The ultimate beginner's guide to PC FANS

[disfunktional]

yup just looked into that. A1357 itsa 80mm. would that be suficient? or should i find another use for it and continue my search for the 100mm?

 

[ScrubNinja]

I would see how it goes, and tell us what you think of it. If it's too loud at the speed you need without blowing enough air, it'll help narrow down a lot what your limits are and then we can try again, cos like I say, I never dealt with hps and not certain of your overall plan. I don't think they make a 100mm SFII (92mm is a much more common size, but they still don't make a 92mm sf2 as far as I know). A bigger fan (in this case) is going to push more air at a lower volume.

 

[disfunktional]

hmm....il have to aquire some more experience before i jump into buying a pc fan for main exhaust fans. the more i read here the more i like your 4 fan set up with 2 side by side on each side of the scrubber. thanx to all three of you for the info and help.

 

[disfunktional]

hey Scrub youve gotten me adicted to these pc fans. iv been checking some out and i found this one. i was thinking of trying it my next build and figured that with the cfm and dBA rateings that it might be worth a try. see wutcha think.

 

[Norrath]

hey Scrub youve gotten me adicted to these pc fans. iv been checking some out and i found this one. i was thinking of trying it my next build and figured that with the cfm and dBA rateings that it might be worth a try. see wutcha think.

you can get those MUUUCH cheaper than 13US a pop mate. I paid 6.99ea(Canadian) at NCIX on sale. was one of their hot items down from 9.99.

it's a good fan for the price i paid, that's for sure, pretty darn quiet, (not as quiet as the noctua, but damn close, and for 4:1 for the noctua price)
also has decent bearings apparently so it can be fitted at any angle without recourse.

great bang for thebuck

 

[maryjohn]

.38 a is kinda wimpy. If it's gonna be wimpy it better be silent.

 

[oldone]

activated carbon volume?

activated carbon volume?

Hi Scrub,

I have been busy and my cab is 75% complete (as if they are ever done).

Got 6 beans sprouted and I'm on my way.

I'm trying to calculate how much carbon to buy for my ~374 sq in (2400 sq cm) flat filter. Can you help me out?

Thanks,
OO

 

[Norrath]

.38 a is kinda wimpy. If it's gonna be wimpy it better be silent.

it is both wimpy and silent

 

[ScrubNinja]

Oldone, hey dude good to hear. In mine I used 2kg activated carbon and that was... whatever I said...I think just under an inch thick. I forget the sq in, but I mentioned earlier so scroll back if needed. I get zero smell from a big ass plant in full flower.



Disfunktional, I thought you had a blower fan lined up for exhaust? Keep in mind I ditched the 4 fan setup as stacking directly on top of each other is not a good idea. I use this: (old pics so plug/timer setup is different now)



So, two exhaust fans total. The one at the rear, exposed the most, runs on hmmm I think it's 6v when the lights are on, and the internal fan below the carbon is adjustable - I turn it to 12v at lights on and back down to 4.5 or 6 at lights off. So since lights off is through the daytime when someone could show up, there is only one silent exhaust fan running inside.

All in all deciding on a fan for this purpose should be the simplest part of building your cab. I explain in the first post to pull your desktop apart temporarily and listen to/feel the fans. Google their model number and look up their specs. Run them inside your fridge one by one and compare. You will instantly have a very good idea of what you, as in specifically your cab and situation and ambient noise and desired level of stealth etc etc etc, will need. Far more accurate than asking me, imo. All these things are almost impossible to relay over a forum.

Once you decide on a decibel rating just get the one with the most cfm that's under your db limit. Don't let it be a holdup.

But I'll warn you in advance, 250w is a lot of bare bulb to cool. You should be looking at a cooltube or heat shield setup imo. How stealth do you want it? You seemed pretty keen to get a silent fan to blow on the bulbs but that's the quietest fan in the whole cab. If you were expecting a silent fridge, then I think you will be disappointed.

For the most part, there is no such thing as a good true stealth grow If you are limited by noise, you will be limited on how much wattage you can run. If you want the wattage, you have to take it up the arse in the stealth dept. Cooling takes noise. The only way around this apart from an AC or a loud covering device or something, is better design - A cooltube (for example) lets you cool the hps much more effectively and thus you will need less cooling power, commonly referred to as noise.

