How to check your laptop battery health

• Open Command Prompt as administrator.
• Type: powercfg /batteryreport and press Enter.
• Open the HTML file it saves and compare 'Design capacity' with 'Full charge capacity'.
• If the full charge capacity is far below the design capacity (for example under 60%), the battery is worn.
• Short backup and sudden shutdowns also show a worn battery.

A new battery brings back the original backup and is cheaper than a new laptop.