Economical multi LED Chip Projects for Growing

[nfhiggs]

That Chinese led isn't cheap.
30 euro for a "50 watt led" is expensive.

A Citizen chip that can do 250W is cheaper actualy. (CLU048 181

I have a very easy time finding LEDs way cheaper than a generic epistar/epiled chink crap.

http://www.reichelt.de/LED-Modules/SDW-85F1C-G10/3/index.html?ACTION=3&LA=2&ARTICLE=158940&GROUPID=3031&artnr=SDW+85F1C+G10&SEARCH=%2A
http://www.reichelt.de/LED-Modules/GW7MM-C40/3/index.html?ACTION=3&LA=517&ARTICLE=158927&GROUPID=3031

In fact, they're the same price as a CXB3070 on Mouser.

You can buy those all day long on Ebay for under 3 USD.

 

[DIY-HP-LED]

1 ohm resister will dissipate 1 W per amp of current, and will drop one volt per amp - total voltage really doesn't matter. I'm running six 100W cobs in parallel, at 32.8 volts, 9 amps total, 1.5 amps per COB. Each COB has its own 1 ohm, 2W series current limiting resistor to prevent thermal runaway. I'm not terribly concerned about 6W of wasted heat - not out of 300W total.

Yeah, constant current is the preferred method, but its roughly 4-6 times the cost per watt. A 400W Meanwell CC driver is $170. My 420W 36V supply cost $35.

For your setup, yeah they (thermal cutoffs) make sense. I tend to look at things through the lens of my own setup sometimes. Carry On!

I'm always looking for cheaper ways to drive COBs, What kind of power supply are you using? I was thinking of using an ebike or golf cart charger and current limiting buck converters with a 2 or 3 series arrangement of the COBs (depending on the voltage of the charger).

 

[tutaj5]

220 Volt Driverless COBs
I was thinking of writing a little cautionary tale called, Jimbob and Cletus die, or maybe fry.
I've been noticing dirt cheap driverless COBs online that run on 220 AC, hook em up to a clothes dryer cord stuff. Now these probably use bridge rectifiers and perhaps capacitive droppers, are not isolated from mains voltage and it looks lethal to touch them and perhaps the heatsink they are mounted to, scary stuff. I wonder if someone would be stupid enough to try a water cooled light bar, full of these, maybe Jimbob and Cletus, what could go wrong? Maybe I'll call it, Low Cost 'n Lethal

Alas, we should write from experience, and playing with one of these things might be the end of all experience. I like my life and think I'll hang on to it for awhile. One of these could suddenly end a thread, the last post would be, "Got one of those new driverless 220 volt chips today, think I'll try it out".

I am curious though, I wonder would they be driven at 50% by 110 volts AC? Also, what would the effect of the 60 cycle flicker be on PAR? They would in effect be at low or no power 60 times a second as line voltage dropped to zero then rose, there's no capacitive reserve to mitigate this that I can see.

Kinda looks like something for those with big balls and small brains, hope they use a lot of copper grounding everything near the thing. If your working with 220 AC you'll definitely want a spec sheet written in clear ENGLISH from a reliable source. UL labs would cry at the site of this thing and the EU might put you in jail for selling it. For 220 volts AC, the line and neutral contacts look real close and I don't see an isolation gap in the PCB between them either, no ground contact on the chip that I can see...
View attachment 3780986

Did you order and test them before calling them dangerous? Cause ive seen tests of these, and they are completely safe in every way, just not too efficient. Mains are isolated up to 700V.

 

[DIY-HP-LED]

Did you order and test them before calling them dangerous? Cause ive seen tests of these, and they are completely safe in every way, just not too efficient. Mains are isolated up to 700V.

Thanks for dropping in. These COBs are dangerous, in fact potentially lethal, if your not very careful, and don't use a well grounded heat sink.

Having said the above, I recently ordered 10 of the CW and 4 ea. of the grow spectrum 50 watt 110 volt versions for testing. I have some unused air cooled fixtures to try them out on. These could be an economical alternative for those who know what they are doing, but the risks are obvious, more so with the 220 volt version. I don't think it would be wise to use these COBs with a water cooled system. I recently made a post about this in the "driverless COBs or AC COBs" thread I believe.

If your gonna use these COBs make sure everything is well grounded and be very, very careful, one faulty chip could cause a bad day.
GOOD LUCK!

