More Money Than Brains - a water cooled cab build

OK, someone was dumb enough to do it! Is it a good idea? We will see.

First off, thanks to many folks who have helped and/or inspired me including: flux, supra, psua, pico, bbspills, smokey, gaius, and everyone else here at the RIU LED forum. This is the place to be if you're DIY LED growing.

I pay so much for Cannabis at the dispensary that I decided to grow my own. My outdoor space is not ideal and I want to keep everything low-key so I'm building a cabinet to go in a closet. The closet is more of a wide shallow alcove with very lightweight sliding doors so I need to enclose the grow inside something. Most tents don't fit well in my space and I want it to not obviously look like a grow if I leave the closet door open so I'm converting an ordinary cabinet. I considered converting big totes but decided that top access to the plants would be a huge PITA so I searched for a cabinet that would fit in my space. I also want the whole thing to be as quiet as possible since I spend a lot of time in the room.

I'm tight on vertical space and I feel like every extra inch will mean more buds so I'm using water blocks to cool the COBs. By using water blocks, I can reduce the thickness of the entire fixture, including any space above the fixture necessary for cooling, to about 5/8ths of an inch. Maybe I could get pretty close if I had a thin heatsink mounted to the top with a bunch of those square DC blowers forcing air between the fins. I think it would be a lot louder and I would also need a larger exhaust fan. Cutting holes in the top of the cab and using CPU coolers while disguising it with plastic bins on top would also have been an option with the flowering chamber. I don't have a workshop and I'm not super handy so I probably would have messed it up pretty good. This way I keep use of the top of the cab too. The radiator is also very efficient so overall fan noise should be lower. I'm also thinking about converting to a vertical flowering arrangement once I get things figured out, which should be relatively easy with the thin blocks. I also get all of the heat out of the closet, which is helpful because I have no air conditioning. OK, there is nothing rational about this entire project but please bare with me.

I found this old TV cabinet at a thrift shop. Cost less than a new particle board cabinet and is made from solid, but soft, wood. Flowering chamber is 35L x 17.5W x 31.5H American. Mom and Veg chambers are 17L x 17.5XW x 21H each. Three 4kK Vero 29's in the top, an '18 in each bottom chamber. I'm going to do a continuous modular scrog with low pro hempy buckets and Lucas FN bloom.



Painting the inside with marine varnish and paint. Seal it up to make it easy to clean and keep mold from colonizing the wood. Painting is hard, stinky work. My wife must really love me.



I'm using PC water cooling parts and a case to hold them. It's going to fit right in with the working computers in the closet and room. The pump is top quality and has an integrated temp sensor and fan controller to keep the fans spinning at the minimum. I have found Eheims to be extremely reliable where most small pumps like this are very shoddy and prone to failure (I have kept aquaria most of my life.) The radiator is below the drive bays, all copper, and double the thickness of a normal one. It should do the trick but I have room for more radiators if necessary.



The water blocks are $10 eBay specials. They are kinda sketchy, I hope they don't leak. Good American made ones are like $75 each though. These are cut from solid and have deep scratches on the faces. There are plugs soldered into the holes drilled to make channels. I think maybe the water loops around once though there are two holes in the side. I smoothed out the face with sandpaper and water stones.

My wife is obviously a fantastic babe but she gave me one rule: Do Not Burn Down The House. So I got MeanWell drivers. Three 90 watters to power the '29s in flowering (will be dimmed somewhat), a 60W for veg and a 40 for moms. There won't be any high voltage inside the cab and the only mains wiring I'm going to do is screw plugs onto the existing driver wires.

Clamp on a COB sandwich anyone?



The '18s are glued on with Arctic Alumina. The '29s are clamped on with screws and t-nuts.

Building a cab is a lot of hard work. Endless planning, ordering, visiting the hardware store, etc... Still, it's a lot cheaper than buying a premade one that doesn't have a state of the art lighting system. I have some money left over for a tasty adult beverage so I can relax a bit and take care of what brain cells I still have left.



