Viceman666
Well-Known Member
I guess you should hve checked this forum instead of the other forum and you would have been better informed just sayin.. hopefully things work out for you
Order fake LM561C's from Alibaba....
- Thread starter conversekidz
- Start date
tazztone
Active Member
cons: 90cri doesn't even exist in that bin. check the lm561c datasheet. so another scam.
apart from that. 90cri doesn't perform better than 80cri for plant growth.
sorry mate I'm note sure what you mean when referring to 'bin' but I know that 90cri Lm561c's definitely exist..
So 90cri is only better for flowering I presume? I only say it's better because I saw a thread where they tested 80 & 90 cri cobs and I remember reading something about the 90's finishing flower before the 80's by about a week! Sorry I'm still trying to get my head around the technical jargon
Last edited:
They do not make the s6 lm561c in 90cri as stated above so they are lying or it's a typo
tazztone
Active Member
and they get less gpw right?
anyway you lose some photons, because the phosphor layer of the 90CRI LED is different.
you can use these conversion factors (got the from the user livinglight from Ledgardener forum) to get from Lumen (what humans see) to Photons in the range of 350-750nm (what plants need) per watt:
178 lm/W * 0.01485 = 2.64 LM561C 3000K CRI80 (0%)
144 lm/W * 0.01730 = 2.49 LM561C 2700K CRI90 (-6%)
so in this case you lose about 6% efficiency by chosing 2700K 90CRI over 3000K 80CRI. and it get's slightly worse once you start weighing the photons according to the McCree curve, which is an even more accurate measure of plants light needs.
the difference in wavelength distribution might have biological effects too, but mostly it's about the photon count.
thanks mate excellent info, appreciate it!
so you're saying they don't make the 90cri at all or just don't make them in same 'bin'? From what I understand 'bin' refers to the manufacturers grading by quality/specs yeah? And s6 refers to the bin? Which I would assume is the A grade bin?
I'm just not sure if you're saying they don't make 90cri full stop or they just don't make them in the same bin? Because I was looking at data sheets on the Samsung website earlier and they definitely had lm561c 90cri
Attachments
ok found this post by SupraSPL, I can't post links yet but I'll quote his post and hope that he doesn't mind, as it's very informative and probably what you were getting at in regards to the 90cri not being available Ryan?
"Hi CRi leds (~95 CRi) have a more even spectral balance and they have a larger percentage of their output in the deep red range where human vision response is low. It is a slightly more photosynthetically efficient spectrum BUT it comes at a significant cost to efficiency. 70-80CRi LEDs seems to be a good compromise point of very high efficiency, good output in the red/deep red range and high efficiency.
To make matters worse for the high CRi option, we do not currently have access to top bins of the high CRi but we do have access to the top bin 3000K and 3500K 80 CRi."
looks like I'll stick with 80cri, seems to be the sweet spot!
"Hi CRi leds (~95 CRi) have a more even spectral balance and they have a larger percentage of their output in the deep red range where human vision response is low. It is a slightly more photosynthetically efficient spectrum BUT it comes at a significant cost to efficiency. 70-80CRi LEDs seems to be a good compromise point of very high efficiency, good output in the red/deep red range and high efficiency.
To make matters worse for the high CRi option, we do not currently have access to top bins of the high CRi but we do have access to the top bin 3000K and 3500K 80 CRi."
looks like I'll stick with 80cri, seems to be the sweet spot!
Aolelon
Well-Known Member
Yea the reason they cant do that, is lm561c s6 doesnt come in 90 cri, the highest 90 cri goes is s3. So if they tell you that, of course they are lying about other things
Aolelon
Well-Known Member
The samsung lm561c diodes are separated by cri.
They have lm561c 70 cri - 80cri - and 90 cri
The 80 cri goes from bin s1 to s6, the 90 cri goes from s1 bin to s3 bin. Samsung does not.make an s6 bin lm561c 90 cri
Franc Iss
Member
I have just finished a very bad experience with Meijiu Lighting Co. from China/ alibaba. They send DIY kit without connectors, screws, malfunctioning external plastic dimmer - which was priced at 14$ without being asked, very poor communication and not willing to negotiate the reinbursment of their mistake. I managed to get the money back thru alibaba trade assurance, but the nerves, the delay spent wont compensate the cheap price you get there. As more people say and i wouldnt listen, i wouldnt buy again...maybe except pcb, or individual components, nothing assembled there in terms of tech is worth buying... So guys, beware of Meijiu, you might get 1 of 3 complete orders. Dont waste your time and value on cheap things, your brainjuice and health worth more...
thanks mate, completely understand now. In meijius defence I didn't specify s6 they just said it would take 4 days to make the lm301b boards, that was at no additional cost but I'm glad I asked, because I ordered the 80cri units
Aolelon
Well-Known Member
I wouldn't put it past them to try and pull that off anyway.
that's a bummer to hear mate, I decided to give them a go so hopefully my experience is a bit more pleasant, I did however stipulate very clearly, specific terms to be put into the purchase contract, including terms like 'genuine samsung lm561c s6' etc. so if need be there's is always trade assurance, with a bit of luck I won't need it!
If I could afford it I would have loved to buy the HLG 550 but my budget doesn't all for that at the moment, so the Meijiu was basically my choice based on bang for buck, after considering a 450w Clu048 cob build. I more than likely won't use the included dimmer and wago's etc. I plan on using a sonoff wifi dimmer/timer and will probably solder everything and run it into a project box etc
The bin makes a huge difference but yes they do make 90cri in a low bin
Viceman666
Well-Known Member
Dont rely on the trade insurance its for most who have tried it just real bullshit.. however I bought 4 boards from meiju and I will be hitting 1g/w of good buds in a 4x4 at 520w for my first grow so I think thats pretty decent regardless of the led I got legit or not
Aolelon
Well-Known Member
They aren't bad boards, especially for the price. And especially if youre not worried about what youre getting 100%. But for people trying to squeeze every little bit of efficacy and light out of each panel. I would say they probably aren't the way to go.
For sure dude I don't doubt it one bit but for the price point and a 4x4 space I think these will produce good enough results for me, based on the kind of results Viceman and others are seeing.
For my budget it was either these or 9x Citi clu048 1212 80cri's, I think both would probably produce pretty similar results but this setup was slightly cheaper and would take up a lot less space in the tent, be substantially lighter and hopefully generate less heat.
Which will be an issue for me in the summer, for that reason LED was the logical choice for me, then it just came down to getting the most for my money.
I originally decided on cobs but after learning more about QB's, from what I understand there's is slightly more uniformity in par over the grow area and less prone to hotspots etc., so any small advantages for a cheaper price made these a no brainer for me.
I think for those of us on a budget that have a genuine need for LED, these are a perfect starting point
For my budget it was either these or 9x Citi clu048 1212 80cri's, I think both would probably produce pretty similar results but this setup was slightly cheaper and would take up a lot less space in the tent, be substantially lighter and hopefully generate less heat.
Which will be an issue for me in the summer, for that reason LED was the logical choice for me, then it just came down to getting the most for my money.
I originally decided on cobs but after learning more about QB's, from what I understand there's is slightly more uniformity in par over the grow area and less prone to hotspots etc., so any small advantages for a cheaper price made these a no brainer for me.
I think for those of us on a budget that have a genuine need for LED, these are a perfect starting point