# cheap DIY LED



## naoki (Jan 10, 2014)

I'm not sure if this post belongs in "culture" section, but the light source is an important aspect of our slipper culture for us who rely on artificial light. So I thought that some of you might be interested in this.

I was curious about those Chip-on-board (COB) style LED from China. So I saved up my milk allowance and invested $15 to play with this toy.

Here is everything needed:




From right, AC/DC adapter to drive the cooling fan. Some cell phone charger is probably good enough. I wouldn't use those big, super-old ones which aren't efficient. Reflector is made out of tomato sauce can. I put the foil tape (usually used for ducting) inside to make it silver (instead of gold). 30W diode is attached to an old CPU heatsink after putting thin layer of thermal grease. Then at the left, you can see 30W constant current driver (900mA, forward voltage 30-34V DC). The green bottle is the case for the driver. The "listed" spec of the LED is:

30W Warm White
Forward Voltage (VF): DC 33-35V
Forward current (IF): 1050MA
Output Lumens: 2500-3500LM
beam angle: 140 degree





The construction is super easy. 2 wires of the driver need to be connected to AC plug. Then 2 other wires need to be soldered to + and - of diodes. You should solder before attaching it to the heatsink.

*Cost*:
I got a 30W emitter + constant current driver from ebay (about $15 including shipping). Additionally, you need a AC/DC converter, an old CPU heatsink+fan, and cables with AC plug. But it's likely that you can find these for free or very cheaply. I used a tomato sauce can (+ foil tape) for a reflector. So the total cost for me is $15. It is almost as cheap as 23W CFL + 8.5" clip lamp.

*Comparison* against CFL:





Both CFL (left) and LED (right) are at the same hight from the floor (about 10"). The photo gives you an idea of the beam spread. Note that for this photo, I didn't have the reflector attached to LED. Reflector makes the lighted area slightly smaller.

Also, both CFL and LED are "warm" white, and they give relatively similar perceived "color". But most florescent lights have only a few (3-5) sharp peaks in the emission spectrum and white LED has a more continuous spectrum. 

CFL is Lite Source LT-23SP, 23W 2700K with cheap 8.5" Clamp Light (Commercial Electric 277-894 from Home Depot). Actual measured energy consumption is 23W.

30W LED consumes 30.8W. The cooling fan driven at 6V consumes 2.6W (6W @ 12V, 1.8W @3V, and 3V is probably good enough, though). So total of 33.4W.

*Measurement* (with Gossen Ultra Pro light meter, 12" from the tip of the light source):

CFL: 300 fc
LED: 550 fc (520 fc without tin can reflector)

CFL: 300fc/23W = 13fc/W
LED: 550/33.4W = 15.6fc/W

So LED provides about 20% more light per watt.

*Light spread*
To roughly understand the beam spread pattern, I measured right below the light, 6" off-center and 12" off-center. Light is 12" above the measuring plain.

CFL: 100% @ center, 53.3% @ 6" off-center, 23.0% @ 12" off-center
LED: 100% @ center, 65.5% @ 6" off-center, 32.7% @ 12" off-center

So LED has a wider usable spread in this case. In other words, actual advantage of LED is greater than 20%.

*misc*:
This cheap LED is probably crappy (in efficiency) compared to better COB LEDs such as Bridelux Vero or Cree XLamp CXA. I would say that the output of this cheap ebay LED is better than I expected, and it is super cheap and usable for orchids. We'll see how long it will last. In a long term, you'll probably save money with Vero or CXA than the less efficient, cheap LED even though the initial cost is higher. However, the white LED technology seems to keep changing rapidly, so low initial cost could be a good thing.

If you are not into DIY, you can find preassembled LED flood light (e.g. $30 for 30W), which uses a similar LED. You may need to attach AC plug, but you don't need to solder, and you get water-proofed case and reflector. It seems like a pretty good deal compared to T5HO. But I'm not sure how effectively the heat is dissipated, and how long they will last.

Here is a link to something similar (the link will die eventually):
30W LED Warm Cool White High Power 3300LM Lamp Chip 30W Power Driver 85 265V | eBay
100W LED Warm Cool White High Power Lamp Chip 100W Power Driver AC 85 265V | eBay

LED Flood light example:
10W 20W 50W 100W 200W LED Warm AC or DC White RGB Spotlight Flood Light Garden | eBay

I'm linking to the ebay seller, whom I had a good luck with. I received a partially broken LED at first, but they immediately sent me another working one without any troubles.


----------



## Chicago Chad (Jan 10, 2014)

Thank you Naoki. This is all very valuable to me and it saves me quite a bit of time. I will have to save this post for my next enclosure.


----------



## abax (Jan 11, 2014)

In passing, I assume the LED is less expensive to operate as well. Is that
assumption correct?


----------



## naoki (Jan 11, 2014)

Chad, it does generate a bit of heat (I think you grow some nice cool-growers). I don't know how to measure it, but the heat sink was going warmer when I stopped the fan. I would prefer passive cooling (no noise). But the efficiency of LED drops with the temperature, so people seems to think slight energy loss due to active cooling is compensated by the increase in the efficiency.

Angela, it is not a easy question, I think. The efficiency of LED seems to be highly variable among different fixtures (depending on their design). I would "guess" that this cheap LED has similar operating cost (PPF efficiency, i.e. efficiency relevant for photosynthesis) as T5HO. More expensive ones (Vero or Cree CXA) are likely to be more efficient than T5HO. For photosynthesis efficiency, HPS and MH is highly cost effective (much better than T5HO). Some of the top-end LEDs are now better than HPS and MH in terms of operating cost.

Table 2 in 2nd page of this document has a comparison of LED vs HPS vs MH. The two blue columns in the table are the relevant numbers (high PPF efficiency value is better).


----------



## Silvan (Jan 11, 2014)

LED lights are very efficient as long as you remember that they were
created for high light level plants like "medicinal plants" and (for some
reason) lettuces...


----------



## ALToronto (Jan 12, 2014)

What is thermal grease?


----------



## naoki (Jan 12, 2014)

Alla, maybe I'm not using the correct terminology. When you are attaching the CPU to heatsink, you use the gray stuff, which can conduct heat between the CPU and heatsink. Even though the surface is supposed to be flat, there could be some small irregularity, so the heat conductive grease is avoiding the air pocket. There are some thermal grease with adhesive property, too. I drilled holes, used a tap, and attached the LED with machine screws. But if you use the adhesive type, you can just glue the LED to the heatsink.

Have you had a chance to assemble your DIY LED yet?

Silvan, take a look at the link I gave in message #4. The test shows amazing variation. Even though all of the tested LED fixtures are considered to be "high-end", one of them gives 0.84 micromoles/s/W while a better one gives 1.60 micro moles/s/W. A lot of the LED makers use marketing hypes, but this data tells me that we should be careful.


----------



## ALToronto (Jan 12, 2014)

I received the diodes from China, but I haven't had the chance to do anything with them yet. Keep in mind, my goals are as much aesthetic as functional, so until I find an attractive heat sink to attach them to, I won't start on them. I'm looking at aluminum foam as a mounting substrate, just a matter of contacting the manufacturer and getting it in the right shapes and sizes. 

I will need to use an adhesive thermal conductor, as these diodes will be suspended. How would you isolate the soldered leads from the heat sink - shrink tubing?


----------



## Silvan (Jan 12, 2014)

Well all the info provided in the link seems very interesting,
but I don't really have the intellectual capacities to understand
all of it..lol 
I just wanted to warn people not to start with priced plants (orchids)
without knowing their light requirements as I did with my phrags.

kovachii before LED :







kovachii after LED:


----------



## Silvan (Jan 12, 2014)

and it's not the worst looking plant..
Keep a close watch on your plants, because it took about
a month period to go from picture 1 to picture 2. 
Now my phrags used for this experiment are at 4feet under my fixture
at a 12 hours light cycle. The bleaching and burning seems to have stopped.
But they aren't getting better either.


----------



## naoki (Jan 12, 2014)

ALToronto said:


> I received the diodes from China, but I haven't had the chance to do anything with them yet. Keep in mind, my goals are as much aesthetic as functional, so until I find an attractive heat sink to attach them to, I won't start on them. I'm looking at aluminum foam as a mounting substrate, just a matter of contacting the manufacturer and getting it in the right shapes and sizes.
> 
> I will need to use an adhesive thermal conductor, as these diodes will be suspended. How would you isolate the soldered leads from the heat sink - shrink tubing?



I'm using a twist-tie to make it stay to the side of the heatsink. Are you talking about the insulating against the heat? The heat sink doesn't become too hot. For electrically insulating the soldering point on the LED array, I might use the liquid tape, but I probably leave it as is.

Silvan, that's too bad. Which model of LED fixture are you using? With the white LED, I can easily tell the appropriate distance. But with R+B type, I wasn't sure at first. I did have tiny amount of bleaching (with 90W R+B), too, but I caught early on. But in general, I feel like that plants become greener with R+B (just anecdotal) if not too intense.


----------



## Silvan (Jan 12, 2014)

well, I don't want to hijack your thread. I just wanted to warn people
not to use valuable plants for the experiment as I did.. 

the biggest one is running at half capacity as ideally it would
need to be at least 6 feet above the folliage and the ceilling in my
basement isn't high enough ...