I thought it would be a good idea to have quick disconnects on the cooling loop so I can pull the cab out and work on it.



So I knew water cooling was going to be expensive. Check out the prices for pumps, radiators, and reservoirs. Where I got hit, though, was on the fittings. You need a lot and they really add up. The quick disconnects were obscenely expensive and you don't want to cheap out there. Instead of expensive compression fittings I went with barbs and clamps. The water blocks have barbs anyway. I didn't cheap out here, either and got shiny barbs and nice aluminum clamps that seem to be much more secure than the regular type. I have no fear of the tubing being pulled off inadvertently. However, I did nix the idea of using bulkheads for each penetration of the tubing through the cabinet. I only have so much more money than brains. I probably could have hunted down cheaper fittings that didn't come from an overclocking shop. I'm sure I'll forget about the price after a few harvests. In fact, this cab should pay for itself pretty quickly and I'm planning to keep it for a while.

Here's some pics of the flowering lights that I just hung up. You can see how each cob/clamp/block is an individual unit. I <3 Velcro. Industrial strength Velcro is very strong so I'm not worried about them falling. This way I can move them around to get even light. It was either this or shave yaks in Matlab or something for hours to find the perfect spots then be unable to put the lights there because I misdrilled the holes then stripped them out. You can also see how they're a mere 5/8" thin. Some sort of fastener for the tubing is coming.



Next up: wiring and mounting drivers and a dimmer box, installing ventilation and filter, sealing cracks and light proofing, getting the wife regular flowers and something sparkly.

Bravo! Can't wait for the report

Velcro. Genius. Hopefully they stay cool enough so that the Velcro adhesive doesn't fail. Some staples might help it stay put though.

Somebody finally did it...!

Much respect to you for actually 'doing' rather then...'i have an idea...what do you morons reckon about it...will you hold my hand and flick my dick '

Looking forward to watching...

Congrats on taking the plunge! And on you choice of flowering light... the Vero 4000K. You have chosen wisely. From the photo it looks like the smaller veg vero's are 5000K?

I see your flowering room is 80cm heigh. With the three intense lights so close it will be a challenge to get an even covering of the canopy. Probably you will remove those reflectors and start to be happy about every bit of light that travels sideways. The cabinet itself then becomes a better reflector because it diffuses the light.

Do you have the meanwell LPF-90D-42?

Thanks! I'm glad to be in the ranks of the "doers."

If the COBs get hot enough to melt the adhesive then they are probably toast.

MrFlux: they are LPF-90D-48. The driver selection guide section says the '29s can get up to 43.5 volts at 2.1 amps when cold. The 48V drivers have a bit less current but they should always have enough voltage and I think I'll still have more than enough power. For the reflectors, I have no idea how it's going to look once everything is lit up so I got the reflectors just in case. They are the wide versions.

Have you had a chance to fire them up yet? I'm very interested to see how the reflector performs. ledil reflector?

bicit said:

Have you had a chance to fire them up yet? I'm very interested to see how the reflector performs. ledil reflector?

Click to expand...

X2 on this^
Also, where did you get them?

I just picked up a couple vero18s myself. Awesome little poker chips these things are.
.Great build!

Finally got all the lights wired up. I hate soldering and I'm not particularly good at it but its a great skill to have. Half the time I would forget to put the shrink on beforehand and used tape. Got a dimmer box on the back. Once the ventilation is in and the placement more or less final I'll tie everything down

View attachment 3006606

Fired up the loop. There's a problem with the pump I haven't resolved yet so I'm using a normal one from my box of aquarium parts. It's not as quiet is the new one but it's still too quiet to hear unless I stick my head near the case. I think that means I need to replace all the fans in my file server with quieter ones. Also, there is no fan controller on an ordinary pump so I'm not running the fan on the radiator yet.

View attachment 3006607

Now that there is water flowing I can actually turn on the lights. Without water I could only turn them on for less than a minute before the blocks started getting pretty warm. I'm not running a fan yet on the radiator but even at full tilt the lights barely heat up the blocks/water after 15 minutes. There's about a liter and a half of water in the loop. I can run one of the bottom chambers without the fan without the water heating up at all until the pump/fan situation is resolved.

