Another Peltier question...

[Cstolworthy12]

Hey guys I have another question about peltiers, more about powering
them actually. I am looking for a fairly small power supply to run my
peltier off of, the peltier specs can be found here:
https://home.comcast.net/~edmonchau/ebay/nate_pic/dt12-8.pdf

I have found this power supply:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4660&item=3825542782&rd=1
it looks like a pretty decent item for my usage. Is there any reason
I couldn't use this with my peltier? Or if anyone has any ideas for a
small power supply to use I need to hook up 2 peltiers to the power
supply. I was thinking of just hardwiring this power supply, possibly
just opening my PSU and soldering some wire to the AC plug connectors?

TIA
-Chris

 

[kony]

On Mon, 12 Jul 2004 19:39:08 -0600,

Hey guys I have another question about peltiers, more about powering
them actually. I am looking for a fairly small power supply to run my
peltier off of, the peltier specs can be found here:
https://home.comcast.net/~edmonchau/ebay/nate_pic/dt12-8.pdf

I have found this power supply:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4660&item=3825542782&rd=1
it looks like a pretty decent item for my usage. Is there any reason
I couldn't use this with my peltier?

It looks a bit small for a pair of those peltiers.
PS is only 10A. Have you looked up that PS's specs? It might
be rated at that wattage with forced air cooling, in other words
you need a fan. Might be a bit of an electical hazard too since
it's open-frame. Power supply looks to be adjustable down to
minimum of 13.5V, but at that voltage (according to peltier spec)
it needs output about 5.5A per peltier, but you really shouldn't
be trying to run it a 100% output either. Since PS isn't rated
to output 11A, you might find it dropping voltage so question
would then be where the undervoltage protection is set.


Ideally you'd want one per peltier. Many people find it easier
to use 12V from a 2nd computer power supply. It's less effective
but as the peltier graph shows, the power/temp relationship isn't
a linear one, beyond 12V it takes a lot more power & heat for
that last (roughly)

r if anyone has any ideas for a
small power supply to use I need to hook up 2 peltiers to the power
supply. I was thinking of just hardwiring this power supply, possibly
just opening my PSU and soldering some wire to the AC plug connectors?

You could just direct wire it, that would work even if it ignores
the safety issue when considering working inside system by you or
another person, but it would seem better to use a 2nd plug,
whether that be from the first PSU or external cord.
Hopefully you have a large system that you don't mind being loud,
since an extra 214W of heat certainly isn't a trivial thing to
remove from the case (150W PSU @ 70% efficiency), in addition to
the additional heat resulting from the presumed o'c of the CPU.

To me, all this just isn't worthwhile, better to just settle for
nice quiet high-end traditional heatsink, which you come close
enough to needing anyway due to amount of heat you'll have, else
another layer of complexity by using water cooling, but by the
time both of those were employed it'd seem better to just use a
compressor-driven solution instead.

 

[Cstolworthy12]

OK then which one of these would you suggest?
http://www.kepcopower.com/rkwo-mod.htm
I can get a enclosure for the top so it is not open frame. I know
very little about voltages and such, I would like to learn more if you
could possibly suggest a good place/way to learn? Like I said I am
going to run the two peltiers off the same power supply. However they
both will NOT be running at 100% I am going to turn them down so they
cool, not freeze.

 

[kony]

On Tue, 13 Jul 2004 20:29:13 -0600,

OK then which one of these would you suggest?
http://www.kepcopower.com/rkwo-mod.htm
I can get a enclosure for the top so it is not open frame. I know
very little about voltages and such, I would like to learn more if you
could possibly suggest a good place/way to learn? Like I said I am
going to run the two peltiers off the same power supply. However they
both will NOT be running at 100% I am going to turn them down so they
cool, not freeze.

Their power supplies (at least those on page you linked) max out
at 150W. Running a pair of the peltiers you linked will require
a larger (than 150W) power supply. I'd suggest something with at
least 14A output.

You write that you will turn them down, but with what method?
It's conceivable that if you reduced current enough, a single PS
like you first linked would work. The power supply itself will
only allow adjustment down to 13.5V, so taking that 13.5V you can
see how much current is needed from the graph on the pletier spec
sheet. Using that graph you could determine how high the voltage
could go and stay within any given power supply's spec, but I
can't predict how much cooling you'd need for your application.

There are a number of variables that only you can consider.
Things like the allowable size for this power supply, assuming it
"must" fit inside the system case rather than being external.

If you could settle for an external PSU, and @ 12V, you would
certainly have more power than needed with this:
http://www.mpja.com/productview.asp?product=13549+PS .
but you'd definitely want to fab a cover for it, to isolate the
input power.

I don't often run across ~ 15V power supplies, at least not
though channels where they'd be reasonably priced (affordable).
Here's more examples of 12V supplies that're a bit more finished
for inside-case use,

http://store.yahoo.com/davidandkarma/meansp12vol2.html
http://www.mpja.com/productview.asp?product=15078+PS

http://www.excess-solutions.com/POWERSUP.HTM
(search page for "ES3096")

Well, there was one 15V that looked promising on ebay but I have
no idea if it would fit in your case:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=36323&item=3827391685&rd=1