Same here: Installed Update yesterday and a significant Battery Drain is notable -> before I had iOS 13 -> Usage all day without any Problems (Battery has still 82% Capactiy)  Now I can watch Battery running down ... Deactivated SIRI and Location Services and Widgets -> now it looses less Battery but doing Tasks -> E-Mail or Safari -> it drains again very fast  This is a shame ... my iPhone has still 60GB Memory left and worked fine until the update and I am not willing to buy a new one. Apple has to fix this.