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How much power, amps, and voltage would a Panasonic plasma's USB port supply and would it run a computer fan? Answered

I would like to run two small computer tower fans off of the two USB ports on a Panasonic TCP50ST30 plasma TV. I am planning on recessing the tv into the wall so it is not visible from the side and I was going to use the two fans mounted in the wall directly behind the television to draw the heat the tv makes out of the cavity. Is this possible? Each fan uses 1.32 W at 0.11 A with a voltage range of 4- 13 VDC. If not is there any other cost efficient suggestions.


a usb port can (if specced properly) support 500mA at 5 volts, this is about 2.5 watts. It's common for usb ports to share this 500mA (if connected to a hub, etc).
I would be worried the TV is non-standard and does not support much power out from the TV.

12v fans run at 5 volts are generally unhappy fans; in my experience under 7 volts gets them near stall speed. They are dead silent, but barely move any air.

I would recommend getting a proper 12 volt fan and run it with a fan controller (there are a bajillion on ebay/dealextreme) that slows the fan with pulse width modulation. The controller should only cost a few dollars.

The only other hurdle is having it turn off when the tv is off. You could get a fan controller that allows having thermal control, where it doesn't power up the fan until the temperature in the cavity gets to a certain point.

I too would recommend getting a proper 12 volt fan.
But people just can't resist wanting to use USB ports if they've got 'em...


Agreed, just usb fans tend to be le poo.

Try googling Ohms law instead of wanting us to do the math for you. Don't be afraid to learn.