Q:

Getting the voltage of an 18650 battery with an Arduino

I'm using a Arduino Pro Mini (5v) to sense the voltage of an 18650 battery. The battery (that is being sensed)is also used to power the Pro Mini but the MCU is behind a boost-converter which outputs 5.05v. Would I be able sense the right voltage of the battery?

simulate this circuit – Schematic created using CircuitLab
The boost converter has an input voltage ranges to 0.9 to 5 volts and current of 600mA.

A:

Yes, if Vin- and Vout- are joined together inside the boost converter or share a common ground on the boost converter circuit board such as this one:

