Peltier /w Dual PSUs?

I was wondering if it's possible to hook up 2x 13-14amp 12v ATX PSUs to power a single 12v 25amp peltier?

Or would it cause a short of some kind?

Thanks

I dont think it would short but computer PSUs dont reall like being run at theri max on the 12v rail. At the very least you will need to put a load on the 5v rail.

ls7corvete said:

I dont think it would short but computer PSUs dont reall like being run at theri max on the 12v rail. At the very least you will need to put a load on the 5v rail.

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no short, but lets look at the economics.

2x $35 PSUs=$70
no chance at putting those in your case with your main PSU
wouldn't it be worth it to find a suitable supply on eBay?
not to mention the 5v rail needs to be loaded

I think a suitable PSU would cost more than that, cuz the swiftech pelt requires 25amps @ 12v... Very hard to find.

I have 2 spare PSUs lying around so I guess i'll try running them 'n see how long before they last before frying, lol

greenman100 said:

no short, but lets look at the economics.

2x $35 PSUs=$70
no chance at putting those in your case with your main PSU
wouldn't it be worth it to find a suitable supply on eBay?
not to mention the 5v rail needs to be loaded

Click to expand...

Also remember that the TECs run at 15v not 12v, your cutting yourself short running at 12.

somethings to consider, you can run them in series to double the voltage need ie 2tecs =30v 4tecs=60v etc....

greenman: have you done this before? How did you go about loading the 5v rail?

He is not cutting himself short at 12v - he is getting an advantage. Running at 12v instead of 15v makes the peltier create far less heat, but retain almost all of its cooling power... So 12v is actually much better!

I was reading up on this sort of thing, and shopping around for an appropriate dedicated PSU for my peltiered GPU setup recently. Although 25 Amps @ 12V seems like a lot, it's not particularly hefty as far as dedicated PSUs seem to go, and you should be able to find one eBay easily for a very good price. Try for a 30 Amp Dedicated 12V if you can find one.

On greenman100's advice, and with some help, I managed to find and purchase a 24V / 15A dedicated PSU for $9 USD on eBay. I don't know if that's a great price for what I got, but it's pretty cheap. It's bulky, but I intend to run it outside of the case anyways, and it's perfect for my application (one 24V peltier).

Apparantly it isn't even too hard to lower it's output to the optimal level (~22V?) IMOG mentioned.

From the volts/deltaC curves i have see the most efficient point is at 15 v.

running it at less may be good sence the heat sink cant take the full heat of the cpu and tec.

ls7corvete said:

greenman: have you done this before? How did you go about loading the 5v rail?

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no, but you could do it with a bank of resistors and a fan (horribly, HORRIBLY inefficent) or you could partly do it by putting it in parallel with the main system's 5v rail, but I don't suggest it.

hkp0lice said:

I think a suitable PSU would cost more than that, cuz the swiftech pelt requires 25amps @ 12v... Very hard to find.

I have 2 spare PSUs lying around so I guess i'll try running them 'n see how long before they last before frying, lol

Click to expand...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=36323&item=3811006792&rd=1

$34 shipped, 32A. Adjustable down to 12.6V Add a resistor if you need more drop than that.

And that's from under a minute of eBaying, I bet I can find a better deal if I cared

felinusz said:

On greenman100's advice, and with some help, I managed to find and purchase a 24V / 15A dedicated PSU for $9 USD on eBay. I don't know if that's a great price for what I got, but it's pretty cheap.

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Great? Insane would be a better term. you got it for about 10% of retail

ls7corvete said:

From the volts/deltaC curves i have see the most efficient point is at 15 v.

running it at less may be good sence the heat sink cant take the full heat of the cpu and tec.

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1.) wtf? what curves are you looking at? max delts C != efficency, <removed>
2.) wtfx2? heatsink? not on a >100w tec

Ok, I don't get where you're gettin this 15v figure from, but I was planning on gettin this:

http://www.swiftnets.com/products/mcw5002-PT.asp

The pelt is rated for 12v, 25amps, wouldn't running it at 15v be kinda high?

Thanks

Greenman, we don't sarcastically call our members "geniuses" around here - thats called a personal attack. There are other places for that. Also, you have been around long enough that you should be familiar with the edit feature - you could combine those 4 quotes into a single post.

ls7corvete said:

From the volts/deltaC curves i have see the most efficient point is at 15 v.

running it at less may be good sence the heat sink cant take the full heat of the cpu and tec.

Click to expand...

15V is Vmax for 226 watt pelts, so you must be misinterpreting the curves you are looking at. 80% Vmax is the point you want to be at, which equals 12V for a rating of 15Vmax. For a pelt with 24Vmax, 19 or 20 volts is the best point to run at. 80% drastically reduces overhead heat output while maintaining something like 95% of cooling capacity - the reduction in overhead more than compensates for the lower total power.

hkp0lice said:

Ok, I don't get where you're gettin this 15v figure from, but I was planning on gettin this:

http://www.swiftnets.com/products/mcw5002-PT.asp

The pelt is rated for 12v, 25amps, wouldn't running it at 15v be kinda high?

