Why does my PSU squeak when I hook up my peltiers?

[nicspits]

I just got a powerwin 450w that is rated at 20amps on the 12v line. One of my peltiers is rated to draw 6 or so amps at that voltage but, when I plug it in the power supply starts to make a high pitched squeaking noise and it starts to get more and more high pitched. Is this overloading the PSU or what?

I also have an antec 400w rated at 12a on the 12v, does the same thing.

I have a codegen 350w rated at 12a too and it doesn't do that. What is up?:confused:

[nicspits]

I took off the top plate of the PSU and I think it was coming from (forgive me I don't know the tech names) the big piece in between the two heatsinks which wasn't a capacitor but it was white, had 2 round sides and a piece in the middle that was raised and also had a piece of yellow tape across the middle short ways, I might be able to take a picture tonight and post it up.

Somebody please help, I don't want to blow either of these power supplies
:( I need them and i need my peltiers powered.

-Nic

[Lt. Max]

powering a peltier off of a psu is generally not safe.. im getting a dedicated non pc psu for my friend 226w pelt..

[nicspits]

it does this when I'm only plugging in 1 silverprop 80w peltier, 15v 8.5 amp. at 12 v that should use only like 6 amps... no answer.

[tensop]

Silverprop Peltiers are in the US already?
anyhow the PSU shouldent be doing it, its obvious it has bull**** specs. Take it back... :)

Make sure red on the TEC goes to yellow(12) and black to black.

[nicspits]

Well I actually got my whole peltier setup from a guy in Australia off of ebay so no, they're not, but in my case they are. :D
I'm just going to go - online and get a powmax 500w, sound good to everyone? it's rated at 22a on its 12v, what do ya think?

[donny_paycheck]

That squeaking is the filter capacitors on the output rail charging and discharging rapidly because the output is being taxed.

Switching power supplies (read ATX PSUs) need to have at the minimum, a 20% load on their primary output to function properly. For these, the +5v rail is the primary output. You can get by with less than a 20% load, but you do need to load it somewhat.

Get some 10 ohm wirewound resistors from Radio Shack. These are the kind that are inside a block of sand/ceramic. Put two of these in parallel on the 5 volt rail. They will load it with 1 amp, which should be enough to stabilize the output and stop that sqeuaking you're hearing. Make sure the resistors are placed in such a way that them being hot won't cause problems. They'll get pretty toasty, close enough to almost be able to burn you. Epoxying them with thermal epoxy to the case is a good way to do it.