OLD ATX 5V Output to heat bed

I have a old P4 ATX power supply can I use its 5V output to power heatbed. I have to print PLA. At my place room temperature is about 30 ºC. I have to increase 20 ºC only. Is there any idea to make 5V heater.
My ATX is 300 Watt.
Its Specifications are

+5V -- 30A
+12V -- 12A
+3.3V -- 14A

Edited 1 time(s). Last edit at 06/03/2017 01:00AM by himanshu.

the resistance of the bed is fixed and its this that determines how much current it will pull.

standard pcd heated bed are 1.1 ohm so at 5v it will draw 4.545amps.

Thats 22.72watts vs the 130 on 12v

so whats that in temperature? that’s beyond my math skills..

but my guess would be it would take several hours to get to 50c

Edited 2 time(s). Last edit at 06/03/2017 03:14AM by Dust.

You'd need a purpose designed 5v heater to really get the most out of it, and it does seem a shame to have this rail with no real application. But heaters work best at higher voltages where currents are then lower. A 5v heater which could give you 120w would need to be drawing 24 amps! It would have a resistance of just 0.2ohms, which isn't far off a full short circuit. You'd need some big cables.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions