grow led diy - Page 1
Forum section: electronics / beginners

author: Irukandji
author_rank: Contributor
timestamp: March 03, 2019, 01:40:10 pm
content: Hi guys,i'm new to the Led subject and i have some questions about my Project. I want to build my own diy grow lamp.My Problem is that i'm not sure if the calculation is wrong or not. My other question is are there some alternatives instead of my choosen led's.LED from China all in all $18 for the LED`S for 60 LED's.Here is the link of the LED's :https://de.aliexpress.com/item/10-st-ck-UMAKED-High-Power-1-Watt-3-Watt-LED-Chips-Lampe-Licht-SMD-Warm/32847256118.html?spm=a2g0x.search0104.3.43.48e34ec4bEGrJX&transAbTest=ae803_3&ws_ab_test=searchweb0_0%2Csearchweb201602_9_10065_10068_10547_319_317_10548_10696_10084_453_10083_454_10618_10304_10307_10820_10821_537_10302_536_10902_10843_10059_10884_10887_321_322_10103%2Csearchweb201603_59%2CppcSwitch_0&algo_pvid=f5cff3e2-8f46-41ac-ae2b-e1457b82ac3b&algo_expid=f5cff3e2-8f46-41ac-ae2b-e1457b82ac3b-66x 1w blue led (15-25lm) (300mA-350mA) (3,0V -3,2V)18x 1w red led (40-50lm) (300mA-350mA) (3,0V -3,2V)If you know some LED alternatives within the pricerange of 20$ for all LED's:Blue needs to be 450nmand Red 650nmThis Driver i would buy:MW LPV-35-24 ... LED-Driver, 36 W, 24 V DC, 1500 mA.So the Resistor should be around 50 Ohm.I would choose a parallel circuit with a Series circuit.The Example belove.If you have some better opinions about a diy grow led please let it me know.Thanks for your help.

author: madires
author_rank: Super Contributor
timestamp: March 03, 2019, 02:09:16 pm
content: Beware of Chinese Watts.If the LEDs are fine then I'd order a few more as spares. Also I recommend to run the LEDs at a lower current (70-80%) than rated and to provide sufficient cooling (large heatsink). This way you'll get a LED light with a reasonable lifespan. I've built a few myself, e.g. for a fish tank.

author: Irukandji
author_rank: Contributor
timestamp: March 03, 2019, 02:24:55 pm
content: Thanks for your reply,whats about the lumen output of the Led? Is it a lie or close to the specification of the lumen output? You know some alternative Led's?What about the Driver should i buy some other? I will order atleast 40 red and 20 blue.Which Driver would u prefer for the 3W Led's same Setup?

author: madires
author_rank: Super Contributor
timestamp: March 03, 2019, 03:13:59 pm
content: Same as Chinese Watts.The only way to be sure is to measure the lumens. I can't recommend any specific no-name LED because you get the cheapest available in Shenzhen. No, a MEAN WELL driver is a good choice.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 03, 2019, 03:35:02 pm
content: I like to make a grow LED also, for the PSU i would shenzen not for the LEDS.I have this galvanic wire for the LEDS.And i will buy Cree LEDS only.I dont think Cree have diffuse LEDS, i dont know if its needed or not ?For the power i will use switching for each LED plane, so can have many LEDS from the same power, i dont know if its good or not to grow.Now i go smoke thanks to you.

author: Irukandji
author_rank: Contributor
timestamp: March 03, 2019, 05:21:26 pm
content: @ Jan AudioWhat PSU u use? any link?What cree led u will use? Link?ThanksHow to calculate the driver for a single Series circuit. Like the one in the picture belove.He use 3w LED.Link for the video. The explanation is to short.Anyway i got it.

