How many case fans can one fan header drive/monitor?

I see 3-pin and 4-pin fan splitter cables advertised, but how many fans
can a single drive header power and monitor without problems?

The motherboard in this case is an Asus F1A75-V Pro -- if the specific
board makes a difference.

Perce

Percival P. Cassidy wrote:
I see 3-pin and 4-pin fan splitter cables advertised, but how many fans
can a single drive header power and monitor without problems?

The motherboard in this case is an Asus F1A75-V Pro -- if the specific
board makes a difference.

Perce

Your manual contains no guidance on the subject.

On my motherboard, it says:

1) No more than 1.000 ampere from a single fan header.
This would be a pin limit, for the tiny pins on the header.

2) No more than 3.48 amps, from all four fan headers.
That is a limit defined by the dimensions of the copper
track distributing the +12V.

The second line varies from one motherboard to another.
It can be as low as 2.x amps on some motherboards. So
if I had four fan headers, and I had to "guess", I'd limit
myself to four 0.5 amp fans. Or two 1.0 amps fans.

If you wish to power fans from a Molex 1x4, a Molex is probably
good for 8 amps. It depends (slightly) on the wire gauge in
the cable. The main connector (24 pin Molex) is 6 amps per pin,
due to so many pins being adjacent. The 4 pin Molex is a bit
better, at 8 to 10 amps, and we'll assume 8 amps.

If you wish to power a fan off SATA, the 3x5 wafer power connector
of SATA, is good for around 1 ampere per wafer contact. The three pins
for +12V then, would have a 3 ampere limit. And this is much
worse than when using a Molex for power distribution. Still,
3 amperes will run a few fans, if you want. SATA power is a poor
choice, for "daisy chained" cabling.

I have one fan that draws an ampere, and I run that off a Molex
rather than a fan header. Most other fans I've got, don't
really challenge the above limits.

Paul

On 08/21/13 09:15 pm, Paul wrote:
Percival P. Cassidy wrote:
I see 3-pin and 4-pin fan splitter cables advertised, but how many
fans can a single drive header power and monitor without problems?

The motherboard in this case is an Asus F1A75-V Pro -- if the specific
board makes a difference.

Perce

Your manual contains no guidance on the subject.

On my motherboard, it says:

1) No more than 1.000 ampere from a single fan header.
This would be a pin limit, for the tiny pins on the header.

2) No more than 3.48 amps, from all four fan headers.
That is a limit defined by the dimensions of the copper
track distributing the +12V.

The second line varies from one motherboard to another.
It can be as low as 2.x amps on some motherboards. So
if I had four fan headers, and I had to "guess", I'd limit
myself to four 0.5 amp fans. Or two 1.0 amps fans.

If you wish to power fans from a Molex 1x4, a Molex is probably
good for 8 amps. It depends (slightly) on the wire gauge in
the cable. The main connector (24 pin Molex) is 6 amps per pin,
due to so many pins being adjacent. The 4 pin Molex is a bit
better, at 8 to 10 amps, and we'll assume 8 amps.

If you wish to power a fan off SATA, the 3x5 wafer power connector
of SATA, is good for around 1 ampere per wafer contact. The three pins
for +12V then, would have a 3 ampere limit. And this is much
worse than when using a Molex for power distribution. Still,
3 amperes will run a few fans, if you want. SATA power is a poor
choice, for "daisy chained" cabling.

I have one fan that draws an ampere, and I run that off a Molex
rather than a fan header. Most other fans I've got, don't
really challenge the above limits.

Thanks for the reply.

I meant "fan connector," of course, not "drive header."

The manual says that the CPU Fan connector can supply 2A, but I found
nothing about current ratings for the Power Fan and Chassis Fan connectors.

Maybe I'll just stick with one fan per on-board connector and use "taps"
into the drive power cables for the others.

Perce

Percival P. Cassidy wrote:
On 08/21/13 09:15 pm, Paul wrote:
Percival P. Cassidy wrote:
I see 3-pin and 4-pin fan splitter cables advertised, but how many
fans can a single drive header power and monitor without problems?

The motherboard in this case is an Asus F1A75-V Pro -- if the specific
board makes a difference.

Perce

Your manual contains no guidance on the subject.

On my motherboard, it says:

1) No more than 1.000 ampere from a single fan header.
This would be a pin limit, for the tiny pins on the header.

2) No more than 3.48 amps, from all four fan headers.
That is a limit defined by the dimensions of the copper
track distributing the +12V.

The second line varies from one motherboard to another.
It can be as low as 2.x amps on some motherboards. So
if I had four fan headers, and I had to "guess", I'd limit
myself to four 0.5 amp fans. Or two 1.0 amps fans.

If you wish to power fans from a Molex 1x4, a Molex is probably
good for 8 amps. It depends (slightly) on the wire gauge in
the cable. The main connector (24 pin Molex) is 6 amps per pin,
due to so many pins being adjacent. The 4 pin Molex is a bit
better, at 8 to 10 amps, and we'll assume 8 amps.

If you wish to power a fan off SATA, the 3x5 wafer power connector
of SATA, is good for around 1 ampere per wafer contact. The three pins
for +12V then, would have a 3 ampere limit. And this is much
worse than when using a Molex for power distribution. Still,
3 amperes will run a few fans, if you want. SATA power is a poor
choice, for "daisy chained" cabling.

I have one fan that draws an ampere, and I run that off a Molex
rather than a fan header. Most other fans I've got, don't
really challenge the above limits.

Thanks for the reply.

I meant "fan connector," of course, not "drive header."

The manual says that the CPU Fan connector can supply 2A, but I found
nothing about current ratings for the Power Fan and Chassis Fan connectors.

Maybe I'll just stick with one fan per on-board connector and use "taps"
into the drive power cables for the others.

Perce

There are no fuses in the fan power path.

If you overdo it, the track burns out. And there
are some people who have suffered that fate. Hasn't
happened to me yet, but not for lack of trying.

At the very least, when playing around, don't plug
in fans with the power on. In case you have an "off by one"
event, or some other calamity like bending some pins until
they touch one another.

I've even had a computer crash, just by attempting to plug
in a fan "hot". So... don't do that :-)

And if you have questions about a fan setup, by all means use
the Molex solution. Fat wires, for the win...

Paul