Chosen Solution

Hi I got Samsung Tab A 8.0 (P355) sent in to me for repair regarding battery percentage decreasing while charging. After changing a new battery, the battery percentage are increase. But when the Tab are not charging the battery was draining very fast (1 minute 5% decrease). What is the possible problem ? Does the cause came from the charging IC ? I dont have the schematic for P355. So What should I do next ?

Try to Factory reset your Tab it will default all of your settings, the reasons why the is so fast to drain is because of the usage and performance.. When your Device is in the idle mode try to off (Wifi, Data, Bluetooth and other apps. including the other tab)

likewise, draining fast and losing percentage while charging. Maximized battery conservation options are not pretty.