author: Irukandji
author_rank: Contributor
timestamp: March 04, 2019, 02:02:07 pm
content: Hiif i use the 3w 700mA leds, could i use a driver with max 700ma for one row or do i need some more output like 800mA?For this example i will not use the voltage of the led and driver.Driver:MW APC-35-700

author: Zero999
author_rank: Super Contributor
timestamp: March 04, 2019, 02:45:36 pm
content: Quote from: Irukandji on March 03, 2019, 01:40:10 pmYou've got the resistance value wrong.For a string of six blue LEDs:R = (V-VF)/IFV = 24VVF= 6*3 = 18VIF= 0.3AR = (24-18)/0.3 = 6/0.3 = 20OhmThose forward voltages for the red LEDs don't look right to me. Red LEDs have a lower forward voltage, than the blue ones: 2.0V to 2.2V.To save power, use two series strings of nine red LEDs.R = (V-VF)/IFV = 24VVF= 9*2 = 18VIF= 0.3AR = (24-18)/0.3 = 6/0.3 = 20OhmQuote from: Irukandji on March 04, 2019, 02:02:07 pmThat's a constant current driver, which is perfect. Use half the number of 700mA LEDs connected in series, using the MW APC-35-700 and no resistors. The MW APC-35-700 efficiently limits the current, without any power being wasted in resistors.

author: Irukandji
author_rank: Contributor
timestamp: March 04, 2019, 03:12:00 pm
content: Thank for your help!If u look on the video above he set all of his Leds in one row. There are blues and also Red LED's in and i'm sure they use different voltages as u said. I also checked the data sheet of the LEDs and u right about the specification.So how he can manage all his LED in only one row?Also i only need 700mA Driver for 700mA led's? I rad about a prozentage about 10%-20% above the max of 700mA. So the Driver should have around 800mA? I'm right?(Sorry for asking again but im confused about it)

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 04, 2019, 03:41:30 pm
content: No i dont have PSU and i wanted to buy normal 5mm LEDS, not just a few, a whole lot, i dont know if its better, i just had this idea in my head, maybe a few 3W LEDS are more efficient then ?, saves a lot of soldering for sure.

author: Zero999
author_rank: Super Contributor
timestamp: March 04, 2019, 04:35:30 pm
content: Quote from: Irukandji on March 04, 2019, 03:12:00 pmIt's not convenient for me to watch the video at the moment, so I can't comment on it.QuoteNo, if anything, to prolong the life of the LEDs, driver should be rated for slightly less than their maximum current rating.The best way is to use one constant current driver with all of the LEDs connected in series and no resistors. The maximum output voltage of the LED driver should be greater than the sum of the LED forward voltages.

author: Irukandji
author_rank: Contributor
timestamp: March 04, 2019, 05:34:40 pm
content: @ Zerothanks again i think i got it now. So the mA can be the same as used (700mA Driver for 700mA LED) but the volateg should be above the sum of the LED's in a row (2xLED(3,2V) = 6,4, the driver should have 8V).Who ever added the comment about the mol per day thx for that!!!If you dont want to post here pls mail me private

author: Irukandji
author_rank: Contributor
timestamp: March 06, 2019, 01:11:06 am
content: Hi there i have one more question.I have choosen two different LED manufactorer.The First one are the chinese no Name LED with 3W and the seconds are from Osram a well know manufactorer.3W Deep Red 660nm 2.4-2.6v 700mA 60-70lm3w royal blue 440-445nm 3.2-3.6v 700mA 30-40lm(I cant find any lumen specification or how to calculate the mole)High Power LED OSRAM OSLON® SSL 80 660nm hyper 3WHigh Power LED OSRAM OSLON® SSL 80 451 nm deep blue 3WWho of them are better? I know its a stupid question but maybe someone tested both of them.

