If your battery percentage is jumping around, use a built-in calibration method or software like BatteryCare to reset the charge indicators.

The only real way to "double" your battery life today is with a high-capacity External Power Bank that supports USB-C Power Delivery.

Use the Windows "Best power efficiency" or Mac "Low Power Mode" settings to immediately reduce background activity.

While claims to double your laptop’s autonomy by optimizing settings, it is important to understand that it is a very old software tool (dating back to around 2003-2004) and its "serial number" is often associated with pirated or "cracked" versions found on sketchy websites. The Bottom Line