----------



## DavidCampen (Jan 13, 2014)

naoki said:


> Alla, maybe I'm not using the correct terminology. When you are attaching the CPU to heatsink, you use the gray stuff, which can conduct heat between the CPU and heatsink. Even though the surface is supposed to be flat, there could be some small irregularity, so the heat conductive grease is avoiding the air pocket. There are some thermal grease with adhesive property, too. I drilled holes, used a tap, and attached the LED with machine screws. But if you use the adhesive type, you can just glue the LED to the heatsink.


Thermal grease is a term people use; if you want to be more precise then Thermal Interface Compound is a better term. I use Arctic Silver Ceramique 2:
http://www.arcticsilver.com/cmq2.html
it is a white colored paste. I started using the grey colored, silver filled, Arctic Silver 5 but it is so tenacious that I had to be very careful to not leave grey smudges all over the house.

The pastes work much better than the tapes. If you need an adhesive material then the two component epoxy thermal compounds would be better than tape.
http://www.arcticsilver.com/ta.htm


----------



## naoki (Jan 13, 2014)

No worry of 'hijack', it's great to hear your experience, Silvan! Those seem to be pretty nice (and expensive) models. It looks similar to Bysen, but it is backed up with good warranty, and quality diodes (Cree+Bridelux, I don't think Bysen uses Cree+Bridelux). Yes, with 480W (actual), you can easily bleach orchids! For Paphs, I'm getting decent growth with 12 W/sqft.

Thank you for the recommendation, David! I used left-over grease from assembling computers. I'll get the one you recommended.


----------



## Ryan Young (Jan 13, 2014)

I got myself a smaller red/blue led fixture to try out, so far it's going alright.

http://www.tmart.com/Red-Blue-225-LED-Plant-Grow-Light-Panel-Hydroponic-Lamp_p85567.html

not a bad price and free shipping


----------



## naoki (Mar 31, 2014)

*Cree CXA-3070 is amazing!*

A bit of update:

Wow, there is no comparison between Cree vs ebay cheap LEDs. Cree CXA3070 is one of the cutting-edge white LEDs at this moment. Compared to ebay COB LEDs, CXA3070 is putting out about 60% more light per watt!!! Most of us are happy with whatever we have been using until we see the difference since we don't know what's out there.

OK, here is the punch line. CXA3070 is $40+$2.23 for holder, and 100W ebay LED is $8. So Cree is 5 times more expensive initially. But after running it 1.04 years, Cree becomes cheaper (I'm using $0.19497/kWh, which is probably higher than most of you). So it doesn't make sense to get the cheap LEDs. I started this thread with the cheap ebay LED. But now, I would recommend Cree CXA3070 over ebay LED. It's difficult to compare against florescent light (or red+blue type LED grow light). But I'm guessing that this CXA3070 is one of the most cost effective ways to grow with artificial lighting. The total costs is about $60 per 50W module of CXA3070 (pretty comparable initial cost to T5HO). You can drive it at a higher wattage (e.g. 100W), but I didn't want to push it to the maximum capacity.

*Materials*

_LED_: 
Cree CXA3070-0000-000N-Z230F ($40 from digi-key) + _LED Holder_: TE Connectivity 2-2154857-2 ($2.23 from digi-key)
vs
_LED_: ebay "100W" Warm White (similar to the one posted in the begining of this thread, but it has 100 diodes instead of 30 diodes for 30W). $8+free shipping from China

CXA3070 (3000K) comes in 3 grades (bins) depending on the efficiency: Z4 (most efficient), Z2, Y4 (least efficient). Mine is the middle bin (Z2). The LED holder is a bit tedious to use (drill holes to the heatsink), but you don't have to solder/glue the LED.

Here is the CXA3070 + holder:




Comparison of the size:



Clockwise from top left: Cree CXA-3070 (3000K, middle bin; Z2), ebay "100W" Warm White (around 3000K), ebay "100W" Cool White (around 6000K), ebay "30W" Warm White (around 3000K)


_Drivers_: I had 3 kinds of constant current drivers, all from ebay:



From top to bottom: 50W (1.5A), 30W (1.05A), 20W (0.6A).


_Heatsinks_: whatever CPU heatsink with a fan.



From Left to Right: Cree CXA3070, 3000K, ebay "100W" Warm White, ebay "100W" Daylight White, ebay "30W" Warm White.

_Wire_: Cerrowire 18-2 Thermostat Wire (18 gauge, 210-1002BR from HomeDepot). 
_Thermal paste_: Arctic Silver Ceramique 2

*Measurement:*
Explanation of the data columns:

"fc.1ft": I placed a light meter 12" away from the emitter, aligned to the center of the emitter. It was measured after running it for a minute or more (to stabilize the temperature).
 "input.W": watt used by LED + driver. This was measured by kill-a-watt meter.
 "Vf": forward voltage, the voltage across the + and - or the LED (unit: V)
 "current.A": current going through the LED (unit: A)
 "LED.W": watt used by LED (excluding driver). This is Vf * current.A
 Drvr.Effic: Driver efficiency. (=LED.W/input.W)
 fc.per.inW: footcandle at 12" per given input watt (=fc.1ft/input.W)
 fc.per.LEDW: footcandle at 12" per given input watt (exclude power loss due to driver) (=fc.1ft/LED.W)


```
LED        Driver     fc.1ft input.W    Vf current.A LED.W Drvr.Effic fc.per.inW fc.per.LEDW
CXA3070    20W(0.6A)     520    19.0 33.58     0.469 15.75      0.829       27.4        33.0
CXA3070    30W(1.05A)    970    33.8 35.04     0.864 30.27      0.896       28.7        32.0
CXA3070    50W(1.5A)    1500    59.0 37.03     1.427 52.84      0.896       25.4        28.4
ebay-100W  20W(0.6A)     320    18.8 27.51     0.552 15.19      0.808       17.0        21.1
ebay-100W  30W(1.05A)    480    27.2 28.06     0.866 24.30      0.893       17.6        19.8
ebay-100W  50W(1.5A)     730    46.0 28.81     1.425 41.05      0.892       15.9        17.8
ebay-30W   30W(1.05A)    520    30.1 31.01     0.866 26.85      0.892       17.3        19.4
```

LED on the left, and lightmeter on thr right:




Results (graphical representation):




*Notes:*

 With regard to the driver efficiency, those cheap ebay drivers (30W and 50W) are pretty good (89% efficiency). But the 20W driver is not great (around 82%).
 When you look at fc.perLEDW, you notice that efficiency of Cree and ebay LED increases with lower current. I think some other people calculated that radiometric efficacy of this Cree can be >40% with 20W (0.6A) driver. In other words, 40% of electic enegy can be converted to light energy (the rest is wasted as heat).
 However, running Cree CXA3070 at lower current is a false economy. You can run 2x CXA3070 @50W, or 3x CXA3070 @30W to get the similar amount of light. But it takes 10.7 years to make the cost (initial + electricity) even (13h/day). So I'm going to run it with 50W driver
 As mentioned earlier, after 1.04 years (13h/day), Cree CXA3070 becomes cheaper than ebay LED.
 I was a bit surprised, that luminous efficiency of the 30W ebay LED isn't so different from 100W ebay LED.

These measurements are approximate. For example, the color spectra could be slightly different even though both Cree and ebay LEDs are warm white (around 3000K), and I used footcandle instead of PPF of PAR. Additionally, the light spread could be slightly different and 1-point measrement at the center may be misleading (I think the light spread looks similar).


----------



## Ray (Apr 1, 2014)

I sure would like to see the spectral difference.


----------



## MorandiWine (Apr 1, 2014)

I agree with Ray. 

Thanks for all the input!

Tyler


Sent from my iPhone using Tapatalk 2


----------



## naoki (Apr 1, 2014)

Spectral difference between Cree vs cheap ebay? Since ebay LED doesn't have data sheet, I guess we need a spec photometer. I have been considering this DIY spectrometer, but I haven't done it yet. Has anyone played with this $40 spec.? Eventually, I might be able to compare PPFD of PAR, though. It's a bit tedious, and I haven't had time to do so. When I get around, I'll post the data (but not any time soon, though).


----------



## DavidCampen (Apr 3, 2014)

naoki said:


> Spectral difference between Cree vs cheap ebay? Since ebay LED doesn't have data sheet, I guess we need a spec photometer. I have been considering this DIY spectrometer, but I haven't done it yet. Has anyone played with this $40 spec.? Eventually, I might be able to compare PPFD of PAR, though. It's a bit tedious, and I haven't had time to do so. When I get around, I'll post the data (but not any time soon, though).



I can't find a link to the detailed step-by-step construction.


----------



## naoki (Apr 3, 2014)

David, here is a "practically-free" version:

http://publiclab.org/wiki/foldable-spec

Basically, you need to print out this pdf. It needs printer, paper, glue, and wasted DVD-R (and some camera). This foldable version is something I didn't know about. The earlier version (USB Desktop version) was using a webcam, which I don't have. But with this new one, it looks like that you can use any camera like this:
http://publiclab.org/notes/cfastie/12-3-2012/spectrometer-testing
When I have some time, I should try it with my camera.


----------



## DavidCampen (Apr 3, 2014)

I looked at the pdf:
http://old.publiclab.org/sites/default/files/8.5x11mini-spec3.8.pdf

I don't see what it does. How do you scan the frequencies? For example, if I have a tungsten-halogen lamp as the light source and I want to determine the relative strength (either power or photon count) of the light coming from this source at 2 different wavelength bands, say from 500-550 nm and 550-600 nm, how do I manipulate the spectrometer in order to make this determination?


