



Laptops inch towards all-day battery life


David Flynn

The era of all-day computing without plugging in is almost here, writes David Flynn.

Upwards of eight hours battery life ... Acer TimelineX

Upwards of eight hours battery life ... Acer TimelineX

It's the holy grail of any laptop user who spends most of the day out of the office.

Yes, thinner and lighter laptops are a blessing. But how about a notebook that will run all day without recharging? When will we be able to hit the road but leave the AC adaptor at home?

The answer to that question is "today", depending on the price you're prepared to pay and the compromises you're willing to make (see sub-section below).

Within the next few years it won't be an issue. The march of technology in computer chips and other components will make all-day computing a trait of almost every laptop.

"The challenge for us is to bring all-day battery life to the mainstream so that you take the laptop to work and leave the power supply at home," says Mooly Eden, the general manager of Intel's Mobile Platforms Group.

"But all day means different things to different people. For me it might be eight hours, for you it might be 10 hours. And we need to do even more than that, because as the laptop gets older, the battery life will slowly get lower. We need to deliver 10 to 12 hours without the charger. And we will be able to do that, because all-day battery life is not just possible, it is inevitable."

Making notebooks better is what Eden does. Through his revolutionary work creating Intel's Centrino laptop technology, the foundation of the Core line of processors, Eden is considered the father of modern mobile computing.

The Core i3, Core i5 and Core i7 chips run faster than any previous generation of Intel silicon, while drawing less power. And even that extra speed is being channelled into eking out extra battery life.

If you divide the laptop's typical working day into tiny slices of time, most of them are spent being idle. More processing muscle means the notebook can do the heavy-lifting faster, allowing it to return to the low-power idle state more quickly. The more time it spends there, the longer the battery lasts.

Eden calls this feature "hurry up and get idle" and it's enhanced by turbo boost modes that further accelerate the processor for short but intense bursts - opening an email attachment or displaying a PowerPoint deck as thumbnails.

"The idea is wake the notebook up, do the job and then go to sleep again," Eden explains. "If the chip does the job faster, it can go back to sleep sooner, so you get better performance and you also get extended battery life. This is the real secret of energy efficiency."

Yet the processor is just one part of the notebook. The screen is responsible for the largest portion of a laptop's power drain, followed by the hard drive. Efficiencies in these are slower to come, with fewer breakthroughs and smaller leaps.

That said, notebook screens with LED backlighting draw less juice than the non-backlit models, while also providing a brighter picture.

And while solid state drives draw almost no power compared with the conventional platters of a hard disk, their high price and relatively low capacity makes them impractical for many notebook users. Seagate is leading the way to a new wave of hybrid hard drives that partner a high-capacity hard disk with solid state memory that automatically stores the most commonly used files and data.

There's also a growing trend towards lightweight operating systems that allow email, music or movies and web-browsing without loading Microsoft Windows.

Typically based on Linux and embedded in a flash memory chip inside the laptop, they spring to life within seconds instead of the hard-disk hammering (and power-sucking) minute Windows often demands - which makes them a boon for shorter work sessions on the go.

Asus, Dell and HP all offer some form of "instant on" mode. Dell's impressive Latitude ON implementation is bolstered by a tiny secondary processor and has inbuilt Citrix VPN support, making it possible to sidestep Windows for much of the day and let the notebook stride into Day 2 without an AC outlet in sight.

Once we hit true all-day computing for all laptops, this will be the target: a notebook that rocks around the clock, and then some.

How to join the all-day computing revolution

If you want all-day computing, here are some shopping hints.

Acer's TimelineX family uses Intel's ultra-low voltage Core i3, Core i5 and Core i7 powerplants to deliver upwards of eight hours in a slim and stylish chassis. The mid-range model with a generous 40-centimetre screen sells for $1600 but you can also get models in a near-netbook 30-centimetre screen size.

Option up your new laptop. In most business notebooks the standard battery can be replaced by a higher-capacity pack. Dell, HP and Lenovo also offer secondary batteries that replace the CD/DVD drive or attach to the notebook's underside (sometimes called a "travel slice") so you can hit the road with two full tanks of juice.

Look for laptops with fast-charge technology so you can top up the battery quickly by plugging into a power point for just half an hour. Also, place a premium on power-management software that can disable hardware such as the USB and network ports, fingerprint reader and even

CD/DVD drive, if they're not being used. All those tiny voltage savings add up.

Squeeze the most out of your existing notebook by turning down the screen brightness and turning off 3G, Bluetooth and

Wi-Fi unless you need them. After a few years your laptop's battery will be wearing down and running at much less than its original capacity. You can buy a new battery but you'd be much better off to buy a whole new notebook.

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