How to check your arduino's battery pack level?

Hardware Arduino 101
1

Hi, I wanted to share this script, the battery pack connects to analog A0 for + and negative to gnd

And when the battery reaches a new low it will store the percent in the battery_percent variable from 0-100

int lowest_level=1024;
int read_battery_level=0;
int battery_percent=100;
int temp_math=0;
void setup() {
Serial.begin(9600);
}

void loop(){
read_battery_level=analogRead(A0);
if(read_battery_level<lowest_level){
lowest_level=read_battery_level;
temp_math=int(String(read_battery_level/1024.0).indexOf('.'));
if(int(read_battery_level/1024)!=1){
Serial.println(String(read_battery_level/1024.0).substring(2,4) + "%");
battery_percent=String(read_battery_level/1024.0).substring(2,4).toInt();
}else{
Serial.println("100%");
battery_percent=100;
}
}
}
2

Connecting batteries directly to an analog pin is a bad idea without a divider network made to suit the particular voltage of the particular battery.
That at least offers some protection to the analog pin.

Simple enough to do as shown here

3

Nice thanks