The ultimate beginner's guide to PC FANS

Hey man, thinking about it, if you glass-shield the main cfl, it would be better to actually cooltube it I think. That way all of the air flow is rushing right over the bulb instead of wasting noise/velocity slowly blowing all the extra air at the sides of the heat shield. I'm not sure I've seen anyone cooltube a cfl, but why not? A proper glass cooltube is going to have much better light throughput than a flat perspex one which a lot of people seem to use. I don't know, maybe the large CFLs don't fit or something? Anyways, dat's my suggestion.

ScrubNinja said:

Hey man, thinking about it, if you glass-shield the main cfl, it would be better to actually cooltube it I think. That way all of the air flow is rushing right over the bulb instead of wasting noise/velocity slowly blowing all the extra air at the sides of the heat shield. I'm not sure I've seen anyone cooltube a cfl, but why not? A proper glass cooltube is going to have much better light throughput than a flat perspex one which a lot of people seem to use. I don't know, maybe the large CFLs don't fit or something? Anyways, dat's my suggestion.

Click to expand...

I had a similar idea when I first started designing cabs (oh so very long ago... a whole month!) to have a ceiling of PL-L's with a window between them and the grow compartment, so that the plants could grow all the way up to the glass. This would also allow for separate ventilation, since the lights need high-cfm but pressure doesnt matter, and the plants need high-pressure but a high cfm isn't so important for them. This would allow you to (theoretically) get quieter fans.

Tell you what, if you are willing to wait an unknown amount of time (probably a week or two), I can post the exact heat levels and rise above ambient I get running around 150 watts with one thermaltake running at various voltages, and a carbon filter. It's PLLs but should still give you a good idea. Sound good?

Click to expand...

Sound good? That sounds awesome! Beyond the call of duty awesome! It'll take me longer than that to even get started to insulate up there. Then there's the small matter of getting electricity up there too, I'm not rush.

About the filter you've planned - that's actually no good because it's 100mm and your fan/s will be 120mm most likely, and it'll choke the flow needlessly. I would get 5" or higher.

Click to expand...

Whoops, noob error 256!

Could always have a PC as mom room. I guess you don't exactly feel like building a PC though, after you do all the rest.

Click to expand...

You guessed right! Depending on the space available though I'm willing to compromise. I could have a tiny clone room that could keep a few small clones ticking over whilst I flower their mums then just keep it going. No real 'mum to speak of. I know there's rumors of genetic degradation, but a clone's a clone imo. And I need to compromise wherever I can!

"average consumer desktop"

Click to expand...

I'm totally happy to err on the cautious size and keep my grow achievable. So let's aim for your 35db idea. And I don't have a pathological hatred of your Thermaltakes or anything (!) so if they fit the bill (and they're what you're using for testing) sounds poifect to me!

Massive thanks mate. Not giving up just yet!!..

Aero reckons you loose lumens (I think, don't wanna put words in his mouth!) with a glass screen. Not sure if it's a lot or what though. And he did do a screen with his own PC grow in the end not sure if it was glass though, or am I thinking of another PC grower? I'd certainly entertain the idea if it didn't add size to the cab etc or extra fans (and noise).

Strangely said:

Aero reckons you loose lumens (I think, don't wanna put words in his mouth!) with a glass screen. Not sure if it's a lot or what though. And he did do a screen with his own PC grow in the end not sure if it was glass though, or am I thinking of another PC grower? I'd certainly entertain the idea if it didn't add size to the cab etc or extra fans (and noise).

Click to expand...

You absolutely do lose light any time it passes through a phase change, twice in the case of a glass panel (gas to solid, then solid back to gas) it's a basic principle of quantum electrodynamics my good watson. A percentage of the light is reflected, but you allow the plants to grow closer to the bulb. The reason I decided not to go through with it is that I think you would lose more from the glass than you gain from increased intensity when doing this with flouros, as they are not nearly as hot as HID.

