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The ultimate beginner's guide to PC FANS

OBK

Member
Actually it's t-5's you gotta watch for with the fans... I got the answer:



That's very interesting about the controller. Mine does the varying speed thing a little but it's no big deal although it could be annoying to a stealther. There's no squeal at least. It's a good reason to go with an adjustable high amp supply, there's less points or chance of failure.

I forgot to answer you about PWM. I don't know much about it so I just avoid it. PWM fans are not so common and so there's not a good selection, plus I've heard of bad times trying to get it all working with various speed controllers etc.

Crap, you're right about the Military Switch Baybus :eek:: I don't read the fine print, sorry. Who on earth would pay that much money for that? I'll keep my eye open for heavy duty controllers that are suitable.

No worries, I missed the fine print too. It actually is a three-positiion switch--off, 5v, 12v...still kind of a novelty item and pricey! One thing I learned from trying out the Smart Fan2 is how cool the knob-based speed control is, because it allows tuning the speed perfectly for temperature AND vibration. There's a very sweet spot on the rpm dial where the exhaust fan's vibrations seem to melt into the other ambient sounds in the cab. I don't know if it's just me but I'm more sensitive to vibration than sound, so tuning speed for that (as well as using a rubber gasket in between the PC fan and the cab) works well here.

Can you fill me in a little more about the "dedicated power supplies"? I have a 1600mA AC/DC converter that has 4.5,6,9 and 12v (works well but not enough amps to put anything in parallel). Are you talking something like that? Or is a PC-power supply, or one of those adjustable power supplies for bench testing? Sorry guess I'm dense on what you meant.. :eggnog:

Edit: Hey also had a question about your ScrubScubber(tm) Scrubbing System, the one that blows a pc fan into a tray with another fan above the carbon to exhaust. I want to design something like that (maybe with two fans at the exhaust), but what I'm wondering is does the relative pressure of each fan matter? Does the fan that pushes through the carbon need to have higher pressure/higher cfm/work harder? Should the two fans be about equal? Does it even matter?
 
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ScrubNinja

Grow like nobody is watching
Veteran
There's a very sweet spot on the rpm dial where the exhaust fan's vibrations seem to melt into the other ambient sounds in the cab.

Hey bro, I couldn't agree more! People ask me which fan and I don't know! So I just say that one and it covers most situations. :)

Can you fill me in a little more about the "dedicated power supplies"?

Yeah I mean like this which is 3 amps:



Maryjohn has some more sophisticated lab power supplies I believe. In my opinion these in general are the best things to use if you got the cash. They're rated for continuous use, they're just better quality and feel safer and reliabler, and are high-ish amps and adjustable, and have air vent slots. They're regulated and overload protected which is a good thing and most wall warts probably aren't. (less equipment damage/fire risk). Some PSUs are overoad protected but not all. You can wire in a simple resistor yourself if you want this feature (and you do) if your PSU doesn't have it.

Now, because mine is 3 amps, I was recently planning to use one single Delta to replace the two SFII's in my cupboard. So I was thinking the 2.7amp delta would be great. That gives me some overhead and it's all good. But at the same time am I ever going to run it on 12v? I doubt it. 6v is much more likely. So basically, if it's 3 amps at 12v, it's like it's supplying 6 amps at 6v (simplified). In reality, your fans are using half the wattage/amps...the power supply isn't actually supplying more. It can all be calculated with those volts/watts/amps formulas I gave if you're dealing with a different voltage like 7.5.

MJ's power supplies have a lot more amps than mine if I remember right, too. Mine cost approx $70 US locally without hunting for a bargain.

The PC PSU is also a great option. Look at all the voltages it gives out!

picture.php


Ok so in reality it's no more than the stupid bay bus thing, but, by using different wiring combinations of the + and - voltages, you can achieve a lot of other voltages to your fans, only it's not easily switchable....unless you build a switch unit for it. See here to see what I mean.

The voltages that can be output by this unit are 24v (+12, -12), 17v (+5, -12), 12v (+12, 0), 10v (+5, -5), 7v (+12, +5), 5v (+5, 0)

You could also utilize wiring in series to get even more possibilities, although I'm sure you're aware of the risks of series wiring.

Does the fan that pushes through the carbon need to have higher pressure/higher cfm/work harder? Should the two fans be about equal? Does it even matter?

