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powering a few peltiers

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merthos

Registered
Joined
Feb 25, 2001
Location
Texas
ok everyone im new here to the forum but i do have a question for you experts.


I have 3 peltiers on my classic athlon
side by side they are 51 watt 15v 8 amp
I have an extra 230 swtiching power supply
running them.
theyre water cooled so i know cooling them isnt the problem
what im seeing with this setup are temps between 44c and 46 c
Is this powersupply enough to power these peltiers?
I just really dont feel like spending another 100 dollars for more power please help
athlon 700/800core @900 with 1.8v
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
Is that a total of 50 watts or 50 watts each. According to your specs you need at least 120 watts (15V x 8A). Your psu can supply that but are you running it/them at 12v? If you are then their efficiency is reduced.

If it's a total of 50 watts cooling then it's not enough, and if it's 3 X 50 watts your psu isn't providing the power needed. Measure the voltage on the peltiers to be sure the output voltage isn't being pulled down by too high a current drain.

If you can I'd suggest running them at 15v.
 
OP
M

merthos

Registered
Joined
Feb 25, 2001
Location
Texas
ok how do i get the 15 volts and still have the amperage?
what watt powersupply will i need?
and how do i get it to 15 volts?
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
You need to find a power supply that is adjustable, most have a pot with small voltage range, so if you can find a switching supply that gives 13.8v you should be able to tweak it to 15v. Be sure that it will supply the current required as if it is under-rated then excessive current draw will not only result in a drop in output voltage but also overheating and ultimate failure of your supply.

To figure what you need then add the current required by all the peltiers and multiply it by the desired voltage to give you the total power requirement. Now add at least another 50 watts for headroom/safety. Now you know the size of psu.

You failed to mention if you were running three 50 watt pelts, if so that's a total of 360 watts (3 x (15v x 8a)) - so that's a 400 watt supply to be on the safe side. However, based on your temps I suspect it's a total of 50 watts peltier cooling, so get a 15v 10 amp supply - but it's not going to help that much as 50 watts is insufficient for cooling your Athlon.
 
OP
M

merthos

Registered
Joined
Feb 25, 2001
Location
Texas
ok they are 50 watts a piece
there are 3 of them
so i take it i am really under powering them with a 250watt psu dedicated just to them then....
is there any way to overclock a psu????lol
if someone knows let me know......lol
 
OP
M

merthos

Registered
Joined
Feb 25, 2001
Location
Texas
ok thank you for your help !!!!!!!!!!!
I just pulled off all the fans off the second power supply
temp dropped from 44c to 35.8.
I am reading about 10 volts going to the peltiers
I've tried putting the +12 to the -5 (multimeters @ 15v)
to try to get a little more but it shuts down the psu.
I want to get these 3 peltiers to bring the cpu down to at least room temp 25c-26c.
considering Im overloading this psu should i just use 2 of these 50 watt peltiers .......I do not believe this is enough to cool the cpu down but I dont have enough exp with cpu output wattage vs peltier wattage
I really dont wanna add a third powersupply....lol
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
The problem is that your peltiers consume 120 watts each. A regular computer psu will be hard pressed to supply the necessary power. Using the +12v and -5v will not work because the -5v section is not a high current circuit, hence the shutdown.

Look for switching psu's on E-Bay (try Ham Radio section), or try to find a surplus store that sells used psu's. Radio Shack sells a 13.8v 20 amp unit for $100 that should run two easily and probably three if that's all you ask it to do.

You may well find that two peltiers being run at their correct rating will cool better than three under powered peltiers.
 
OP
M

merthos

Registered
Joined
Feb 25, 2001
Location
Texas
ok I took and dis connected 1 of the peltiers from the loop........
31c now
were getting there albit slowly........lol
tried just leaving one not really any temp difference
tells me the 250 watt supply can power the 2 pelts just not 3
Im thinking of adding that 3rd powersupply
ill have to build a damn cabinet just for all these extra psu's......haha
I know i should really go for higher wattage pelts
mostly im wondering if multiple pelts will do the same job as one high watt pelt......
 

@[email protected]

Senior Member
Joined
Dec 18, 2000
Location
Chapecó-SC
Yeah, a more powerfull peltier will do the same as 2 half power ones.... If you don´t want to spend u$100, just buy another used psu for a cheappo price and run the third Peltier..... Of course thr right would be a very powerfull 13,8v psu with a 100w Peltier bla bla $$$blá Ouch my pocket :) Do what you can afford, the more you pay the more you get... Chec out what other people are getting with similar setups.. so that you don´t waste your time extracooling to reach 20 mhz more.... Good luck man.