 

[MMJ Dreaming 99]

You can buy those all day long on Ebay for under 3 USD.

Are the Chinese CObs worth buying at $3 versis maybe a cheap Citizen or brand name for maybe $12 or 13? Just wondering?

 

[DIY-HP-LED]

Are the Chinese COBs worth buying at $3 versus maybe a cheap Citizen or brand name for maybe $12 or 13? Just wondering?

I bought 10 ea of the citizen CLU048 1212s for a good price and they work better and, last longer than the Chinese flood light LEDs. The really cheap ones don't last long at all, but I haven't had the better ones (with the heavy rounded copper base) fail. The Citizens run at a slightly higher voltage than the Chinese LEDs, but put out much more light. I'm buying Citizens from now on and will gradually replace the Chinese flood light COBs over time. That's regular DC powered COBs, I'm gonna have a look at the AC chip driven COBs soon as the order arrives.

 

[CobKits]

ive got citizen 1212 on my site starting at $7-$8

 

[MMJ Dreaming 99]

ive got citizen 1212 on my site starting at $7-$8

Cool. If I put 8 on a frame - what driver or drivers do you have? Thanks

 

[DIY-HP-LED]

The site where they sell the COBs have a good price on matching drivers. I've found that these 50 watt drivers will drive the CLU048s at 1.5 amps, though you'll have to enclose them. It depends on how much you wanna spend, running them in series with enclosed Meanwell drivers would be the simplest build

 

[CobKits]

Cool. If I put 8 on a frame - what driver or drivers do you have? Thanks

hlg185h-36A will run any number of those. maxed out its 5.9A so 4@~1475mA, 5@~1080, 6@~975....8@740mA, etc

 

[nfhiggs]

I'm always looking for cheaper ways to drive COBs, What kind of power supply are you using? I was thinking of using an ebike or golf cart charger and current limiting buck converters with a 2 or 3 series arrangement of the COBs (depending on the voltage of the charger).

I'm just using "no-name" brand 350W power supplies from Ebay. You can buy them all day long for $20-$25. You can get them in 12, 24, 36 and 48 volts. The output voltage is very stable, and adjustable by +/- 10%.

 

[nfhiggs]

The site where they sell the COBs have a good price on matching drivers. I've found that these 50 watt drivers will drive the CLU048s at 1.5 amps, though you'll have to enclose them. It depends on how much you wanna spend, running them in series with enclosed Meanwell drivers would be the simplest build

I've actually got a handful of the drivers in your second link. I ordered the 50W drivers but they sent me the 30W drivers instead, so they have been sitting unused for 6 months.

 

[MMJ Dreaming 99]

I'm just using "no-name" brand 350W power supplies from Ebay. You can buy them all day long for $20-$25. You can get them in 12, 24, 36 and 48 volts. The output voltage is very stable, and adjustable by +/- 10%.

350 watts? Shipped from China or USA? Thanks.

 

[nfhiggs]

350 watts? Shipped from China or USA? Thanks.

Some from china, some from US importers.

 

[DIY-HP-LED]

I got some 110 volt driverless COBs a few weeks back and I'm gonna test some on one of my air cooled fixtures soon. I was laying out the parts on the heatsink and found the mounting holes in the COBs mach up with the holes for the 100 watt floodlight LEDs, so it simplifies things a bit.

The lamp will be composed of a heatsink, 2 X CW 50 watt AC COBs, 1 X 50 watt full spectrum 50 watt COB, a 120mm 12 volt fan and a power supply module for the fan. Not sure If I'll bother with a switch, but a three prong grounded chord with a good ground on the heat sink is a must. I obtained the heatsink at the salvage yard, it's an old microwave amplifier housing used in microwave towers. After I stripped out the electronic guts and cleaning it up I found this foot long,15 LB chunk of aluminum to be a great fixture for a double LED 100 watt lamp with a 10" COB spacing. I have four of these heatsinks and I bought 10 CW and 4 full spectrum COBs, so if this works out, I'll have four 150 watt grow lights. Best of all the CW COBS cost less than $2 CDN each and the full spectrums were around $3 CDN each. Also I've got a couple of spare CW COBs.

Here are a couple of pics of the layout for a lamp, I hope to have it complete in a couple of days and will post more then.

