Question How much power does a USB 3.0 port on a laptop provide

Mar 22, 2019
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I have a crazy project. I'm trying to hook up a 12v aquarium pump and three 12v 40mm fans for the radiator to a laptop. They pull around 31.56 watts.
 
May 4, 2019
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The only USB standard that can supply 12+ volts is USB C, and that will require the peer (in this case the 12 volt devices) would need to be usb C capable for power delivery. Even if the laptop provides a type C port, it does not have to supply more than the 5v default at 900 ma. Some will supply 1.5 amps, and a few will supply 3.0 amps, but likely still at 5 volts.

Why are you trying to power this from a USB port? What is the actual problem you are trying to solve? Some 12v HDD external supplies will supply 12 at 3 amps. Cheap and readily available.