// ARDUINO SOLAR CHARGE CONTROLLER 
//Version-2.0
//by deba168,INDIA
//Dated : 22/10/2014


#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#define SOL_ADC A0     // Solar panel side voltage divider is connected to pin A0 
#define BAT_ADC A1    // Battery side voltage divider is connected to pin A1
#define CURRENT_ADC A2  // ACS 712 current sensor is connected to pin A2
#define TEMP_ADC A3   // LM 35 Temperature is connected to pin A3
#define AVG_NUM 10    // number of iterations of the adc routine to average the adc readings
#define BAT_MIN 10.5  // minimum battery voltage for 12V system
#define BAT_MAX 15.0  // maximum battery voltage for 12V system
#define BULK_CH_SP 14.4 // bulk charge set point for sealed lead acid battery // flooded type set it to 14.6V
#define FLOAT_CH_SP 13.6  //float charge set point for lead acid battery
#define LVD 11.5          //Low voltage disconnect setting for a 12V system
#define PWM_PIN 3         // pin-3 is used to control the charging MOSFET //the default frequency is 490.20Hz
#define LOAD_PIN 2       // pin-2 is used to control the load
#define BAT_RED_LED 5
#define BAT_GREEN_LED 6
#define BAT_BLUE_LED 7
#define LOAD_RED_LED 8
#define LOAD_GREEN_LED 9
//--------------------------------------------------------------------------------------------------------------------------
///////////////////////DECLARATION OF ALL BIT MAP ARRAY FOR FONTS////////////////////////////////////////////////////////////////
//--------------------------------------------------------------------------------------------------------------------------

byte solar[8] = //icon for solar panel
{
  0b11111,0b10101,0b11111,0b10101,0b11111,0b10101,0b11111,0b00000
};
byte battery[8] =  //icon for battery
{
  0b01110,0b11011,0b10001,0b10001,0b10001,0b10001,0b10001,0b11111
};

byte energy[8] =  // icon for power
{
  0b00010,0b00100,0b01000,0b11111,0b00010,0b00100,0b01000,0b00000
};
/*byte alarm[8] =  // icon for alarm
{
 0b00000,0b00100,0b01110,0b01110,0b01110,0b11111,0b00000,0b00100
};*/
byte temp[8] = //icon for termometer
{
 0b00100,0b01010,0b01010,0b01110,0b01110,0b11111,0b11111,0b01110
};

byte charge[8] = // icon for battery charge
{
  0b01010,0b11111,0b10001,0b10001,0b10001,0b01110,0b00100,0b00100,
};
byte not_charge[8]=
{
  0b00000,0b10001,0b01010,0b00100,0b01010,0b10001,0b00000,0b00000,
};


//--------------------------------------------------------------------------------------------------------------------------
///////////////////////DECLARATION OF ALL GLOBAL VARIABLES//////////////////////////////////////////////////////////////////
//--------------------------------------------------------------------------------------------------------------------------
float solar_volt=0;
float bat_volt=0;
float load_current=0;
int temperature=0;
int temp_change=0;
float system_volt=0;
float bulk_charge_sp=0;
float float_charge_sp=0;
float charge_status=0;
float load_status=0;
float error=0;
float Ep=0;
int duty =0;
float lvd;
float msec=0;
float last_msec=0;
float elasped_msec=0;
float elasped_time=0;
float ampSecs = 0;
float ampHours=0;
float watts=0;
float wattSecs = 0;
float wattHours=0;

// Set the pins on the I2C chip used for LCD connections:
//                    addr, en,rw,rs,d4,d5,d6,d7,bl,blpol
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address // In my case 0x27
//******************************************************* MAIN PROGRAM START ************************************************
void setup()
{

