Arduino overvoltage

[fredrik]

Depends on what Nano you have, and how much power you pull through the onboard regulator:

Design glitches: Arduino Nano supply voltage

(thought I’d collect my nano supply notes in one place to make it easier to link to) A common design glitch in circuits that use an Arduino Nano is to connect regulated 5 V to the VIN pin instead of the +5V pin. This results in the Arduino running at a lower internal supply voltage, often 4 V or below, which may be a problem if the design depends on analog inputs or digital output levels. Voltages below 4.5 V are also out of spec for the 16 MHz clock used by the Nano. Details below, but TL;DR …

The 1117 regulators on the common Nanos can handle 15 V, but there’s usually room for “slightly over” even for the “absolute maximum” specs (if they meant 15 V exactly, they’d written 15.0 V).