"COBlurple" Build

Indoor Growing
#1

OK, I’m going to do something a little bit wacky, because that’s just how I roll; going to build a hybrid COB / blurple light that I will affectionately refer to as the COBlurple.

Because the idea popped into my head and woke me up one night and now I want to build it.

The plan, in a nutshell, is to take my existing Meizhi “450w” (~200 real watts) and add 5 Citizen CLU048-1212C4 3500K 90CRI COBs to it.

Each COB will have it’s own heat sink (which have been harvested from various PCs over the years), but will be fanless. These heat sinks will be screwed to the Meizhi chassis in such a manner that the Meizhi’s exhaust air will blow through the heat sink fins. The heat sinks are all capable of cooling up to 125 watts when active, so they should have no trouble dissipating 18 heat watts (planning on running each COB at around 36 watts, ~50% efficiency) with a slightly warm breeze over them. COBs will get a thin layer of Arctic Silver or whatever I have laying around in the bins, and be secured with kapton tape.

Going to power the 5 COBs with a Meanwell HLG-185H-36A, wired in parallel. This should be perfect for running the COBs at ~36 volts x ~1000mA (which is the sweet spot according to the Citizen white paper).

This project will nearly double my light power and also provide an incredibly wide (but still “specialized”) grow spectrum.

It’ll be ugly AF, but I don’t care. Stick around if you want to see this thing get built and have a laugh at me. :laughing:

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Cogitech's Conservatory
Cogitech's Conservatory
#2

You could save some cash and use CLU038 chips if your only running them at 36w.
CLU038-1206C4_P3390_1115.pdf (1.1 MB)

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#3

This does not appear to be an “ask why” kind of a thread.

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#4

Well, I already own the COBs.

(And I want to run them below 1/2 power because the efficiency is much better when doing so. They’ll also run cooler and last longer when “under-driven”.) :slight_smile:

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#5

They certainly do, i ran the CLU038 chips at around 30w each. They are very bright at that level but still inside that max efficiency zone so still run cool.

Your CLU048’s certainly wont need much cooling at only 36w and you will be able to let plants get very close :thumbsup:

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#6

Okay, so if you fine folks don’t mind - please verify my logic regarding wiring between the driver and the COBs.

I am thinking about locating my driver outside my tent (on top), so I figure my max cable length will be 3m.

I used this http://www.solar-wind.co.uk/cable-sizing-DC-cables.html calculator and input 36V and 1.2A (for some wiggle room). The calc says I need 21 AWG to achieve 1% loss.

I’ve got plenty of 24 AWG solid core CAT-6.

I used this https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html to determine that 2 runs of 24 AWG = 21 AWG

So I figure I can use 4 cores of CAT-6 (2 for + and 2 for -) to power each COB safely and with acceptable loss. It should be easy to solder a pair of 24 AWG to each of the COB terminals.

Solid?

#7

Most don’t recommend solid core because those pads can be twisted off by stiff wire but that stuff is very thin so if your careful it should work.

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#8

Good point, but I think I agree that it’ll be OK since they are so thin. I do plan to zip-tie or otherwise secure the wires near the COB connections in such a manner that they can’t move.

#9

So I was right about nearly doubling my light power, but sort of wrong too.

True, I will be drawing an extra 180w from the wall on top of the 195w I am drawing now.

However, I just learned that the Meizhi “450w” only produces 11,595Lm (for an abysmal 59Lm/w ! :rolling_eyes: )

 MEIZHI Reflector Series 450W LED Grow Light
Specification:

    DB: 53
    Led Brand: Epistar
    Par Value: 535 umol at 18"
    Frequency: 50-60 HZ
    Input Voltage: AC85-265V
    Amp: 1.781A@AC110V 0.9042A@AC220V
    Lumen: 11595Lm ±5%@AC110V 11632Lm ±5%@AC220V
    Spectrum: 450~475nm 620~630nm, 650~660nm, and white
    50000-100000 hours lifespan, ETL certification

However, the 5 COBs I am adding will produce 22,500Lm (36 watts x 125Lm/w x 5 COBs) !!

So I will be effectively (nearly) tripling the lumen output of my system. It is a 5 sq. ft. tent and it’ll be running ~34,000 lumens, for ~6800 lumens per square foot.

According to http://www.growmedical420.com/how-many-lumens-or-watts-per-square-foot-of-light-do-i-need/ that’s pretty decent.

Yes, yes - I know lumens are for humans but I am guessing the PAR/umols/PPFD/whatever will be damned good enough. After all, I grew some pretty good friggin’ weed with just the blurple. :grin:

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#10

Now you know why i was never impressed by those blurple panels :laughing:

Seriously though they have put a lot of people off using led grow lighting. They certainly put me off for a number of years but cob rigs showed me what is possible and solstrips totally clinched it with their light distribution.

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#11

The blurples “do grow weed”, but the efficiency is basically not much better than CFL.

Thinking now that I might actually use those veg/flower switches on the blurple.

COBs + veg for veg stage / COBs + flower for flower stage. Be using right around 300w all the time and pushing enough PAR to grow well. We’ll see.

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#12

You nailed it right there bro! A single X2 solstrip at 48w can produce 9000 lumens which makes those meizhi panels poor value for money imo.

Those panels do have one advantage though, they are unlikely to overheat your grow :grin:

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#13

So why not crack open that thing and replace the blurple with COBs? Then you can increase the efficiency of that unit too?

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#14

Thought about that. I even cracked it open to investigate. From the outside, it looks like 3 individual panels of LEDs and my initial though was to rip out the middle panel and install one of my 5 COBs in the middle and then the other 4 COBs on the outside corners, keeping two of the LED panels active.

Well, once I got it opened up, I realized that it is just one large physical LED panel that has 3 electrically separate “zones” (and 3 drivers - one for each “zone”), so ripping out the middle isn’t an option. The only option would be to rip out the entire panel and then mount the COBs inside somehow. The drivers, being useless with COBs, would get ripped out. So then I’d have ruined the blurple and used it as a chassis. Not productive in my mind.

If that’s the way I wanted to go, I’d sell the blurple (or use it for something else) and build an aluminum frame for the COBs.

I want to try this hybrid idea. I said it was wacky, right? I can always change things up later when I have budget for more COBs, if I feel the need.

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#15

I dunno how much this helps but Mars and meizhi use the same drivers as far as I’m aware. https://m.youtube.com/watch?v=1CvL4-Sbs90
I was thinking about doing something similar a while back.

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#16

Yes, I’ve seen that before. He does a nice job of it, and I considered doing it.

Since I already have a high quality, dimmable/adjustable, efficient driver for the COBs, I figure it doesn’t make sense to hack apart my blurple. Some day I may decide to run a mother tent, or a tent to isolate my males, and I think it makes sense to maintain the option of using the blurple for that. This COBlurple idea is 100% reversible in the event that I change my mind at a later date.

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#17

I’ll be honest. I love my meizhi 600. It’s served me well. I tend to remove the meizhi last 3 weeks and finish them off with a hps 600. I’d never let it go. It grows bud. Maybe not as good as Samsung diodes do but it does OK. I’ve just ordered a mother tent and it will be going in that until I can put a new solstrip together. I’m one of them people. If it’s not broke don’t try and fix it :+1:

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#18

That’s mad that I had the same kind of idea idea last night :wink:

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#19

Built the sumbitch last night!

Things are a little warmer in the tent now! Will have to look into a higher CFM inline fan to move some more air.

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#20

Warm is good unless it’s in the high 80s :+1:

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