Thanks

Click to expand...

hkpolice, I would bet dollars to donuts that the swiftech site is incorrect on that. They are citing that the pelt will draw 25 amps when powered at 12V but I am almost certain that is wrong... Imax for the pelt is very likely 25 amps, and when powered at 12 volts it will draw less than that - something close to 19 amps or so I think.

I am not aware of any pelts, anywhere, that will draw 25 amps when powered at 12 volts... And I think its pretty safe to say that swiftech buys their pelts from someone, they don't make their own AFAIK.

BTW, if you look further down on that link you gave me, they cite the pelt specifications as 15.2Vmax and 24Imax... So they are contradicting themselves. There is some confusion there on swiftechs part, or they just weren't careful when editing/checking the final page.

any pelt can be run at any voltage....

you get different results when you run it at these different voltages....


e.g.
run it at 39,000 volts, and it probably melts/blows up/causes your pets to pee on your couch

run it at 15 V, and it gets maximum performance, and beginging to see diminishing returns, after raising above 12-13 volts

run it at 12v, and this is where most commercial pelts (those that have jacked up prices at computer supply sites, or others) are designed to be operated at.

IMOG said:

Greenman, we don't sarcastically call our members "geniuses" around here - thats called a personal attack. There are other places for that. Also, you have been around long enough that you should be familiar with the edit feature - you could combine those 4 quotes into a single post.

Click to expand...

1.) you're right, I guess I've just gotten tired of correcting other people, as I've been doing it a lot lately. I should realize not everyone knows everything, but it bothers me when they think they do. (See this post in watercooling) The pointis, it was out of line on my part, and I will go back and edit.
2.) yes, I was familar with the edit feature, I normally do use it, but if you look, I'd posted, came back, posted, came back, re-read parts of the thread, etc. I probably shough have combined to one post, though.

IMOG said:

15V is Vmax for 226 watt pelts, so you must be misinterpreting the curves you are looking at. 80% Vmax is the point you want to be at, which equals 12V for a rating of 15Vmax. For a pelt with 24Vmax, 19 or 20 volts is the best point to run at. 80% drastically reduces overhead heat output while maintaining something like 95% of cooling capacity - the reduction in overhead more than compensates for the lower total power.

Click to expand...

fo' sho

IMOG said:

hkpolice, I would bet dollars to donuts that the swiftech site is incorrect on that. They are citing that the pelt will draw 25 amps when powered at 12V but I am almost certain that is wrong... Imax for the pelt is very likely 25 amps, and when powered at 12 volts it will draw less than that - something close to 19 amps or so I think.

I am not aware of any pelts, anywhere, that will draw 25 amps when powered at 12 volts... And I think its pretty safe to say that swiftech buys their pelts from someone, they don't make their own AFAIK.

BTW, if you look further down on that link you gave me, they cite the pelt specifications as 15.2Vmax and 24Imax... So they are contradicting themselves. There is some confusion there on swiftechs part, or they just weren't careful when editing/checking the final page.

Click to expand...

PM billA

TheMightyBuck said:

any pelt can be run at any voltage....

you get different results when you run it at these different voltages....


e.g.
run it at 39,000 volts, and it probably melts/blows up/causes your pets to pee on your couch

run it at 15 V, and it gets maximum performance, and beginging to see diminishing returns, after raising above 12-13 volts

run it at 12v, and this is where most commercial pelts (those that have jacked up prices at computer supply sites, or others) are designed to be operated at.

Click to expand...

covered already

greenman100 said:

I should realize not everyone knows everything, but it bothers me when they think they do. (See this post in watercooling)

Click to expand...

Your insinuations weary me and your attitude is unappreciated.

If you want to pick a fight with someone, choose someone who doesn't carry blues and you might have more luck... But most people around this forum are good enough members that they will not fall for it. I was asking questions in that thread and looking for better explanations, so I think that is a clear enough statement that I do not claim that I know everything.

IMOG said:

You insinuations weary me and your attitude is unappreciated.

If you want to pick a fight with someone, choose someone who doesn't carry blues and you might have more luck... But most people around this forum are good enough members that they will not fall for it. I was asking questions in that thread and looking for better explanations, so I think that is a clear enough statement that I do not claim that I know everything.

Click to expand...

(replied in PM to avoid derailing current thread)

Hmm, thanks for the info, i'll keep it at 12v then.

"Vmax is the most efficient voltage"

http://www.overclockers.com/tips45/

cant find those graphs, Ill look tommorrow.