author: daniel444
author_rank: Regular Contributor
timestamp: March 06, 2019, 11:23:10 am
content: i have built a grow light using 4 of these in serieshttps://www.digikey.com.au/product-detail/en/bridgelux/BXRC-40G10K0-B-73-SE/976-1581-ND/6557083mounted on a heatsink i got from a large solar inverter scrapthey use poke in wire connector , i prefer the solder connector but these are cheaperthey have 90cri and people are successfully using them in grows , more pleasant to the eyei recommend you put 2 of them in series on a large heatsink , the heatsink is the hardest part to find , try to get a large used onefor the driver something like thishttps://www.digikey.com.au/product-detail/en/mean-well-usa-inc/ELG-100-C700/1866-1472-ND/7702924

author: Zero999
author_rank: Super Contributor
timestamp: March 06, 2019, 11:49:45 am
content: Quote from: Irukandji on March 06, 2019, 01:11:06 amThe trouble is you've not provided part numbers. The lumen output for the no name LEDs might be a bit optimistic.I Googled for OSRAM OSLON SSL 80 and found the following relevant links. The test current is 350mA, but they're specified up to 1A, although I wouldn't recommend running them at such a high current continuously.https://www.osram.com/apps/product_selector/#!/?query=*&sortField=&sortOrder=&start=0&filters=productbrand,OSLON,SSL,80&filters=productbrand,OSLON,SSL&filters=productbrand,OSLON&deeplink=https://www.digikey.com/catalog/en/partgroup/oslon-ssl-80-leds/53317

author: Irukandji
author_rank: Contributor
timestamp: March 15, 2019, 08:27:45 pm
content: Sorry for the late response.Thanks for your feedback so far.I found these LED's on ebay, but im not sure if they have enough power for my little grow box.Linkhttps://www.ebay.com/itm/10-x-High-Power-LED-OSRAM-OSLON-SSL-660nm-hyper-red-Platine-3W-Pflanzenwachstum-/172846213449All in all its for some garden plants like Physalis, paprika and chili.The box size is 90 x 60 x 60 cm. Im not quite sure if i get enough light out of my LED' stripes. They running with 5050 smd LED's.Link:https://www.ebay.com/itm/5pcs-SMD-5050-LED-Grow-Light-Strip-Lamp-for-Indoor-Veg-Flower-Plants-Hydroponic/264077183863?hash=item3d7c3a0b77:g:Mn4AAOSw3fxcCiz-&frcectupt=true

author: honeybadger
author_rank: Contributor
timestamp: March 15, 2019, 11:25:21 pm
content: Why do you want RED-BLUE combo? I guess it is obsolete, go full spectrum, all plants will benefit from that. Bellow 4000K for bloom, above 4000K for greens.You can use for example these PROLIGHT OPTO PACE-28FNL-BC4P. If you drive them at around 10W each you will get 200lm/W - it is comparable with most efficient and most expensive grow lights.And for 90x60x60 you will need a LOT of power so don´t be surprised. I guess at least 100W for blooming plants. A sunny day outside is 100k-200k lux - you can calculate how much lumens you need for your box.It is a LOT

author: Zero999
author_rank: Super Contributor
timestamp: March 15, 2019, 11:34:01 pm
content: I thought plants grow best with mostly red and a little blue light. I'm aware that other wavelengths are often useful, to instigate flowering and fruiting, but not most of the time.

author: honeybadger
author_rank: Contributor
timestamp: March 15, 2019, 11:39:17 pm
content: The blue-red combo it is most useful for chlorophyll only but there is a lot more.Check this:https://en.wikipedia.org/wiki/Photosynthetically_active_radiation#Yield_photon_flux

author: thedoc298
author_rank: Contributor
timestamp: March 16, 2019, 02:29:04 am
content: For a string of six blue LEDs:R = (V-VF)/IFV = 24VVF = 6*3 = 18VIF = 0.3AR = (24-18)/0.3 = 6/0.3 = 20Ohm20 ohm ^^^^

author: nowlan
author_rank: Frequent Contributor
timestamp: March 16, 2019, 03:28:06 am
content: I have a cob led over my reef tank, driven by 700ma meanwell LPC driver, and passive cpu heatsink.https://www.digikey.com/product-detail/en/bridgelux/BXRC-30E4000-F-23/976-1255-ND/5180227

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2019, 06:42:57 am
content: Lumens are essentially meaningless for non-white light anyway, and the specs on random Chinese LEDs are usually just made up numbers having little to no relation to what the parts are actually capable of. Some of them are quite good, others are not, you can't really tell from the specs though.