Haha, oh man, I hate questions like these :hide: I really don't know! I've been so half-arsed with my grow, I can't say A is better than B, only gut feelings. The setup I'm using now has a 12v SFII internally, blowing into the carbon at 12v. The external pulling SFII runs on something less, I forget but I think it's 6 or 7.5 volts. Basically I have a metric shit tonne of various wallwarts, so I balanced the sound so the external one is about as loud as the internal 12v one. Smart huh? It does feel though like the external one is kind of not pulling it's weight or helping much, but it seems to work well enough. I get approx 2 or 3 degrees over ambient, dpending if I crack the doors a little (the intakes are getting restrictive, probably filled with dust and shit by now). I think the best would be to not use a SFII undervolted as the external fan, but to use a low decibel, high cfm fan there instead. I should try that.

Hope that helps and if I can help with anything else, lemme know :yes:
 

maryjohn

Active member
Veteran
My power supply is also very bulky and heavy, don't forget. there's always a tradeoff.

It's 5 amps max, not enough to get the delta's up to full speed, but almost enough to make the cab start flying. I posted a link in this thread somewhere for an american version of what scrub has. I think they are in the 30$ range, and I could have gone with two of those.

I have a reading for volts and amps with rough and fine adjustment for both. As I lower the volts, the amps automatically go down quite a bit. As far as the amps control, it isn't all that handy, since my two delta's can eat up over 6 amps. I always leave it cranked to max.

It was close to 100$.
 
i guess im stupid because i cant figure it out...
my power supply only has 4pin molex connecters coming out of it..and the 20 of course..
my fans have 2 wires...what do i hook it up to?
 

ScrubNinja

Grow like nobody is watching
Veteran
Yup that's right or this diagram shows:

picture.php


And as stated by Topic, you will need to "hotwire" your psu with a bit of wire or paperclip. Link to instructions in first post if you need more info.

If that doesn't make sense, what colour are the wires on your fan.
 

OBK

Member
Hey bro, I couldn't agree more! People ask me which fan and I don't know! So I just say that one and it covers most situations. :)



Yeah I mean like this which is 3 amps:



Maryjohn has some more sophisticated lab power supplies I believe. In my opinion these in general are the best things to use if you got the cash. They're rated for continuous use, they're just better quality and feel safer and reliabler, and are high-ish amps and adjustable, and have air vent slots. They're regulated and overload protected which is a good thing and most wall warts probably aren't. (less equipment damage/fire risk). Some PSUs are overoad protected but not all. You can wire in a simple resistor yourself if you want this feature (and you do) if your PSU doesn't have it.

Now, because mine is 3 amps, I was recently planning to use one single Delta to replace the two SFII's in my cupboard. So I was thinking the 2.7amp delta would be great. That gives me some overhead and it's all good. But at the same time am I ever going to run it on 12v? I doubt it. 6v is much more likely. So basically, if it's 3 amps at 12v, it's like it's supplying 6 amps at 6v (simplified). In reality, your fans are using half the wattage/amps...the power supply isn't actually supplying more. It can all be calculated with those volts/watts/amps formulas I gave if you're dealing with a different voltage like 7.5.

MJ's power supplies have a lot more amps than mine if I remember right, too. Mine cost approx $70 US locally without hunting for a bargain.

The PC PSU is also a great option. Look at all the voltages it gives out!

picture.php


Ok so in reality it's no more than the stupid bay bus thing, but, by using different wiring combinations of the + and - voltages, you can achieve a lot of other voltages to your fans, only it's not easily switchable....unless you build a switch unit for it. See here to see what I mean.



You could also utilize wiring in series to get even more possibilities, although I'm sure you're aware of the risks of series wiring.



Haha, oh man, I hate questions like these :hide: I really don't know! I've been so half-arsed with my grow, I can't say A is better than B, only gut feelings. The setup I'm using now has a 12v SFII internally, blowing into the carbon at 12v. The external pulling SFII runs on something less, I forget but I think it's 6 or 7.5 volts. Basically I have a metric shit tonne of various wallwarts, so I balanced the sound so the external one is about as loud as the internal 12v one. Smart huh? It does feel though like the external one is kind of not pulling it's weight or helping much, but it seems to work well enough. I get approx 2 or 3 degrees over ambient, dpending if I crack the doors a little (the intakes are getting restrictive, probably filled with dust and shit by now). I think the best would be to not use a SFII undervolted as the external fan, but to use a low decibel, high cfm fan there instead. I should try that.

Hope that helps and if I can help with anything else, lemme know :yes:

:thanks: Hey scrub thanks for the info it does help. I went by my local electronics discount superstore and looked at some power supplies, I think they called them bench power supplies. Definitely like the look of them, most most were only 1A boo hoo. They did have a 3 amp for about $100US. It looks beefy enough, but then all the fans runing off of it have to run the same voltage? If there are two or three deltas running off the same supply how does one dial each fan in individually for speed, or is 6v the standard for undervolt?

