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Power source for 120mm fan

M

manny1222

Gawd
Joined
Mar 11, 2012
Messages
732
Hi all
I modded my Logitech G25 a while ago by adding a 120mm fan (gentle typhoon ap-15 I think) to cool the electric motors. I snaked the cable plus an extension into my pc, connected to my fan controller. How it has looked unsitely and I've always wondered if I could connect it a different way.

Can I connect the fan to a usb port? If so, how? What wire should go were?

I have a powered usb splitter to connect several peripherals I use for racing and it would be perfect if I could connect to this without issue. This is the splitter I have
New 7 Port High Speed USB 2.0 HUB with AC Power Adapter for PC Laptop Durable
It says it provides 400mA at 5v. Is this sufficient without affecting the other peripherals I have connected? I don't mind that is just 5v as it would be quiet and I just need some air movement inside the wheel.
Thanks
 
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That should work, cut up a spare USB cable and see if that 5v gets the fan spinning. Presuming the USB cable has color coded wiring, red is power and black is ground.

Here is the pin out for a normal fan header:
Darkside Connect Pinout
(Second post)
 
These fans normally run off 12 volts, so I have my doubts they'll spin up at all at 5 volts supplied by USB.

See here where the spin-up voltage was just above 5v (42%of 12v = 5.05v).


iUoDrpG.png


That's pretty close, but even if you get lucky and get a better sample, you'll still be moving 1/3 the air it normally does. And if you're right on the hairy edge as far as activation voltage goes, you're going to have to get paranoid about checking the fan is running every time you boot up :D

What you really need is this:
Amazon.com: DROK®Micro LED DC-DC Digital Boost Voltage Converter LM2577 3-34V to 4-35V 5V/12V 2.5A Step-up Adjustable Volt Regulator Board Module Power Supply Transformer for Solar Panels Car Battery Charging: Electronics

Just hook up the usb power to the inputs, and adjust the potentiometer until the output voltage reads 12. That's all you have to do!
 
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defaultluser said:
These fans normally run off 12 volts, so I have my doubts they'll spin up at all at 5 volts supplied by USB.

See here where the spin-up voltage was just above 5v (42%of 12v = 5.05v).


iUoDrpG.png


That's pretty close, but even if you get lucky and get a better sample, you'll still be moving 1/3 the air it normally does. And if you're right on the hairy edge as far as activation voltage goes, you're going to have to get paranoid about checking the fan is running every time you boot up :D
Click to expand...

The AP-15 has max rpm of 1850 not 876 (AP-12). They make several versions of this fan based on rpm. If you look down at the bottom of the link I posted, you'll see the AP-15 has a start up voltage of 3.5v. I should be good. I haven't had time to test it yet because of work.
So if 12v gives 1850 rpm, 5v will give about 770 rpm which is almost the max for the version of the fan that you posted a picture of.
 
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I needed to cool a closed cabinet in my desk to help with heat on my old GTX 470 (aka space heater) build back in the day. Cut two 3" holes in the desk and used that to power two 120mm fans. Worked like a charm.
 
That looks great but I'll try the usb route first, especially if I don't have to spend anything extra. I'm sure I've got plenty of disposable usb cables.
I would be more inclined to consider it if it was like a controller where I could adjust the voltage through that range, instead of just a choice between the two voltages (5v or 12v).
If the usb doesn't work, I'll look into it
 
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Skillz said:
Well if you wanna use USB just so it will power on/off with the PC then use a USB to Molex connector. They're like $6.

Amazon.com: Computer PC Fan 12V 4 Pin to 5V USB 2.0 Adaptor Connector Cable: Computers & Accessories

Sure you gotta spend money, but it will be a much cleaner look. In my experience those USB cables are rarely color coded. You'll have to get a pin out diagram and use a multimeter to track down the correct wire to splice into.
Click to expand...

Most fans have fan headers and not Molex connectors.
 
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When you say that you modified the wheel, did you do this by hacking the fan into the housing somehow?

If that's the case, I'd disassemble the housing again, and probe the power connector to see if you can get 7-12 volts from there. If so, connect the fan to power inside the housing, so your wiring is entirely internal to the unit, vs. having a separate cable that has to go somewhere.
 
RazorWind said:
When you say that you modified the wheel, did you do this by hacking the fan into the housing somehow?

If that's the case, I'd disassemble the housing again, and probe the power connector to see if you can get 7-12 volts from there. If so, connect the fan to power inside the housing, so your wiring is entirely internal to the unit, vs. having a separate cable that has to go somewhere.
Click to expand...

Yes. I cut into the housing, installed fan with screws and glued it to the case. But that was two years ago and I didn't investigate connecting to the internals at that time because I didn't want to somehow screw something up to where the wheel didn't work anymore. Also having it connected to my pc fan controller meant I could make sure the fan wasn't loud. I'm not sure what the voltage inside the wheel would be

Not that I can readily afford another wheel right now, but I guess I can give it a try.
 
manny1222 said:
Yes. I cut into the housing, installed fan with screws and glued it to the case. But that was two years ago and I didn't investigate connecting to the internals at that time because I didn't want to somehow screw something up to where the wheel didn't work anymore. Also having it connected to my pc fan controller meant I could make sure the fan wasn't loud. I'm not sure what the voltage inside the wheel would be

Not that I can readily afford another wheel right now, but I guess I can give it a try.
Click to expand...

The adapter that Skillz posted that just supplies 12V is probably your safest bet. The G25's power brick provides 24V, so you'd need to either ghetto rig a resistor in series with the fan's wiring, or use an elaborate converter that may or may not fit.

Serious question: Is overheating of the wheel really a common enough problem to justify hacking a fan into it?
 
Well not everyone feels that way. But I'll say I was noticing decreased force feedback strength after racing for long periods of time. I've had my G25 since 2005 and Ivery had this mod for almost two years (maybe less). I started to notice the issue with force feedback after joining iracing and doing endurance races where I was racing 2, 3, 4, hours at a time instead short 3, 4 lap races on need for speed, Dirt3 and other arcade type racing games I was using in the past.

Has it helped? I believe it has. I have no scientific way to prove but I think it has. I don't know if it's common (like every one has this problem) but I didn't consider it a difficult or risky mod since it was all a body mod and there is no messing with functional internals of the wheel
 
Found a usb cable I wasn't using anymore, cut it and rigged it into the plug for the fan. I connected it to usb port and got exactly what I was looking for. The fan is spinning at a low speed and is barely audible with my pc and everything else off. I have it all taped up but I did order the "usb to fan header" cable.
 
defaultluser said:
Didn't realize they made those. Good find :D
Click to expand...
I've made a few of these from old laptop or printer power bricks as long as they converted to 12 Volts or 19 volts. If it was 19 Volts I just added a small circuit to convert the 19 to 12 volts.

Really easy way to make a good multi fan external supply.
 
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