Wiring computer fans to take DC current...

[kyle1284]

I am going to be puting a couple of holes in my canopy to install 4 120mm computer fans. i figured out how to wire up one fan to a 12V source. is there anyway to wire up 2 fans to one 12V source and still have the same fan speed as a single fan being hooked up to that 12V source? if not is there a certian way to do so?

thanks in advance

 

[Bluewater04]

not really sure what you are asking. but to wire up two just do it in parallel.

 

[fragmatic]

If you wire two 12VDC fans in series using a 12VDC power supply they will each run at "sort of" half speed. If you wire them both in parallel they will both run at full speed. This is IF the power supply can handle them.

This is because if you wire them in series you have divided the 12 volts between them, and each will run on 6 volts.

For those tagging along, don't try this with AC.

 

[Greg@LionfishLair]

I agree with Bluewater. If you have a 12V power supply, wire them in parallel. This way, each fan will see 12V, however the current will be divided between the two fans, so if your fans are rated at 12V, 100 mA (just tossing numbers out there for reference), and your power supply is 700 mA, you could conceivably run seven fans off that power supply if you wire them in parallel.

However, if you wire them in series, the fans will each drop half the voltage, but will see the same amount of current (in this case 700 mA). In this configuration, the fans will each run at half speed.

HTH

 

[Greg@LionfishLair]

I know what I said was mentioned already, but I was just explaining it a bit to help you understand.

 

[kyle1284]

If you wire two 12VDC fans in series using a 12VDC power supply they will each run at "sort of" half speed. If you wire them both in parallel they will both run at full speed. This is IF the power supply can handle them.

This is because if you wire them in series you have divided the 12 volts between them, and each will run on 6 volts.

For those tagging along, don't try this with AC.

what do you mean by "if the power supply can handle them"? thanks for the reply BTW

 

[steveb]

if the required current of each fan is say 700ma you will need a power supply that can provide at least 1400ma.

 

[kyle1284]

i learned something new today! thanks!!

If you wire two 12VDC fans in series using a 12VDC power supply they will each run at "sort of" half speed. If you wire them both in parallel they will both run at full speed. This is IF the power supply can handle them.

This is because if you wire them in series you have divided the 12 volts between them, and each will run on 6 volts.

For those tagging along, don't try this with AC.

 

[kyle1284]

makes even more sense!! thanks!

I agree with Bluewater. If you have a 12V power supply, wire them in parallel. This way, each fan will see 12V, however the current will be divided between the two fans, so if your fans are rated at 12V, 100 mA (just tossing numbers out there for reference), and your power supply is 700 mA, you could conceivably run seven fans off that power supply if you wire them in parallel.

However, if you wire them in series, the fans will each drop half the voltage, but will see the same amount of current (in this case 700 mA). In this configuration, the fans will each run at half speed.

HTH

 

[kyle1284]

I agree with Bluewater. If you have a 12V power supply, wire them in parallel. This way, each fan will see 12V, however the current will be divided between the two fans, so if your fans are rated at 12V, 100 mA (just tossing numbers out there for reference), and your power supply is 700 mA, you could conceivably run seven fans off that power supply if you wire them in parallel.

However, if you wire them in series, the fans will each drop half the voltage, but will see the same amount of current (in this case 700 mA). In this configuration, the fans will each run at half speed.

HTH

i am starting to understand how electricity works and is calculated but i have another question after reading your post... would it be a issue if, in your example, you only ran 2 100mA fans on a 700mA power supply in parallel? would it over drive them?

 

[Decalf]

No it will be fine. The loads draw what they need. Everything should be fine as long as your not suppling to little amps or not the right voltage.

 

[icedearth15324]

You could buy something like this:

SilenX IXA-FCEX Controller, Panel - Newegg.com

It's an external fan controller. Plugs into DC, and can control up to 4 fans. No wiring required.