----------



## naoki (Apr 4, 2014)

David, my understanding is that you take the photo of the "rainbow" which DVD produces. Then you upload it to a web-based software called Spectral Workbench, which evaluates the brightness of each 'rainbow' bands to produce the frequency spectrum plot. I think you need to take a photo of CFL and the source you are interested. The peaks in CFL is used as the calibration point of the frequencies. But I don't know the details (the web site is rather difficult to navigate), for example, I would guess that the white balance of camera could screw up the relatively brightness of different color band. But if you are using the same setting of a same camera, you may be able to compare different light sources.


----------



## naoki (Dec 24, 2014)

*Philips Luxeon XF-3535L*

This is a super easy version of DIY LED with high performance. Almost no tool required (wire insulation stripper does help). No need to solder nor drill, so much easier than the other DIY LED. Efficiency is pretty high (> 140 lumen/W).

*Parts*:


LED: Philips Luxeon XF-3535L. ($19.37 from DigiKey)
Driver: 900mA, 30W constant current driver from FastTech ($12.02)
heatsink: Aluminum 3/4" C channel (about $13 from HomeDepot)
3-prong AC-plug
24-gauge wire
Wire-Nut (something like this)
Optional: Kapton tape (something like this, but you can get it cheaper via eBay)

*Step-by-step assembly*
The LEDs come as a flexible strip. Mine is 525mm long.





The backside of LED strip has adhesive already, so you peel the backing and attach it to the aluminum C channel (I cut the C channel to 22" length with a hacksaw) like a sticker.





This is the close-up of the diodes:





Each end of the LED strip has a connector. One is for + and the other is - (labeled). This connector (AVX 9176-400) is pretty simple to use. If you use 24 AWG (gauge) wires (either solid or stranded wire), all you have to do is push the wire in. You don't have to strip the insulation neither.





After I pushed in the wire, I used Kapton tape to cover it. It's unlikely to short it, but I happen to have Kapton tape.





You connect the + connector of LED to + (red) wire of the driver, and - connector to - (usually white or black) wire of the driver. I used this cheap driver (LEF-30W). Note that the sticker is reversed. So the DC output is actually on the left side with red and white wires (even though the label says that the DC out is right side). These are connected to the LED connectors. The wires of the driver are short, so you need to add a couple feet of 24-gauge wires (with wire-nut or solder). 





Then the other side of the driver has brown, blue, and green/yellow (yellow with green stripe) wires, which is AC input. You need to connect an AC plug. The round stick is the Ground (refer to the next photo for the AC outlet). Then there are two flat blades; the bigger one is Neutral and the smaller one is Hot (Live). So you want to connect:
Green/Tellow = ground (round stick)
Brown = Live/Hot (smaller flat blade)
Blue = Neutral (bigger flat blade)







That's all you have to do. Here is the assembled and finished LED. I use soldering, but you can use wire-nuts to connect wires.





A test run. It doesn't look bright in the photo, but it is pretty bright, so you might want to wear sunglasses.






The next photo is showing the beam angle. From 1' distance, it provides about 2' wide homogeneous light. The C-channel looks like a decent reflector. The Cheerio box is not an ordinary Cheerio box. It is modified, and it is actually a DIY spectrophotometer (based on the one we talked earlier in the thread).





The aluminum C-channel, which is acting as a heatsink, does become quite warm, but it is not hot. A better heatsink would improve the efficiency, but the cost will go up quite a bit (LED is more efficient, when it is kept cooler).

*Measurement*
_Driver:_
AC input: 22.7W
Vf: 21.38V
DC current: 906mA
Driver efficiency: 85.3% (a bit low-end)

_Light measurement_ at 1' away from the LED in the middle:
PPFD: 110 micromoles/m^2/s
footcandles with LX1330B: 655fc
footcandles with Gossen Ultra Pro: 420fc (the response curve of this meter is quite different, but I'm including it for the comparison with the measurements of my older posts).

The LED is about 2' long. Here is the values of 1x 24W 2' T5HO (actually consumes about 18.15W per bulb in 4 bulb fixture).

AgroBrite 6400K 24W (brand new)
PPFD: 58 micromoles/m^2/s

AgroBrite 6400K 24W (2 years of use)
PPFD: 33 micromoles/m^2/s

Odyssea Plant 24W (new, purplish "plant" light)
PPFD: 81 micromoles/m^2/s

Odyssea Plant 24W (after 3-5 months)
PPFD: 63 micromoles/m^2/s

With 4x bulb fixture with 4 bulbs in it (bulbs are not brand-new), you get
PPFD: 160 micromoles/m^2/s

So 2x XF-3535L (45W) can outperforms (about >30% more light than) 4x 24W T5HO (consumes 72.6W). The cost of this DIY LED is similar or cheaper than 4x 2' T5HO.


*Comments:*
There are several versions of XF-3535L. I chose 4000K version. This can do 147 lumen/W if you are driving it at 800mA. I couldn't find a cheap 800mA driver, so I'm slightly driving it harder (900mA). This means the efficiency (i.e. the amount of energy converted to light instead of heat) is a bit lower than 147lumen/W. With any LEDs, if you drive harder, the efficiency goes down. Warmer ones like 3000K may have slightly better light suitable for plants because it has more red light. The lumen/W goes down if you use warmer light, but lumen isn't a good measure for plants. From several measurements I have done with LED (with PPFD of PAR, not irrelevant fc or lux), the output relevant for plants (PAR) doesn't go down with warmer light. So I think using 4000K or something lower than that is optimum. Also XF-3535L comes in several CRI. Stick with the lowest CRI for the given corrected color temp (80 CRI instead of 85 in case of 4000K). Higher CRI ones have lower output for plants. There is also 4' version (and 900mA driver works well), so this would be a good candidate to replace 54W T5HO.

Note that the performance of this LED is impressively high. But the price is relatively high compared to COB LEDs like Cree CXA3070 or Bridgelux Vero series (I recently assembled Vero 29, and I'm very impressed by it, I'll try to post more about it when I get some time). DIY COB-LED is pretty easy, but it is slightly more time-consuming than this strip light (e.g. drilling holes and tapping). Other high performing COB LEDs exist (e.g. Citizen, Samsung), but I can't get a few samples. I also heard that improved LEDs are coming out pretty soon. It is difficult to compare the performance between COB and the linear XF-3535L, but I'm guessing that they are pretty similar to each other. So if you are for ultimate cost-performance ratio, go with COB. So year of 2015 will be exciting for us artificial light growers!

Note that there are lots of other "strip-light"-style LEDs. Most others are not worth using for plants. The efficiency is really low (for most of them).


----------



## Ozpaph (Dec 25, 2014)

a great project with great instructions. Very Interesting. Thanks
arent you worried about an unearthed and home built 'appliance' in a 'wet' environment?


----------



## naoki (Dec 25, 2014)

Ozpaph said:


> a great project with great instructions. Very Interesting. Thanks
> arent you worried about an unearthed and home built 'appliance' in a 'wet' environment?



I'm not particularly concerned about it. Majority of florescent fixtures are not technically rated for wet conditions, neither. But we use them with common sense, I guess. 

I think most LEDs are enclosed in silicone or something, and they have been tested in high humidity environment (I think 85%RH or so, and it is mentioned in the data sheet). But it isn't a good idea to submerge these under the water.  I occasionally splash water to COB LEDs, but they haven't caused any problems (well, it is difficult to short circuit without putting them under water).

Do you mean no case ground by "unearthed"? This particular IP67 driver doesn't have the ground connected to the case of the driver, and the ground wire is simply connected to a ring. I think if this driver is installed inside another metal case, the ground ring is supposed to be connected to the external case. Since I don't have any external metal case, I'm not using it. Do you think I should connect the ring to the body of the driver? It seems that there isn't any need for the case ground (to the driver's body) since the waterproof driver is filled with silicone or something.


----------



## Ozpaph (Dec 25, 2014)

Im not an electrician so cant answer the question regarding grounding (=earthed). If its properly grounded then an earth leakage device will protect you. I would suggest that if you make something using mains voltage then you should know the answer. Of course 12V and low amps via a transformer is a different story and much safer. Id just hate it if you electrocuted yourself or a short started a fire. Please be careful. Sorry if thats a bit 'mothering'.


----------



## fibre (Dec 25, 2014)

What an interesting thread! 

My basement culture needs lots of light. I use Osram T5HO 865 bulbs. They do a great job. I had to remove the reflectors because they were too bright. 

My experience is that my Paphs seem to like the cool light better. I have one 840 bulb but flower stems grow away towards the 865 bulbs. 

As I have to extend my basement culture I don't like to add more heat. That's why I would prefer to use LED stripes or LED tubes for more light.


----------



## naoki (Dec 25, 2014)

That's an interesting observation, fibre. I looked up the spec of 865 (6500K) and 840 (4000K). In terms of lumen, 840 is putting out more. Tyrone probably knows which one has higher PAR (he has a nice spreadsheet of florescent bulbs). But PAR might not explain the direction of the stem growth (this is called phototropism, and it is auxin-mediated response). As described at the bottom of wikie page, some plants appear to use blue light for this reaction (e.g. arabidopsis where phototropin is used as the sensor). Maybe Paphs are one of them. But this doesn't necessarily mean that Paphs grow (photosynthesize) better with blue light, though.

