Arduino Addons: Battery Level Indicator

#include <LiquidCrystal.h>
// select the pins used on the LCD panel
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
void setup() {
  // Initialize LCD
    lcd.begin(16 , 2);
}

void loop() {
  // load battery icon on position 15,0
  batterylevel(15,0);
  
}
//draw battery level in position x,y
void batterylevel(int xpos,int ypos)
{
  //read the voltage and convert it to volt
  double curvolt = double( readVcc() ) / 1000;
  // check if voltge is bigger than 4.2 volt so this is a power source
  if(curvolt > 4.2)
  {
    byte batlevel[8] = {
    B01110,
    B11111,
    B10101,
    B10001,
    B11011,
    B11011,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 4.2 && curvolt > 4.0)
  {
    byte batlevel[8] = {
    B01110,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 4.0 && curvolt > 3.8)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 3.8 && curvolt > 3.6)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B10001,
    B11111,
    B11111,
    B11111,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 3.6 && curvolt > 3.4)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B10001,
    B10001,
    B11111,
    B11111,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 3.4 && curvolt > 3.2)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B10001,
    B10001,
    B10001,
    B11111,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt <= 3.2 && curvolt > 3.0)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B10001,
    B10001,
    B10001,
    B10001,
    B11111,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
  if(curvolt < 3.0)
  {
    byte batlevel[8] = {
    B01110,
    B10001,
    B10001,
    B10001,
    B10001,
    B10001,
    B10001,
    B11111,
    };
    lcd.createChar(0 , batlevel);
    lcd.setCursor(xpos,ypos);
    lcd.write(byte(0));
  }
}
//read internal voltage
long readVcc() {
  long result;
  // Read 1.1V reference against AVcc
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Convert
  while (bit_is_set(ADCSRA, ADSC));
  result = ADCL;
  result |= ADCH << 8;
  result = 1126400L / result; // Back-calculate AVcc in mV
  return result;
}