PC PSU is a cool idea, didn't know all those voltage combinations and there's one sitting right on the desk over there. :cool: I see some fun experiments coming... :stocking::respect:
 

ScrubNinja

Grow like nobody is watching
Veteran
Hey bro cool :yes: Yeah the downfall is that they will all be at the same voltage. If they were thermaltakes you could use the dial to adjust further. All I could think of is to research rheostats and have the deltas on seperate dials but it would be tricky/complicated.

So yeah, the PSU is looking like the best bet to me. It would still be logistically tricky though, but I'm too high to really comprehend how it would work. The fan controller would be best if there's a reliable one available...there must be?

Edit: Sunbeam rheobus extreme? 30w per channel.

You can also get these things. I've seen one before that had a very weak max wattage, but that page says "Control any of your 4-Pin molex driven devices manually with the Manual 12V Variable Speed Controller." so maybe it's worth looking into.

Hopefully the final edit: I wanted to say, don't forget that a fan is an electrical device like any other. When a large growroom does the calculations for heat etc, they often include the wattages of every single device down to the air pumps and anything else. All electrical devices put off heat. So remember that more fans is no real substitute for better design. Some of these fans we talk about are more wattage than a CFL, so they're contributing to the heat as well as helping. :)

Edit to the power of edit squared: There is this too but it's kind of expensive.
 
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ScrubNinja

Grow like nobody is watching
Veteran
Sah-weet. Yeah it seems like a good option! Lol @ v1 not being put together straight - it seems like most/all fan controllers have an element of shonkiness to them. My Vantec came with CCFL lights and I plugged them in and I could wave my hand around the unit and affect the lights without touching anything.
picture.php


I suspect since I use it with no PC case, that I should earth the fan control to the PSU? Anyone clued up on that? Well, let us know what you think of it, OBK, cheers.
 

ScrubNinja

Grow like nobody is watching
Veteran
Nice, yeah I don't think you can go wrong following red's ideas. I've got a lot of love for the blue led thermaltakes, they were my intro into better than usual fans. :) One blows the main air circulation in my current cab. Good luck with your tests.
 
actually my fan has 3 wires on it...they arent really colored though

the 2 outside ones are silver with black stripes and trhe center one is just silver wire

its a big antec fan that was plugged straight into my motherboard

any ideas>?
 

topic

Member
third cable is for checking RPM...

U can check all configurations on cables... nothing wrong will not happen...
 

ScrubNinja

Grow like nobody is watching
Veteran
Does it have the plug on it? Just compare it to the diagram I posted (the small 3-pin one on the left). Otherwise yeah, just brush the wires together in different combinations, it only takes a minute.

:smokeit:.
 

BC Chronic

Paging Dr.Greenthumb
Veteran
Hey Scrub..+I was wondering if you could help me find a fan speed controller..mine blew, lucklily I was close..I just need a couple of names of good speed controllers..Now my Delta is running the way its supposed to.. 161 watts and temps are 76-77 all the time..ambient heat in the room its in is 73 so not bad...I can't find ANY good fans with speed controllers on them either..
Thanks Scrub if you can help..Merry Christmas..
 

ScrubNinja

Grow like nobody is watching
Veteran
Hi BC well I'll help you on your journey with a tip - you have to help others to help you. What is the wattage or amperage of your fan? Thermaltakes are the only common ones I've noticed with a speed control dial included, although some fans have other methods, but it's rare.

Merry xmas :santa1:
 

BC Chronic

Paging Dr.Greenthumb
Veteran
Thanks Scrub..Point taken but I don't have much to offer in the help department ..I am learning from all of you..Its a Delta 1.6 amp fan..I feel bad now asking....
Thanks Scrub
 

ScrubNinja

Grow like nobody is watching
Veteran
That's ok BC :petting: Well, you have 19.2 watts so you need to find a speed control that handles 20w per channel or more. The case-mod style speed controls we've just discussed for delta's are probably not much use since you need a PSU to power them, or do some tricky wiring. I'm not dead certain, but I'm pretty sure this would work just great. Otherwise I would seek out an adjustable power supply like the black one I posted above, or an adjustable wall wart style if you can find one. If you will ever want to run the fan at 12v, you will need a 1.6 amp or greater supply. If you don't need 12v, you won't need as many amps on the power supply, but I think you want 12v right? Hope it helps.
 

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