What can you do to make lenovo ideapad c340 15 battery last longer?

There are several things that will help the battery last longer:

    Use the product's power saving controls to reduce battery use in a normal day. For example, turn Bluetooth off if not needed and reduce the screen brightness if possible.
    Avoid exposure to extreme temperatures. If the system is exposed to extreme cold or hot temperatures, allow the system to warm up or cool down before use and before charging.
    All batteries wear with use and time. When the runtime is no longer sufficient for your needs, consider purchasing a new Lenovo battery from shop.lenovo.com.
    The Lenovo Vantage application provides several advanced battery management features. See the Power settings section under My Device Settings.
    Additionally, Microsoft Windows Battery Saver Settings provides multiple ways to optimize your battery performance, including Battery Saver mode and lists of applications draining battery life.

The above sources from pcsupport.lenovo.com.

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