Question about step-down-module.

  • If I have a power supply that delivers 12v 10A and use a Buck converter to step down the current to 5v. Can I still draw 10A from the power supply?

  • @Cliff-Karlsson
    Yes that would be possible but it depends of the components that step-down the voltage.
    If the seller wrote 12v 10A, I understand that as 10A.
    Normally when you half the voltage you can double the amps. 12v* 10A= 120 watts
    So maybe you can draw 24 amp from the step-down at 5v.
    120watts / 5v= 24 amps
    Google ohm's law

  • They specify in Description section: Output Current: 12A, so this is maximum, still ok if you need 10A

  • Ok, I only asked as I noticed that the buck-converter has big heat-sinks witch would indicate that it will get hot. My guess would be that some energy is lost as heat. But you mean that there are no energy loss when transforming from 12v to 5v? Where does the heat come from in that case?

  • Hero Member


    Don't be silly. Of course there's energy lost in the conversion, which is the source of the heat.

  • @NeverDie
    Well I have to admit that I don't really understand this subject. But the buck converter was specified to in:7-32v out:7-32v 12A. If I connect my PSU 12v 10A will I automatically be able to drar the max 12 A from the buck converter?

  • Hero Member

    Assuming your PSU is only driving your buck converter, then, if the device data can be believed (a big IF by the way), then yes, I would expect it could deliver 12a at 5v. That said, you're buying a cat in a bag, and from a no-name Chinese manufacturer no less. So, for instance, who knows whether the parts are actually rated for what they proclaim themselves to be.

    Those are electrolytic caps. Usually, they don't do well when exposed to heat, and in that design they look to be quite close to the heat sinks. Are the caps really rated for whatever heat you might encounter? That's a big unknown with these types of cheap boards. On the other hand, it's only $4, so maybe that's a trade-off you're willing to live with.

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