Flux was right, the light is too uneven with the reflectors until you get to the bottom of the chamber. I need to rig up a stick to hold the sensor to take some accurate readings but just hand holding it looks promising. Dialed back to 80-70% I was getting 800-900 umol/s in the center about 2/3rds up and dropping off to 600 on the edges.

Really need to finish ventilation, circulation, and light proofing in the next couple weeks.

Maybe this'll work better. Drivers and dimmer box.



Fill 'er up.




I used a stand to hold up the PAR sensor in the cab. I guess with all the light bouncing around it's always going to be brighter in the center than on either side. So it's handy to be able to dial back the center light a click or two to make it more even with the sides. I noticed that losing the left door makes it brighter on the right side of the cab too. I'll test out the reflectors for you, I really need to get the fan going on the radiator first because you want steady temps.
I got a reflective emergency blanket, I wonder if putting that up around the top half will help brighten up the sides. I didn't use primer under the paint which turned out to be not as opaque as one would hope.

Very interested in seeing your progress. I've been considering something similar. Do you know what the power draw of your cooling system will be overall?

Not much to report. The fancy pump I ordered that has an integrated water temperature sensor and fan controller (and is made by and would integrate with the touch screen controller I was thinking about running my system on) turned out to be DOA. The company is sending me a new controller board to solder in myself because it's not worth shipping the whole pump back and forth!



In its stead I've been running an ordinary Eheim of the same model that the fancy pump is based on that I had sitting around in my box of aquarium parts. Sure, I could have just used that pump in the original plan if I had thought of it, but then it wouldn't have cool auto adjusting fan speed and this wouldn't be More Money Than Brains.

So I'm circulating the loop with the Eheim but I haven't turned on the fan since I need to wire up or acquire a power supply adapter. The dead pump has the same 12V Molex power input that old hard drives use and has a fan connector. The new pump plugs straight into the wall, hence the need to provide the fan some juice. It's just temporary so I don't want to waste a bunch of time on it. The Eheim uses 3W according to the KillAWatt, so I'm hoping my total cooling consumption will be around 5W, we'll see. The fancy pump has different electronics and sophisticated software on board (and is totally configurable) so it will surely have different power consumption than the stock one, maybe less since it won't necessarily run the pump full tilt.

Right now with no fan it runs the 50W Vero 18 without warming up the water at all. If I turn on the flowering lights you can feel the water warming up pretty fast. What's cool though is if you turn off the lights and put your finger on the side of one of the water blocks that was not on at all you can feel it cooling down immediately. That's without the fan on the radiator, which is stuffed inside a PC case and doesn't get any natural air flow so I think the performance will be quite good. All of the tubing outside the cabinet (about 30-40 feet) and the big metal quick disconnects contribute a small amount to the cooling.

I popped a five pack of TGA Timewreck last week and am growing them out in the veg compartment. Here they are about 10" below the 4kK-Vero18-LPF60 where they are getting about 450 umol/m/s. They have been growing visibly by the hour. They look a bit stretchy because they were in a not very bright window for the first day while I rushed to finish wiring the drivers.



The 4kK Veros have a very white light with maybe a touch of yellow to my eyes. No problem getting good photographs unlike very yellow HPS or very pink nonwhite LEDs. So far I'm pretty excited about the lighting in my cab and am confident it will be able to produce some kind buds.

SUBBED!!!!^^^ to this, love what you did in here...............good luck with your grow and be safe

Attachments breaky

Congrats on the ta-da!

I rigged up the fan on the radiator so now I can turn on the flowering lights and see whats going on. I'm still using the ordinary pump without fan controller but the fan has a low/high switch. At low you can only barely hear it if you stick your ear right up to it and I have to feel the breeze to be sure it's on. At high (full 12V) it makes a whoosh sound that is louder than I'd like. It's a 120mm Antec TrueQuiet Pro.

