Using a PC PSU to run 12v ?

[AnthonyB]

This may seem a stupid question (and it probably is), but would a 240v PC PSU be suitable to run the various 12v circuits in a caravan ? One of my spares will support around 12A at 12V output. I know I'd probably have to put a load resistor on to get it to power up (some PC PSU's won't power up unless there is a load on them). I'm looking to run 2 fluorescent lights, and 1 water pump off it. As it's a switching power supply it should give a steady output even if the mains voltage fluctuates.

Good or bad idea ??

 

[rob_jax]

Hi,

Not sure either way.

One the one hand it's free, on the other PC power supplies are designed for a non-condensing environment (and a caravan on an Autumnal morning is anything but), they are designed to be used inside another earthed case (which you may be able circumvent if located sensibly), and the PSU fan will run all the time.

But all new caravan power supplies use switch mode internals - so nothing intrinsically wrong.

I'll take your word that your PSU will supply 12A at 12V - or is this the sum of the negative and positive supplies?

If your target PSU came from the newer ATX or a later series PSU then you need to ground pin 14 (PSU_ON) to a convenient earth (pin 15) otherwise the PSU won't even power up.

And you may still need to fit a loading resistor.

We use old computer PSU to drive test or experimental rigs (these are taken from very old working computers that can't run Windows or Linux)

Robert