Lighting DIY COB Based LED Growlight Build In Progress!

[Atulip]

Yes Optic and a couple other companies make similar lights. And very good ones at that! The peoblem with CXB3590 based lights run with lenses is that they need 24" - 30" of clearance from the canopy.Run near peak efficiency, they put out 147 lm/watt! And the lenses and or reflectors add weight and cost to the light.

Height mainly depends on the spread you need, 90° reflectors/lenses are just a bit more narrow than the cobs natural 115° angle. 19" height at 90° gets the same spread as 12" at 115°.


@Ripper if you have a lux meter, most are using .014 as the conversion to par for cree 3500k. (Lux x conversion = par)

Or overall lumen output divided by square meters times conversion for average ppfd over the space. (90,000 lumens over a 1.2x1.2, 90,000/1.44 x .014 = 875ppfd)

The other method is using efficiency percentages and calculating par watts.

 

[pop22]

Unfortunately, you have to take the beam angle of the lenses and reflectors with a grain of salt. Checkout Growmau5's videos as he does a rough check of the beam angle os some lenses and reflectors. the 115degree reflector was more like 90 degree and the 90 was 80 or less. Getting an accurate beam spread is not as easy as it sounds as the LED lighting industry doesn't care all that much, only that the lenes/reflectors actually concentrate light.........
But for those with the height and doing conventional grows, the lights running lenses and reflectors certainly give superior penetration.

and I want to be able to get real close as this is a specialized light aimed at SCROG grows, I want to lay the light over the buds like a blanket! The penetration of lensed lights is not needed in a flat plane canopy. And that's what's great about DIY, you can tailor your light to your style and needs!

Height mainly depends on the spread you need, 90° reflectors/lenses are just a bit more narrow than the cobs natural 115° angle. 19" height at 90° gets the same spread as 12" at 115°.


@Ripper if you have a lux meter, most are using .014 as the conversion to par for cree 3500k. (Lux x conversion = par)

Or overall lumen output divided by square meters times conversion for average ppfd over the space. (90,000 lumens over a 1.2x1.2, 90,000/1.44 x .014 = 875ppfd)

The other method is using efficiency percentages and calculating par watts.

 

[Atulip]

Just took a couple lux readings to compare spreads. My bare 115° Crees behave like 110-115°. 12" height, 75,000 center and 36,000 at 19" out.

My plc with 90° reflectors looks accurate to 90° though, at 12" height 120,000 lux center, 57,000 12" from center. That's measured height from cob not height from reflector.


I'm sure some reflectors are better than others, but all are pretty unneeded unless you want the ability to raise your lights higher to get the same spread. (It is nice not working under 12" high cobs when leaning over plants in the back of the tent)

Penetration has little to do with lenses/reflectors, but the amount of light you're hitting the plants with. No reflectors needed, just drop any light closer to the canopy and you increase penetration and decrease spread.

Reflectors are just narrowing the beam and either providing the same light in less area, or providing the same light in the same area at a higher height. (Technically they lose some light based on reflector efficiency)

 

[pop22]

Ok! Got my pots, Arctic Silver, and the project boxes today.

I masked the heatsinks with painter's tape ( the blue stuff ). I made a pencil line down the middle of the heatsink for a reference point for the template.
I made a template using a sheet of white construction paper I got at Dollar Tree. I spaced the end COBs 2" in from the ends of the heatsink, with the COBs spaced 9" on center.
I marked and pierced the screw locations, taped the template to the heatsink and and marked the screw locations on the heatsink.
I used a center punch and punch the locations for the screw holes.

Tomorrow I'll start drilling. Going to have to do it by hand, no drillpress available.

One thing I haven't liked about most of the DIY lights I've seen, is wiring showing on the LED side of the heatsinks. I'm going to drill holes right at the edge of the cob holders and pass the wire thru to each cob. The wire should be almost invisible from below. Just want to make it look neat is all, I'm going to be seeing it for a long time..lol!

 

[thetreeman]

Finally got pics of what I have so far. I've enough to build 2 bars and enough LEDs for the third bar. All I'll need is one more driver and one more heatsink. Should have those before month's end. I'll not be building the vertical hanger yet. Going to do a standard scrog grow with it first. Don't want too many headaches all at once....lol!

I ordered some 100k pots for the dimmers and a digital, combo volt/amp meter and a couple fancy project boxes. The boxes will house the WAGO connectors and wiring, the dimmer pot, the meter ( each will have its own in the end ), and a 9 volt power supply to run fans if I decide to run the light at higher power.

I also ordered more LED holders and one more CXA2530 that I'll use in my clone cab to boost the light levels of the DIY light already in there.

Parts:
View attachment 550408

Link to the cob holders you are using please....

 

[pop22]

Here's the link. You may find them cheaper elsewhere. These are nice as no soldering in required.

http://www.newark.com/te-connectivity/2213407-2/led-holder-cree-cxa-array/dp/52X5731?ost=TE+CONNECTIVITY+-+2213407-2&selectedCategoryId=&categoryNameResp=All+Categories

Link to the cob holders you are using please....

 

[MeefChief]

Here's the link. You may find them cheaper elsewhere. These are nice as no soldering in required.

http://www.newark.com/te-connectivity/2213407-2/led-holder-cree-cxa-array/dp/52X5731?ost=TE+CONNECTIVITY+-+2213407-2&selectedCategoryId=&categoryNameResp=All+Categories

THIS is genius.

 

[pop22]

Today I'll start drilling. things have been busy so I fit the work in when i can. If I can, I'll complete one panel and test it. Pics when one is completed!

 

[thetreeman]

Here's the link. You may find them cheaper elsewhere. These are nice as no soldering in required.

http://www.newark.com/te-connectivity/2213407-2/led-holder-cree-cxa-array/dp/52X5731?ost=TE+CONNECTIVITY+-+2213407-2&selectedCategoryId=&categoryNameResp=All+Categories

I like the look of those, kinda pricy but looks like they have mini reflectors built in to direct some of the sideways light back down, nice feature and also solderless is a big bonus. The ones I used required soldering and didnt have as much photon management built in. They were only like .60c each tho. Did you see the cxb2530s at cutter for $10 each? Top bin, but 90cri... Thats what I ended up using with the 1.8" heatsink profile. 42" for 6 cobs @ 700mA needed a couple fans to keep cool. I used old PC fans that hang over the edge, but its kinda nice as it provides some airflow downward, probably make circulation fans unnecessary in a tent.

 

[Ozone69]

Solderless is a big, BIG bonus for me. While I don't mind soldering, I realize that I really, really suck at it. End up with malformed, oversized blobs of metal everywhere or wires that pull off if you look at them funny with a light breeze blowing at them. Thanks for the info on the holders!!!