Hey guys, as some of you may know I got a new computer (laptop) still haven't updated my specs. So anyway, with my old laptop I had a cooling stand, but now with the old one, I'm trying to make one, everything works great! all but for the actual power going into the fan, it's just not enough. It's the normal 5 volts going into the 12 volt fan, (old computer fan) So this is what I'm wondering, the port that I'm using on my laptop has a lightning bolt next to the usb symbol, that means the port can go up to 12 volts right? I just looked it up. And now I'm just trying to figure out how to make the port go into 12 volt mode. Thanks in advance.
Then what's this? (second answer) http://www.pcadvisor.co.uk/forums/1/tech-helproom/4134577/usb-port-with-lightning-bolt/
No USB port goes into 12v. None of them, well except some US army gear which uses a USB connector but *IS NOT* USB, literally they reuse the plugs for something else (think its RS485 actually). The lightning symbol means 1 of 2 things (or both). Port is powered when the device is shut down. So you can charge your phone without PC being on. Port has a higher current limit than standard (which is 500mA for USB 2.0 and 1200 for 3.0). @Technicolor And its not a "5v current" or a "12v current", current and voltage are 2 seperate properties.... If you want to run a 12v fan from 5v, you are going to need to attach a 12v boost converter to the 5v of the USB. However it should be noted that DC switch mode power supplies, much like transformers in AC power supplies, will convert volts to current and vice versa, to increase voltage on output requires more input current. In DC electronics, current is drawn not pushed. So to cover the previous point mathematically. If we have a 12v fan and it draws 150mA, we are going to pull 150mA from the output of our boost converter (which is set to output 12v). Power must be conserved. 12*0.15 is 1.8 watts of power on the output. We must therefore have 1.8 watts on the input (assuming 100% efficiency, in reality you are lucky at about 70% from a cheap boost converter so I'd say 3W is a safer bet, many advertise higher than 70% efficiency, always assume wrong). 1.8 watts at 5v is 1.8/5 or 0.36A, or for my revised estimate of 3W required on input side: 0.6A (above USB2.0, within spec of 3.0, should be doable on your funky high power port). Something like this should do: http://www.ebay.co.uk/itm/XL6009-DC...676?pt=LH_DefaultDomain_3&hash=item5d5502d9a4 You would need a multimeter available for setting the output voltage (adjustable with the little screw on that module). Then in theory, anything between 3v and the output voltage will be stepped up to the output voltage. Plus you'll need a soldering iron to attach it to a USB cable and the fan. - - - Updated - - - That did of course assume the fan ran at 150mA, the back of the box for my AF120 performance edition fan here says 0.33A. 12*0.33 = 3.96W. Guesstimate that to a 6W input required. thats actually 1.2A required from the USB port. If you have a 12v source available and a multimeter/ammeter, you can confirm the current draw of your fan. Just be aware that if the fan is rubbing against something, that causes the motor to draw more current, at stall they can draw over 10 times as much as they do at no load. So avoid stalls perhaps
