12. Battery Tests

Along with our performance oriented benchmarks we also naturally measured the time required to complete charge and discharge the batteries in these systems under load. These battery measurements were taken for three different scenarios: To begin with, the battery started out with a full charge. Each separate measurement ran an Office application (a PowerPoint presentation), a game (demos of 3D Mark 2005), or a DVD-video (Apollo 13) in an endless loop until the battery was drained.

Extreme Real-world Relevance: Charge Time For The Battery Under Load

For a mobile PC it's interesting to measure not only how long a full charge lasts in any of the three usage scenarios, but also to measure how quickly the battery can take a full charge. In practice, you seldom can't or won't stop working just because the battery runs out of juice. That's why we measure the charge time when the system is running under the kind of load that's typical for Office applications, wherein we run our tests in a continuous sequence. At the other extreme, we also applied the same technique while a 3D game was underway. In each case we kept things up until the battery had acquired a full charge. The results from the gaming scenario also make it clear if the power supply is too weak to handle maximum system load and lay down a charge, or if it's been designed to handle such loads and charge the battery at the same time.

To make the results from the notebooks as comparable to each other as possible, we set the brightness of all displays to a fixed value of about 100cd/m2 prior to starting our tests.