There is a way that I DO plan to do this; after I get my grow set up and I get a little momentum, I will be building an LED/CMH hybrid flower cab. It will be a CMH "box" on top that is like I talked about before, independently ventilated. The corners will have angled LED lighting, likely custom panels so that I can experiment with different light mixes.
This may be as much as a year off in the future, but my current plan (I'm sure it will change) is for it to be 1.5' x 2.5' (3.75 sq ft) 3.5' tall, using 150w CMH and 1 1w LED diode per inch around the top corners (106) for a total of 256w or 68.2 w/sq ft. The LEDs produce very very little heat so the actual chamber where the plants go would be nice and cool, and would require much less ventilation than normal. Quiet would be the name of the game.

I have also thought about getting crazy and putting 3 23w CFL's on flexible arms (the ones that let you you put them in ANY position and they stay put) underneath the canopy, but that would take away from the original concept of removing the heat of the lights. It would be cool to see what happens when you have THAT much of mix of light. LOL one Warm cfl, one cool, and one daylight. Plus with mixed LED's the plants could be getting 10 different kinds of light!!!

Strangely, no probs, as I have to do it anyway when it's not gonna cause issues for my seedlings. Don't get me wrong, I am a very very happy customer of thermaltake. I think they'd be good in this cab. The speed dial really comes in handy and frankly, I found it impossible to find a traditional wall wart adjustable power supply that would power one lone thermaltake properly. So it keeps things simple.

You will lose light going through glass or plastic, more through plastic I think. People are using the general idea of a glass or plastic shield with CFLs to great effect, plenty of rubbermaids, I think one of red's cabs, etc etc. Lets say you get a 10% drop in light (I don't know the exact numbers), well you're getting much much more than 10% increase in cooling, and that's sort of your issue. A properly vented cooltube is almost stone cold.

Another way to look at the cooltube vs flat sheet idea is, and this is just something I read, I can't speak for it's accuracy, but say if a sheet of glass of 4mm causes a 10% loss. Well CFLs as we all know lose their grunt very quickly the further the light travels. So there is more light close to the bulb right? So if this 10% reduction happens close to the bulb, you lose less light, as opposed to blocking 10% of the weaker light, further away. So a cooltube would be best if that's true. Hope that makes sense.

Archi, that would be an amazing box to see! I can tell you're doing your research so good on ya. Would the LEDs be outside the glass shield then?

ScrubNinja said:

Archi, that would be an amazing box to see! I can tell you're doing your research so good on ya. Would the LEDs be outside the glass shield then?

Click to expand...

It will be amazing, even if god forbid, I only get as far as a 3d model. I have big ideas.

Yes the LED's would be inside the actual grow chamber. Ideally, the membrane of the chamber at those corners (the top edge, where the LED's will be) would be a very thin aluminum sheet with holes in it and the diodes poking through. The diodes dont actually emit most of the (already miniscule) heat from the LED's so the chamber would still remain relatively virgin.

The idea is ultimate stealth. Mothers, clones, and veggies will be scattered around my home in stealth compartments - a PC here, a stack of comic-book boxes there, probably a rubbermaid for clones... but I want to be able to have this in my bedroom.... and I bring ladies of questionable character home, so they can't notice anything in the dead of night. If they snoop, they'll just think it's a locked dresser.

Architechno said:

The idea is ultimate stealth. Mothers, clones, and veggies will be scattered around my home in stealth compartments - a PC here, a stack of comic-book boxes there, probably a rubbermaid for clones... but I want to be able to have this in my bedroom.... and I bring ladies of questionable character home, so they can't notice anything in the dead of night. If they snoop, they'll just think it's a locked dresser.

Click to expand...

Heh, my place would be just like that if the power billing setup was different. Have you ever seen a movie called Growing Op? It's a dumb movie but funny because they have plants all over the house, but not micro, just big ol' HIDs hanging everywhere - the living room etc.

I wish I could understand LEDs. I like them and all and I think they have potential, but it just seems so hard to actually do it. Like for the PLLs for example, it's pretty easy to find all the info you need to start and finish a cab right here on IC and all in a cannabis growing context. I just don't see threads like that for LEDs telling me simply what I need, and how to wire it up. Then again I don't pay much attention to those threads due to the colour of the pics. Does something like that exist?

ScrubNinja said:

I wish I could understand LEDs. I like them and all and I think they have potential, but it just seems so hard to actually do it. Like for the PLLs for example, it's pretty easy to find all the info you need to start and finish a cab right here on IC and all in a cannabis growing context. I just don't see threads like that for LEDs telling me simply what I need, and how to wire it up. Then again I don't pay much attention to those threads due to the colour of the pics. Does something like that exist?

