iPhone 5 charge issues

Replaced battery in iPhone 5, worked fine for about a month, then dropped phone, got a small dent in bottom left corner and one in top right. Screen cracked. Started having charger issues, when battery drained it wouldn't charge, only displayed a red battery symbol.

Rebooted it with home+lock button pressed for 30s and after that it jumped to life after having charger plugged in for 2 minutes.

Replaced cracked display and cleaned out the lightning port from lint. Did a full reset in iTunes. Still having charger issues. Sometimes when left charging over night, battery percentage hasn't gone up. This problem has occured after dropping phone. What could be the issue? Lightning port?