Arduino nano no issues with 12.5v vin

Hi all,

I want to use 12v to supply power to arduino nano.

I read a lot of people having blown up or very hot voltage regulators when doing this.

I understand the v_reg is a linear v_reg and the voltage drop is dissipated as heat.
As in, the heat dissipation = v_drop x current

Since v_drop for 12v_in = 7v, and the current of a nano at 5v = 0.018A
Power dissipation = 0.126W

This doesnt seem to be enough to get very hot from my experience.

Anyway, I have a thermal camera and tested my nano.

  1. Set v_in to 12v
  2. wait 30 minutes
  3. T_Junction reads 39C..
  4. Touch with hand, doesnt feel hot at all
  5. Upped to 12.5v
  6. repeat same steps above
  7. No change

My particular use case will only be the nano turning MOSFETS on and off and insignificant current draw.

In this particular use case, it appears 12v or 12.5v is no problem for the nano.

The nano I used is a cheapo from ebay. I tested two of them, both with the same results.

I suspect those who blew theirs up or had theirs go very hot were drawing current from i/o pints (more than the 18ma of the stock). Drawing 50ma from a I/O pin would lead to approx 0.5w.. I could imagine that can start to get quite warm after being left for a while.

Conclusion: It appears to be safe to use 12v or 12.5v input if you are not using the I/O pins for power draw

It's also quite common for other 5V devices to be powered from the Arduino, which makes the thermal dissipation even higher. That's why long-timers advise caution when using that 5V output in general. You're right, the Nano, by itself, isn't at risk with 12V or even higher input(but do pay attention to your regulator's input limits), as long as the Nano is the sole consumer.

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