I agree with the heat issue; I can stuff more light with LEDs into my grow tent without causing heat stress. Also, since electricity is more expensive in Europe, you'll get more benefit by moving to (high-quality) LED than us in the US. For me, the payback period (i.e. the initial cost is covered by the savings in electricity cost) is 1-2 years.


----------



## fibre (Dec 27, 2014)

Unfortunately I can't find any high-quality LED here in Europe that are essentially more effective than my Osram T5 HO. And their heat is an additional bonus for my basement in winter.


----------



## TyroneGenade (Dec 27, 2014)

Great data, thanks Naoki!

FYI, if the beam angle is 120 o (i.e. 60 from the vertical) then you want the sides of the rail bent a little to focus the light more. At 1 ft from the LED, the light would cover a diameter of more than 3.4 feet (tan 60 etc... you can do the math).

David, see http://www.apsa.co.za/xenforo/threads/light-spectrum-data-base.4454/ . There is a database of spectra of various lamps. Osram gave us data in mW/lumen/5nm which was very helpful. Essentially, if you have the spectrum you can exstrapolate the photon per bandwidth (or at least make a very good guess). The issue with cheap digital cameras though is that they don't capture blue/violet/purple well. If you email Greystoke he will share the most upto data dataset with you as well as explain how to do the exstrapolation based on a few known "standard" peaks (such as typical mercury green, blue and orange peaks). A nice page with LED/spectral data is http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/ which will give you lux/PPFD conversion.

As regards LED strips, the 5630 LED strips are very good. 4 parallel strips gave 145 PPFD (at 10 cm), see http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/ These are cheap and easy to install.

Naoki, blue light is also used to signal the opening of the stomata so there is more involved than phototropism.


----------



## naoki (Dec 29, 2014)

Ozpaph said:


> Id just hate it if you electrocuted yourself or a short started a fire. Please be careful. Sorry if thats a bit 'mothering'.



Thank you for the concern!  But DIY LED isn't that complicated, and putting pre-made parts together; this is slightly more complicated than playing with lego or assembling a computer from parts! Other hobbyists (e.g. aquarium people) seem to design and build the constant current drivers from scratch, which is over my head (for now).



fibre said:


> Unfortunately I can't find any high-quality LED here in Europe that are essentially more effective than my Osram T5 HO. And their heat is an additional bonus for my basement in winter.



I've heard that LEDs could be a bit more expensive outside of the US (even in Canada). But I think you can order via AliExpress to get the same cheap price as in the US. I can recommend Amelia Liu (Shenzhen OT-LED Technology Co.,Ltd) for Cree:

http://www.aliexpress.com/store/815938

She is easy to communicate with, and I managed to get the highest efficiency (top-bin, which is difficult to get) CXA3070 for cheap (same price as the lower bin). Here is the link to CXA3070:

http://www.aliexpress.com/store/pro...m-White-3000K-LED-Chip/815938_2052849889.html

You need to ask for the top bin via email, I got 5000K BB-bin since they didn't have AB-bin 3000K at that time. Everyone growing plants is looking for 3000K AB-bin CXA3070. Lower bins can be easily found from digi-key etc, but to get higher bin, you usually needs to order 20 or more pieces (i.e. you usually can't get 1-4 pieces from the usual domestic source). You'll get killer LEDs (no, it won't kill you as long as you use common sense) with these! 2x CXA3070 (at about 50W each) would be a good replacement for 4x T5HO (4', 54W) to cover 4'x2' area.

In Alibaba and eBay, you need to be careful because there could be sellers which sell fake. But this company seems to be honest.

If assembling isn't something you want to do, this European based Hans Panels seem to use good design and parts to achieve high efficiency. I calculated the cost of making a panel with similar parts, and it turned out that you don't save much. There are 65, 80, and 150W version. I was going to order these, but I figured out how easy it is to do DIY if I use COB-type LEDs.



TyroneGenade said:


> FYI, if the beam angle is 120 o (i.e. 60 from the vertical) then you want the sides of the rail bent a little to focus the light more. At 1 ft from the LED, the light would cover a diameter of more than 3.4 feet (tan 60 etc... you can do the math).



I think the C-channel is acting as about 90 degree reflector. I agree that it is not the best profile for the reflector at all. So you are saying to open the channel: i.e. instead of |_|, it should be\_/, right?



TyroneGenade said:


> A nice page with LED/spectral data is http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/ which will give you lux/PPFD conversion.



Thanks for the interesting links, Tyrone. But I believe that this link is not what you meant. If you can correct the link, I appreciate it!



TyroneGenade said:


> As regards LED strips, the 5630 LED strips are very good. 4 parallel strips gave 145 PPFD (at 10 cm), see http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/ These are cheap and easy to install.
> 
> Naoki, blue light is also used to signal the opening of the stomata so there is more involved than phototropism.



The link seems to use SMD5050 not 5630 (which is a bit more efficient). I haven't kept up with the LED strip light technology, but according to this page (message #14), none of them have decent lumen/W.

http://www.candlepowerforums.com/vb/showthread.php?365587-Recent-LED-Strip-Comparisons

Are there better strip LED products now? The one linked in APSA thread seems to give only 62.5 lumen/W, which is even lower than household LED light bulbs. Philips XF-3535L is at least twice as efficient (147 lumen/W). This is why I mentioned that this is not same as the older generation strip light. Well, this is just based on lumen comparison (and not using PAR), but I think that there will be a similarly big difference in the PAR comparison. Indeed, I think XF-3535L may pretty good for planted tank, and I may use it for this purpose. A bit pricey, but you'll save money in a long run over SMD5050.

Yes, cryptochrome is the sensor for blue light, and is involved in several processes in plants.


----------



## TyroneGenade (Dec 29, 2014)

The correct link: http://www.1023world.net/diy/spectra/

Silly me, I got ahead of myself. Wolf switched from 5050 to 5630 later on: http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/page-5 (but never gave me a Lux measurement). The 5630s are 3x brighter than the 5050s. So that should be 435 PPFD at 10 cm which would be about* 80 PPFD at 1 foot.

*This is a rudimentary estimate. I gave up working out the geometry of LED strip lights when I started exploring the geometry and calculus of overlapping circles. I must return to this problem at some point... There is at least 20% error in this guess as my simple model treated the point sources as squares, not round points.


----------



## ALToronto (Dec 30, 2014)

Thanks for the link, Naoki. Have you tried the lower power CXA LED's? I'm getting far better flowering on my latest living wall, which is lit by a combination of 6000K and 3000K 5W LED's, as compared to my earlier living wall, lit by Ray's 13W combination LED light bulbs (which are overwhelmingly cool white). 

I'm getting great green and root growth on both walls, but only the latest one has plants in bloom. So I'm thinking that a blend of colour temperatures is the way to go, and 50W is a little harsh for a single point source of light.


----------



## fibre (Dec 30, 2014)

Thank you Naoki!
I'm growing most of my Paphs in shelves. Currently I use two T4 HO 865 54W (>4100 lm each) per shelf with good success. 
What I'm looking for is a strip-light style LED system. And I don't like to have the driver in my growroom with all the water splashing around. 
Maybe I will use something like this: http://www.leds.de/LED-Leisten-Module/MultiBar-LED-Leisten/Lumitronix-MultiBar-49-kaltweiss.html


----------



## TyroneGenade (Dec 30, 2014)

fibre said:


> And I don't like to have the driver in my growroom with all the water splashing around.
> Maybe I will use something like this: http://www.leds.de/LED-Leisten-Module/MultiBar-LED-Leisten/Lumitronix-MultiBar-49-kaltweiss.html



I use them for my aquariums---lots of water splashing there---and just wrap them up in some plastic tied with insulation tape to keep them dry. No problems.


----------



## naoki (Dec 30, 2014)

TyroneGenade said:


> The correct link: http://www.1023world.net/diy/spectra/
> 
> Silly me, I got ahead of myself. Wolf switched from 5050 to 5630 later on: http://www.apsa.co.za/xenforo/threads/wolfs-led-diy.11072/page-5 (but never gave me a Lux measurement). The 5630s are 3x brighter than the 5050s. So that should be 435 PPFD at 10 cm which would be about* 80 PPFD at 1 foot.



Thanks, Tyrone. The spectra link is interesting, I should play with it. So it looks like Wolf's light is this one which uses Samsung chips. The web page doesn't have much info about energy consumption and other details (I'm more interested in the efficiency than the total output because you can increase the total output by increasing the number of electricity you use). But if it is using this LM561A, it can have fairly good efficiency. While I was looking for info quickly about 5630, I learned there are more efficient 5630. For example, Lite-on LTW-5630AZL looks pretty interesting (I didn't look at the data sheet in detail, but similar efficiency as XF-3535L). Also Seoul Semiconductor seems to have something similar. I should look into these in more detail.



ALToronto said:


> Thanks for the link, Naoki. Have you tried the lower power CXA LED's? I'm getting far better flowering on my latest living wall, which is lit by a combination of 6000K and 3000K 5W LED's, as compared to my earlier living wall, lit by Ray's 13W combination LED light bulbs (which are overwhelmingly cool white).
> 
> I'm getting great green and root growth on both walls, but only the latest one has plants in bloom. So I'm thinking that a blend of colour temperatures is the way to go, and 50W is a little harsh for a single point source of light.



Alla, it sounds like your DIY LEDs are working well! Did you update your living wall thread?

