The battery life of the new MacBooks and the MacBook Pro 17" has dropped dramatically in the new revision. From being the top battery performer with 5.75 hours, the 2.6GHz MacBook Pro 17" has fallen to 4.5 hours. Exactly like the MacBook, which drops from 6 full hours battery life. There are some explanations, but none of them can explain the change because the number don't add up:
First is Apple's new "Wireless Productivity" battery life. According to Apple, this measures the battery life under typical Wi-Fi use, browsing web pages, working with mail and other Internet-related applications. It seems like if Apple is now being a lot more conservative and strict in their battery performance tests. But while this may explain the drop, it doesn't seem that simple.
The MacBook Pro 15 battery life, for example, remains unchanged across all CPU speeds (the higher the speed, the more energy it consumes) even with the new battery test method. Unofficially, Apple sources point out that the use of LED screen backlighting saves 30 minutes of battery life. But is that enough to compensate against the drop in battery life of the MacBook 17"? And how could the battery life be the same for three different frequencies?
This is another reason that can't explain the problem with the MacBooks, for example. While these don't have LED backlighting, there's no reason to see 1.5 hour lost in a 0.2GHz CPU bump, specially when the new Core 2 Duo is allegedly more efficient than the previous generation.
And yes, maybe it's a combination of all these things, but that wouldn't explain why the MacBook Pro 15 keeps its battery life intact. The bottom line remains the same, however. Whatever are the reasons, the fact is that, according to Apple, you won't get the same mileage from the new MacBooks and MacBook Pro 17". [MacBook and MacBook Pro]