How can I cool my laptop?

July 9, 2009 3:55 PM

How can I get a 12v fan to run off of a USB port? Alternately, how can I make my laptop not overheat and die?

Hello, Metafilter,

I've got a laptop that's really prone to overheating; if you do anything intense for longer than ~20m, it heats up to about 100C and shuts down. I picked up a USB-based cooler that's basically a piece of aluminum with two weak fans screwed into the back; it helps a bit, but not very much.

What I wanted to do was to find a way to replace the cooler's fans with more powerful ones; I have an old and quite dead PC lying about that I've scavenged the CPU fan from, and thought that might do the trick. Tragically, though, the USB port doesn't have enough power to start the fan.

Do any of you know how or what I could do to get this fan to work? Alternately, are there other (cheap/free) ways to cool a laptop?

posted by Chionophilia to computers & internet (10 comments total)

Laptops shouldn't do that. Have you blown out the inside? It may be clogged up with dust, and itself have no room to push the air internally.
posted by tybeet at 4:00 PM on July 9

Also, I don't know what the specs of your laptop are, but harddrives produce a mass amount of heat. You can reduce the usage of your HD by turning off the paging file in the OS, and turning off Windows Search service and the indexer both of these things heavily and consistently use your HD, so this would cool things down a bit.
posted by tybeet at 4:03 PM on July 9

Alternately, are there other (cheap/free) ways to cool a laptop?


I have a laptop prone to overheating, and it has helped very much to sit it on two stacks of about four cd cases, leaving an air channel underneath the laptop. Bang-for-buck the best cooling strategy I've found.

Alternatively, I have also used notebook hardware control to underclock a particularly hot/crap machine, which returned it to stability at the cost of about half the clock cycles.
posted by pompomtom at 4:05 PM on July 9

You do not want to try to send 12v down the usb cable.

http://www.hardwarebook.info/Universal_Serial_Bus_%28USB%29

USB is 5V...
posted by iamabot at 4:19 PM on July 9

Buy a laptop cooling pad. I literally had things melting inside my old Gateway laptop (3 times to the shop to be repaired under warranty) until I bought one... then I never had a problem again. They run off USB.
posted by IndigoRain at 4:19 PM on July 9

The way 90% of laptops are designed, the CPU is at the back of the machine with the heat sink sitting on top of it and a fan (generally on the bottom of the device) either sucking or blowing air over the surface of the heat sink. These sinks get clogged up with some regularity, depending on the environment, and so does the filter on the fan. If you're comfortable with it, get yourself a screwdriver, a tin of compressed air and an old toothbrush (and some thermal paste). Remove the fan and the heat sink and give them a thorough blowing/scrubbing (don't let any dust fall onto the surface of the now-exposed CPU, however), put a smidgin of thermal paste on the CPU, put everything back together, and give it another try.
posted by turgid dahlia at 4:28 PM on July 9

Dust is the main issue here. If you really really want the fan, here's a tutorial video on how to make one. I strongly recommend that you heed the advice on addressing the problem with the dust, though. What sort of laptop do you have? If it's a Dell, you can try the i8k fan control to keep the fans at maximum revs.
posted by spiderskull at 8:53 PM on July 9

You could try a voltage regulator, but I'm pretty damn sure you can't power a fan on the amperage USB and USB cables are designed for.
posted by pwnguin at 9:03 PM on July 9

Nice answers! Thanks, everyone. The laptop is a four-year-old MSI (MS-1036) notebook; I've already cleaned out the dust, but the internal CPU fan is weak (it's had overheating issues since I picked it up.) I was hoping there was some sane way of stepping up the voltage fom 5v to 12v, but googling turned up nothing and I thought I'd ask the hive mind.
posted by Chionophilia at 9:16 PM on July 9

Why 12 volts? USB is 5 volts and there is almost a limitless supply of fans that can run at 5v. (And minimal amps.)
posted by Ookseer at 11:32 PM on July 9