As far as I know the regulation of battery charging is done inside the phone. The typical method of charging lithium cells is constant current charging followed by constant voltage charging where you shouldn't let your battery voltage go over 4.2V.
However it seems my charger keeps pushing the maximum possible current and increasing the voltage far beyond 4.2V. At 100% the voltage gauge is at 4.4V and if I remove the charger it's going down to 4.25V, which is again above the safe levels.
So it seems my charger is killing my battery. Is it possible to somehow tell the system to stop increasing the voltage above 4.2V or preferably 4V?