Click to expand...

there is the LED Lab 2009 but it's not quite that. Lots of people talking about old crap like "I just got this amazing 2 spectrum 90w UFO from ebay!" distracting from the up to date info. I often wish there was an "elite micro growers" subforum for people who dont dick around.... maybe there is and I haven't been admitted to the club yet

The truth is, I dont fully understand LED's right now, and I could not build a panel today if I wanted. But I know that I am smart enough to learn it and figure out how to do it within a year. At the very least thats enough time to slowly leech the appropriate knowledge off the people on here who have it

And my power bill is one of my biggest problems - someone else pays my bill and they can not notice too much or too sudden of an electricity increase!

At this stage I'll consider anything. Any quiet ones you would recommend Aero?

Click to expand...

Hey Strangely, There are plenty of blower fans that are quiet but you would need several to make up for one large noisy one (65 dba) I'll try to get some pics up of different blowers I know to be quiet. The blower style fans have a lower pitched noise than axials, more of a air howl like a can fan. How quiet do you need it to be for security purposes? I can barely hear my PC from the doorway to the room it's in and it can't be heard with the door closed even with my ear to it. Since you can't risk odor, you are likely going to have no choice but to go with a centrifugal fan and scrub the air.

Archi, how many watts do you think is ok for that? I'm in a similar position and draw the line at about 250w including all grow equipment, fans etc, but I'm probably too paranoid.

I should have a trashcan cab finished this week using the cooler master aero 70mm (0.9A) for exhaust. This one:


Also I made some spacers and stuff with 80mm fans. Not for any particular project.



I still have another spacer and third fan of the same model. Ran out of bolts but I'd like to put 3 fans together just to see what happens. The spaced stacking seems to work as advertised although I'm pretty high and I'd like to do some side by side tests with a non stacked fan hooked up.

as far as how much wattage is kosher, I'm not counting numbers at this point, just figuring out how to hide it. Over the summer I have used a TON of electricity, even left windows cracked sometimes to get the AC working overtime.... normally power consumption would drop off a LOT for me in the winter as I live in a warm climate and dont use central heating, but this year it will drop off a little less thanks to my new "luminous heating" technology ... That way there is no sudden increase in electrical use, and hopefully no fuss. I know I will get a warning if my electricity bill is too high before any sort of inquisition. I plan on moving before next summer anyways.

The cooler master aero 7 - I looked this up online and it says it only pushes 20cfm, even though it is very high pressure. Are you going to be running other fans in parallel? I am very interested in this type of fan design as it is compact and generates a lot of pressure, using two side-by-side could come in very handy when ventilating the grow room separately from a cool tube / hood.


Those spacers look nice - clean and effective. I have been slicing fans up too - my ThermalTake silent cat (http://images.google.com/imgres?img...e+fan&hl=en&client=safari&rls=en-us&sa=N&um=1) blows air the wrong way (intake is from the side with the lateral vents, I wanted them to be on exhaust) so I just cut the fan ribs where they met the sleeve, turned it around, and superglued it back in place. Works fine and it is absolutely SILENT. They produce very respectable pressure as well (2.22mm-h2o) so I might run them side by side to increase cfm. They're cheap too, $10 at compUSA.

One thing I would (am) look for is fans that spin in the opposite direction of most others. By stacking fans spinning in opposite directions, I think you actually DO increase CFM, as well as pressure.

To tell you the truth I think stacking with spacers is a bit of a waste of time for micro situations. It takes up 3 times the space and gives minimal results. Far better to buy one fan that does the job imo. I think it has potential for stealth uses but even still, two fans is louder than one so it's a bit of a merry-go-round.

2.22mm-h2o is a long way from respectable, bro, even for an axial. But if it works for the situation - cool

About the opposite direction fans - all I can say is there's a lot of research and design goes into modern fans, and trying to get performance boosts. Yet nobody is marketing opposite direction fans for PCs or otherwise pushing the stacking route. I think that says it all really. Like I said though, could have potential for stealth.

The cooler master aero is rated very low CFMs yes, alarmingly low perhaps but it all comes back to what I typed in the first post about cfm and pressure. Without suitable pressure, you won't get your flow. So I am getting (made up figures) 90% of my cfm whereas an axial user with a couple MM's h2o is getting 5% of his cfm with the same filter.

