Reptile & Amphibian Forums

Today I picked up 2 small [3"] computer fans. I plan on having one blowing air into the tank, and one blowing out. Obviously not for this season, but next summer as i have lost a mantella due to heat problems. I just dont want to wait 8 months to ask.

Anyway, enough of my life story.

1) Which side should i place them for best results? Both blowing in? Blowing out? One blowing in, and out? (I sound like Dr. Seusse)

2) How would i install one into the sockets without killing myself? The fans have a red/black (p/n) but i need to somehow use in a electric socket.

3) The fans only have a 12V capacity. How would i lower the voltage from the sockets? Transistors? Tansformers?

Im going to use a timer in 5 minute intervals.

Fan specs (if that helps):

DC brushless fan
DC 12V 0.14A

Thanks for the help,

M.N

I would have one blow in on one side of the tank, and one blow out on the other. The side that has the fan blowing in will probably have lower humidity than the other side. You also could try having them both blow it. I would just experiment to see what works best. As for wiring, you will need to buy a 12v AC adapter to be able to plug them into the wall. You may even have one sitting around that you can use. They are those cube shaped plugs that come with various pieces of electronic equipment. I think you should be able to use the same AC adapter to power both fans. Then just hook them up. to = and – to –

Somebody correct me if I am wrong, I’m no Electrical Engineer. (I’m a Mechanical Engineering student )
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0.0.5 Blue Dendrobates Auratus
3.2.1 African Dwarf Frogs (Hymenochirus boettgeri)
2.2.0 Asian Floating Frogs (Occidozyga Lima)
1.1.0 White's Tree Frog (Litoria caerulea)

Damn...i have found an adaptor, but it has the output of 24. Is that a problem? Also, it has the 'pin hole' end. How would i connect that? Strip the wire?

Also, heres a quick drawing to help clear it up..

community.webshots.com/scripts/editPhotos.fcgi?action=showMyPhoto&albumID=95578156&photoID=99422950&security=fuxgoh

I think 24 volts will eventually burn up the fan. To connect it I would just strip the wires of the adaptor and solder the fan wires to the adaptor wires.
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0.0.5 Blue Dendrobates Auratus
3.2.1 African Dwarf Frogs (Hymenochirus boettgeri)
2.2.0 Asian Floating Frogs (Occidozyga Lima)
1.1.0 White's Tree Frog (Litoria caerulea)

I cant view the drawing because I don’t have a account at webshots.

One other thing...you could use the circular plug to hook up the fans if you buy a female plug that will fit the plug on the adaptor. These should be available at Radio-Shack. The male/female plug arrangement will allow you to disconnect the fans if you need to.
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0.0.5 Blue Dendrobates Auratus
3.2.1 African Dwarf Frogs (Hymenochirus boettgeri)
2.2.0 Asian Floating Frogs (Occidozyga Lima)
1.1.0 White's Tree Frog (Litoria caerulea)

Thanks, i have found a 12V adapter. I tried it out right now, and it seems to work great.

M.N

Also, will the fans/electrical wiring ever cause a hazard, or break down from the high humidity? Should i use electrical tape?

M.N

When I wired my fan I soldered the wire connections, then used electrical tape to insulate the connection. I don’t think that the humidity will harm the wire.
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0.0.5 Blue Dendrobates Auratus
3.2.1 African Dwarf Frogs (Hymenochirus boettgeri)
2.2.0 Asian Floating Frogs (Occidozyga Lima)
1.1.0 White's Tree Frog (Litoria caerulea)

AT power supplies are the old style, where the power button on the computer case was connected directly to the power supply, so most of them had long cords with switches on them or a connector to go to a cable hanging off the front of the computer. These days ATX power supplies are used, where the power supply connects to the motherboard, which is then connected to the switch. I have several AT power supplies lying around. Wouldn't it be easier to just use a power supply rather than messing around with soldering wires and AC adaptors? Would this work?