No, I have used only CXA3070. Using many smaller ones would give more uniform coverage. Also in your case, where you want to have a narrow beam pattern (to get distance between plants and light), you can find better/cheaper lens/optics for the smaller LED or COB. But I use the bigger COB for the ease of making them. Note that CXA3070 can be driven really soft at a low current, and it will give amazing efficiency. But the initial cost becomes too high, and it takes long time to get the high initial cost covered by the efficiency advantage (and by that time, this will be an obsolete technology). If you are interested in lower power COB, I've heard that Vero 10 have pretty good performance/cost (and you have the skill to make these LED panels with many diodes). I think it is around $4.60, and cheap efficient drivers are available.

Recently announced Cree XHP might be interesting to you. XM-L2 like performance with much cheaper price.

Could the difference in your DIY and Ray's be from the difference in the beam pattern (and difference in the intensity at the plant leaves)? I personally can't tell 5000K or 3000K is better with orchids. They seem to grow and flower well in either. In theory (and from my limited measurement of PAR), warmer ones (like 3000K) seem to be better for photosynthesis. In theory, 5000K, which uses less phosphor, should be giving more total light output, but my PAR measurement says 5000K and 3000K doesn't differ too much. In this case, red-enriched 3000K should have more useful light for photosynthesis. But it is possible that my old Li-Cor PAR sensor became off (it is known that the blue sensitivity of this sensor decreases with age).

In some cases, different color temp LEDs use different blue emitters. Then combining them could increase the width of emitted spectra. But frequently, the difference is just the thickness of phosphor with the same blue emitter. In this case, I'm not sure if there is a theoretical advantage to mix different color temp. For example, if 4000K has the best spectrum for plants, you may get the same results by achieving the spectrum by mixing 3000K and 6000K.

Fibre, I'm not familiar with that one, but it seems like a nice one (although it seems very pricey for the performance). You should give it a try! My drivers are outside of grow area to reduce the heat in the grow tent. I have a short AC to driver cable, and long DC cable from the driver to the LEDs. So they don't get to take shower even though they are waterproof (or outdoor) drivers.


----------



## Ray (Dec 30, 2014)

One thing that concerns me about PAR sensors is that it says nothing about wavelengths. An equal number of 450nm or 650nm photons per area per time is the same PAR, but obviously will give entirely different growth. 


Ray Barkalow (via Tapatalk)


----------



## ALToronto (Dec 31, 2014)

Just did a search on 'cree xhp led' on aliexpress.com - and got a 'no items found'. Must be a first! I guess the factories are getting ready for the new generation of chips (and Bridgelux can't be far behind) so we're seeing old technology led's being sold off at fire sale prices. 

I haven't updated my living wall thread - I will do it early in the new year. Right now I have 3 plants still in bud, I'll wait until the flowers open.


----------



## TyroneGenade (Dec 31, 2014)

Ray said:


> One thing that concerns me about PAR sensors is that it says nothing about wavelengths. An equal number of 450nm or 650nm photons per area per time is the same PAR, but obviously will give entirely different growth.



Yeah, have a look at http://www.advancedaquarist.com/2013/2/equipment . My issue is that all seem to waver a little in the violet/UV range and then all drop off suddenly in the far red even though photosynthetic response does not seem to do this for terrestrial plants (the sudden drop in action spectrum is a limit of detection, not a real photosynthetic limit). The apogee might be the worst as photosynthesis peaks at about 680--690 and the apogee doesn't detect this at all!

I'm not sold on PAR being the end all of lamp selection. I think the spectrum is more important. The main virtue of LEDs is that their spectrum mirror photosynthetic response very well compared to flourescents. 

Bye


----------



## naoki (Jan 1, 2015)

Ray & Tyrone, yes, although PPFD of PAR is closer to what plants want than lux/footcandle, and we use PPFD in publication of horticultural (and plant) science, it is not perfect as you mentioned. If the emission spectra are known, Yield Photon Flux (YPF) can be calculated, and it incorporates the action spectrum of plants (i.e. red light is more useful for photosynthesis than blue). Even with YPF, it is not a complete predictor of plant growth (Fig. 8a of the poster below).

This poster is an easy demonstration, and there are lots of things we can learn from it:
http://cpl.usu.edu/files/publications/poster/pub__2576523.pdf

There are several reasons. Action spectrum of plant photosynthesis is calculated under monochromatic light (measure PS rate with a light with narrow range of wave length). So it doesn't quite match with photosynthetic rates when light with several different wave lengths coexists (e.g. white LEDs). One example is the usefulness of green light depends on the intensity of light (when there are lots of red and blue light, the usefulness of green light increases, Fig. 8b). Also different spectra influence the photomorphogenesis (e.g. blue light makes more compact leaves, reduces stem elongation etc, top fig. of Fig. 7 and Fig 8), which is not reflected by PPF or YPF.

Although PPF is not a perfect measure, but it is pretty decent estimate of "usefulness" of light. Take a look at the bottom fig of Fig. 7. 4 blue diamonds (500 micromol/m^2/s) have higher dry biomass than 4 red squares (200 micromol/m^2/s) regardless of proportion of blue light. More PPF gave more growth in this case (obviously the relationship between PPF and growth isn't linear). The proportion of blue light changes almost no blue to mostly blue, and yes, red light (less blue) gives more overall growth, but the effect is not as dramatic as what you expect in terms of total dry mass. So from my measurement, since 3000K and 5000K COB LED showed similar PAR, I guess that neutral to warmer LED would be the sweet spot. But the shape of plants could be somewhat different.

Ideally, it would be nice to do the experiment similar to the lettuce with several species of orchids, but it would take much longer than with lettuce!

Alla, XHP isn't available yet.

Tyrone, yes, I didn't know about the Apogee issue until DavidCampen pointed it out. Percival Growth Chamber comes with a Apogee sensor, but they may have been calibrated for florescent light which is used in the chamber. There are several sensors with nice spectral response other than Li-Cor (which is commonly used among scientists). 

http://www.apogeeinstruments.com/content/Quantum Sensors-LEDs.pdf

But all (except Apogee) is expensive. Mine is an old Li-Cor. Even Li-Cor has the problem with sensor shift (blue response become weaker).

http://cpl.usu.edu/files/publications/factsheet/pub__6622553.pdf

So they need to be calibrated periodically (and you have to specifically mention blue shift calibration). Calibration costs almost $200, so I haven't calibrated mine yet.

For those, who are interested in this kind of topic, I put bunch of related link to this thread, which I should update at some point.

Similarly, there is a HUGE variation in the spectral sensitivity of consumer level lux/footcandle light meter. So values from one meter may not be comparable values from another meter. But they are still useful to give some rough idea.


----------



## TyroneGenade (Jan 1, 2015)

Great links! Thanks. That poster has lots of cool data.

There is a "cheap" quantum sensor in the form of the Seneye for aquariums. It would work just as well if all you want is a relative measure. The Skye and Kipp & Sonen seem the best options for a "true" measure.


----------



## naoki (Jan 2, 2015)

TyroneGenade said:


> Great links! Thanks. That poster has lots of cool data.
> 
> There is a "cheap" quantum sensor in the form of the Seneye for aquariums. It would work just as well if all you want is a relative measure. The Skye and Kipp & Sonen seem the best options for a "true" measure.



I didn't know about this product, thanks! It seems that the response of Seneye sensor is worse than Apogee, and Seneye isn't much cheaper than Apogee, isn't it? If you connect Apogee to a multimeter, the cost is $155 or so.


----------



## TyroneGenade (Jan 2, 2015)

You can simply attach the apogee sensor to a multimeter? Sounds to good to be true. I guess this gives you an object quantum count instead of the measure run through the sunlight/Cool white models.


----------



## fibre (Jan 7, 2015)

Yeah, I found a source for LUXEON XF-3535L! 
I will give it a try and buy a pair of L235-4080AULM5JAI0 and L235-5080AULM5JAI0.
Now I'm not sure what driver is the proper/best one.

This is my preselection:
APV-35-36, 
LPV-35-36,
LPC-60-1050

Are these drivers suitable for the long LUXEON XF-3535L - 900mA - 36V?


----------



## TyroneGenade (Jan 7, 2015)

Contact the manufacturer and ask them what they suggest.


----------



## fibre (Jan 7, 2015)

Of course I did. 
The instant message I got back was a link to the online-shop with some hundreds of drivers to choose from...


----------



## naoki (Jan 7, 2015)

Tyrone, yes, you can just get the Apogee sensor (maybe attach an alligator clip?), and use a digital multimeter to read ppfd.

Fibre, does your source carry 1150mm version of XF-3535L? In the US, I think that it is not in stock yet (at least for a small scale order).

With regard to the driver, the first two mean-well drivers are constant-voltage drivers, which aren't appropriate. You need constant "current" drivers. The last one is CC, and it seems to be good. It output 1050mA (should work with XF3535L), and the range of voltage is 9-48V (CC driver gives constant current and adjust the voltage to achieve the target current). Max efficiency is 87% which is usually achieved when the voltage is close to the max (48V in this case). When it is driven at around 36V (XF3535L), the efficiency is a bit lower, so it is probably around 85% (just a guess). But see below for a similar (and probably better) option where you need only 1 driver instead of 2 drivers to drive 2 LED bars.

The cheap chinese driver which I linked has a similar efficiency. I measured it to be 85%, but it was at 21.83V, so if you use it with 1150mm version (36V), then the efficiency should be higher than this. While the measured current was 906mA, the voltage range is a bit short 18-35V. It probably works, but no guarantee.