I turned all of the lights in all three compartments on full blast and let the temperature stabilize after a couple hours. I'm measuring the temp of the water in the coolant reservoir. With the fan on low the coolant temp is 42C (107F) once the system reaches equilibrium. With the fan on high the coolant is almost 38C (100F).



I tried to measure Tc with a really crappy infrared thermometer right after turning off the light. It was about 46C when the coolant was 38C. So I'm closer to 50C than 25C, probably 60C, but my lighting system is almost silent and most of the heat is removed from the cab without any additional noise and none of that noise is in or near the cabinet. The cooling system consumes 5.3W right now. I'm confident the new pump will be even more quiet but it is going to require a good long burn in period in a bucket before installation for me to trust it. The case has room for another radiator. Another radiator at $75 can pay itself off in 3 years or so if it provides 3% more light. The cooling system wont go obsolete like the COBs.



I rigged up a stand for the sensor on an Apogee QMSS-E and took some measurements. I got this when Apogee discontinued this model and it hasn't been calibrated since it was made. I did take it outside at noon on a clear day and compared the reading to the expected value off Apogee's website and it was pretty close but it jumped around because I wasn't using a stand for the sensor. Also, this thing is calibrated for "electric light" but not for these LEDs so the value could be off by 10% or more. I think it's in the ballpark but don't take these numbers as gospel.

PAR-tay at my place!



I measured 1/4th of the flowering compartment from 12" and 18" below the COB, that's about 12.75" below the ceiling. Since it's symmetrical, I expect almost identical readings on the other three sides. Taking these readings is a PITA. I used a tape measure to try to be reasonably accurate, but these numbers are just for entertainment purposes.

drumroll please....

View attachment 3010558

I put the Angelina-W reflector on the center light but at 12" it overloaded the meter! Well over 2000 umol/m/s in the dead center. However, it dropped from 950 without to 750 with reflector halfway to the wall in the center. So the reflectors are good if you want to put the lights further away than 12" (i.e. you want a lot of penetration.)


It looks like I got a pretty sick lighting system in my flowering compartment, what do you think?

You're just using cheap 40mm waterblocks off ebay correct?

ETA: Just looking at your setup I'd like to offer 2 suggestions. 1: I'd say get a larger reservoir, at least 4-5 gallons, to help lower and stabilize your temps. 2: I'd run your radiator after your LED's and before your reservoir to help remove as much heat energy as possible into the air so it isn't transferred into your reservoir.

I think I made an error on my diagram, I'm actually getting about 100 umol more in the very center than the wings, about 1170 umol under the center light.

I tried an experiment to see how much loss I get from heat. With cold water I flipped on the lights with the sensor setup on the stand right in the center. I got about 1185 umol in the very center when the emitter was cold. That dropped to 1180 within about 20 seconds. Then it slowly drops down to 1170 as the water heats up and holds steady after an hour or two. That's a 0.8-1.2% difference between cold and hot, and less difference than having one of the doors open a crack. With my setup, we're talking a couple bucks a year. So I probably shouldn't waste any more time or money on improving performance of the cooling loop, though reducing space could be worth it.

bicit: yes, 40mm copper waterblocks off ebay. Theres lots of discussions about placing the radiator on the PC watercooling forums. I'm not sure it'll make much difference but I going to swap out the pump anyway in a week or two so I could reconfigure the loop then. I could turn a big tote or something into a huge reservoir but it would take up a lot of space and not save me much money, apparently. Also, I'd be risking gallons of water on the floor instead of less than half a gallon. I think the main things we get out of the reservoir is protection from the pump running dry when filling and over time as water slowly evaporates through the tubing. Don't forget to give the blocks a good shake when filling to get the air out of them. You can see above about a third of my reservoir missing from all the air hiding in the loop after initial filling.

Next task is to make a carbon scrubber and test my ventilation fan to make sure it can pull through it...

Timewreck seedlings growing, 12 days. You can tell which ones sprouted a day later than the others.

Update!