Serial.begin(9600);
pinMode(BAT_RED_LED,OUTPUT);
pinMode(BAT_GREEN_LED,OUTPUT);
pinMode(BAT_BLUE_LED,OUTPUT);
pinMode(LOAD_RED_LED ,OUTPUT);
pinMode(LOAD_GREEN_LED,OUTPUT);
pinMode(PWM_PIN,OUTPUT);
pinMode(LOAD_PIN,OUTPUT);
digitalWrite(PWM_PIN,LOW);  // default value of pwm duty cycle
digitalWrite(LOAD_PIN,LOW);  // default load state is OFF
lcd.begin(20,4);   // initialize the lcd for 16 chars 2 lines, turn on backlight
lcd.backlight(); // finish with backlight on  
lcd.createChar(1,solar);
lcd.createChar(2, battery);
lcd.createChar(3, energy);
//lcd.createChar(4,alarm);
lcd.createChar(5,temp);
lcd.createChar(6,charge);
lcd.createChar(7,not_charge);
lcd.clear();
}

void loop()
{
 read_data();             // read different sensors data from analog pin of arduino
 system_voltage();        // detect the system voltage according to battery voltage
 setpoint();      // decide the charge set point according to system voltage
 charge_cycle();         // pwm charging of battery
 power();                // calculate the load power and energy
 load_control();         //control the load
 led_indication();       // led indica
 print_data();            // print in serial monitor
 lcd_display();           // lcd display
 }
//************************************************************ PROGRAM END *************************************************


//------------------------------------------------------------------------------------------------------
////////////////// READS AND AVERAGES THE ANALOG INPUTS (SOLRAR VOLTAGE,BATTERY VOLTAGE)////////////////
//------------------------------------------------------------------------------------------------------
int read_adc(int adc_parameter)
{
  
  int sum = 0;
  int sample ;
  for (int i=0; i<AVG_NUM; i++) 
  {                                        // loop through reading raw adc values AVG_NUM number of times  
    sample = analogRead(adc_parameter);    // read the input pin  
    sum += sample;                        // store sum for averaging
    delayMicroseconds(50);              // pauses for 50 microseconds  
  }
  return(sum / AVG_NUM);                // divide sum by AVG_NUM to get average and return it
}
//-------------------------------------------------------------------------------------------------------------
////////////////////////////////////READ THE DATA//////////////////////////////////////////////////////////////
//-------------------------------------------------------------------------------------------------------------
 void read_data(void) 
 {
    //5V = ADC value 1024 => 1 ADC value = (5/1024)Volt= 0.0048828Volt
    // Vout=Vin*R2/(R1+R2) => Vin = Vout*(R1+R2)/R2   R1=100 and R2=20
     solar_volt = read_adc(SOL_ADC)*0.00488*(120/20);
     bat_volt   = read_adc(BAT_ADC)*0.00488*(120/20);       
     load_current = (read_adc(CURRENT_ADC)*.0488 -25); 
     temperature = read_adc(TEMP_ADC)*0.00488*100;
     
  }
  //------------------------------------------------------------------------------------------------------------
/////////////////////////////////POWER AND ENERGY CALCULATION //////////////////////////////////////////////
//------------------------------------------------------------------------------------------------------------
void power(void)

{
msec = millis();
elasped_msec = msec - last_msec; //Calculate how long has past since last call of this function
elasped_time = elasped_msec / 1000.0; // 1sec=1000 msec
watts = load_current * bat_volt; //Watts now
ampSecs = (load_current*elasped_time); //AmpSecs since last measurement
wattSecs = ampSecs * bat_volt; //WattSecs since last measurement
ampHours = ampHours + ampSecs/3600; // 1 hour=3600sec //Total ampHours since program started
wattHours = wattHours + wattSecs/3600; // 1 hour=3600sec //Total wattHours since program started
last_msec = msec; //Store 'now' for next time
}

//------------------------------------------------------------------------------------------------------------
/////////////////////////////////PRINT DATA IN SERIAL MONITOR/////////////////////////////////////////////////
//------------------------------------------------------------------------------------------------------------
  void print_data(void) 
  {
    delay(100);
    Serial.print("Solar Panel Voltage: ");
    Serial.print(solar_volt);
    Serial.println("V");
    Serial.print("Battery Voltage: ");
    Serial.print(bat_volt);
    Serial.println("V");
    Serial.print("Syestem Voltage: ");
    Serial.print(system_volt);
    Serial.println("V");
    Serial.print("Charge Set Point:");
    Serial.println(bulk_charge_sp);
    Serial.print("Temperature:");
    Serial.print(temperature);
    Serial.println("C");
    Serial.print("Load Current: ");
    Serial.print(load_current);
    Serial.println("A");
    Serial.print("Power: ");
    Serial.print(watts);
    Serial.println("W");
    Serial.print("Energy: ");
    Serial.print(wattHours);
    Serial.println("WH");
    Serial.print("Duty Cycle :");
    if (charge_status==1)
    {
    Serial.println("99%");
    Serial.println("BULK CHARGING");
    }
    else if (charge_status==2)
    {
    Serial.print(Ep);
    Serial.println("%");
    Serial.println("FLOAT CHARGING");
    }
    else
    {
    Serial.println("0%");
    Serial.println("NOT CHARGING");
    }
    if(load_status==1)
    {
     Serial.println("LOAD IS CONNECTED"); 
    }
    else
    {
     Serial.println("LOAD IS DISCONNECTED");   
    }
   
