How to Calibrate Your Laptop’s Battery For Accurate Battery Life Estimates
 

So you’re using your laptop and, all of the sudden, it dies. There was no battery warning from Windows — in fact, you recently checked and Windows said you had 30% battery power left. What’s going on?

Even if you treat your laptop’s battery properly, its capacity will decrease over time. Its built-in power meter estimates how much juice available and how much time on battery you have left — but it can sometimes give you wrong estimates.

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