my phone is sony ericsson, the charger is not workin anymore, so i started to use my dads charger...and when you charge the mobile they say (optimised charging) but now it started to say (charging alien battery) i got freaked out....loool.....do you why is it sayin like this?my dad`s phone is sony ericsson too but its another model acttuly

Ask your Dad to buy you a new charger. There may a compatability issue and your battery may be at risk.