    Serial.println("***************************");
 }
//----------------------------------------------------------------------------------------------------------------------
//////////////////////////////////SYSTEM VOLTAGE AUTO DETECT ///////////////////////////////////////////////////////////
//----------------------------------------------------------------------------------------------------------------------
void system_voltage(void)
{
  if ((bat_volt >BAT_MIN) && (bat_volt < BAT_MAX))
  {
     system_volt = 12;
  }
  /*
  else if  ((bat_volt > BAT_MIN*2 ) && (bat_volt < BAT_MAX*2))
  {
    system_volt=24;
  }*/
  else if ((bat_volt > BAT_MIN/2 ) && (bat_volt < BAT_MAX/2))
  {
    system_volt=6;
  }
  
}
//---------------------------------------------------------------------------------------------------------------------------
 ////////////////////////////////////CHARGE SET POINT ///////////////////////////////////////////////////////////////////////
//---------------------------------------------------------------------------------------------------------------------------
 
void setpoint(void)
{
  temp_change =temperature-25.0; // 25deg cel is taken as standard room temperature 
 // temperature compensation = -5mv/degC/Cell 
  // If temperature is above the room temp ;Charge set point should reduced
  // If temperature is bellow the room temp ;Charge set point should increased
  if(system_volt ==12)
  {
     bulk_charge_sp = BULK_CH_SP-(0.030*temp_change) ;
     float_charge_sp=FLOAT_CH_SP-(0.030*temp_change) ;
     lvd =LVD;
  }
 
  else if(system_volt ==6)
  {
     bulk_charge_sp = (BULK_CH_SP/2)-(0.015*temp_change) ;
     float_charge_sp= (FLOAT_CH_SP/2)-(0.015*temp_change) ;
     lvd=LVD/2;
  }
  /*
  else if (system_volt == 24)
  {
   bulk_charge_sp = (BULK_CH_SP*2)-(0.060*temp_change) ;
   float_charge_sp= (FLOAT_CH_SP*2)-(0.060*temp_change) ;
   lvd=LVD*2;
  }
  */
  
}
//--------------------------------------------------------------------------------------------------------------------------------
 ///////////////////////////////////////////////////PWM CHARGE CYCLE @500 HZ //////////////////////////////////////////////////
 //-------------------------------------------------------------------------------------------------------------------------------
void charge_cycle(void)
{
  if (solar_volt > bat_volt && bat_volt <= bulk_charge_sp)
  {
  
   
   if (bat_volt <= float_charge_sp) // charging start
  {  
     charge_status = 1; // indicate the charger is in BULK mode
     duty= 252.45;
     analogWrite(PWM_PIN,duty); // 99 % duty cycle // rapid charging 
     
   
  }
  else if (bat_volt >float_charge_sp && bat_volt <= bulk_charge_sp)
  {   
      charge_status = 2; // indicate the charger is in FLOAT mode
      error  = (bulk_charge_sp - bat_volt);      // duty cycle reduced when the battery voltage approaches the charge set point
      Ep= error *100 ; //Ep= error* Kp // Assume  Kp=100
      
      if(Ep < 0) 
       { 
        Ep=0;
        }
      else if(Ep>100) 
        {
         Ep=100;
        }
      else if(Ep>0 && Ep <=100) // regulating
       {
         duty = (Ep*255)/100;
       }
       analogWrite(PWM_PIN,duty);
   }
 }
   else
   {
   charge_status=0;  // indicate the charger is OFF
   duty=0;
   analogWrite(PWM_PIN,duty);
   }
}
//----------------------------------------------------------------------------------------------------------------------
/////////////////////////////////////////////LOAD CONTROL/////////////////////////////////////////////////////
//----------------------------------------------------------------------------------------------------------------------  
  
