My asus g74sx laptop won't charge the old or new battery I just bought. I tested the AC adapter and it's outputting 19.1 instead of 19.5. Could this power drop cause it to power the laptop but not charge the battery?
Turn off the laptop and see if it will then charge the battery. If yes, then your cord is probably going to need replacing.
If it still won't charge, even when off, but the cord is running the laptop, then I would consider looking at the charging circuit.
NOTE: If the battery you replaced it with is an aftermarket battery, then it may not work correctly. Best to go with OEM in the case of laptop batteries.