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2019, 07:55:37 am
content: Quote from: honeybadger on March 15, 2019, 11:39:17 pmI know, but I maintain blue and red are the most important colours. It depends on the application. If he's just trying to suppliment existing natural light i.e. grow plants indoors near a north facing window, then I don't see why red and blue LEDs won't do.And I've corrected my previous post: plants need more red, than blue light, rather than the reverse.

author: honeybadger
author_rank: Contributor
timestamp: March 16, 2019, 01:03:54 pm
content: Quote from: Zero999 on March 16, 2019, 07:55:37 amIt will look like in a whorehouse. I had a DIY blue-red combo few years ago. Full spectrum is the only way.And you won't be able to find most efficient blue and red LEDs. All the efficiency development is focused on white LED. And efficiency is the most important factor there is.

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2019, 02:05:43 pm
content: Quote from: honeybadger on March 16, 2019, 01:03:54 pmWho cares what it looks like?Using separate red LEDs is more efficient because it cuts down on the losses when blue light is converted to longer wavelengths in the phosphor: look up Stoke's shift. Producing lots of green and yellow light is also wasteful because it's just reflected by the chlorophyll, rather than used for photosynthesis. If plants used green light for growth, then they wouldn't reflect it, so would be a different colour than green.

author: honeybadger
author_rank: Contributor
timestamp: March 16, 2019, 03:12:17 pm
content: Using red and blue is not more efficient because there are no efficient red and blue LEDs. There are white LEDs with 210lm/W because that is what market wants. Yes there is a luminofor loss but overall white is an efficient winner.Plants are not made entirely from chlorophyll. Plants only reflect small amount of green light. Yes from all colors they reflect, green is dominant, that is why they look green, but they still absorb more than 80% of green light.Try to live in the same room with red-blue grow light - it is not possible (at least for me).

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2019, 05:08:52 pm
content: There are lots of efficient blue LEDs, white LEDs are just a blue LED with a white phosphor. The efficiencies of red LEDs are not bad either, but you can't use lumens to measure the efficiency of non-white LEDs.

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2019, 06:50:29 pm
content: Quote from: honeybadger on March 16, 2019, 03:12:17 pmNonsense, red and blue LEDs are more efficient than white ones and Lumens per Watt is meaningless in this context.QuoteEven if that's true. it doesn't change the fact they mostly use red and blue for growthQuoteNot everyone lives in the same room as their plants.

author: honeybadger
author_rank: Contributor
timestamp: March 16, 2019, 08:38:56 pm
content: Most efficient grow lights with most PPFD/PAR output are full spectrum based around CREE CXB-3590 or Samsung LM301B or some Luminus white COB LEDs. I don't believe there is any blue-red grow light with comparable efficiency, no matter how expensive. But of course it is OK if you don't agree.

