Great site,thanks LED Gardener. Making the switch to LEDs is like taking a college course in electrical engineering and your posts have really helped. I was going to do a COB build but came across Ichi's build & then found a source for the LM561 flexible strips.
My strips are different than Ichi's. They have no resistors and have 12 LEDs wired in series and then parallel, 60 LEDs per meter. I think I have enough for 4ft X4 ft grow space. I was thinking 16 strips with 72 LEDs on 4 ft. aluminum extrusions.
Confused about how to power these and can't start looking for drivers until I do. I've looked for I-V curves to try and figure out what volts & amps is best. Seems like a lot of options, maybe 2.7 volts @ .150 mA? And then parallel or series? Parallel seems the easiest as the strips are already wired that way and i can keep the voltage lower,but then what about thermal runaway? I can cut the strips every 12 LEDs & do a combination parallel & series. Appreciate any help,thanks
New build with LM561 flexible strips
Hey 60s, welcome! Glad you're getting some good info from the site.
Do you have a link to these strips? If they're LM561C and wired 12 per string in series, you can expect a voltage of about 36V per strip. You could run them all in parallel and maintain a nice, safe low voltage across the whole light.
Your math checks out. 16 runs of 72 diodes would be the exact equivalent of 4x HLG QB288 quantum boards, which will work in a 4x4. I would run the diodes at 150mA - If you were to run constant voltage at 36V, you'd need a pair of HLG-240H-36 drivers to pull this off (you'd connect 8 runs to each driver and they'd produce just a touch under 150mA per diode).
The more I run LEDs in parallel, the more I like the idea. A lot of popular lights are now running parallel rather than series (like the PLC 6). Thermal runaway can happen, but I've had no issues with it unless I run an unreasonable amount of current into whatever I'm testing.
Before you buy, don't forget to send that link so we can double check our math.
Do you have a link to these strips? If they're LM561C and wired 12 per string in series, you can expect a voltage of about 36V per strip. You could run them all in parallel and maintain a nice, safe low voltage across the whole light.
Your math checks out. 16 runs of 72 diodes would be the exact equivalent of 4x HLG QB288 quantum boards, which will work in a 4x4. I would run the diodes at 150mA - If you were to run constant voltage at 36V, you'd need a pair of HLG-240H-36 drivers to pull this off (you'd connect 8 runs to each driver and they'd produce just a touch under 150mA per diode).
The more I run LEDs in parallel, the more I like the idea. A lot of popular lights are now running parallel rather than series (like the PLC 6). Thermal runaway can happen, but I've had no issues with it unless I run an unreasonable amount of current into whatever I'm testing.
Before you buy, don't forget to send that link so we can double check our math.
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stuck in the 60s
- LED-Curious
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Thanks for the quick reply. These strips are a custom build for a large electrical supplier that bought them for a customer. I'm getting them from someone that works at the company,a friend, These are what they have left. I'm trying to get the source since I would like more because the ones I'm getting have are 5000 K and I would like some at 3000 K. I contacted some Chinese companies but can only find strips with the resistors. I'll let you know when I find a source. I have removed the paint on one strip from the one roll I currently have and they are definitely 12 LED strips in series and then parallel.
I did find a guy that 's making a clone quantum board and his are wired in 12 LED series strips and then in parallel. His sun board has 240 LM561c and only $40. He also has what he calls a fusion board a mix of LM561c and 40 Nichia 660 nm red chips. Might buy those if I can't get more of what I have in 3000K
https://www.photonfantomdesigns.com/
On another note I ran into someone that said a friend of his is running his COB build with a computer power supply with a boost converter regulating the current & voltage. Does this sound possible and safe? If so I will get more details. Thanks again for the site. I'm really looking forward to leaving the heat behind with HPS & MH.
I did find a guy that 's making a clone quantum board and his are wired in 12 LED series strips and then in parallel. His sun board has 240 LM561c and only $40. He also has what he calls a fusion board a mix of LM561c and 40 Nichia 660 nm red chips. Might buy those if I can't get more of what I have in 3000K
https://www.photonfantomdesigns.com/
On another note I ran into someone that said a friend of his is running his COB build with a computer power supply with a boost converter regulating the current & voltage. Does this sound possible and safe? If so I will get more details. Thanks again for the site. I'm really looking forward to leaving the heat behind with HPS & MH.
Adding the 660nm is a nice touch, but I wonder why he didn't take the obvious step and add instead 670nm & 700nm for the Emerson effect.
Other than that it looks like PhotonFantomDesigns sources the PCB LED-arrays with the same factory that HLG do. And while HLG are selling at ~$0.24/diode PFD sells at $0.16/diode (or $0.21 not on sale). Just need to find out where that is and buy directly... (And do the 670+700nm thing properly!)
As for the computer power supply etc. - I haven't a clue, sorry
Other than that it looks like PhotonFantomDesigns sources the PCB LED-arrays with the same factory that HLG do. And while HLG are selling at ~$0.24/diode PFD sells at $0.16/diode (or $0.21 not on sale). Just need to find out where that is and buy directly... (And do the 670+700nm thing properly!)
As for the computer power supply etc. - I haven't a clue, sorry
I think the main advantage of the HLG over the PFD is that HLG makes pre-drilled heat sinks for their boards whereas PFD doesn't sell sinks and you'd need to make your own. I heard somebody saying the PFD boards don't need heat sinks but knowing how hot the QBs get near their max current, I'm skeptical of this.
I did some research into the boost converter thing months ago but the slight savings you'd get are not worth the reliability and safety of getting a real Mean Well driver.
I did some research into the boost converter thing months ago but the slight savings you'd get are not worth the reliability and safety of getting a real Mean Well driver.
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Another good reason to go with HLG is that they at least have some business experience. PFD sells the same product (give or take), but is in operation only since February and who knows how long he'll be around. I vote buying directly from Shenzhen, but if buying from a middleman then might as well go for the more reputable one.
Thinking of making a lm561c strip build for my 2x2ft tent (60x60cm).
Is it better to get cc or cv strips? Whats the most efficient?
I am going to get strips form Alibaba, assuming they are genuine Samsung ones. 80cri strip gives out more lm/w than 90cri, is 80cri the best idea so?
I will use some alu profiles for the frame with no heatsinks, how should I build my light to reach 800-1000ppfd?
Is it better to get cc or cv strips? Whats the most efficient?
I am going to get strips form Alibaba, assuming they are genuine Samsung ones. 80cri strip gives out more lm/w than 90cri, is 80cri the best idea so?
I will use some alu profiles for the frame with no heatsinks, how should I build my light to reach 800-1000ppfd?