I just did quick search, and this ebay driver seems to work. Also, FastTech has  this 30W driver, which can go to higher voltage, but it has a low power factor (I don't understand "power factor" fully, but higher is supposed to be better). I don't have thise models, though, so I don't know the actual current or efficiency. From my experience buying and testing cheap Chinese drivers, efficiency could be decent to surprisingly good, but the actual current could be a bit off. You can look for a driver, something around 800-1050mA, and the voltage range contains 36V (or slight higher than that). Usually, they are sold as 30, 40, or 50W drivers.

But if you prefer name brand drivers (Meanwell etc), here are a couple options (I didn't go through all possible ones).

LPF-40-42 (960mA) or LPF-40-48 (840mA), efficiency close to 90%

LPF-40D-42 and -48 have the ability to dim.

One of LPC-100-1050 can drive 2x XF-3535L at 1050mA. This is probably more economical option than 2x LPC-60-1050.

I agree that Mean Well site should have a better way to search for a driver. If you want to go with name brand driver,s I can probably look into more details about other MeanWell models.


----------



## DavidCampen (Jan 7, 2015)

fibre said:


> Yeah, I found a source for LUXEON XF-3535L!
> I will give it a try and buy a pair of L235-4080AULM5JAI0 and L235-5080AULM5JAI0.
> Now I'm not sure what driver is the proper/best one.
> 
> ...



The APV and LPV models are constant voltage drivers and I presume that you do not want a constant voltage driver but rather want a constant current driver like the LPC or LPF models.


----------



## DavidCampen (Jan 7, 2015)

naoki said:


> ... You need constant "current" drivers. The last one is CC, and it seems to be good. It output 1050mA (should work with XF3535L), and the range of voltage is 9-48V (CC driver gives constant current and adjust the voltage to achieve the target current). Max efficiency is 87% which is usually achieved when the voltage is close to the max (48V in this case). When it is driven at around 36V (XF3535L), the efficiency is a bit lower, so it is probably around 85% (just a guess). But see below for a similar (and probably better) option where you need only 1 driver instead of 2 drivers to drive 2 LED bars.
> ...
> But if you prefer name brand drivers (Meanwell etc), here are a couple options (I didn't go through all possible ones).
> 
> ...


The MeanWell LPC-100-1050 can drive up to 96 volts which makes the output significantly dangerous. I prefer drivers that will not exceed 48 volts.
http://www.trcelectronics.com/led-power-supply-class-2.shtml

I had been looking at the MeanWell LPC series for my next purchase. The LPF series is similar but more expensive because it has active Power Factor Correction. I think that most residential users do not care about Power Factor since they are not paying for reactive power. 
http://www.nist.gov/pml/div684/power_121509.cfm

This place seems to have the best prices for MeanWell drivers: http://www.trcelectronics.com/Meanwell/power-supply-lpc.shtml


----------



## fibre (Jan 8, 2015)

Thanks a lot for your help, naoki and David!

Now I have to check all your links and so learn more about LED-drivers. 

The Luxeon XF-3535L I like to use is the one of 1150 mm length, 36V, 900mA, 157 lm/W, 4536 lm - 5076 lm.


----------



## naoki (Jan 8, 2015)

DavidCampen said:


> The MeanWell LPC-100-1050 can drive up to 96 volts which makes the output significantly dangerous. I prefer drivers that will not exceed 48 volts.
> http://www.trcelectronics.com/led-power-supply-class-2.shtml
> 
> I had been looking at the MeanWell LPC series for my next purchase. The LPF series is similar but more expensive because it has active Power Factor Correction. I think that most residential users do not care about Power Factor since they are not paying for reactive power.
> ...



Thanks, David. This guy also says that PF is not so important. It mentions that low PF for residential appliance has only small impact environmentally (in addition to no impact with electricity bill). So the FastTech (or other eBay) driver with low PF and no PF correction should be ok. But with the price of LPC-60-1050 linked by David ($17.5), a bit extra cost for the name brand might be a better option. I don't know how well Octopart covers European sources, but this place has it for 14 euro. Octopart couldn't find LPC-100-1050, so it might be hard to find it any way.

With regard to voltage, we all know that higher voltage is scarier, but I wonder how much more dangerous it is in practice (both medical and fire hazard). I put my fingers into gel electrophoresis (accidentally), but I don't remember the voltage (I guess it wasn't so high because it was just mildly ouch). I was thinking that HLG-185H-C1400 ($69.10) + 4x Vero 18 ($13.41 ea), whose total is $122.74 (+ heatsink if you don't have free heatsinks), would be a sweet deal; about 170W actual consumption to cover 4x4' area. The driver shows one of the highest efficiency (max of 94%), but it goes up to 143V, so it may not be for everyone.

fibre, if LPC-60-1050 is within your budget, that seems like a nice and solid choice. For the cheap eBay drivers, this thread contains lots of good info:
http://www.rollitup.org/t/diy-leds-how-to-power-them.801554/
It is probably too much info, but I learned quite a bit from it.


----------



## DavidCampen (Jan 8, 2015)

naoki said:


> ...
> With regard to voltage, we all know that higher voltage is scarier, but I wonder how much more dangerous it is in practice (both medical and fire hazard). I put my fingers into gel electrophoresis (accidentally), but I don't remember the voltage (I guess it wasn't so high because it was just mildly ouch).



You just got a tiny voltage gradient; if you had touched both electrodes you likely would not be posting here.
http://ehs.unl.edu/sop/s-electrophoresis_safety.pdf

I would have no worries about working with an electrophoresis unit in a laboratory but I would not operate one in my home. I do work on household wiring (120 & 240 v) without shutting off the power but I do wear insulating gloves and safety glasses and take precautions to exclude anyone else from my work area. I have also worked in chemical laboratories and manufacturing plants with explosives and potent toxins. Still, for a few dollars more, in my greenhouse, I prefer that the DC voltage to LED fixtures is kept below 48 volts.



naoki said:


> ...
> I was thinking that HLG-185H-C1400 ($69.10) + 4x Vero 18 ($13.41 ea), whose total is $122.74 (+ heatsink if you don't have free heatsinks), would be a sweet deal; about 170W actual consumption to cover 4x4' area. The driver shows one of the highest efficiency (max of 94%)



I keep finding good deals on LED PAR38 spotlights, $10 for a 17 watt input LED:
https://www.1000bulbs.com/product/114019/GE-63105-SP.html
These, unlike the ones that I purchased from Home Depot, are rated only for dry locations but where I plan to mount them in the greenhouse should be in a place and high enough up that the dry location only rating should be sufficient (or I will put them in PAR38 housings.)


----------



## fibre (Jan 8, 2015)

naoki said:


> ... But with the price of LPC-60-1050 linked by David ($17.5), a bit extra cost for the name brand might be a better option.
> 
> I don't know how well Octopart covers European sources, but this place has it for 14 euro.



Thanks a lot for this link! Looks like a good source. And yes, LPC-60-1050 is within my budget. 



naoki said:


> fibre, if LPC-60-1050 is within your budget, that seems like a nice and solid choice. For the cheap eBay drivers, this thread contains lots of good info:
> http://www.rollitup.org/t/diy-leds-how-to-power-them.801554/
> It is probably too much info, but I learned quite a bit from it.



Puh, very much info there! The most difficult thing is that it isn't easy to understand all these terms in German but in English...


----------



## TyroneGenade (Jan 8, 2015)

fibre said:


> Puh, very much info there! The most difficult thing is that it isn't easy to understand all these terms in German but in English...



Sometimes I think the datasheets and other info are deliberately written in such a way to confuse people. It probably a vast conspiracy by electricians. oke:


----------



## DavidCampen (Jan 8, 2015)

You could use a single LPC-60-1400 or LPC-60-1750 and for the same price as an LPC-60-1050 you could drive a pair of Luxeon L235-xxxxAULM in parallel.

Except, I just looked at the price for the Luxeon L235-xxxAULM strips and they are about twice the price of the LPC drivers so it is better to maximize the power from the LED strips at the expense of not maximizing the power from the drivers.

As a side note, one thing to be aware of when you are using a CC driver that can supply significantly more voltage than your LED assembly requires is that the driver should always be disconnected from mains power when the connection to the LED is made. For example, the L235-xxxxAULM LED strip requires about 36 volt to drive it at 900 ma but the LPC-60-1050 will supply up to 48 volts. If you put a switch between the driver and LED string so that you could open the DC side of the circuit and plugged the driver into mains power with the switch open then the driver will take its output to 48 volts in a futile attempt to drive 1050 ma and then when the DC side switch is closed the driver will not instantly reduce its voltage so for a while it while be driving the LED string at a very high current (because of the high voltage), possibly enough to destroy some of the LEDs.


----------



## naoki (Jan 8, 2015)

DavidCampen said:


> I keep finding good deals on LED PAR38 spotlights, $10 for a 17 watt input LED:
> https://www.1000bulbs.com/product/114019/GE-63105-SP.html
> These, unlike the ones that I purchased from Home Depot, are rated only for dry locations but where I plan to mount them in the greenhouse should be in a place and high enough up that the dry location only rating should be sufficient (or I will put them in PAR38 housings.)



