1
\$\begingroup\$

enter image description hereI need to power 4 peltier plates (tec1-12706) with 12V and 5A for a thermoelectric cooler project. I wish to have maximum cooling. Also I need to attach a few(4) computer cooling fans to dissipate the heat from all 4 peltier plates.

Please let me know what will be the best power supply to power all those altogether? (Excuse me if I have asked a very basic question because I don't have an electrical background) (I found some articles on computer power supply but not sure if it will give me enough power to power all 4 peltiers if so how to connect them parallel or series)

\$\endgroup\$
  • 1
    \$\begingroup\$ 4 HDD plugs ought to do it from a surplus ATX PSU. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 2 '17 at 21:54
  • \$\begingroup\$ @Tony I searched for ATX PSU Foxin FPS 800 12 volt DC SMPS Power supply with 450W Output. Will these kind of power supply will be okay? Do I need to consider any wattage configuration or something? If i use 4 HDD plugs will that give me enough current and voltage to all of them? \$\endgroup\$ – Rivu Mar 2 '17 at 21:58
  • \$\begingroup\$ You'll have to vastly oversize the heat sinks and fans to reliably use them without a controller and safety circuits.... Also, there is the matter of how you are going to arrange the plates themselves? If you are going to stack them for higher temperature differentials, there needs to be much more care taken with the design regarding controls and mechanical design. (As always though... giant heatsinks with lots of thermal paste and a reasonable ATX power supply like a 500W EVGA 500 W1, 80+ WHITE 500W Power Supply 100-W1-0500-KR and tons of fans should get you thru your project) \$\endgroup\$ – david1024 Mar 2 '17 at 22:22
  • \$\begingroup\$ Check out the pics! This is what is in my mind. This pics has two peltiers. I will have another two with the same prototype. \$\endgroup\$ – Rivu Mar 2 '17 at 22:41
  • \$\begingroup\$ What you show is actually a PC water cooling system dissipater, not a peltier. If your cold side does not have a fan then the heatsink area will need to be much much larger. Your hot side may be about half or less the cold side area depending on your fans and ambient temperature. \$\endgroup\$ – Jack Creasey Mar 2 '17 at 22:56
2
\$\begingroup\$

Short answer is you need around a 25A 12V (300W) supply. A PC supply would work for that.

However, the long answer is those things are really finicky and die easily. You really need to use current and temperature sensing for each plate, and getting rid of 60W of heat per plate is no simple task. Making sure the heat exchanger is intimately touching the surfaces with a good heat exchange medium between them is also key.

Also, they need to be sealed, any moisture in there will also kill you.

\$\endgroup\$
  • \$\begingroup\$ Thanks Trevor! I will take your advice. By the way how shall I connect these plates in parallel right. Lets say if I use any SMPS power supply from the market (eg. ATX PSU Foxin FPS 800 12 volt DC SMPS Power supply with 450W Output) the extra watt(450-300) will that harm my setup? And I have seen the PC supply has some 12v wires some 9v 3v etc. Will those each 12v wires can be used to power every individual peltier plates? \$\endgroup\$ – Rivu Mar 2 '17 at 22:08
  • \$\begingroup\$ Since you need to regulate each unit separately, they will in effect be in parallel. Like I say, you need to ensure the current does not exceed your chosen tolerance level (5A is a good choice) and that the hot side never exceeds around 100C. \$\endgroup\$ – Trevor_G Mar 2 '17 at 22:12
  • 2
    \$\begingroup\$ Also note you need to get rid of a lot more than 60W per plate in the heatsink, add the heat it's pumping to the input power. I'd size teh heatsinks for about 90W. \$\endgroup\$ – Brian Drummond Mar 2 '17 at 22:28
  • 3
    \$\begingroup\$ @JackCreasey So power input is 60W electric and about 20W of heat into the cold side ... and you claim the power output is just 60W. Where does the rest go? \$\endgroup\$ – Brian Drummond Mar 2 '17 at 23:00
  • 2
    \$\begingroup\$ The PWM thing is often misquoted. The truth is the modules can not withstand frequent thermal modulation. ie. turning it on full power till it reaches a temperature, then turning it off till it reaches some lower temperature governed by hysterics is BAD. PWM itself, if the frequency is sufficient does not cause this effect. \$\endgroup\$ – Trevor_G Mar 3 '17 at 1:22
1
\$\begingroup\$

If the goal is to find the amount of power that you need then use Imax*Vmax. Make sure the current of the supply is greater than or equal to Imax of the peltier.

If your using this in a real design you may want to size the supply for your needs. The first thing is to calculate the max temperature across the peltiers (often called dT or deltaT the thermal version of voltage). For that, you will also need to take into consideration the thermal resistance of the materials and the heatsinks. Then you will need to find the ammount of heating\cooling power you need (how fast you can move heat, analogous to current or Q in watts) If you are using air cooling then you will also need to take into account convection.

Anyway, find or estimate the max deltaT and the heat power and more often than not the manufacturer will have a graph like this:

From http://www.everredtronics.com/files/Peltier_instructions.pdf

Draw a line across from the deltaT side of the graph and find your current for the amount of heating or cooling power you need. The other gotcha is if you are heating with the peltier, the graph will be different than for cooling because there is internal resistance in the peltier that works against cooling but helps heating.

After you find the amount of current that will be drawn from the graph, you can size the supply appropriately (the supply needs to be greater than or equal to the current in the graph), which may be less than Imax which will save you money on buying a supply.

\$\endgroup\$
0
\$\begingroup\$

ATX PSU's have high 12V ports for power hungry multiple GPU plugins which most people never use. The 5V is used for primary feedback with the 12V by high mutual coupling, so sometimes the 5V needs a 10% load if you use all the 12V capacity and none for 5V in order to regulate properly.

It's always best to get the datasheet or basic specs.

examples:

  • Corsair RM550X +3.3V@25A, +5V@25A, +12V@45.8A, -12V@0.8A, +5VSB@3A
  • Corsair RM850X +3.3V@25A, +5V@25A, +12V@70.8A, -12V@0.8A, +5VSB@3A

Some 800W ATX's have 4 V12 ports with 20A each

The heatsink ought to resemble a CPU heatsink with <<1 'C/W

If it doesn't look adequate for a big CPU, it won't work well for a Peltier cooler of similar power input.

\$\endgroup\$

protected by Community May 13 at 4:37

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.