Powering Peltiers someone please help...

[a5]

I have an Abit Vp6 and I will be using 2, 80W peltiers on my two p3 850s. Here is the specs for one peltier:

Potted Peltier rated @ 80W 8A 14.4V. Comes with Molex Connector ready to use on any power supply with a rating of 12V and 8A or more. PLEASE NOTE: IF THIS DEVICE IS USED WITH A POWER SUPPLY RATED UNDER 8A, FAILURE OR DAMAGE MAY OCCUR WITH THE POWER SUPPLY AND OR OTHER COMPONENETS! !! POTTED=EDGES SEALED WITH EPOXY FOR MOISTURE PROTECTION

My question is whether or not there is a Switching Power Supply on the market that will provide the ideal load for two of these Peltiers. I just dont understand the power requirements in terms of Watts,Volts, or Amps. It says it's a 14.4Volt. Does this mean I can't go over 14.4v or do I want more? Same goes for the Wattage and the Amps, although it does state that I need over 8. But I need to know; How much over 8amps?

To top this off I will need to power two Peltiers and I'm not sure If I have to double the specs for a Switching Power Supply or not. So if someone could tell me(and the forum) how to choose a power supply based on the specs of the Pelt, then in the future no matter what TEC we get we can determine what it needs to run at optimal load.

For example: Do I find a Switching Power Supply that is 20% over the total wattage of the pelt? While also being 20% more amps than required? While also providing 20% more voltage?(my use of 20% is completely arbitrary since I have no clue as to what the power supply needs to be.)

I have heard everyone say that you should'nt power pelts on the same psu as everything else. What if you have a 550W psu? Does that not put out enough amps? Is that the problem?

I know a lot of people have this same question because I see it all over the board. To the person that can answer these many questions....my deepest gratitude.

[Tim-]

The rating you quoted means that the pelt will pull 8 amps at 14.4 volts. On a computer power supply at 12V it's going to pull proportionately less. I would use a commercial power supply that is independent of the computer, but that is just my taste. If you figure it will pull 15% less at 12v it will still be around 7 amps for each pelt. That's 168 watts for both, and a pretty heavy load on the 12v supply.

A 15-20 amp commercial supply can probably be had surplus for about the cost of a computer supply ($50-75) and on the plus side most could be adjusted up towards 14.4v to get the most cooling from the pelts.

[a5]

Of course It's Tim.
I almost titled my subject " Powering Peltiers...Help me Tim" but I did'nt want to abuse your help. This just makes me laugh.. Do you read all the posts or do you search for my name to help me? No matter.

So basically from what you said, I should look for a power supply that will provide 15-20 amps and be adjustable over 12volts. Is there a limit as to how many amps or volts I use? And most importantly will that work for two pelts?

[LimeyGreg]

a5 - consider the voltage as the force that is pushing the current. The higher the voltage the more current you can push, it is linked to the resistance of the device your are trying to push the current through. The higher the resistance the harder you have to push to make the required current go through. Power is the product of the voltage and the current (ie 12v @ 10amps = 120 watts).

Your peltiers require 8a @ 14.4v = 115.2 watts to work best. You state that the peltier is an 80 watt device, but as you can see it needs 115 watts to work properly - that's because it is only approx 70% efficient. If you try to power it with a supply that does less than 8 amps @ 14.4 volts then you will experience a drop in output voltage and a drop in the peltiers cooling ability - not to mention overheating the power supply.

For the two devices you should be looking for at least a 250 watt supply (with cooling fan), preferably 300~350 watts to give yourself some headroom (you can power a few fans with it and maybe your pump if your going water cooled). Make sure it is variable to say 18v and will supply 20 amps to attain maximum efficiency from your peltiers, that way you can "overclock" them a little if you want to :)

Hope that clears up some of your questions.

[a5]

Thank you both very much. Now I will be searching for this power supply and more importantly I know WHY I need it. I did a little digging through my old Physics class work and I found the equation: Power=(voltage)(current). So I was really stumped when 14.4volts * 8amps did not equal 80W. I had no idea it was only 70% efficient.

anyway, thanks again.

IF ANYONE CAN SUGGEST A PLACE TO SHOP FOR THIS PSU PLEASE SEND A LINK. THANKS...........