The reason for the battery not lasting the amount expected is because the battery is faulty or other charging components arent working properly. Other problems that can also cause this include having dust inside your vents which can be fixed by cleaning out the vents and cause the fans to work properly. Another problem that should be revised before changing your battery should be to try and change the charging ports and wall ports to make sure those charging options arent the problem. The battery over time loses its charging capabilities and causes battery to work harder and in result start to overheat. We suggest replacing the battery if these are not solutions.