The ultimate beginner's guide to PC FANS

[cork144]

hey scrub

im just wondering, i can plug couple fans on one adaptor,
ex adaptor:

3 fans:
1. 120mm x 120mm, 12 V, 0,16 A
2. 2x 80mm x 80mm, 12 V, unknown A

aslong as the total amps of all the fans dont exceed the adaptors max output, then youll be fine.

 

[ScrubNinja]

[m8] - The answer is "unknown" as in your amps. I can't tell you the unknown Find out, or work out the amps on the 80mm's, and then you've got an answer. There's a formula near the end of the first post to work out your amps if that helps. Otherwise google the serial numbers of the fans. But yes, that is the same adjustable adaptor I was referring to so you can use more than one fan if the amps are ok. (lol you beat me, cork)

The following backs up what Aero just said and is a good reason not to try to squeeze too much out of an adaptor:

using a 1.5 amp adaptor
a 0.9A fan runs well
when a 0.48A fan is added, the 0.9A slows noticeably.

So I would not mess around and personally, I would even aim for >20% overhead after I saw that happen.

Architechno, great advice - just watch out because you will find one occasionally that is AC output, as in AC to AC adaptor. It had me tearing my hair out the first time I tried to use fans.

 

[Architechno]

Architechno, great advice - just watch out because you will find one occasionally that is AC output, as in AC to AC adaptor. It had me tearing my hair out the first time I tried to use fans.

good lookin out my man, one of them was indeed AC.

 

[Strangely]

Right this is the quick Sketchup I was on about ScrubNinja. Sorry for the delay, had to some work!

The red and green parts represent gaps for air to pass through. Green is for fresh air passing to mini-mum/clone room and flowering room (sporting this for the flower room to save space http://www.3ch.co.uk/lights/fluorescent-grow-lights/cfl-red/prod_121.html). Red is for warm air passing through to the 120mm PC fan pulling through an off the shelf scrubber (smallest one here http://www.growell.co.uk/p/0585/Carbon-Filters.html). You should be able to just see the rectangle intake holes on the back of the cab as well.

120mm FAN -
60mm x 3.14 = approx 190sqmm. x 2 as the old rough rule goes = 380mm. So 380mm of passive intake it is.

Mini-Mum/clones ROOM -
22cm wide x 34cm tall x45cm deep (including lights/top section)
= 3.37sqm (right?!)

Flower ROOM -
28cm wide x 55cm tall x45cm deep (including lights/top section)
= 5.94sqmm (right?!)

So if my maths is right (big if!) then the flower cab is roughly twice the size of the other room so twice the air flow needed. So 125sqmm intake for smaller room and 250sqmm for larger flower room roughly.

Questions oh wise one!...
1- Will the fan cope with this (http://www.quietpc.com/gb-en-gbp/products/noctuafans/nf-s12b-flx)? Think you said it would be ok on the bigger model previously, that had more but weaker lights, so just double checking!
2- There's a shared intake for both rooms with a supplementary one for the glassed off light section. What size for the supplementary light cooling one do you think?
3- Should I make the mum side gaps half the size of the other side to encourage even air distribution? Other than that does size matter here or just ratio (mum side to flower side)?
4- Red gaps, same question as 3 really.
5- Light leaks (whilst I'm here! ; ). Looks a bit iffy to me around the opening to the scrubber/fan? Do you think it's worth putting piping (with a bend at the top facing towards) the scrubber coming up from the mum room instead of the (red) gap/opening? 2inch pipe would only about 80sqmm, so I guess I'd need 2.

Thanks in advance, and sorry for the mammoth post!

 

[ScrubNinja]

Hi mate, epic! Nice simple functional design there. I'll try to keep this condensed:

Your calcs are out, I believe. First up, here is a fantastic page which will help you a lot I think. A 120mm hole is 113.1 sq cm or a square hole 10.6cm x 10.6cm. So for the 120mm fan, you would need an intake sized say, 10.6cm x 21.2cm. (for double intake rule)

For the cabs you are trying to measure the volume so you can't use those dimensions. Your mom cab is 0.03366 cubic meters. Flower is 0.0693. But yes, flower is roughly double the size of mom room.

Onto the actual questions!

