my xiaomi note 5 xiaomi.eu with dev rom 8.12.27 works 6-7 days non stop with automatic mode off GSM when I sleep, and with about 20 calls per day, some photo, some wifi and e-mail. My battery is non stop in savemode, and all apps is kill in background, . I don`t use sync and LTE or 3G Internet transmission , use 0.5 Amper changer or charging with usb PC, and screen in minimum power. I live in city and my network 2G is full.