void load_control()
{
 if (solar_volt < 5  ) // load will on when night
{ 
  if(bat_volt >lvd)   // check if battery is healthy 
  {
  load_status=1;
  digitalWrite(LOAD_PIN, HIGH); // load is ON
  }
  else if(bat_volt < lvd)
  {
    load_status=0;
   digitalWrite(LOAD_PIN, LOW); //load is OFF
  }
 }
 else // load will off during day
 {
   load_status=0;
   digitalWrite(LOAD_PIN, LOW);
 }
}


//-------------------------------------------------------------------------------------------------
//////////////////////////LED INDICATION////////////////////////////////////
//-------------------------------------------------------------------------------------------------
void led_indication(void)
{
  battery_led();           //Battery status led indication
  load_led();              //Load led indication
}

//----------------------------------------------------------------------------------------------------------------------
/////////////////////////////////////////////BATTERY LED INDICATION/////////////////////////////////////////////////////
//----------------------------------------------------------------------------------------------------------------------
void battery_led(void)
{
  
   if( (bat_volt > system_volt) && ( bat_volt <bulk_charge_sp))
  {   
      leds_off_all();
      digitalWrite(BAT_GREEN_LED,LOW);  // battery voltage is healthy
  } 
  else if(bat_volt >= bulk_charge_sp) 
  {
      leds_off_all();
      digitalWrite(BAT_BLUE_LED,LOW);  //battery is fully charged
  }
   else if(bat_volt < system_volt)
  {
      leds_off_all();
      digitalWrite(BAT_RED_LED,LOW);  // battery voltage low
  }
}
//----------------------------------------------------------------------------------------------------------------------
/////////////////////////////////////////////LOAD LED INDICATION/////////////////////////////////////////////////////
//----------------------------------------------------------------------------------------------------------------------  
  
  void load_led()
  {
    if(load_status==1)
    {
      digitalWrite(LOAD_GREEN_LED,HIGH);
    }
    else if(load_status==0)
    {
      digitalWrite(LOAD_RED_LED,HIGH);
    }
   }

//------------------------------------------------------------------------------------------------------
//////////////////////// TURN OFF ALL THE LED///////////////////////////////////////////////////////////
//------------------------------------------------------------------------------------------------------
void leds_off_all(void)
{
  
  digitalWrite(BAT_RED_LED,HIGH);
  digitalWrite(BAT_GREEN_LED,HIGH);
  digitalWrite(BAT_BLUE_LED,HIGH);
  digitalWrite(LOAD_RED_LED, LOW);
  digitalWrite(LOAD_GREEN_LED, LOW);
}
//------------------------------------------------------------------------------------------------------
//////////////////////// LCD DISPLAY///////////////////////////////////////////////////////////
//------------------------------------------------------------------------------------------------------
void lcd_display()
{
 lcd.setCursor(0, 0);
 lcd.write(1);
 lcd.setCursor(2, 0);
 lcd.print(solar_volt);
 lcd.print("V");
 lcd.setCursor(14, 0);
 lcd.write(5);
 lcd.setCursor(16, 0);
 lcd.print(temperature);
 lcd.write(0b11011111);
 lcd.print("C");
 lcd.setCursor(0,1);
 lcd.write(2);
 lcd.setCursor(2, 1);
 lcd.print(bat_volt);
 lcd.print("V");
 lcd.setCursor(14, 1);
 lcd.write(2);
 if((charge_status==1) | (charge_status== 2))
 {
 lcd.write(6);
 }
 else
 {
 lcd.write(7);
 }
 lcd.setCursor(0,2);
 lcd.write(3);
 lcd.setCursor(2,2);
 lcd.print(load_current); 
 lcd.print("A");
 lcd.setCursor(13,2); 
 lcd.print(watts); 
 lcd.print("W"); 
 lcd.setCursor(0,3);
 lcd.print("Energy:"); 
 lcd.print(wattHours);
 lcd.print("WH"); 
 

 
   
  
}