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How To: Automatically Enable Low Power Mode When Your iPhone Is Locked to Save Battery Life

Though not as flashy as Face ID and other features, Low Power Mode has become one of the unsung heroes of iOS. When you're away from a charger, enabling this feature will dial back performance and networking to help you eke out up to three extra hours of battery life. If your device is jailbroken, you can even automate Low Power Mode to ensure your battery never dips to critical levels while out and about.