convert 12v fan to USB

[jimmsch]

OK, so I want to build a little laptop cooler, but I don't want to buy alot of stuff to do it with. I have alot of 120mm fans lying around and , of course, more USB cables than I casn use. Is there a way to solder the fan leads to a USB cable so it will work when plugged into the USB port of the lappie?

Thanks -Jim

[JamesXP]

If the fan is fine runnin of 5V it's fine!


http://pinouts.ru/Slots/USB_pinout.shtml

[rapter_F22]

no its not, usb ports will fry if more than 5mA is drawn from them. most computer fans are 2W fans. some math 2W/5V=400mA. you need to run a fan that is significantly lower in power rating if you want to do that, and I don't think any 120mm fan will be low enough.

[bchur83]

No, USB will allow up to 500mA draw each. You should be fine. Worse comes to worse, most USB ports have an overload protection and will shut down.

[jivetrky]

no its not, usb ports will fry if more than 5mA is drawn from them. most computer fans are 2W fans. some math 2W/5V=400mA. you need to run a fan that is significantly lower in power rating if you want to do that, and I don't think any 120mm fan will be low enough.

Actually USB can do 500mA, not 5. It'll be fine with any normal 12v fan running at 5v (And by normal I mean anything that draws 6W or less, which is most normal fans) And even most fans that would draw more than 6W at 12v will not draw too much at 5v.

[JamesXP]

What he said^


What about that silly USB TEC cooler eh :P

[jimmsch]

Thanks guys, I did this and it worked beautifully. The problem that arose was the draining of the laptop battery. I wonder if I can make the fan work with a 9v battery or something like that?

Open to all suggestions.

[JamesXP]

Does it drain the laptop battery that much :o

[Ben333]

9v? not a problem other than it will need to be changed now and again... You should hook up a speed control for the fan...

[jimmsch]

Does it drain the laptop battery that much :o

Well...the battery only gets me 1.5 to 2 hours at 100% charge, and with the fan spinning it was at the lower end of that.

[thideras]

Well...the battery only gets me 1.5 to 2 hours at 100% charge, and with the fan spinning it was at the lower end of that.I wouldn't use the fan if you were on battery ;)

You can't be demanding much from the laptop when it isn't plugged in, unless your folding on the go or something. Also, if you aren't stressing it, you won't need the extra cooling. :beer:

[jimmsch]

I wonder what would be an acceptable temp for it? It has AMD Turion 64 X2 CPU.

I really only built this so my wife can just plop it on the bed and not smother the vents on the bottom. It will do what I need it to do, which is have some airflow underneath it, without a fan.

I still would like to know an acceptable temp for that CPU. I never had an AMD b4...or a mobile PC of any kind.

[JamesXP]

http://www.amdcompare.com/us-en/notebook/details.aspx?opn=TMDTL56HAX5CT

[aaa]

It should idle at less than 60c, load less than 80c.

How about simply putting something non-smothery underneath it, like a thin hard book or something.

And you might want to try undervolting with RMClock, it's an extra thing to do but it cools the laptop quite a bit.

[gangaskan]

i know this is silly, but have you looked into purchasing a aftermarket notebook cooler? Antec makes one that buy.com and the likes usually have a great deal on that has 2 blower style fans on it for around $0-9 after rebates (- 10 after GCO on buy.com) also, TT makes that X-oft pad or whatever it is that does a good job as well.

i have the antec cooler cause it was free after rebate and i love it, battery life isnt that demanding either.

[Skeith]

no its not, usb ports will fry if more than 5mA is drawn from them. most computer fans are 2W fans. some math 2W/5V=400mA. you need to run a fan that is significantly lower in power rating if you want to do that, and I don't think any 120mm fan will be low enough.

you mean .5Amps not 5mA, a usb mouse draws at least 15mA.

[Skeith]

It should idle at less than 60c, load less than 80c.

How about simply putting something non-smothery underneath it, like a thin hard book or something.

And you might want to try undervolting with RMClock, it's an extra thing to do but it cools the laptop quite a bit.

Ouch load at 80c thats insane. My laptop loads at about 65.

[asusradeon]

USB is only 5v

[JamesXP]

If the fan is fine runnin of 5V it's fine!