Running 3x 0.33A fans off single motherboard header

Control: management of fans, temp/rpm monitoring via soft/hardware

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee

Post Reply
kiwijunglist
Posts: 10
Joined: Mon Jul 13, 2009 2:18 am
Location: Chch, NZ

Running 3x 0.33A fans off single motherboard header

Post by kiwijunglist » Sat Oct 13, 2012 11:19 pm

Hi

I just build a new HTPC

Silverstone Grandia GD07 HTPC Case
3x Silverstone 120mm / 1,200 rpm / 12 V / 0.33A 3 pin fans (Honghua HA1225L 12SA-Z)
GA-Z68XP-UD4 Motherboard / Intel I3-2100 w. stock cooler

The motherboard has 4 fan headers, but only the CPU header + the SYS2 header have fan speed control, the others run at a constant 12 volts.

Using the 12V headers the case fans run ~ 1300rpm and are too noisy.
SPCR Fan Noise Results for same fan in TJ-04E Case 7V 12-16dB, 9V 15-20dB, 12V 23-25dB
If I use the variable speed header the fan is sufficiently quiet for me in the range of 550-950 rpm

Would it be safe to run the 3 fans off the single SYS2 header using a 3 way split cable?

I'd prefer to run all 3 fans off the SYS2 header so I can set a quiet slow speed in speedfan and have them only increase if the case gets too hot.
The other alternative is to use a Molex -> 7Volt adapter for 2 fans with the 3rd running on the SYS2 header or a speed controller for 2 with the 3rd one SYS2.
However I'd prefer to have the HTPC automatically control all the fans.

The 3 way splitter cable is the tidiest option and the cheapest at only $2.95 incl P&P
ImageImage

edh
Posts: 1621
Joined: Mon Mar 17, 2008 1:49 pm
Location: UK

Re: Running 3x 0.33A fans off single motherboard header

Post by edh » Sun Oct 14, 2012 3:22 am

Some motherboards have the maximum current/wattage for the headers listed in the manual so I would take a look there. Bearing in mind that you are using fairly low speed fans, the 0.33A is fairly high for the speed. For reference I just looked up a really high CFM Delta fan which uses 1.42A and it is listed as 'not suitable for connection to typical motherboard'.

Post Reply