http://forums.trossenrobotics.com/tutorials/how-to-diy-128/cheap-battery-monitor-using-resistive-voltage-divider-3264/
(http://s11.postimg.org/3zqx20vbz/adruino_Voltage.jpg) (http://postimages.org/image/3zqx20vbz/)
(https://i.ibb.co/fHK25J3/ACS712-hookup-arduino.webp) (https://ibb.co/fHK25J3)
(https://i.ibb.co/C6HZM7Y/ACS712-Arduino-Circuit.jpg) (https://ibb.co/C6HZM7Y)
https://theiotprojects.com/battery-status-monitoring-system-using-esp8266-arduino-iot-cloud/
https://youtu.be/9wG1noM9PQI