Hi @KOMBAT, welcome to our forum!
Has your phone always charged at this rate or have this changed after you for example, updated your device or installed a new application?
I would recommend that you start with rebooting your phone in safe mode and that you charge your phone using the charger that was included together with your phone and a wall socket. This way we can make sure that a third party application isn't the cause of the rate the phone is charging at. You can also turn off your phone and charge it and see how long it takes, according to the information that is available in the environmental document the estimated time to charge an Xperia M4 Aqua from 0% to 100% is 3 hours and 50 minutes.
Do note that this information is only valid if the phone is powered off and that you are using the original charger and a wall socket.
Let me know how it goes!
