#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);  // set the LCD address to 0x27 for a 16 chars and 2 line display

int i = 0;

unsigned long previousMillis = 0;  // will store last time

// constants won't change:
const long interval = 3000;  // interval at which to blink (milliseconds)

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.print("Hello World!");
  delay(1000);
}

void loop() {

unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time
    previousMillis = currentMillis;

    switch(i) {
      case 1:
      infoOne();
      break;
      case 2:
      infoTwo();
      break;
      default:
      i = 0;
      break;
    }
    i++;
  }

  delay(200); // this speeds up the simulation
}

void infoOne() {
  lcd.clear();
  lcd.print("Vbat: ");
  lcd.print("12.4"); //example
  lcd.print("V");
  lcd.setCursor(0, 1);
  lcd.print("Ibat: ");
  lcd.print("-500"); //example
  lcd.print("mA");
  lcd.setCursor(15, 1);
  lcd.print("1");
}

void infoTwo() {
  lcd.clear();
  lcd.print("Vout: ");
  lcd.print("12.2"); //example
  lcd.print("V");
  lcd.setCursor(0, 1);
  lcd.print("Iout: ");
  lcd.print("480"); //example
  lcd.print("mA");
  lcd.setCursor(15, 1);
  lcd.print("2");
}