my phone is s8+ the battery drain very fast approximately 20% each 25 minutes, sometimes i disconnect the phone from charger and the phone is on standby still drains like 7 to 8 percent every 40 minutes
you have got some serious issue .. check ur batary usage in options and you will find which app.is using more batary so unstall that or els go to samsung repair center and replace the Android operating system🙄
