May 9, 2009

MacBook batteries and sleep vs. hibernate

As a new MacBook owner, I'm paying careful attention to how the thing is working etc, just in case I've got a bad one. As it seems, everything is pretty good, some strange console messages, but on the whole it's a pretty fine beast. I bought it with the intention to start blogging and to maybe explore something a bit more creative given the logical way in which I go about my normal 9 to 5 job.

Being a gadget boy (both self-confessed and labelled by others), one thing that always concerns me is battery life. Like many others have reported in the Apple Support Forum I noticed my MacBook slowly lose charge when in sleep mode. For example, I'd charged it overnight one night - 100% in the morning - and then on the trip to work (I'd put it to sleep), it would wake up to 96% after a 15-20 minute trip.

Yesterday, I let the battery drain completely (doing pretty much nothing, it took about 4.5 hours), which then put the MacBook into Hibernate mode. I left it charging yesterday evening until the power adaptor went green, then unplugged and left it as is over night. This morning, it's still showing full charge when I plug it back in.

It seems that the new MacBooks (as compared to my 2004 PowerBook G4) have a different sleep mode where it's a low-power mode holding memory contents rather than writing them to disk. This means there is a slow drain when in sleep mode, although the definition of "slow" can differ from laptop to laptop and person to person.

There is a preference pane/tool called SmartSleep that can be installed to control what my MacBook does when the lid is closed. I'm going to test this out over the next week and see what effect it has when I set it to hibernate instead of sleep. I don't see a real need to be able to open the lid and have it ready to go, and am happy to wait the few seconds for it to come back to life. I've just been reading comments on the Apple site above that there may be battery cost while it comes out of hibernate but will see how things go.

The other things I'm going to do over this weekend is go through a couple of full charge/discharge cycles to try and calibrate the battery.

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