#define vbat A2
#define led1 3
#define led2 2
#define led3 1
#define led4 0

void setup() {
  pinMode(vbat, INPUT);
  pinMode(led2,OUTPUT);
  pinMode(led3,OUTPUT);
  pinMode(led4,OUTPUT);

}

void loop() {
  delay(1000);
  int voltage = map(analogRead(vbat),0,1023,0,100);

  if(voltage <= 20){
    digitalWrite(led1,1);
    digitalWrite(led2,0);
    digitalWrite(led3,0);
    digitalWrite(led4,0);
  }
  if(voltage > 20 && voltage <= 50){
    digitalWrite(led1,1);
    digitalWrite(led2,1);
    digitalWrite(led3,0);
    digitalWrite(led4,0);
  }
  if(voltage > 50 && voltage <= 75){
    digitalWrite(led1,0);
    digitalWrite(led2,0);
    digitalWrite(led3,1);
    digitalWrite(led4,0);
  }
  if(voltage > 75 && voltage <= 100){
    digitalWrite(led1,0);
    digitalWrite(led2,0);
    digitalWrite(led3,1);
    digitalWrite(led4,1);
  }

}