Powering Peltiers

[Second_Impact]

I'm planning on building a crazy dual peltier cooled rig. My question is how do I power two 120watt peltiers(the ones at dangerden.com) so I get their full power. I was thinking dual 350 PSU's with one just for the peltiers and a couple 120 fans. However I don't know enough about eletronics to know exactly how PSU's work. This is the only problem I have ran into when designing my rig. Any help would be very much appreciated, or links that would teach me.

Second_Impact

 

[Christoph]

Welcome to the forums!!!!

I'm pretty close to questioning your sanity for using two pelts, but I won't. I reserve my sanity-questioning for 3+ pelts or any attempt at sustainable LN cooling. There's another current thread about the best way to power a pel, and there's lots of info here. Have you looked them over? It's always a good idea to check for previous threads about your subject before you start a new one.

 

[Darrenct]

Welcome to the forums!!!!

I second that motion.

Anyway, for anyone who's curious and is also too lazy to look up the other links, here gos. The 120 Watt pelts at Dangerden are rated for a max of 7.9 Amps. They usually run at about 75% of that. So about...*busts out calculator, then realizes how blazingly simple the problem is*... 6 Amps. So as long as your peltier PSU is rated for a little more than 12(6 X 2) amps, you will be fine.
Any good 350 Watt PSU(like Enermax) will be able to put out more than 12 amps on the 12 volt rail. It will say on the PSU specs.

 

[Wonko The Sane]

you may be able to find a power supply on e-bay for the pelts. I won mine from an e-bay auction and paid like 30 with shipping for it. it's rated for 12A at 15V (adjustable voltage).

 

[Second_Impact]

Ok thanks for all your help, I did try to read all threads pertaining to my topic but just wanted to be sure. A few more questions so hopefully I can figure all of this out myself in the future. First how come they only run at 75% of their max, second @dangerden it said I should drive 18v for a 24v pelt, which the 120watt is, so how many watts am I accually removing running it at [email protected] I would like to remove 200+ watts combined with both peltiers, should I move up to the 172watt or get a PSU with adjustable voltage, or something different altogether. One last thing does anyone know how much power the new XP's use?

Thanks
Second_Impact

 

[Darrenct]

The pelt only pulls 75% of the Amps because you are not running it at its maximum voltage. The pelts have a curve on how much cooling power compared to power consumption. That curve has an optimum performance at a voltage that is not it's max(i.e. 18v instead of 24v).

As far as powering 24 Volt pelts, You really aren't going to come close to decent results using a 12 Volt Computer PSU. You will have to get a seperate 24 volt PSU for them. If you get a couple of ~16 Volt(Optimal ar 12v) pelts instead, you could use a 350 Watt Computer PSU.

At the top of this article there is a formula to find out what your temps will be based on the size of peltier and watts put out by the processor.

The XP's don't use the 12 Volt Rail... They use the 3.3v or the 5v... Not sure which one. However, all your drives and fans use some power off of the 12 volt. It should say how much power they use on the fan/drive.