Let’s face it—just because something is in plain site doesn’t mean you’ll pay attention to it. That’s why Windows XP has an alarm to warn you when your battery is low. Best of all, it can be adjusted to suite your needs.
Go to Start/Control Panel/Power Options and look for the “Alarms” tab.
Check the box “Activate low battery alarm when power level reaches…” then adjust the slider. You can keep it around 10%, if you’re paranoid keep it higher, or for you daring types, go lower.It’s your call.
Next, click the “Alarm Action” button. Here you can choose to have just a display message or an actual sound alarm.
You’ll also notice the “Critical battery alarm”. This should be at a lower setting than the Low Battery Alarm so you’ll know to save your data and get to the nearest wall outlet immediately.