1- Will the fan cope with this

No. Not even close to coping. Not even in the same postcode as helping. You will fail miserably if you buy that fan or any of the noctuas. The only nice thing I've ever said about Noctuas is that they are quiet and some people seem happy with them. You just cannot cool and scrub a decent wattage efficiently with no noise though. Not with pc fans anyway. If you look at the specs of the noctua, can you even tell me why you think it'd be suitable? 1.31mm/h2o? Through a scrubber? Man, tell me what you are smoking, I need to order seeds, lol. Just messin' with ya, bro, but seriously, look at the specs of the noctua, and read back over the tutorial and my rough/recommended levels. The Noc has 0.1 amps. Not gonna cool anything this size. What is your total wattage of lights in each room anyway? There are a few wattages of the cfl you linked to. But as a very very rough guide, you are gonna need like, up around 1 amp of fans, or even more depends on your watts. You're cooling two rooms, lets say at least 150w of light, pulling it all through a hood, and then a scrubber. I hope you don't have any ideas that you can do this silently and have the box in a public space, and have good temps.

2- There's a shared intake for both rooms with a supplementary one for the glassed off light section. What size for the supplementary light cooling one do you think?

Me personally, as not an expert, I would go 1:1 intake:exhaust or larger if I had the ability. Plenty of people use 1:1 for this purpose.

3- Should I make the mum side gaps half the size of the other side to encourage even air distribution? Other than that does size matter here or just ratio (mum side to flower side)?

I'm not certain but I have thought about this before for a design of my own and I'd have a sliding door setup, or tape, to adjust the ratio as needed. I'd make the system as open as possible, and adjustable at one point, to KISS. Size is always important. Any tight spots will cause a bottleneck. Which is why I decided on leaving it adjustable cos otherwise I'd fuck something up.

5- Light leaks (whilst I'm here! ; ). Looks a bit iffy to me around the opening to the scrubber/fan? Do you think it's worth putting piping (with a bend at the top facing towards) the scrubber coming up from the mum room instead of the (red) gap/opening? 2inch pipe would only about 80sqmm, so I guess I'd need 2.

Yep you will definitely hit problems there. I would simply construct another light trap out of wood for the mom room.

Thanks in advance, and sorry for the mammoth post!

That's okay buddy Hope it helps or inspires and by all means, ask any other questions or clarification. Or just argue! I'm not right all the time. For a lot of the stuff regarding intake sizes etc, I would suggest asking in Red or Hoosierdaddy's threads for more experienced answers.

One controversial closing thought... Isn't our exhaust size equal to the little gaps of air between the pieces of carbon? You tell me. I'm not saying the dummy's rule of double intake is a bad idea, but it is only a rough rule, and I found that thread very interesting. Peace

 

[ScrubNinja]

You know Strangely, I would consider trying to vent the heat shield seperately. I note that Red does that and recommends it as the best way. That would be your best bet to use the quietest fan power possible. You just use one quiet but high CFM fan for the heat shield, and a seperate fan for the grow areas/carbon scrubber with the focus on mm/h2o. The heat shield fan has no restriction or scrubber and keeps the lights very cool with a massive turnover of fresh air. The grow areas need much less ventilation (and scrubbing) as a result. More efficient means less fan power means less noise overall. I would strongly suggest looking at some grows doing this. Red's is a fine starting place.

You may also want to look into the Panasonic Whisperline or S&P mixed flow fans. They offer a lot more cooling per decibel, than PC fans. But they take up more space.

 

[XxGanja*ninjaxX]

the computer fan i am using is a 3 pin connector...how would i go about powering that with the computer supply i have powering the other fan?

 

[ScrubNinja]

the computer fan i am using is a 3 pin connector...how would i go about powering that with the computer supply i have powering the other fan?

How is the other fan wired up? By molexes or just bare wires? If molex > buy a 4pin to 3pin adaptor, they come included with most fans. You simply plug it in and it's pre-wired in parallel.

If bare wires > just connect the wires to the same place you connected the other fan wires. Keep red to red and black to black. This is wiring "in parallel" and there is an example diagram in the first post if you need help. I'll also take a photo soon-ish to try and make it clearer.

Always check you have enough amps on the power supply any time you plug in a new fan. Check you have 20% free.

 

[Aerohead]

There is no miracle fan that moves lots of air through a scrubber quietly, unless you build some kinda muffler box. I have noticed that while all fans that move lots of air tend to be noisy, they have a different pitch to the sound, try a few and choose one that blends best with your environment. Another thing I noticed is that some fans (different pitch noise) work well together and drown each other out a little bit, white noise maybe? but there is no way other than trying lots of fans to get that combo. It was dumb luck but my radiator fan on the sump cooler somehow changes the overall sound of the blower fan and makes it a more tolerable frequency, seems quieter. Also, the blower style fans (same DBA) seem to have more of a air whoosh sound with less high pitch whine as the axials, they also can pull through a scrubber way better. Blowers are superior for cooling small spaces and should be explored by more micro growers.

