I had these 12v 2a power supply(adaptor) and rgb box labeling INPUT: 12VDC OUTPUT: 12v 6a(Max Current).

I can light up led without problem but when I connect peltier, the supply is dropping down and up repeatedly.

I know that rgb box is for led, but I use it for peltier because I don't have a power supply for peltier.

I buy this peltier online, it says that 12v 6a is need to cool peltier.

Why is that ?

Is there any suggestion to stabilize the output current and voltage apart from buying a power supply ?

I don't have money so I build from scratches.

  • 3
    \$\begingroup\$ It sounds like you're overloading your 2A power supply with the 6A peltier and the power supply is going into overcurrent protection mode. \$\endgroup\$
    – vir
    Jun 15, 2021 at 18:40

2 Answers 2


You can't use a power supply that is capable of providing 2A to power a load that requires 6A.

The peltier element tries to draw more current than the power supply can supply so voltage may not reach 12V.

The power supply has overcurrent and/or undervoltage protection so it senses that something is not right and turns off to protect both the supply and load, but it will repeatedly then start up again but only to find out the problem still persists.

  • \$\begingroup\$ Thank you so much \$\endgroup\$ Jun 19, 2021 at 14:51

You need to look at the wattage: the load draws (6A * 12V = 72W). Your existing source can supply (2A * 12V = 24W), that is only 48 Watts short. When you pick the source pick at least 72 watts at 12 VDC, plus a few more watts to spare. Since you are supplying 24 watts to a 72 watt load, something has to give, that is probably the power supply protection circuits.These circuits are designed to protect the power supply, not its load.

Your power supply can source more then 6 amps that will not be a problem as long as the voltage stays at 12V. Since you build from scratches you could build a power supply with a transformer, a few CAPs, a series pass circuit and a rectifier circuit, be careful with the ripple, most peltier devices do not like it.

  • \$\begingroup\$ May I ask about the rgb box I mentioned above, it says input is 12vdc and the output is 12vdc 12a(Max) but it seems it doesnt work either. Btw thank you for suggestio. \$\endgroup\$ Jun 19, 2021 at 14:52
  • \$\begingroup\$ Check the watts, you cannot get more out then you put in. \$\endgroup\$
    – Gil
    Jun 20, 2021 at 0:32
  • \$\begingroup\$ Wattage of ? Idk what i need to check. Btw thankyousomuch \$\endgroup\$ Jun 20, 2021 at 12:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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