I have this peltier module: Link

And I am having some trouble understanding how to power it. I have a 5V 3A power supply, but whenever I hook up the peltier module to this power supply, it starts to provide ~4.2V ~5A. My question is, does this happen because the peltier is trying to draw too many amps and the power supply is lowering the voltage to try and deal with this?

Also, am I correct in thinking that, if I supply the peltier with a specific voltage, it will need a corresponding number of amps, based on the "current vs voltage" graph below and/or on the peltier module resistance? e.g. if I supply the peltier with 14V, it will try to draw around 22A.

What happens if I use a power supply with 13.8V, but can only provide 11.5A? What about the other way around, if I have a power supply that can only provide 5V but 30A? Will the peltier and/or power supply function under these conditions?

I have never really worked with power supplies or peltier modules before, so I'm sorry if these questions don't make sense. Thank you for any answers!


  • \$\begingroup\$ Great Scott has a video on that on YouTube, he showed that these device consume alof of current, seams to be an array of silicon diodes or so, he also added a mechanism with a timer to keep the current use somewhat acceptable. p.s. they also can create current if you attach big enough cooling elements on both side and heat one side with a candle or something a like. \$\endgroup\$ Feb 10, 2023 at 16:52
  • \$\begingroup\$ What exactly is your application for the Peltier Module? \$\endgroup\$
    – earl
    Feb 10, 2023 at 16:59
  • \$\begingroup\$ I am cooling a pump using the peltier and a cpu fan/heatsink. I need the liquid that goes through the pump to stay at or below room temperature, so I need to cool the pump down to (at least) slightly below room temperature. \$\endgroup\$
    – Anthero
    Feb 10, 2023 at 17:19

1 Answer 1


The load (peltier module) will determin the current required, while the power supply tries to produce that current, and maintain its voltage. If the supply cannot deliver the required current Someting Bad will happen - the supply may reduce the voltage or shut down, and may be damaged.

The graph you included clearly shows that the Peltier module will require about 10 amps at 6 volts, or 20 amps at 12 volts, so your power supply is not capable of powering that module.

The current rating of most power supplies is the maximum current it can supply - if that is more than the load wants, the supply won't force its rated current through the load.

(There are "constant current" power supplies that will adjust their voltage in an attempt to deliver their rated current to the load - often used to drive LED lamps)

  • \$\begingroup\$ That all makes sense, thank you! Quick follow up question, if I connect the peltier to a constant voltage power supply that provides 5V and 30A, the peltier will only draw around 6A correct? It won't draw any more? \$\endgroup\$
    – Anthero
    Feb 10, 2023 at 17:21
  • \$\begingroup\$ Yes - that is correct. \$\endgroup\$ Feb 10, 2023 at 17:30
  • \$\begingroup\$ if at 5V the peltier consumes 6A, then as long as the supply can provide at least 6A, it will consume 6A (even if the supply could supply far more). If the supply can't supply 6A, then it will either get destroyed, or lower it's voltage until the voltage and current can "match" (the lower the voltage, the less current the poltier module consumes). Which one happens depends on the power supply \$\endgroup\$
    – Sandro
    Feb 10, 2023 at 17:32

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