user42175: Can I measure lithium ion cell voltage with Arduino ADC which is used to power the same Arduino through a boost module (XL6009)? The output voltage of boost module is 9 volts.

user19867: I'm the author of a library called BatterySense and you can use it to achieve your goal. In the repository Readme you can also find wiring diagrams and usage examples, but to give you a rough idea...

Verify the negative side of your battery has continuity to the GND pin of your Arduino: you need to identify if the boost module is messing the common ground, but if you have continuity then you are fine
Add a connection from the battery positive terminal going into one of the Arduino analog pins
Use the BatterySense library to get the battery voltage and percentage level


42175: <p>Can I measure lithium ion cell voltage with Arduino ADC which is used to power the same Arduino through a boost module (XL6009)? The output voltage of boost module is 9 volts.</p>
 19867: <p>I'm the author of a library called <a href="https://github.com/rlogiacco/BatterySense" rel="nofollow noreferrer">BatterySense</a> and you can use it to achieve your goal. In the repository Readme you can also find wiring diagrams and usage examples, but to give you a rough idea...</p>

<ol>
<li>Verify the negative side of your battery has continuity to the GND pin of your Arduino: you need to identify if the boost module is messing the common ground, but if you have continuity then you are fine</li>
<li>Add a connection from the battery positive terminal going into one of the Arduino analog pins</li>
<li>Use the BatterySense library to get the battery voltage and percentage level</li>
</ol>
