This problem started this month. The percentage will sometimes start to drop from 30% dropping 1-2% every minute until it suddenly drop from 15% to 0% or sometimes it will have sudden drop from 30% to 10% then to 0% then switch off in less than 1 minute. Downloaded GSam battery and found out the screen is 40+% (but the screen always drain my phone battery so i guess this is not the cause?) Tried wipe partition cache but doesn't work. How should I fix this? Hopefully I don't need to to replace the battery, it's quite expensive.