 

[DIY-HP-LED]

110 Volt AC Driverless COB Lamp Test
I completed the 110 volt AC driverless COB lamp today, it was a one day build. It seems to draw 200 watts from the wall according to my Kill-o-meter (will have to check on that). The fixture runs at about 40C and the single COB light output appears to be about the same as a 32 volt DC floodlight COB running at 50 watts. It tested ok for grounding and there's no current leaking through the COB packages to the heat sink and the lamp is well grounded with a three prong plug.
Now for some pictures.

I used a terminal block salvaged from a streetlamp to hook up the wires. On future builds I might just solder them together and cover with shrink tubing, then I can tuck them under a reflector, if I want to add one. I used gobs of silicone to hold down the wires and to hold the chord strain relief in firmly. For added safety I could put gobs of silicone on the soldered COB contacts too.


I could tape on some sheets of plastic to the top of the heatsink fins to increase cooling efficiency, but the lamp runs cool enough.


During bench testing the lamp ran at 40 C and appeared to draw 200 watts, the fan draws less than 3 watts. I need to look further into this.


You can see the flicker these COBs produce in this picture as horizontal lines and estimate the loss of light by measuring the width of the shadow band as compared to the lighted band. I've got the light on test over a plant for now and it produces about 50K LUX on the grid at a 12" distance, also the full spectrum (burple) COB might be throwing off the LUX readings.

 

[tutaj5]

I tested those 50W COBs yesterday, all of them consumed 65watts on 238volts. I used old CPU coolers with 8cm 12v fans to cool them down and put 75C thermal switches on the heatsinks for safety. They remain relatively cool to touch. I also put some hot glue on the solder points to insulate them. They are completely safe to touch anywhere you want.

 

[DIY-HP-LED]

Tube Side Lights
I've built several side lights made from 2" and 3" x 1" rectangular aluminum tubing, like that used for my water cooled lights. I use a mix of CW and WW 10 watt LEDs, powered by a 12 volt supply and drive them through a buck converter. I both current and voltage limit the converter using the adjusting screws to protect against a rise in current if an LED fails. I've found that a 3" fan can cool the lamp, power supply and buck converter if designed right. An actively cooled 30" long 3"x1" like those shown can handle up to 150 watts of power and run at less than 40 C. Here are a few pictures to show you what I mean.

The side light extends my canopy area and provides light to it at an angle, this one covers one end of my grow table. The fan cools the lamp, power supply and buck converter. The reflector is made from aluminum flashing and is attached with silicone rubber adhesive.


You can see the spectral mix of CW and WW LEDs in this pic. This lamp has 12 LEDs and runs at 100 watts total power (including PS and buck converter).


Some detail in the power supply and buck converter. I used a hole saw and an electric drill to cut the 3" hole for the fan in the aluminum tube and attached the fan with silicone rubber adhesive.


If I were going to build this again, I might opt for disassembled 100 watt (15 watt) dollar store light bulbs. Some of these bulbs (globe brand) have nice little 15 watt drivers and I'd mount the LED light engines on the front of the tube and silicone the drivers next to them. In the states you can get these light bulbs for a buck or less, so 10 on a 3"x1" piece of aluminum tubing with a fan won't cost much.

 

[DIY-HP-LED]

Here is a link to a video that shows a tear down of a 40 watt Globe LED light bulb and shows the light engine and driver. 10 x 100 watt (15 watt) versions are similar and ten mounted to an aluminum tube will make a nice 150 watt CW grow light for about $20 in bulbs, aluminum, fan and 12 volt wall wart to drive it. Blow a buck and buy one, tear it down and see if you can stick the guts on a piece of aluminum.

40 watt LED bulb teardown.

 

[DIY-HP-LED]

Another Tube Light Design
Here is another 130 watt tube light design I'm using on the back wall of my grow table. It's 40 " long and made of 2" x 1" aluminum rectangular tubing with some flashing to cover the 4 buck converters mounted on the rear of the tube with stand offs and the 2" fan. It has 16 X 10 watt LEDs in 4 X 4 parallel arrays running at 600ma. It's powered by a 200 watt 12 volt X box power supply I picked up at a thrift store for $5 and it sits on a nearby shelf.

I originally was running this lamp at 750ma, but had to adjust down the buck converters to run the lamp a bit cooler. I might rebuild this light using 3" x 1" X 60" tube and add a buck converter and another array of 4 LEDs for a total of 20 LEDs on a five foot long tube lamp. If I do this I'll use 2 fans next to each other in the center rear of the tube for increased airflow and run the diodes at 750ma.

Here's a picture of the "back light".