 

[XxGanja*ninjaxX]

first of all thank you for responding. Secondly, the other fan is a normal 4 pin connector and the second fan i installed tonight was a two pin so i took your advice off the first page and connected the red to yellow and black to black but with thoose two fans the pc with only one 26watt cfl is at a constant 90 degrees...so i need to try and connect the three pin fan to see if it helps cool the pc, but i didnt buy it so i dont have a connector and have no clue how to even go about connecting it. but my 6 plants are all starting there second set of leaves and i need to finish this cab asap.

 

[ScrubNinja]

No problem fellow ninja. So let me get this straight. You have a 4 pin and a 2 pin fan in the PC now and they're wired by twisting the wires. And you have a third 3 pin fan that you would like to use?

Just wire it in like the others, you can use as many fans in parallel as your amps allow. If I misunderstood and they are connected via molex fittings, just get the suitable adaptor for it. If you need 2 pin to 4 pin, search google for "2 pin to 4 pin pc fan adapter". Or just ask at a computer nerd store. Hope that helps.

 

[XxGanja*ninjaxX]

you are correct. and just so im not mistaken you mean connecting red to red yellow to yellow and black to black? are you a down ninja?

 

[ScrubNinja]

I'm down with the dojo, word is bond About the wiring, you just forget about the yellow wires, don't connect them. I usually cut them off once I've established the red and black wires ARE the red and black wires. I think yellow is used for temperature monitoring or RPM or something, when hooked up to a motherboard.

 

[XxGanja*ninjaxX]

okay sweetness. do you think three fans is enough to keep it cool?

 

[ScrubNinja]

I think two is enough to keep it cool if everythings designed optimally and you have high amperage fans. Tell you what, we can just discuss that on your thread when you're ready. Peace out.

 

[Strangely]

Appreciate your honesty Scrub! I'm not going to lie here, I'm close to chucking in the towel after that. Temp testing showed my grow area (loft with small skylight) temps fluctuate between 65f and 90f already so, I'm up against it there before even starting. I'll need to insulate between the joists and see how much that helps. If that doesn't do the trick it's all over already.

My minicab wouldn't be in a public space (my loft) but would need to be very small, to get a green light from the Mrs, be pretty quiet, and utterly scentless as the loft is joined to neighbours either side. House is very old, loft spaces never even used to have separating walls, so bound to not be 100% sealed so any smell would carry.

I could certainly entertain the idea of cooling the 'hood' area separately. Would that noctua do that? Or other fan recommendation that would (quietly!)?

Blowers are superior for cooling small spaces and should be explored by more micro growers.

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

 

[Strangely]

Trying to find dimensions for the Panasonic Whisper Fan (not that I can find a single uk retailer,but anyway). Anyone any idea what Dimensions: 11-13/16'' x 11-13/16'' means? Between 11 and 13 inches by 16 inches right? That can't be right surely? That's MASSIVE!

 

[ScrubNinja]

Well damn I don't want to be responsible for someone quitting! Don't panic, we will work something out. Something always gets worked out.

First of all, yeah, 90f is kinda hot. That's the same sort of temps I'll be facing soon. On the other hand, I sort of get the impression you may be in the northern hemisphere, so wouldn't you be looking ahead to cooler weather soon? That's actually the best time imo - vegging plants can take more heat than in flowering, they even like it I think. Then by the time cool weather rolls around they're flowering. Anyways, if your ceiling is uninsulated now, it should help a lot to insulate. How about a mini AC? I think running co2 allows you to run much hotter temps so maybe that's an area to explore. Maybe shrink things down so there's less wattage.

We still don't know the wattage of the bulbs you're using so that is kind of important to get accurate advice! How many watts in the mom room and how many watts for the main cfl? The Noctua may be good for the light cooling. Two side by side would be better as you'd get double the potential CFMs. My standard recommendation to anyone really is to get a powerful fan, and undervolt it, so you can always turn the knob to eleven when you really need it. So that's my advice. Perhaps the Scythe Ultra Kaze 3000 with an adjustable voltage power supply? The Scythe outspecs the Thermaltake Smart Case Fan II that I'm familiar with, but I think the Thermaltake would be a great choice for your lighting section. It comes with speed dial so you can easily slow it down without an adjustable adaptor. You can get stronger fans but I think you'd be wasting your time as they really get loud. Something like an adjustable Scythe or the Thermaltake covers most bases for something like this imo. But by all means, the Noctua (or two) is worth a shot.

How is the noise insulation between you and your neighbours in the loft? Like, on a quiet day could you hear them if they were having a conversation up there and you were on the other side?

