Looking after a laptop battery: extending runtime and lifespan

In short: Laptop batteries age through heat, full charges and deep discharge; keeping them cool, mostly charging between about 20 and 80 percent and using power-saving mode extends their life considerably.

In more detail: Modern laptops, phones and tablets use lithium-ion or lithium-polymer batteries. They have no “memory effect” but lose some capacity with every charge cycle and over time. After a few hundred cycles often 80% remains.

In Depth

What harms the battery

• Heat: the biggest enemy (car in the sun, laptop on a bed or sofa, blocked vents).
• Permanently at 100% and warm at the same time, for example continuous use on the charger under high load.
• Deep discharge to 0%, especially during long storage.
• Extreme cold while charging.
• Cheap or wrong chargers.

What helps

• Set a charge limit if the software offers it (many makers: “battery care”, 80% limit). Especially worthwhile for permanent desk use.
• Keep it cool: hard, flat surface, vents free, remove dust.
• Use power-saving mode and lower screen brightness; close background programs (autostart).
• For storage charge to about 50% and keep it cool.
• Use the original or certified charger.
• Install BIOS/firmware and driver updates (power management).

Checking condition and replacing

• Windows: powercfg /batteryreport at the command prompt produces a battery report (design capacity versus full charge capacity).
• macOS: System Information → Power (cycle count, condition).
• Replace when runtime has dropped sharply, the case bulges or a warning appears. Swollen batteries are a fire risk: stop charging, have a specialist replace them.
• Disposal only through take-back points (retail, recycling centre), never in household waste.

See also: Cooling and thermal paste, Reducing power use, Disposing of old electronics