I need your help for remaining percentage of battery.

Hello everybody
I am currently working on a project and I need to know the remaining percentage of a battery that powers an Arduino card. I did several searches but I found nothing functional. So I need your help to know how to realize my project. Thank you all.

Okay? You might want to ask a question.

DrAzzy:
Okay? You might want to ask a question.

The forum has bug because when I send my message it was display and there is nothing. I modified.

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