Dim lights on case fan...

EniGmA1981 · 16 Jan 2011 at 16:49

Could using a fan controller make my case fan get less voltage than it would recieve if it were plugged into a mobo header or directly into a molex?

I only ask as my front fan LED seem to be really dim - they get REALLY dim when I turn the fan controller down (as you would expect...) but I was wondering if maybe it could be getting less than it's full 12v

Any ideas? (really can't be bothered taking the side off and moving the wiring to check as the fan wire is pretty well hiddin in my "loom"(mess) lol

Thanks in advance...

w3bbo · 16 Jan 2011 at 17:19

By using a fan controller you are reducing the watts, which includes the LEDS so they will get a lot dimmer as they are not recieving the full wattage when they are turned down. If you are saying they are dimm with the fan controller on full then it's possible you are overloading the controller with too many fans/excessive watts.

f12f12 · 16 Jan 2011 at 17:27

just passing through a fan controller normal takes >0.5 V off its power.

EniGmA1981 · 16 Jan 2011 at 17:54

I've only got one fan per channel, 3 fans on an akasa fan control jr - the 3x230mm fans in my haf

Half a volt shouldn't have any effect should it?

Could it be a fault developing with the FC? I've had it a few years now...

G-Dubs · 16 Jan 2011 at 18:52

I know this might sound daft, but if the rig has been up a few years now, could it be a build up of dust that's making them look dim?

Spray some air in or have a go with the vaccy and see what happens.

EniGmA1981 · 16 Jan 2011 at 20:12

I cleaned it out before I put my tights over the fans the other day and there wasn't that much dust actually on the fan itself - it's no dimmer with the tights at least

May have to just plug it into a molex and see if it's any brighter or if it's just a dim fan...

I'll get back to you with that one

Tealc · 16 Jan 2011 at 20:37

Apparently some LEDs do dim over time, especially if they are over-volted.

It's more likely just the voltage drop though. In a LED fan each LED is wired to the incoming source voltage with a 400-500 ohm resistor in series. As the incoming voltage is dropped the amount of current available to the LED is dropped in proportion until a point is reached when it can no longer light.

If you wish fully bright LEDs you will need to disconnect the existing LEDs from the fan's power supply and internal resistors and power them directly.