Powering some 12v fans

[Inwardjim]

What would you guys recommend to power multiple 12v computer fans? I was planing on just using a computer power supply, but the fans don't seem to go as fast as when they are connected to a 12v cellphone charger. I want to know the safest method more importantly.

 

[svchop889]

well get a 12v charger that has enough amps to power multiple fans the 12v pc fan I have is .30A so if I wanted to power 2 i would need to wire the fans in a parallel circuit connected to a charger with an output of 12v and .30A that would be the easiest way. you could wire them in series but you would need a 24v power source with .6A good luck finding that...

 

[dingbang]

svchop889 absolutely correct, make sure you wire them parallel.

there are a few DIY threads about this if you need a visual also...try the search function.

also, your power supply output can be more amps than your fan is rated for but no less. the less amps that are drawn off of the power supply, the cooler it runs, which is key to my small closet grow. so for example one of my fans is a 12V 800mA axial fan powered by a 12V 1250mA power supply that contributes almost no heat to cramped area where it's stored.

 

[svchop889]

svchop889 absolutely correct, make sure you wire them parallel.

there are a few DIY threads about this if you need a visual also...try the search function.

also, your power supply output can be more amps than your fan is rated for but no less. the less amps that are drawn off of the power supply, the cooler it runs, which is key to my small closet grow. so for example one of my fans is a 12V 800mA axial fan powered by a 12V 1250mA power supply that contributes almost no heat to cramped area where it's stored.

yes basically the amps on the power supply is the maximum the unit wil be able to supply I am glad you added this i forgot to mention it. parallel is basically this with the multiple fans you want all of the + wires from the fans connected and all of the - wires connected.then the + wires from all the fans connected to the positive of the supply and the negative to the negative.

 

[Nocturn3]

I was planing on just using a computer power supply, but the fans don't seem to go as fast as when they are connected to a 12v cellphone charger.

You are aware that the 12 volt wire on a computer psu is the yellow one, not the red one, right? I remember being confused by this myself when I encountered the same issue with fans being slower on a PSU.

 

[svchop889]

huh mine must be really old they only have a red and a black but that is good to know nocturn the new ones look like they have two speeds.

 

[Nocturn3]

Many of my fans themselves only have a red and black wire. When connected to a 12 volt DC adapter (charger etc.) they will spin fast.

However, when connected to the red/black side of a computer PSU, they will only spin at half speed, since the red wire on the PSU connector is +5 volts. But, if you connect them to the yellow/black side of the PSU, you will get your full 12 volts.

This is only an issue if you are using a computer PSU.

EDIT: Like this:-

 

[Inwardjim]

Thanks for the replies.

 

[Inwardjim]

I hooked the red up to the yellow and it works great. Thanks

 

[Kalibre]

Works great for me! I also added/spliced a few extra feet of wire to the 4 pin connector so i could keep my PSU (500W) outside the box.

 

[CLOSETGROWTH]

Many of my fans themselves only have a red and black wire. When connected to a 12 volt DC adapter (charger etc.) they will spin fast.

However, when connected to the red/black side of a computer PSU, they will only spin at half speed, since the red wire on the PSU connector is +5 volts. But, if you connect them to the yellow/black side of the PSU, you will get your full 12 volts.

This is only an issue if you are using a computer PSU.

EDIT: Like this:-

Great post Brother..very detailed kudos!