Optimize your settings.
There are some simple ways you can preserve battery life — no matter how you use your device: adjust your screen brightness and use Wi-Fi
Dim the screen or turn on Auto-Brightness to extend battery life.
– To dim, open Control Centre and drag the Brightness slider to the bottom.
– Auto-Brightness adjusts your screen to lighting conditions automatically.
– To activate it, go to Menu Settings -> General -> Accessibility -> Display Accommodations and set Auto-Brightness to On. That is helpful according to the lightning conditions
When you use your device to access data, a Wi‑Fi connection uses less power than a cellular network — so keep Wi‑Fi on at all times. To turn on Wi‑Fi, go to Settings > Wi‑Fi to access a Wi‑Fi network.