The price is amazingly cheap (about $0.6/W). But don't you think that the efficiency seems to be kind of low (I think I mentioned this in your OB thread, but I might have forgotten)? This GE is 39 lumen/W and the HD one was about 50 lumen/W, I believe. lumen/W isn't completely useful for plants, but it is about one-third lumen/W of the luxeon or one-half of COB. Vero 18 is a bit overdriven @1.4A, but I think it will be at least 100 lumen/W even with warm white.



DavidCampen said:


> You could use a single LPC-60-1400 or LPC-60-1750 and for the same price as an LPC-60-1050 you could drive a pair of Luxeon L235-xxxxAULM in parallel.
> 
> Except, I just looked at the price for the Luxeon L235-xxxAULM strips and they are about twice the price of the LPC drivers so it is better to maximize the power from the LED strips at the expense of not maximizing the power from the drivers.



Yes, these Luxeon seems to have high efficiency and ease of assembly, but the price is a bit high ($36 to get around 32 watt).

Actually LPC-60-1750 in parallel (875mA for each) may be a good idea to get higher efficiency (close to the driver's max, and "reference" current for diodes). I usually don't think of parallel circuit because if one entire strip breaks (unlikely), the other strip is getting 1750mA, which is below the maximum for the Luxeon, but close to the max current.

I usually don't put a switch since it gets plugged into a timer, but it is an interesting point that the switch should be in the AC side (I think most example circuits are like this). I guess that the driver could waste energy if the switch is in the DC side.


----------



## fibre (Jan 11, 2015)

I took a decision. Tomorrow I will order 5 pairs of Philips Lumileds LUXEON XF-3535L 1150mm 5700K. I will use 2 Luxeon for each shelf of 60 x 120 cm at a distance of about 20-30 cm. I like the cool white more than the warm 4000K - not for the benefit of the Paphs but for my eyes. I have two T5 HO 6500K bulbs (4100lm each) per shelf in use with good success. Sometimes I evan think these are too bright. The Luxeon 5700 K reach 4536-4644 lm each. So I will probably get more light because the bulbs emit in all directions while the LEDs are focused downwards. 
A pair of T5HO consumed 108 Watt, the Lumileds will consume 64 Watt. I think this is a very good progress!

I will use one LPC-60-1750 CC-driver for two Lumileds in parallel. But also I will give a try to one LPC-60-1400 just to see what happens.

Unfortunately I will have to wait more than 8 weeks for delivering. But as I will get the new seedlings from the lab not before Mai I will have enough time to prepare the new shelves.

Thank you again naoki and David for all your help and good advices!


----------



## naoki (Jan 11, 2015)

Cool, it will be interesting how 5700K works with orchids. The emission spectrum of 5700K shows lots of blue. Note that the emission spectra are very different between florescent (several jugged peaks) vs LED (2 peaks).

With 5700K CRI 70, typical luminous flux is 5076 lumen (a bit less than this in reality due to dealing with heat). If you drive it at 1.4A, you probably will be getting around 7000 lumen (if the cooling is adequate). T5HO output decreases with age, so one strip at 1.4A is similar to 2 of T5HO bulbs.

The maximum current for this strip is 1.8A. But most people use LED at 50% or less of the maximum current because the efficiency decreases with higher current (total output does increase). So it it the compromise between the total output vs efficiency. Also, heat is an issue with LED. More substantial heatsinks can lower operating temp, and efficiency increases. Additionally, the longevity should increase with lower temp. If you can find a better heatsink (or use active cooling with a fan), it might be beneficial for overdriving. You can try it (I personally wouldn't do it), but you should be aware of these issues.


----------



## fibre (Jan 11, 2015)

Good additional advices! 
I will use CRI 80. Not so effective (4644 lm), but as an artist I like to have more 'true' colored flowers in my basement. 



naoki said:


> If you drive it at 1.4A, you probably will be getting around 7000 lumen



No, I like to drive two stripes at 1.4A. This should work well for some new deflasked seedlings. If it isn't bright enough I could follow your suggestion and drive only one Luxeon at 1.4A...


----------



## naoki (Nov 3, 2015)

I made a blog post about how to make Chip-on-board (COB) based LED fixtures (here is the link). The basic contents are similar to what I posted earlier in this thread. I included a little bit more assembly details (maybe too much for most people), information about driver selection, and new measurement data using PPFD. Also I came across a couple of useful youtube videos, so the links are provided at the very end of the post. I started this thread with cheap eBay COB, but the video provides the reason why these are not worth getting.

There are newer generations of COB LEDs (Bridglux Vero Version 2.0 and Cree CXB series) after I posted the messages in this thread. Some people are achieving close to 70% radiant efficiency with Cree CXB3590 (only 30% of electricity is wasted as heat, and 70% is converted to light energy). A cheaper way to grow orchids under artificial light!


----------



## naoki (Mar 17, 2016)

For DIY COB, drilling and tapping heatsink is probably the most intimidating part. The rest is something which can be done by anyone who can strip wires and use a screw driver.

I noticed that Cutter is starting to offer pre-drilled heatsink + COB kit. It is not the cheapest, but for the people who doesn't want to drill, this could be an easy option. The shipping is a bit expensive for people outside of australia (especially if you are interested in only a few units). There is 10% discount for the first 2 items with the coupon code.

passive cooling, CXB3590:
https://www.cutter.com.au/proddetail.php?prod=cut2901
About 50W for $80 (+$35 shipping). You'll need to get your driver (about $20, including shipping) separately. I would prefer a bit beefier heatsink, but it probably works well.

The following is similar, but it comes with 4x COB (about 200W) and a driver (i.e. a complete kit). About $430 with shipping:
https://www.cutter.com.au/proddetail.php?prod=cut2900


Active cooling version:
CXB3590 ($66 + $19 shipping)
https://www.cutter.com.au/proddetail.php?prod=cut2792
CXB3070 ($56)
https://www.cutter.com.au/proddetail.php?prod=cut2791

You'll need a driver and an AC/DC adapter 5-12V (e.g. cell phone charger).

For the driver, you can use something like Meanwell LPC-60-1400 (data sheet).
Here is the current price (about $16 + shipping):
https://octopart.com/search?q=LPC-60-1400


----------



## Kawarthapine (Mar 20, 2016)

One of the best threads I've come across.

Thanks to all who contributed.


----------



## naoki (Jun 10, 2016)

I came across this CXB3590 kit, which was released in 1-2 month ago:

http://timbergrowlights.com/200-watt-cree-cxb3590-4-cob-kit-meanwell-hlg-power-supply-free-shipping/

This is good for people who doesn't like to assemble since no assembly is required. It will be good to cover 4'x4' (or 8'x2') area for moderate light orchids.

Similar to the Cutter kit, but for the US, it is a bit cheaper. Good components; 4x top-bin CXB3590 driven softly (50W per COB) and the best MeanWell driver. I'm not familiar with the heatsink they use. It is all pre-assembled, so you don't need to do anything. You only need to figure out how to hang them. Dimmer is included (goes down to 10%). $399 + free shipping for 200W (4x 50W). If you assemble the components by yourself, you can save $100 or so, but for people who doesn't have time to assemble or not sure how to assemble, $100 extra may be worth. They also have 5x50W version for $499. http://timbergrowlights.com/products/diy-grow-light-kits/

This is pretty much the best in terms of PAR efficacy (about 2.5 micromol/J from my calculation), and most LED grow light can't touch it. The PAR efficacy is measuring how many photons relevant to plants are produced for a given amount of electricity. In comparison, Fluece (=BML) SPYDRx, released in early 2016, is one of the very best and achieves only 2.2 micomol/J. I said "only" 2.2, but it is a very high efficiency number. You should know that cheaper LED grow lights give about 1.0 micromol/J, only slightly better than T8 or T5HO. Very good HPS is around 2.0 micromol/J. In terms of lumen (not so relevant, but people are more familiar with it), it is giving about 177lm/W. 

In terms of COB front, I recently learned about a better alternative to Cree. I don't need a newer grow light for me, but if you are interested in DIY route, I would definitely look into Citizen CitiLED COB Series Version 5. There are several sizes, but something around CLU048-1212C4 seems to be the sweet spot in terms of price and efficiency ($12.55 from CDI). This is a smaller COB, so you'll need 2 of CLU048-1212C4 to replace 1x CXB3590. At the moderate driving current, the efficiency is very close to CXB3590. Maybe you can drive it at 1050mA (36.8W), which gives 169lm/W @ case temperature (Tc) of 50C, or better yet at 700mA (23.7W), which gives 179lm/W (similar to CXB3590 @ 50W).


----------



## naoki (Oct 23, 2016)

There are quite a few interesting LED arrays released this year. But Samsung H-series is pretty excciting, and it is finally shipping. I received mine 1-2 weeks ago after waiting for a couple months. I won't have time to assemble them for a while, but I'll post about it sometime later this year. I thought that I should give a quick heads-up in case someone is considering linear (strip) array style LEDs.

It is a bit costly, but the spec. is quite amazing! Here is the link to the data sheet. It achieves 187 lm/W for 4000K (>2x efficacy of T5HO or commonly available LED bulbs). It has a higher efficacy than many COBs, so it is impressive.









I got 30x Samsung H-series H282D, 4000K, SI-B8T05128HUS LED strips and a couple of Meanwell drivers (APC-16-700 and APC-25-500). I got 1' length, but it comes in 2' and 4', too.

$10.93 per strip from digikey (link), but I got $7.83 ea for the volume discount.

