View Full Version : Can a 226W Peltier be powered by +3.3V or +5V?
Anyone know if I can power a 226W Peltier with +3.3V from a ATX PSU? It's OK for me if it works as a 50W unit.
and
How to make +6V, +9V, +12V DC power out of +3.3 or +5V?
Currently I use a 365W Enermax PSU to power a +12V Peltier. I have nothing to load +5V and +3.3V other than dummy loads (5- ohm resistors). I want to make use of +3.3 and +5V from a PSU.
KnightElite
02-17-2003, 06:10 AM
At 3.3V, it will require 5.2A, and will cool at 49W. It should be doable.
As to making other voltages, it requires using the -12V, -5V and -3.3V lines. Those lines are not rated for very much current though, so you probably won't be able to do it.
docah
02-17-2003, 06:56 AM
I tried using the -12v before to power just a fan. The psu was really cheap and would instantly shut down most times i hooked the fan up. But when it didnt... man that was cool :) (and loud)
Thanks. Using a peltier at low-watt is better than using dummy loads on PSU, in my opinion.
Schitzo
02-17-2003, 10:41 AM
Here's my question... what happens if you hook up the +3.3 and the -12?
Do you get 15v @ 30A, if your 3.3 can put out 30A?
KnightElite
02-17-2003, 05:10 PM
No, it can only output that much power. So, 3.3V at 30A = 100W
So if you had 15.3V you would only be able to do 6.5A.
It's so because -12V is no more than 0.5 to 1.0 Amp, isn't it?
KnightElite
02-18-2003, 11:03 AM
No, because with a higher voltage, in order to source the same amount of power, you use less current. So, it would probably blow up if you tried it... ;). Of course, I could be way off, and it might work, but if it was that easy, I imagine it would have been done by now, and 15V, 30A power supplies would be as cheap as 3.3V 30A supplies.
Pedant
02-18-2003, 11:56 AM
If you were daring and your power supply could handle it, it may be possible to cut and solder the internal elements on your peltier and run them in parallel.
It would be a major modification and would probably end up killing it.
KnightElite
02-18-2003, 12:20 PM
Originally posted by Pedant
If you were daring and your power supply could handle it, it may be possible to cut and solder the internal elements on your peltier and run them in parallel.
It would be a major modification and would probably end up killing it.
They already are running in parallel, which is why the peltier has such an extremely low resistance.
Pedant
02-18-2003, 02:51 PM
Sorry to be argumentative but not so.
http://www.kryotherm.ru/what_is.htm
To make up a TEM, thermocouples are connected electrically in series and thermally in parallel and sandwiched between two ceramic substrates.
http://www.coolworksinc.com/thermote.htm <- this link has a picture and my peltier is definitely connected in this manner. I was suggesting cutting at the ends then wiring those in parallel. You would need to work out what number of lines to cut them into though.
Sandwiched between the ceramic exterior of a TEM are many small pieces of n + p doped bismuth telluride coupled together and connected electrically in series.
KnightElite
02-19-2003, 12:36 PM
Lol, thanks for correcting me. I guess I need to learn what I'm talking about :D. If they were connected in parallel, it would be almost like a short, probably, and you would need a monstrously huge power supply to supply enough current to run the thing.
Tedinde
02-28-2003, 11:39 AM
I've ran a 226 watt pelt off the 5volt, no problems