Why you should keep a laptop battery between 20 and 80 per cent

A laptop battery that loses half its capacity within two years is usually not a quality problem — it is the result of how it was charged. The simplest rule is to keep the charge between 20 and 80 per cent.

Why the middle of the range matters

Holding a lithium battery at 100 per cent keeps its internal voltage high and puts the chemistry under constant stress. Running it to zero does the opposite kind of damage: electrode wear and thermal stress. The 20–80 band sits at a balanced voltage with low mechanical pressure and stable cycling. Staying inside it can take a battery from roughly 500 useful cycles to something closer to 2,000.

Most current laptops can hold that limit for you. Every manufacturer just calls it something different.

ASUS — Battery Health Charging

1. Open the MyASUS app.
2. Go to Customization → Power & Performance → Battery Health Charging.
3. Choose Maximum Lifespan Mode.

In that mode charging stops between 60 and 80 per cent and resumes once the charge falls below 20.

Lenovo — Conservation Mode

1. Open Lenovo Vantage or Lenovo Energy Management.
2. Select Battery Settings → Conservation Mode.

With it on, charging stops at roughly 55 to 60 per cent.

Dell — Battery Charge Threshold

1. Open Dell Power Manager or Dell Command | Configure.
2. Go to Battery Information → Advanced Charge → Custom Mode.
3. Set "Start charging at 20%" and "Stop charging at 80%" by hand.

On Dell machines the same setting exists in firmware: BIOS → Power Management → Primary Battery Charge Configuration.

HP — Battery Care Function

Use HP Support Assistant, or press F10 at startup and go to BIOS → Power → Battery Care Function, then choose Maximize Battery Health. On HP this holds roughly a 25 to 80 per cent range.

MacBook — Optimized Battery Charging

Go to System Settings → Battery → Battery Health and turn on Optimized Battery Charging. macOS learns your routine, usually stops at 80 per cent, and only fills to 100 shortly before you need it.

If your laptop has no such tool

• Battery Limiter — a free Windows app that alerts you when the charge reaches a limit you set, such as 80 per cent.
• BatteryBar Pro or Smarter Battery — charge history and wear graphs.
• On Linux, TLP can set the thresholds directly: tlp setcharge 20 80.

If none of that is available, the manual version still works: unplug once it is full and plug in before it gets close to 20 per cent. If the laptop lives permanently plugged in at a desk, turning on one of the modes above matters more than anything else on this list.