motherboard fan current?

[Tiwaz]

How much current does a motherboard fan connector have? I definitely know that they got 12V, but how many mA do they have?

[Electronics Wizardy]

Normally about 1A, most fans use about .1 to .2 amps.

[mariushm]

They're usually rated for maximum 2A , or 1A for cheaper / budget motherboards.

 

Physically, the connector contacts for the molex KK series (which is the connector for fans) are rated for 4A but the circuit traces and the wire thickness make it so you shouldn't connect devices that use in average more than 1A.  Look at the ratings of the fan, you should see  the current (in A) or the power on the label ( power in watts / 12v = current in A) and try not to exceed 1A per connector. Keep in mind that for a few seconds as the fan starts spinning and reaching the desired speed, the fan will actually draw more current than its advertised value, sometimes as much as 2-3x times the value.

Circuit boards  designed to tolerate that much over a few seconds but why push it? That's why I suggest not going over 1A in total per connector (so there would be about 1A reserve for such situations)

 

PS. Some higher end motherboards have fans labeled water pump or PWR_FAN

The PWR_FAN headers are usually headers meant to be used with bigger 140mm-180mm fans that are usually mounted on the top of a case, which may use more current than normal fans. In general they're beefier, let's say they're rated for 2A when the others are rated for 1A on a budget board

 

The water pump headers usually have thicker traces and can handle 2A or more 24/7, with the idea being that they may be used to power the actual pump in a water cooling system and not a fan.

 

[Tiwaz]

7 minutes ago, Electronics Wizardy said:

Normally about 1A, most fans use about .1 to .2 amps.

nice so i can hook up two aio pumps to one connector with a splitter since they use 12V and 325mA, at least the nzxt AIO ones. BTW. there is a reason why i need them on the CPU_FAN header both if i get a 2nd AIO for GPU cooling

 

3 minutes ago, mariushm said:

-snip-

 

[done12many2]

22 minutes ago, mariushm said:

They're usually rated for maximum 2A , or 1A for cheaper / budget motherboards.

 

For clarification, most high end boards rate their fan headers at 1 amp and pump headers up to 3 amps.  1 amp on a fan header doesn't really fall into the "cheaper / budget" motherboard category.