Unibody Macbook Battery and Charging Time

Two questions:

1) Is it normal for the battery to take several hours, i.e. 4+, to fully charge after being mostly depleted? For example, my battery says it's like 95% charged, yet has 40 minutes to go.

2) Is it normal for the battery time-left indicator to jump all over? When I run it on battery, the amount of time remaining constantly changes. It goes from 5 hours to 3 hours to 4 hours, etc, etc.

The first time I ever used the computer when I got it in December I charged it up fully, kept it plugged in for several hours, then let it completely die out overnight and fully charged it again. I thought that would have calibrated it.

 

1) Yes, that is completely normal, don't worry about it.

2) No mac as yet so I don't know.

That did calibrate it, I don't know what is up with your indicator, I haven't a mac so I am not sure if this is normal. Also be sure to check the Battery Guide, should really help.

 

Battery time left depends on what you are doing and how much power it takes.

Amount of time remaining is an approximation by the computer and changes as you do different things.

 

I understand that. But not much changes in what I'm doing, but the estimation changes quite a bit. I generally only use Firefox, Entourage, Word, and Adium when on battery power. I turn off BT and dim the brightness to 50% or so. I still see the battery meter changing constantly. Maybe that is normal? On my old iBook G4, I didn't notice as much of a change in the time remaining.

I also only get around 3.5-4 hours on a good day. I thought the battery life was supposed to be closer to 4.5-5 hours?

 

No, it is not normal for it jump around too much when the load/settings remain relatively constant. Calibrate your battery a couple of times during the subsequent weekends and this should sort straighten out the issue.

3.5–4 hours on a good day is a reasonably good/normal duration. The life one get outs of their battery is very dependent on what they do with their machine.