The Apple developer note for the new PowerBook announced on 19 October 2005 (1440 by 960 pixels) appears to contain conflicting information about its battery capacity: on page 11 it says: "the computer has a 6-cell battery pack that uses lithium ion cells and provides 50 watt-hours at 12.8 V (nominal) for up to 6 hours." But on page 12 it claims a "50 watt-hours battery with up to 5.5 hours operation."
So where does the new PowerBook get the extra hour, or hour-and-a-half, of extra run time over the previous model's quoted "4.5 hours operation?" The previous model PowerBook also ships with a "50 watt-hours" battery, so it must either be advanced power management ASICs on the logic board or creative marketing.
According to the Macworld review of the new PowerBook:
"if you're actually using the PowerBook, a charge won't last nearly that long. Apple claims that the battery life is 3 hours and 45 minutes for a combination of wireless Web browsing and editing a text document, but only 2 hours and 15 minutes for DVD playback."
So what gives? How can a company market a product with a "5.5 hour" battery that only lasts 3 hours and 45 minutes?" That's a difference of almost 32 percent. Apple and other notebook manufacturers need to reform their marketing practices and advertise actual battery capacities rather than estimates of run time when the display is turned off and no applications are running.