculator | Waveform Lighting

Online calculator to convert luminous flux (lumens) to PPF (micromoles per second).

www.waveformlighting.com

PPFD to Lux Conversion

www.apogeeinstruments.com

Converting Lux to PPFD & Measuring Lux with Smartphone

Spectrometer and Quantum Sensor can cost hundreds to thousands of dollars and not every grower can afford them. A Lux meter app on phone can be used to ensure even light spread across canopy and give estimate of Lux. Use a calibrated Lux meter for better accuracy. Just divide the Lux value you...

horticulturelightinggroup.com

 

[mannitu77]

It will depend on the CRI of the specific diode.

Convert Lumens to PPF - Online Calculator | Waveform Lighting

Online calculator to convert luminous flux (lumens) to PPF (micromoles per second).

www.waveformlighting.com

PPFD to Lux Conversion

www.apogeeinstruments.com

Converting Lux to PPFD & Measuring Lux with Smartphone

Spectrometer and Quantum Sensor can cost hundreds to thousands of dollars and not every grower can afford them. A Lux meter app on phone can be used to ensure even light spread across canopy and give estimate of Lux. Use a calibrated Lux meter for better accuracy. Just divide the Lux value you...

horticulturelightinggroup.com

i know...but like i said, different websites give different results. If you know one where you have good reason to believe its correct id like to try out. I tried a bunch so far and the result shifts up to 15%. I did use your upper link for a while, even if it only had 3500k. I felt like the results were a little to positiv. Also it divides only by "high CRI" and "low CRI"...so what dou you pick with CRI of 82, its probably the middle.

@medical:
if you take 0.016 for 3000k, then 170lumen/watt would be 2.72 umol/J. I guess thats for CRI 80 because its the most common?
That component calculator from Samsung is so cool, why couldnt they just add PAR as well.

edit: i think 2,72 umol/J is too much for 170 lumen/watt. Maybe thats for CRI 90.

i just looked in a shop where they sell Samsung LED Moduls, this is a 3000k strip with LM301B....they use the factor 0.014 for 3000k...meaning 170 lumen/watt would only equal about 2.4 umol/J. Giant difference to 2.72. Last one seems more realistic to me??





@PJ Diaz: there you go, theres the statement for the first diode diode ever breaking 200 lumen/watt. Its not Samsung, but its a Shop in Germany with a good reputation. Maybe i had that wrong in my memory that it came from Samsung. But i feel like i read that more than just 1 time.

 

[growkingky69]

what light are talking about? these QB288 boards? Or a complete light?

I was looking at 650W ones.

 

[mannitu77]

I was looking at 650W ones.

i would not buy such a light just challenging your luck. There are so many cheap lights that have been tested, so you know theyre actually decent...meaning they have at least more than 2.0 PPFD...no need to buy something you know nothing about.

You dont know what difference 301 or 281 makes without knowing the bin. Could be 10%, could also be 30%. But even with LM301s iwouldnt buy that light. Their efficiency cleims are overstated, the marketing looks cheap and repulsive, like usually...just pick something that has been tested. Lots of lights on the Migro-Channel for example.

check out the Medic Grow Fold-6 light 660w for example. Its pretty efficient and has great value for the price.

 

[Tolerance Break]

Anybody have experience with Chinese uva/ir lights?