battery drains fast even after replacement with new battery

"This is a common problem in most Galaxy phones,

#Make sure the replacement battery is original and not a knock-off

Try not to run many apps at the same timeThe phone (or the battery) could not be faulty, the Galaxy Grand is supposed to operate for 3-4 hours with a Li-Ion 2100 mAh batteryConsider buying an external power bank (battery) This power bank should last with you for a good 15-20 hours before needing to be recharged."

this appear when the phone have 3 problem 1- maybe the pf ic is damage.2- you charging is not work good 3- you have a lose connection in charging part

Try using ShutApp its a task killing app the "Force stops" apps running even without your notice. Most of the running apps drain your battery really quick as soon as you turn on mobile data or WiFi so I recommend you use or download ShutApp.