 

[maryjohn]

Well alright then. Good deal.

 

[ScrubNinja]

Haha maryjohn knows what's up with the amps! But yeah there's limits when it comes to stealth sadly. That's why I don't do it for the most part. But that looks like a great fan for the job. No speed control or thermostat but you probably won't need it. I have a similar specced fan:

Cooler Master Long Life Silent Fan

* 0.37 Amps (on sticker)
* 69.69 CFM
* 2.94 mm-h2o
* 19 dBA

It's quite decent, specs seem realistic, and cooler master seems to have a cheap price generally. But the thermaltake would be best methinks.

Edit: for anyone seeking a lot of air at low noise, check the 200mm+ fans, you'll be amazed. But none of the few I looked at would handle a carbon filter. But you get >100cfm at <20db, so good for blowing on bulbs and shit.

 

[maryjohn]

you don't need a loud covering device next to your cab. All you need is something in the room that will explain white noise.

In other words your cover device doesn't have to be in operation to fool someone casually strolling through the room. A space heater that does not work except for the led in front is perfect.

 

[maryjohn]

... double post, sorry.

 

[maryjohn]

triple post!

 

[Strangely]

Dunno why my lights are only on a 5amp fuse. There's others with more, one for shower and another two (35amp those ones I think) for sockets up stairs and downstairs. Is that a bit weak then? I still have a few old school bulbs to replace throughout the house so I was hoping that would help my goal of using the 5 amp lighting circuit for a mini grow.

 

[ScrubNinja]

lol

Strangely, I have no clue bro. Sounds like you're probably right. As mentioned though 5 amps is more than you need and shouldn't be a problem afaia.

 

[OBK]

Big thanks to scrub for starting this thread...got me excited about the idea of pc fans for ventilation and circulation.

Been playing with the Sentry LX controller (http://www.tweaktown.com/reviews/1512/nzxt_sentry_lx_fan_controller/index.html), which allows separate control of 5 fans. But really I just love staring at that screen..

This unit has an interesting auto mode, where the controller dynamically adjusts fan speed based on temperature (There are five temp probes with it). Unfortunately being calibrated for temps on Pc hardware and not grow application, the controller doesn't really kick in until after 90 deg F. I was able to make the controller more aggressive by putting all the temp probes in the cooling fins of the 400w hps ballast. This got the fans pumping!

And as a nice added bonus, when the lights kicked off at the end of the day cycle, the fans went into very low rpm spin. Very stealthy. It worked well hooked to a Delta AFB1212HHE and a ThermalTake 120mm SFII. Anyone else have any experience with this or other digital multi-fan controllers?

 

[ScrubNinja]

Hi OBK, you're welcome and that's awesome someone's using pc thermos! One thing though, they don't mention it on that review, but the Sentry is rated as 4w max per channel. That equates to 0.33 amps, so both your fans are over that. It'd be pretty messed up if your expensive controller blew out, you'd have no fans spinning, so I thought I should mention it. Peace.

 

[OBK]

Hi OBK, you're welcome and that's awesome someone's using pc thermos! One thing though, they don't mention it on that review, but the Sentry is rated as 4w max per channel. That equates to 0.33 amps, so both your fans are over that. It'd be pretty messed up if your expensive controller blew out, you'd have no fans spinning, so I thought I should mention it. Peace.

Ah, thanks for catching that , I'll find another use for the controller. It's especially good to know because today's mail brought me an AFB0912VH (67 cfm, 7.67 max pressure, $4.50 on ebay), which certainly would have killed the controller. I noticed the Delta didn't seem to spinning at full rpms, wonder if that was related.

*Scotty Voice* But Captain, she needs more pressure! Got to have more pressure!*

What's the best way to really bump up the air pressure? Stacking? Multiple fans inline along the exhaust path? From playing around with some of the Delta and some PC fans I'm getting the sense that pressure might be even more important than cfms. My goal is to make a Pc fan-based exhaust with enough juice to really scrub from a decent-sized filter. I can dream...

 

[maryjohn]

two 120 mm delta badass 3 amp fans side by side running 5v oughta do it. I will let you know soon.