Plants are doing their job, which is grow. They seem to be growing just fine under the 4kK Vero 18. I think I've been over nuting them and also one or two plants got a bit dry.



Testing the fan and 4x12 Phresh filter. This is an Soler & Palau TD-100XS "silent" fan. Very fancy and designed to be as quiet as possible. It's got a funky multilayer foam sandwich body that supposedly keeps the motor noise from getting out. It has two settings, low and high. On high it pulls about 32W and makes tons of noise. On low it pulls about 16W and makes not much less noise. The purple thingy is what S&P calls the "Continuous Ventilation Control." It's designed to run the fan continuously at a low rate. I think it drops the voltage in half because the fan runs the same with this thing plugged into the high input as the fan runs normally without it on low (16W.) With the CVC plugged into the low input the fan runs very quietly and pulls about 9 Watts. Most of the noise it makes is air flowing and not the fan itself.



The spec sheet says the fan is rated for 20 CFM at .25" static pressure with the CVC, the fan is rated at 91/48 CFM at .25" SP without it. My cab is only 11 cubic feet in volume so the fan is more than enough. In testing it had no problem pulling through 25' of hose with plenty of bends and pushed it out the filter.

My big question relates to the configuration of the ducting. I don't know if I should ventilate each compartment separately or sequentially. Separately is probably easier for light containment. I want to be able to either veg or flower in the veg compartment so that is a mark for separate/parallel. Having a single inlet and filter is an advantage for sequential. Any advice from experience would be greatly appreciated.



Thanks for watching, more to come!

The two smaller chambers parallel, feeding the bigger chamber. and Out.

guod said:

The two smaller chambers parallel, feeding the bigger chamber. and Out.

Click to expand...

This requires two extra light-proof air passages. I think all three in parallel would be easier and do just fine.

Btw, for my cabinet the airflow is fully serial, going from the flowering to the veg room so as to to warm up and moisten the air for the veg room. For me this was a lifesaver when it was so cold a while ago, but probably not needed for O&R.

Time to Top! I was hoping there would be preflowers by now and I could ditch the males but not yet. One or two seem to be showing but without the pistils I think its inconclusive. So I decided now is the time to top them all and I am attempting to root the cut tops. Once the tops root I'll throw them into flower and the bottoms are destined to be bonsai moms (or compost if male.)

Here's the plants prior to topping jammed into my veg/preflower chamber. I burned the shit out of them early on like a good little newbie. So I waited till I had good growth on the lower nodes before topping.



One 4kK Vero-18 at 1.4A is definitely not enough for this veg chamber. Not only would I like the light to be spread out more but I need maybe twice as much. Raised up here they are getting 800-1000+ umol of PPF. The mom chamber could use a second COB to spread the light out more but I'm not sure if the total amount of PPF is too little/much yet.



TGA Timewreck lined up and ready for cutting.



Tops placed in micro hempies.



Nighty night.

Still to go on the build: light traps for the vents on the back, finish light tighting the flowering chamber doors, circulation for the flowering chamber, scrog screens for the pots I'm going to use in flower (tubs that once contained baby spinach.)

On the exhaust question I went for parallel ventilation. Thank you to the folks that offered their advice. Each chamber exhausts separately then is joined together with wyes prior to the fan. The carbon filter sits on the very end. I have the filter stashed in one of those wire basket drawer things on the other side of the closet. It's low pro and I can leave the door slid open right in front of it and another door open a crack on the opposite side where the cab is to ensure fresh air gets in.

The filter is rated for 200 cfm but the fan in its current configuration is rated for only 20 cfm @ 0.25" SP. So I have wrapped most of the filter with plastic wrap so only a small portion is being used. This was recommended in a video featuring a rep from Phresh filter when using an oversized filter. Without the plastic you can feel that most of the air is coming out of the first inch of filter. When stink starts breaking through I'll just cover the part I've used and uncover an unused part. If you don't do this you'll end up wasting most of the carbon.


Thanks for watching! Y'all come back now, y'hear!