0
\$\begingroup\$

I recently bought a step-up converter module. It is rated to work at 24 volts and output MAX 28 volts and 2 amps. I will connect it to a source that outputs 5 volts and 20 amps. If I connect a power hungry device to the module which draws more than 2 amps, the module will limit it or it will exceed the limit and burn?

Here is the module: https://grobotronics.com/dc-dc-converter-step-up-5-24v-2a.html

It says that the output current does not exceed 2 amps but the input current can exceed it.

\$\endgroup\$
  • 1
    \$\begingroup\$ The answer depends on details of the design of the module that you haven't shared (and that the designer might not have shared with you). You might get an answer by asking them, but there's no way we can give you one. \$\endgroup\$ – The Photon Oct 1 at 20:43
  • \$\begingroup\$ @ThePhoton i edited the question \$\endgroup\$ – Στελιος Λιακοπουλος Oct 1 at 20:46
  • 1
    \$\begingroup\$ If you can read the marking on U1 we might be able to guess at an answer. \$\endgroup\$ – The Photon Oct 1 at 20:47
  • \$\begingroup\$ @ThePhoton i found this image but it is still very blurry images-na.ssl-images-amazon.com/images/I/… \$\endgroup\$ – Στελιος Λιακοπουλος Oct 1 at 20:53
  • 1
    \$\begingroup\$ "No datasheet? No sale!" \$\endgroup\$ – Transistor Oct 1 at 20:59
3
\$\begingroup\$

No-one can know what will happen to your module in that case.

That's because from "Update 2" in my answer on a previous question about the same "XY-016" module, there is evidence of multiple different MT3608 clone ICs being used on those modules. The behaviour could be different depending on the specific clone that you have.

Either don't risk it (which is my recommendation), or try it yourself in controlled conditions (carefully, with fire extinguisher etc. and help nearby) and find out - but your next module might behave differently, if it has a different clone IC.


After more research, I don't think you can draw 2A in your case anyway. That claim in various adverts, is the very best case! That would apply only when there is a small difference between the input and output voltages, even with a real MT3608 IC. The supplier that you linked says:

Maximum output current: 2A (recommended for use within 1A)

(my emphasis above)

I don't know whether you want a 24V or 28V output from your 5V input, but that is a very large difference between the input and output voltages. Looking at the MT3608 datasheet, the closest I can see is a graph on page 5, showing 5V input, 12V output, and the max current shown in the graph is only 0.8A.

This is likely due to reaching the current limit of the internal MOSFET switch.

With 5V input and 24V (or 28V) output, I would expect a much lower maximum current than 0.8A before bad things could happen e.g. possible fire from the module, as shown in the video linked in my answer above.

\$\endgroup\$
  • \$\begingroup\$ is there any way to limit the module to not draw more than 2 amps? \$\endgroup\$ – Στελιος Λιακοπουλος Oct 1 at 21:15
  • 1
    \$\begingroup\$ The MT3608 has an internal switch limit of 4A. Output current is less than input current divided by the step up ratio, so if you try to draw more than 0.8A from the output the internal switch limit will be reached and output voltage will drop. The MT3608 also has thermal protection, so a prolonged overload should shut it down. \$\endgroup\$ – Bruce Abbott Oct 1 at 21:36
  • \$\begingroup\$ @BruceAbbott - Thanks, that's exactly what I was thinking (I was just updating the answer with the contents of my comment). However, I can't get the exact maths you mention (and which I was trying figure out while I was editing) to "work out". 5V -> 12V = 2.4x step-up and 4A / 2.4 = 1.6A at the output, not the 0.8A shown in the graph. Can you help explain the discrepancy? (I agree what a real MT3608 should do when overloaded. However the video in my linked previous answer shows that the MT3608-clones can catch fire when overloaded instead :-( ). \$\endgroup\$ – SamGibson Oct 1 at 21:46
  • \$\begingroup\$ @ΣτελιοςΛιακοπουλος - "is there any way to limit the module to not draw more than 2 amps?" Not on the module, no. You could add a current-limiting circuit after the module. However I have updated my answer to explain that in your case, you can't get 2A output current from that module anyway. \$\endgroup\$ – SamGibson Oct 1 at 21:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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