Q about fans on MOLEX. And y splitters.

[Theocnoob]

~How many fans can I run off of 1 Molex output? I mean the entire Molex chain itself (Modular molex cable with 4ish Molex connectors on it)

I imagine at a certain point they are no longer all receiving 12V?

~Also if I use a fan connector Y splitter will each fan receive 12V or only 6V? Thank you.
I want all fans receiving 12V. TY for the help.

 

[ssjwizard]

The connectors are linked in parallel. In a parallel configuration V is constant and the resistance is recursively reduced. In short they all receive whatever voltage the rail can support at the given load.

Series wiring would result in additive resistance where the voltage is dropped 1/n per resistor. Dont really concern yourself with this unless your planning to do some creative wiring of fans yourself.

Hope this helps.

edit, dont quote me on this as it will vary by PSU and depending on the guage wire used, but a single 12v line should be capable of delivering ~100w within the insulation rating.

 

[Bobnova]

Tons. A molex is rated for 11 amps.
Split away!

Splitting won't drop the voltage unless you start exceeding what the cables can carry, at which point they'll get warm/hot/melt/burn.
I wouldn't daisy chain too many splitters together if the splitters use thin wire, as long as all of them use the same gauge wire as your PSU does for the molex in the first place, they'd fine.

11 amps is enough for >22 normal fans. For the sort of Fans the benching team uses it's more like 2, but those aren't anything you want to hear on a daily basis.

 

[johan851]

Splitting won't drop the voltage unless you start exceeding what the cables can carry, at which point they'll get warm/hot/melt/burn.

Yup. You'd need to have a lot of amperage over some very long wire runs before that would happen.

 

[Theocnoob]

So say running 6 fans off 1 molex line is no problem? Just Daisy chain the molexes together?

 

[Theocnoob]

Series wiring would result in additive resistance where the voltage is dropped 1/n per resistor. Dont really concern yourself with this unless your planning to do some creative wiring of fans yourself.

So 6 fans daiychained each on their own molex connector would run 12 11 10 9 8 7v? (six molexes daisychained to 1 motherboard molex connector? ie, mobo molex, addon, addon, addon, addon....)

My most powerful fans are .5amp each

 

[Automata]

So say running 6 fans off 1 molex line is no problem? Just Daisy chain the molexes together?

As stated, as long as you aren't exceeding the wiring/rail capacity of the power supply cable, you are fine. If you are running 3 amp Delta fans, you will probably have an issue running 6 of them.

So 6 fans daiychained each on their own molex connector would run 12 11 10 9 8 7v?

My most powerful fans are .5amp each

No, they are all the same voltage when wired in parallel.

 

[Theocnoob]

TY Thid

 

[Diggrr]

BTW, don't daisy chain all those fans off of a motherboard header. Last I looked they were only rated for about an amp. They're talking about using a power supply molex, just to be clear.
I'd only ever plug a single <1Amp fan into a single motherboard fan header.

 

[Theocnoob]

BTW, don't daisy chain all those fans off of a motherboard header. Last I looked they were only rated for about an amp. They're talking about using a power supply molex, just to be clear.
I'd only ever plug a single <1Amp fan into a single motherboard fan header.

Yup did it all up on the PSU molex all fans are working 100%. Thanks for the quick replies and reassurance folks.



For future reference since nobody answered- a Y splitter with 3 fan connectors. Do all fans still get 12V? There is no resistor in it. ??