I don’t see why that would not work, in fact I think I remember people using a computer power supply in their fan set-up. The only disadvantage is the size of the power supply.
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0.0.5 Blue Dendrobates Auratus
3.2.1 African Dwarf Frogs (Hymenochirus boettgeri)
2.2.0 Asian Floating Frogs (Occidozyga Lima)
1.1.0 White's Tree Frog (Litoria caerulea)

It should work but I wouldn't use more that 2 or 3 hundred fans on one powersupply.

joe
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3.0.1 Tinc Patricias
0.0.2836 Pea Aphids
0.0.4392 Springtails
0.0.1842 FruitFlies
0.1.30 Dampwood Termites

A power supply is overkill and would run more fans than you would ever need. One other thing to rememeber is to use a low MA rated universal power supply. The higher MA ones will burn out the fans.
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Kyle
www.kylesphotos.com
Dart Links - still a work in progress
1.2.0 D. leucomelas
1.1.0 D. azureus
1.0.1 D. imitators

another thing to think about is that running even a very small fan at full speed will dry out your tank too much.
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Kyle
www.kylesphotos.com
Dart Links - still a work in progress
1.2.0 D. leucomelas
1.1.0 D. azureus
1.0.1 D. imitators

>>another thing to think about is that running even a very small fan at full speed will dry out your tank too much.
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>>Kyle
>>www.kylesphotos.com
>>Dart Links - still a work in progress
>>1.2.0 D. leucomelas
>>1.1.0 D. azureus
>>1.0.1 D. imitators

Yes, but I can put the power supply on a timer and not run it all the time. Plus I have some on hand, and I think it's safer than jury rigging something by soldering fans and AC adaptors. While I know computers inside and out, I really am clueless about wiring.

I believe the side being soldered (2 plcs.) is on the DC side, so safe isn't that much of an issue. A little electric tape, or what I sometimes like to use is hot melt glue to keep from shorting out and protection from the elements. Very simple really and it can be put on a time also.

Actually Kyle, the higher current rating is OK, The fan will only use as much current as listed on the fan. What you need to watch is the voltage rating. If the voltage is too high it could damage the fan depending on the fan design.

joe
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3.0.1 Tinc Patricias
0.0.2836 Pea Aphids
0.0.4392 Springtails
0.0.1842 FruitFlies
0.1.30 Dampwood Termites

Yeah, I was thinking about that also. I was thinking that if anything dropping the voltage to slow the fan down.

I have used CPU fans for this for years. The wiring is very simple. If you are only using a few fans, you might consider a plug in transformer. Get one of the universal power supplies, clip the end off and hard wire the positive and ground. If you really want to get funky you can use one of the universal ones with the voltage selector (its just a switch). The max will be 12 volts... thats what they are designed to run at, but if you go lower the fan will go slower. This is how you can control fan speed.

My self, I use an old AT power supply because it was free as I have been working with computers for years. This is a reliable method to use because the fans have been designed to work with these power supplies. Hundreds of fans on one? No. Off a 300 watt AT I can only run about 15 fans, and each one slows all the others down just a little bit.

Ben

15 fans? slowing down? You should check to see what the max current rating is on the 12V side of your power supply. Sounds like your power supply is geared more towards producing current on the 5V rail. Since most fans only draw 2 watts or less this would mean that your 12V rail is having trouble producing 30watts. That's pretty bad or a pretty old power supply. You are connecting these in parrallel not series?

My old At power supply is capable of 96watts on the 12V rail, that's about 45 fans. Of course you may just have really big fans. I'm referencing the everage 40mmX40mm for these numbers.

Also, you can buy 5V fans and run them off of the 5V rail which wont effect the load of the 12V rail. Then you can get your full 150 fans.

Joe
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3.0.1 Tinc Patricias
0.0.2836 Pea Aphids
0.0.4392 Springtails
0.0.1842 FruitFlies
0.1.30 Dampwood Termites

I am using 80mm case fans... the power supply is older, but this is just how it works out. Now I am not saying you could not put more on, but if you did they would all be going so slow it wouldnt be worth it. I use them mainly to cool lights. When you get about 5 on a power bus you can notice the slow down.

Ben

Try this site out.
http://www.fanbus.com/faq/fanfaq.htm

Bgreen

Thanks for the link, helped alot...

M.N