Monitoring a LiPo battery while powering the Arduino UNO with it - Project Guidance - Arduino Forum
Arduino battery control charge and discharge Battery Level Indicator - YouTube
I have built a battery level indicator and have tested with a 12V battery Would it harm my arduino board if I connect a 48V battery? - Arduino Stack Exchange
A Simple Arduino Battery Tester - Pi My Life Up
Battery (Lithium, NiMH, NiCd) Capacity Tester Using Arduino - Electronics-Lab.com