APC-16-700 $6 ea from Mouser, each can drive 3 strips (link)

APC-25-500 $10.62 ea from Mouser, each can drive 4 strips (link)

I'm going to attach them to Aluminum C-channels like what I did with XF-3535L earlier in this thread. While XF-3535L is flexible, and it comes with double sided tape, H-series is rigid, and you need to use thermal adhesive, screws, or magnets to attach it to the heatsinks.

Some of these will be used for planted aquarium, but others will be for orchids in smaller enclosures (e.g. Rubber Maid plastic containers, smaller aquarium tanks etc).


----------



## naoki (Nov 17, 2016)

I just spent a bit of time to write up a blog post to help DIY LED grow light builders. The DIY COB post is one of the most frequently accessed post in my blog for some reason (even though I think other biological posts are more fun to me), so this is a follow up, and explain more fundamental principles of LEDs. In this post, I tried to explain the basics of driver selection and the design process. Here is the link to the blog post. It talks about the multiple LEDs driven by a single driver, basics of driver and LED efficiency, and super simple thermal protection. I tried to target beginners, but it might be too much information or a bit too technical. Hopefully, it is useful for some people since winter is coming (well, it's been here for a while in Alaska).

Here is my recently cleaned grow tent with 8x COB LEDs. 






Here is a PPFD map of 4x CXB3590 with HLG-185C-1400B. It is showing amazingly even distribution of light over 120x120cm (4'x4') area in the grow tent. The unit is micromol/m^2/s.





Here is the relationship of dimming vs overall efficiency. So with this driver, using dimming function doesn't decrease the efficiency unless you dim it extremely (i.e., as long as you stay above 30% of the full power, it is explained more in the blog post).


----------



## terryros (Nov 17, 2016)

Naoki, what is the dispersion angle on your bulbs? I am guessing that your lights are 100 degrees or more, rather than focused?


Sent from my iPad using Tapatalk HD


----------



## JAB (Nov 17, 2016)

Awesome info Naoki! I think it is a bit over my head, but none the less it gives one plenty to chew on. Thank you for sharing your experience and knowledge so openly. 

Cheers
Jake


----------



## naoki (Nov 17, 2016)

Thanks, Jake!

Terry, I'm not using any optics, so I think the beam angle is 120 degrees. I think there are pros and cons of narrower beam, and I'm not completely sure which would make it better overall. For now, I'm going for the scattered light effects (of wide angle) to reduce shadowing of lower leaves.


----------



## terryros (Nov 17, 2016)

Naoki, there is some published data that vertical light affects leaves of some plant types differently than diffuse light. Because many of my LEDs are 40 degrees or 60 degree beam angle, I have about three years experience watching this affect and I am pretty sure that with mostly horizontal leaf type orchids (e.g. Phals and Paphs) produce thicker and more compact leaves under even low light levels (e.g. 50 micromoles/m2/sec), as though they were seeing high light. I don't see the effect with more vertical leaf types like Miltoniopsis and Cattleya. I overall like it because I get compact plants that still bloom and I don't have to use high intensity light to get it. But, it is certainly strange.


Sent from my iPad using Tapatalk HD


----------



## naoki (Nov 20, 2016)

Thank you for sharing your experience, Terry. It is very interesting. I quickly looked at google scholar, and you are right there are some literature about it. Maybe at the forest floor, there are more diffused light, so directional light may imitate stronger light, and more compact leaves (i.e. the classic sun vs shade leaves). I should read more about it.
With this kind of COB, I can't use too narrow beam because it requires too much head space. Even without any optics, I have to place it 3' above the shelf.


----------



## gonewild (Nov 20, 2016)

naoki said:


> Thank you for sharing your experience, Terry. It is very interesting. I quickly looked at google scholar, and you are right there are some literature about it. Maybe at the forest floor, there are more diffused light, so directional light may imitate stronger light, and more compact leaves (i.e. the classic sun vs shade leaves). I should read more about it.
> With this kind of COB, I can't use too narrow beam because it requires too much head space. Even without any optics, I have to place it 3' above the shelf.



Spaced 3 feet above shelf what is the footprint size the light covers on the shelf?


----------



## naoki (Nov 20, 2016)

Lance, inside the reflective tent, 4 of CXB3590 covers 4'x4'. So each is covering about 2'x2'. I have dimmed down to 160W (each is running about 40W) for Paphs. It might be still a bit too much (I think it is getting more than 150-200 micromol/m^2/s at the leaf level). The PPFD map in post #66 is done with full power (213.2W). So I think 210W of this LED is putting out more than 8 bulbs of T5HO (about 400W), and I get more head space.

Cree CXB3590 is a bit old now, so it isn't the best selection at this moment. Bridgelux Vero 29 Generation 7 is much cheaper and more efficient now. But for non-DIY people, CXB3590 can be had in pre-assembled form (post #64 of this thread) at a reasonable price. Timber seems to have a smaller/cheaper one now; 2x CXB3590 (100W) for $235, or 4x Citizen CLU048-1212 (200W) for $300.


----------



## naoki (Nov 24, 2016)

Happy Thanksgiving!

Another DIY LED update. I made a plastic container based grow space. I used Samsung H series LED linear modules this time. This module was announced in Summer 2016, but it started to ship in October. This Samsung basically beats Philips XF-3535L (I posted about this previously) in all aspects. It has amazing efficacy (187lm/W), even higher than most COB LEDs. I haven't calculated the PAR efficiency, but I'm pretty sure there is no commercially available grow light with this high efficiency. It is a bit more expensive per light output than COB, but it is easier to assemble, and better for a small area. Also, it provides very even light distribution. It costs about $60 to cover 2-3 sq. ft.

I built this for pygmy Drosera, so it is targeting high-light plants. But if you increase the distance or spacing, it will work with orchids, too. I listed an alternative configuration with lower output. It takes about 1 hour to assemble.

Here is the link to my Orchid Borealis blog post.











Drosera dichrosepala ssp. enodes from Scott River. Catalogue #10a of Drosera Gemmae.


----------



## naoki (Sep 20, 2017)

I've been very happy with Samsung H-series (see post #74), but there is an improved version announced at the end of Aug. 2017. It is called Q-series. Very similar to H-series, but about 10% (actually more like 8%) increase in efficiency. Now it exceeds 200 lm/W at the nominal current! In comparison, typical house-hold LED bulbs or LED shop light you can get from Walmart etc. are barely 100 lm/W. The price is similar to H-series. It is more limiting in the driver selection than H-series, though. I've added possible drivers for the new Q-series in my previous blog post (scroll to the very end).

As a different note, which I have forgotten about, I was curious about the longevity of those cheap eBay 100W COB LEDs (the ones in the very beginning of this thread). So even though it is cheaper to replace it with a high quality COB, I kept one running. It lasted 3 years with 13h/day. It was driven at around 45W, I think. It lasted shorter than Cree, but it lasted longer than I expected. Just as a data point.


----------



## Bjorn (Sep 21, 2017)

Naoki, have you seen the Integrated COB that has been offered for some time now? the driver is integrated onto the chip and everything becomes quite neat and you get rid of those bulky drivers. Connects directly to mains in other words.
http://www.ebay.com/itm/220V-20W-30...hash=item3aca6310d9:m:myaZytjrJAeBhaXtewCae1A
I have made a unit with 4x100W (rated but uncertain about its real performance) that is running at my Place now for a couple of weeks. Light seems to be ok (and stronger than expected-perhaps it really is 100W?) But have not made much measurement on them yet.


----------



## naoki (Sep 21, 2017)

Bjorn, I didn't know about it until last week, but I saw it mentioned in Orchid Board. Because of the super cheap price, I got interested in, too. But after looking at this video, it doesn't look too promising. Clive knows well about electronics, and he has been showing informative videos about LEDs:
https://www.youtube.com/watch?time_continue=207&v=KKd2L9Exw0M

Yes, their rated wattage appears to be close to the actual wattage according to the video.

The problem of those so-called driver-less COB is that they appear to be targeted for flood light type application where you don't keep them on for 13h/day. So they are likely to be driving each LEDs at a high current to put emphasis on a higher total output for a given cost, and sacrificing the efficiency. As Clive mentioned, we don't know the spec. of the diodes, so this is just a guess. But the web site mentions 80 lm/W, which is the efficacy level of household LED bulbs from 2-3 years ago. So even if they are given for free, it is cheaper to buy a newer, more efficient modules for most people (With your cheap electricity, you are probably an exception!).

I think the larger makers like Philips have produced similar "driverless" LED modules. It is certainly convenient. The current offering seems to have generally lower efficiency than the separate driver + LED combo, where we can choose the driving current. But once they produce under-driven modules with super high efficiency, it will make DIY even easier!


----------



## Bjorn (Sep 21, 2017)

Had a look at the video. Interesting. Seems that I got some that are slightly different, mine has an attached capacitor and this remioves flickering as far as I can judge. Also the size-I got the elongated design, perhaps they are better-who knows, time will show.


----------



## naoki (Sep 21, 2017)

The long rectangular one (100W) seems to have more diodes than the square 50W ( I counted 81/82 per row, so about 249 vs 79). If they are using the same diodes, it is driven slightly softer.

100W seems to have 10 IC current controller (50W in the video had 5). So they are probably similar design.

I'm not sure flickering is an issue, though. Fluorescent light flickers, right?


----------



## Bjorn (Sep 22, 2017)

No, do not think that plants bother. Nevertheless, I use it to grow salad and Herbs. Much faster than outdoors these days (even in greenhouses). I'll find out re. longivety.


----------

