#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

char battvoltage[7];                          //Store voltage value in string
char battpercent[7];                          //Store percentage value in string

float battV = 0;                              //battery voltage Read A0
float bpc   = 0;                              //battery percentage Read A1
int batC    = 0;                              //battery percentage
int t1      = 700;                            //refresh rate

byte Battcap[8]     = {B11110, B00010, B00011, B00001, B00001, B00011, B00010, B11110};
byte Battwall[8]    = {B11111, B00000, B00000, B00000, B00000, B00000, B00000, B11111};
byte Batthalf[8]    = {B11111, B11100, B11100, B11100, B11100, B11100, B11100, B11111};
byte Battfull[8]    = {B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111};   //Battery Icon Characters
byte Battcapfull[8] = {B11110, B11110, B11111, B11111, B11111, B11111, B11110, B11110};
byte Battcaphalf[8] = {B11110, B11010, B11011, B11001, B11001, B11011, B11010, B11110};
byte Battbot[8]     = {B11111, B10000, B10000, B10000, B10000, B10000, B10000, B11111};

void setup()
{
  lcd.init();
  lcd.backlight();
  lcd.clear();
  
  lcd.createChar(1, Battcap);
  lcd.createChar(2, Battwall);
  lcd.createChar(3, Batthalf);
  lcd.createChar(4, Battfull);                //Create Batt Icon Images
  lcd.createChar(5, Battcapfull);
  lcd.createChar(6, Battcaphalf);
  lcd.createChar(7, Battbot);                                
  
  pinMode(A0,INPUT);                          //we will use analog pin 0 to read voltage from 1s li-ion battery
  pinMode(A1,INPUT);                          //we will use analog pin 1 for percentage reference
                                              //Connect A0 & A1 to battery positive terminal
}

void loop()

{
  lcd_update();
  delay (t1);
}

void lcd_update()
{                              
  battV = (analogRead(A0)*5.00)/1024;         //figure out the battery voltage (make sure arduino 5V pin are set to exactly 5.00V on your step-up module)
  bpc   = analogRead (A1);                    //figure out analog value for current batt voltage to display in percent
  batC  = map(bpc, 613, 840, 0,100);          //Convert voltage analog value to percent value
 
  if(batC > 100)batC=100;                     //Set the max treshold of 100%
  if(batC < 0)batC=0;                         //Set the min treshold of 0%
                                              //To avoid percentage reading going higer than 100% eg: 101% or lower like -1%
  
  dtostrf(battV, 2,2, battvoltage);           //Convert float voltage value to string
  dtostrf(batC, 3,0, battpercent);            //Convert float percentage value to string
  
  lcd.setCursor(5,0);                         //Display the title on top left
  lcd.print ("Vo:");                        
  lcd.setCursor(8,0);                         //Display the voltage on top right
  lcd.print (battvoltage);
  lcd.print ("v");

  if (batC < 12)                              //Displaying the battery icon bar based on batter percentage on bottom left
    {
      lcd.setCursor(5,1);
      lcd.write(7);
      lcd.write(2);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC == 12)
    {
      lcd.setCursor(5,1);
      lcd.write(3);
      lcd.write(2);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC > 12)
    {
      lcd.setCursor(5,1);
      lcd.write(3);
      lcd.write(2);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC == 25)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(2);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC > 25)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(2);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC == 36)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(3);
      lcd.write(2);
      lcd.write(1);
    }

    if (batC > 36)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(3);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC == 50)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC > 50)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(2);
      lcd.write(1);
    }

   if (batC == 60)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(3);
      lcd.write(1);
    }

   if (batC > 60)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(3);
      lcd.write(1);
    }

   if (batC == 75)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(1);
    }

   if (batC > 75)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(1);
    }

   if (batC == 84)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(6);
    }

   if (batC > 84)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(6);
    }

   if (batC == 97)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(5);
    }

   if (batC > 97)
    {
      lcd.setCursor(5,1);
      lcd.write(4);
      lcd.write(4);
      lcd.write(4);
      lcd.write(5);
    }
  
  lcd.setCursor(9,1);                           //Display the percentage on bottom right
  lcd.print(battpercent);
  lcd.print("%");
}