A laptop that used to last all day and now begs for the charger by 11am is one of the most common complaints we hear in Canberra. Sometimes the battery really is worn out. Just as often, though, the battery is fine and something else is quietly draining it.

Check what is running in the background

Open Task Manager on Windows or Activity Monitor on a Mac and sort by energy or CPU use. Browser tabs playing video, cloud sync tools indexing thousands of files, and forgotten apps updating themselves are the usual suspects. Closing two or three heavy background processes can add hours of battery life.

Screen brightness matters more than you think

The display is usually the single biggest power consumer in a laptop. Running at full brightness indoors can cut battery life by a third compared to a comfortable 60 to 70 percent. Keyboard backlighting adds to the drain as well.

Why battery health matters more than the percentage

Every battery wears with use, measured in charge cycles. On a Mac, hold Option and click the battery icon to see its condition. On Windows, run 'powercfg /batteryreport' in the command prompt for a full history. If the design capacity has dropped below about 70 percent, replacement is worth considering.

Malware can drain a battery too

Infected machines often run flat quickly because malicious software keeps the processor busy in the background. If fast drain arrived together with pop-ups, a slow browser, or fans that never stop, a clean-up may fix both problems at once.

When replacement is the right call

If the battery drains fast even when idle, shuts down at 20 or 30 percent remaining, or bulges enough to push up the trackpad, stop using it and have it looked at. A swollen battery is a safety issue. We test batteries as part of every free diagnostic and will tell you honestly whether yours needs replacing or whether the drain is coming from somewhere else.