Yes, that is about the size of the Panasonic I believe, lol, 11-13/16'' means eleven inches and thirteen sixteenths of an inch. Three cheers for metric.

 

[Strangely]

How is the noise insulation between you and your neighbours in the loft? Like, on a quiet day could you hear them if they were having a conversation up there and you were on the other side?

100% yes. My Dad and I were up there dicking around putting a loft ladder up there or something once, and the guy next door, who was in his loft at the same time, reckoned he heard one of us fart!!

How many watts in the mom room and how many watts for the main cfl?

Sorry didn't notice the option on the wattage on that URL, I was just going to plump for the 125W envirolite in the flower room and the bear minimum to keep a small mum and maybe a clone or two ticking over in the mum room.

Maybe shrink things down so there's less wattage.

This is the nub of the matter isn't it really. Each design I've muddled up so far have been coming down in size each time, but maybe I need to start from the other end, the finish. Keep one eye on the ideals like 'Mum room' but essentially work backwards.

So if 'Whisper inside a quiet library = 30 decibels' and 'Normal conversation = 60-70' I'd say 50 decibels or so is probably my limit. One of your badboy Scythe numbers is about 45db so I should probably stick to just the one. So can one of those (rated at 133.6 cfm) pull through the smallest carbon filter here (http://www.growell.co.uk/p/0585/Carbon-Filters.html) stats are...

185 mm circumference, 240 mm length, matches fans 100mm (4”) RVK100 A1 (175m3/hour, flat sleeve size 200 mm x 325 mm

Assuming it can what space and/or wattage would that leave to work with grow room wise?

 

[ScrubNinja]

100% yes. My Dad and I were up there dicking around putting a loft ladder up there or something once, and the guy next door, who was in his loft at the same time, reckoned he heard one of us fart!!

Yeah that is pretty much the level I was picturing. Bugger.

Sorry didn't notice the option on the wattage on that URL, I was just going to plump for the 125W envirolite in the flower room and the bear minimum to keep a small mum and maybe a clone or two ticking over in the mum room.

Thanks bro. Let's say 150 watts total then.

This is the nub of the matter isn't it really. Each design I've muddled up so far have been coming down in size each time, but maybe I need to start from the other end, the finish. Keep one eye on the ideals like 'Mum room' but essentially work backwards.

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.

So if 'Whisper inside a quiet library = 30 decibels' and 'Normal conversation = 60-70' I'd say 50 decibels or so is probably my limit. One of your badboy Scythe numbers is about 45db so I should probably stick to just the one. So can one of those (rated at 133.6 cfm) pull through the smallest carbon filter here (http://www.growell.co.uk/p/0585/Carbon-Filters.html) stats are...

185 mm circumference, 240 mm length, matches fans 100mm (4”) RVK100 A1 (175m3/hour, flat sleeve size 200 mm x 325 mm

Assuming it can what space and/or wattage would that leave to work with grow room wise?

Well, first of all I want to say something - stealth is seriously not my specialty so I kinda want to say that there'd be better people to ask about all this. I'd love if anyone else would like to chime in with their thoughts.

Those decibel comparison charts can be a little misleading. I'd say 50db is way, way too loud. What I did was google all the random fans I had laying around and check their decibel rating and then plug them in and listen and compare. I gotta say, after doing that and ordering some new fans, they were pretty much exactly as loud as I was expecting. Plus they are an actual fan noise so it's a very good way to establish how loud things will be. Seriously, pull one out of a desktop and try.

So...I'm picturing that you would need a noise level about as loud as an average consumer desktop? Any more and the humming would be heard, I would think. (Can you simply say you have a wireless server computer up there? Cos then you could go nuts.) Anyways, if "average volume desktop computer" sounds about right, I would say you should be looking for something vaguely around the 35db level. In comparison, 50db would have the neighbours asking within a day or two what the constant noise is.

The Scythe could be made 35 easily via undervolting, you just have to remember you'll have a lot less pressure and cfm undervolted. I've never used the Scythe so I can't tell you exactly how far you would have to undervolt it. My thermaltake smart case fan II's are 46.5db at 12v, and I just switched them around with you in mind and I think with those, you may get away with them running at 7.5 or 9 volts volts. That's with no real noise insulation so with thick wood and noise insulation efforts, maybe it's not so bad afterall. 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?

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.

I'll save your last question until you verify my assumption about the "average consumer desktop" sound level because that will be the clincher. Cheers bro, and please, someone else chime in and give the guy a second opinion. I get scared when people listen to my advice!