Everything in micro (and a lot of areas) comes down to efficiency. If someone in the regular size grow forum asks about using a 6" inline axial with a carbon filter they are quickly warned off. Everybody in that scene knows that centrifugal is the way to go for best results, without question. They are just the right tool for the job. It's a design/physics thing - even the shittiest centrifugal will outperform an axial. I think a 6" centrifugal is somewhere around 100mm-h2o btw. Heck, someone can plan a $10,000 grow op and yet noone will even mention the mmh20 of the fans. They just say get a "X"cfm centrifugal, and that's fine because they're using the right design of tool for the job. The CFM rating IS representative in their case.

So although 20cfm may seem like underkill, it's just that it's more efficient. I'll get most of those CFMs coming out my exhaust. It'll be the only exhaust fan and was also the only exhaust fan in my tent during veg (about 100 - 120 watts CFL, I can't recall) and worked fine.

CFMs is a myth - almost completely irrelevant for anyone using a carbon filter and axials. It's like me saying I'm using 1000 watts of CFL in my pc growbox (equivalent watts). Except even more misleading.

Well that's my rants for the day Time to smoke some weed

Just to go a bit further - I do use mine inline but the way I've done it is the only way I'd really feel safe about not being innefficient. This is just my feeling on it. But the carbon filter being between the fans blocks any kind of interference or negative influence they would, I think, normally have on each other.

What I mean is, without the carbon in place, I can have one fan running and the other fan will spin by itself because it's a 1:1 thing if that makes sense. If I then turn on the second fan inline, what's actually happening? Isn't it really just spinning, making noise, but essentially not adding to anything? It's free wheeling, you dig?

So with the filter between, in a push-pull config, I am getting maximum use out of the two fans. Each is "fighting" and putting it's power (and noise) to good use. Thus I am genuinely getting more flow than if I had just spacer-stacked two fans.

Opinions welcome

upon further review and testing of how much airflow is reduced per layer of filter, I have been converted. I will be using dual side by side cooler master aero 7's. I can't find anywhere to buy them without the heat sink though, do you know of anywhere that sells them that way?

I got two new off ebay and see them on there often without the heatsink. Mine came from the states. All I know is I have the old Aero (but probably still available). Seems to me the new ones are the Aero 7 and they're 70mm and 80mm. These are one of the hardest fans I've had to find reliable specs for. The multiple models don't help. I saw some specs saying the 70mm is far better than the 80mm so I don't know. I can only really speak for my model which is possibly different to the Aero 7 70mm. Mine came with speed dial, I think others may not.

some numbers from the sticker:

B7070-35BB-5AA-B1

BP806012M-AA

By all means wait a few days and you'll get a good indication of how one performs with filter as I'm leaving to make the cuts I need in a couple hours.

stacking wont increase your cfm, but it will increase the resistance the fans can pull through, looks neat man, are you going to tape it all up to make sure air is going through those blades and not being pulled in through small gaps?

cork144 said:

are you going to tape it all up to make sure air is going through those blades and not being pulled in through small gaps?

Click to expand...

I will if I go any further on it but to be honest, I'm a bit over it now and I need all my tape, haha. There are tiny gaps though so it would help for sure.

*THOUGHT*

taping the inside of the sleeve (the big one) so as to minimize the amount of space between the tips of the fan blade and the bottleneck the air is squeezing through. Should increase pressure...

If anyone reading this has an account on a PC overclockers forum, please inquire if this has been done before.

So with the filter between, in a push-pull config, I am getting maximum use out of the two fans. Each is "fighting" and putting it's power (and noise) to good use. Thus I am genuinely getting more flow than if I had just spacer-stacked two fans.

Click to expand...

I was wondering about your stacking thoughts Scrub. I kept coming up with one main advantage of just spaced stacking - the second fan wont have to work as hard and would thus be quieter. Putting a filter in between would seem to make more sense in getting the most from both fans.

As you know I'm no expert (ahem!) and have posted this as much to gently remind you of your lovely idea of testing what space/wattage I/anyone would be left to play with after scrubbing with a single Thermaltake 120mm through an off-the-shelf carbon filter.
: )