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2019, 09:41:10 pm
content: Quote from: honeybadger on March 16, 2019, 08:38:56 pmI accept you may not want your room light with hot pink light and respect your preference in that regard, but as far as efficiency is concerned, there's no opinion involved. I'm talking about fact.What's important here is, radiometric efficiency in the parts of the spectrum most important for photosynthesis. Radiometric efficiency is a measure of electrical power in vs optical power out in a certain bandwidth. A UV light might have a luminous efficacy of near zero Lumens per Watt, as most of the light is invisible, yet a radiometric efficiency of 30%.Lumens is a measure of intensity scaled to the response of the human eye and is therefore irrelevant to this discussion. A green LED will be brighter than a blue or red one, given the same optical power output, purely because the eye has greater sensitivity in that region of the spectrum. Radiometrically speaking, green LEDs have appalling efficiency, compared to blue or red ones, they just look brighter. Perhaps one day better green LEDs will be developed.As mentioned above, white LEDs are just blue ones with a phosphor to convert some of the blue to longer parts of the visible spectrum. They are radiometrically less efficient, than the equivalent blue LED because a lot of energy is lost in the phosphor: again, look up Stoke's shift. A white LED will appear brighter, than a blue one of the same power level, but that's only because the inefficiency is more than compensated for by the fact that the human eyes are more responsive to the phosphor emission, than the blue light. The white LEDs you've mentioned above are very good, but they have inferior radiometric efficiency, compared to equivalent red and blue ones.I like the Luminus devices products because they specify both radiometric power output as well as luminous flux. Refer to the data sheet linked below. Note how the green LED is 2000lm, yet it only has a power output of 4.1W and the blue LED is only 400lm, yet it has a much higher power output of 7.2W! Do the calculations and you'll find the green LED is poorest in terms of power in vs power out, even though it's the brightest.http://www.mouser.com/ds/2/245/Luminus_CBT120_Datasheet-472561.pdfIn summary: a white LED is pretty inefficient, as a grow light. Not only is lots of light lost in the phosphor, but most of the light is emitted in the middle of the visible spectrum which isn't used by plants.

author: honeybadger
author_rank: Contributor
timestamp: March 16, 2019, 10:19:08 pm
content: So what is the best red-blue combo andwhat PPFD/watt it gives? Currently for full spectrum about 2.1 PPFD/watt is the limit.https://gn.uk/guides/par-ppf-ppfd-and-dliSo why is there such a difference between the absorption spectrum and the action spectrum if chlorophyll is responsible for photosynthesis? The answer is simple: Chlorophylls are not the only photoreceptors that are responsible for photosynthesis. There are other types of antenna photoreceptors (mainly carotenoids) which also promote photosynthesis, and byutilizing narrow band red/blue LEDs in sole-source lighting conditions these pigments are not able to optimize their light harvesting capabilities. Also, it should be noted that green light does in fact promote photosynthesis in chlorophylls, quite efficiently in fact.Recent work has shown that green light is able to penetrate deeper into leaf surfaces to drive photosynthesis in chloroplast located towards the bottom surface of the leaf, in fact, more efficiently than red light at high PPFD.

author: Zero999
author_rank: Super Contributor
timestamp: March 16, 2019, 11:44:21 pm
content: I honestly don't know the answer to that question. I agree that other wavelengths as well as red and blue are used by plants and haven't disputed this. I've just noted the majority of photosynthesis seems to occur in the red and blue regions. I believe the optimum spectrum depends on the plant, the stage of development and is something which is the subject of ongoing research.If you look at the spectrum of a typical white LED, you'll find it looks nothing like that of any grow lamp, hence why I believe it's not optimum, although I can understand why you might prefer it for practical reasons.https://www.cree.com/led-components/media/documents/ds-CXB3590.pdfIt also depends on whether you're growing solely under artificial light or supplementing ambient light. If it's the latter then I imagine it's not too critical.In any case the efficiency of converting electrical energy into different optical wavelengths needs to be taken into account, as well as photosynthesis.

author: metrologist
author_rank: Super Contributor
timestamp: March 17, 2019, 11:49:43 am
content: Solar powered grow lights

author: Zero999
author_rank: Super Contributor
timestamp: March 17, 2019, 01:46:30 pm
content: Quote from: Irukandji on March 15, 2019, 08:27:45 pmWhy not stick with branded produces from reputable distributors? I don't think this is the sort of thing you should be trying to save every penny on.I'd probably go for the LEDs on little aluminium PCBs mounted to a large heat sink.Either something like this:https://www.digikey.com/product-detail/en/thomas-research-products/132541/1121-1640-ND/7693230Or separate red and blue modules: four red and one blue in the middle.https://www.digikey.com/product-detail/en/led-engin-inc/LZ4-40R208-0000/1537-1042-ND/4976732https://www.digikey.com/product-detail/en/led-engin-inc/LZ4-40B208-0000/1537-1037-ND/4976727With a suitable LED driver module.