What's the real battery life?

Anyone who spends time with a notebook knows that manufacturer’s battery life claims can bear little resemblance to what you will experience in the real world.

This is hardly surprising in some respects. I mean, if you are a heavy user of battery pounding features you are likely to get fewer minutes from a fully charged battery than if you are a light user.

But when does this become more than simply one of those facts of life we all know we have to live with, and morph into an important irritation?

Let’s consider Hewlett Packard’s EliteBook 2730p a small, light convertible Tablet PC. My review of this notebook is due to be published shortly, but here’s a little preview relating to battery life.

HP suggests you can get up to 6.5 hours of life from the supplied battery. I chose the HP Optimised power plan, switched wireless networking on, and worked with the laptop for word processing and Internet access for three hours at which point the battery was just below half full.

I had to stop at this point because the screen was extremely dim and I found it difficult to work. I may well have approached 6.5 hours of battery life, but would not have been content to use this powerplan as my everyday favourite.

Meanwhile, Asus’ super new Eee PC, the 1000HE has been in my possession for a little while now. This is a very nice netbook, and I could see myself using it on a long term basis.

But there is a battery life issue. Asus claims this Eee can last up to 9.5 hours on its provided battery. It runs on Windows XP Home, which allowed me to run the Battery Eater benchmark. I did this twice.

On the graphics intensive run I got 6 and a half hours of battery life. A less power-hungry run which simulates someone reading text off the page delivered 7 and a half hours. Now, both of these are pretty good battery life benchmarks and I’d be happy to live with that kind of performance in the real world. I do think, though, that you’d have to be a very light user indeed to get near that 9.5 hours claim.

The unfortunate thing is that there is no industry standard for measuring battery life. Notebook specification sheets sometimes reveal what benchmarking tools they have used to get their quoted battery life, but more often they do not.

This is especially ironic as for most of us the ability of a notebook – or netbook – to work for extended periods away from mains power is a key feature relating to its purchase, and is likely to be one of the more important factors taken into consideration when weighing up machines on a shortlist.