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Boost your battery life: Laptops & netbooks

Posted on 11 Mar 2009 at 16:54

Make Windows do the work

It sounds like a no-brainer, but some of us ignore or even disable the power-management facilities in Windows. This is a big mistake according to Dell's UK field product manager, Bob Bennett, who recommends adopting an option such as Vista's Power Saver plan or a manufacturer's proprietary tool (such as Dell's ControlPoint).

Go to Start | Control Panel | Power Options and check which power plan your laptop is using. These options automatically take care of factors such as screen brightness, hard-disk usage and Wi-Fi power, but more importantly, they throttle the CPU to ensure it's only using the power it needs to. The Balanced setting, for example, allows Windows to determine how much power your current applications need, setting the CPU to run at anywhere between 5% and 100% of its maximum frequency. Power Saver is more aggressive, preventing the CPU from working at above 50% of its maximum speed. You can adjust each setting in detail by clicking on Change Plan Settings under your chosen plan, then clicking on the Change Advanced Power Settings link.

Dimmer can be brighter

The display lamp is the largest consumer of power in the average laptop, according to Dell's senior systems engineer, Tony Salinas. At higher brightness settings, you may only achieve 65% of your optimal battery life. Our tests bear this out - halving the brightness level on the 10.2in Asus N10 screen added more than 30 minutes to the battery's life span, and more than an hour to that of the 15.4in HP 6735s.

In most cases, your default power options will be set to turn down the brightness as soon as you unplug, so don't make the mistake of turning them straight back up again to full, or those overworked cells won't last.

You can usually turn down brightness by using a simple keyboard shortcut (usually a Function key plus number key with a sun icon), but it's more sensible to let Vista's Power Options handle things automatically. In the panel on the left-hand side, you should see a link called Adjust the Display Brightness. Click it, and check the slider under On Batteries. If it's all the way to the right, click and drag it into the middle, before clicking OK.

Turn off Wi-Fi

"If you're not using wireless LAN to connect to the internet, turn it off," advises our man from Intel, who warns that "wireless LAN access uses power even when it isn't in use". The wireless radio in your laptop is always busy, scanning for local networks and trying to create a connection when you're not hooked up, and checking email and update services when you are.

When you don't need to be online, switch off Wi-Fi and Bluetooth too. Most laptops now have a simple Function-key combination or hardware switch to enable this, so check your manual for details. In the unlikely event that there isn't, go to Start | Control Panel | Network Connections, right-click your wireless connection and select Disable. In our tests, turning off Wi-Fi and Bluetooth added up to 26 minutes to the laptop's battery life.

Don't use DVDs

With a motor and a laser to run, optical drives are relatively power-hungry, so avoid using them when you're not plugged in. Copy any documents or content from CD or DVD to hard disk before you leave your desk. If you use an application that accesses the drive during use, see if you can perform a full install to hard disk. Rip music CDs to your hard disk instead of listening to them directly, and if you must copy files or backup, do so to a USB key or memory card rather than CD or DVD.