Question Led fans

[Wickedwesty]

Hi, I bought some Blue led fans for. A budget pc build. Is there a way of connecting them straight to the motherboard and having the leds coming on without giving them the full 12v.. The leds only seem to come on if I set the fans to full speed

 

[Grobe]

It depends on how they're connected and what type of connector used on the fans.

 

[Wickedwesty]

It depends on how they're connected and what type of connector used on the fans.

There 3 pin connectors and ive connect them straight to the motherboard. They do have molex connectors but will that put them on full blast

 

[RememberThe5th]

Can you link the exact model of fans which you bought?

I guess you have those "Chinese" fans with led. Yes they are connected in parallel with 12V rail and ground of fan soldered connector, as you set the fan speed , thats how the voltage changes and leds get brigther or dimmer.

 

[Wickedwesty]

They're some cheap uphere ones on amazon
https://www.amazon.co.uk/upHere-Airflow-Computer-Cooling-W12CM3-3/dp/B07F15GFH1
I take it I either have to have them at 12v full speed to get the leds of or not have the leds

 

[Paperdoc]

Yes, these are LED fans, not the same as RGB fans. In an LED fan, the LED lights are simply connected in parallel with the voltage supplied to the fan motor, so they get whatever the motor gets. They do not need the full 12 VDC to light up, though, so most of the time if your fans are connected to a mobo header and it reduces the fan motor voltage to reduce its speed, the LED's will still light up. BUT at some lower voltage they will get dimmer, and may even seem to turn off if the fan voltage is quite low. There is no way to change that performance.

IF what you see is that sometimes the fans is going so slow that your LED's are too dim, you might try this. In BIOS Setup where you configure the fan headers you are using, you may be able to set a custom "Fan Curve". A Fan Curve is a "graph" of what speed the fan should run at various system temperatures, and the default automatic system has a pre-set curve it uses. Some BIOS's allow you to change to using a custom curve you set yourself. Then you could set that to be similar to the pres-set curve, but never go below a certain minimum speed for the fan. This would prevent the fan voltage from going too low, and thus prevent your LED's from getting too dim.