PowerBook battery life


Not a Moderator

I have a PowerBook G4 and have not been able to get anywhere near the 5-hour battery life Apple advertises? Has anyone else been able to do this?

Maybe they mean you can let it sleep for 5hours with our running out?:D

I have a TiBook, and I'm pretty sure when they say 5 hours they mean you <em>might</em> be able to <em>sleep</em> for 5 hours. I only get 2 to 2 1/2 hours doing simple text editing.

I get upset every time I see Apple claim that 5 hours--not so much because I feel cheated ('cause I didn't see the 5 hour claim before I bought the TiBook) but because they're setting themselves up for an embarrassing revelation.

Thats about all I can get, but I do have an Airport card which uses some power. I also heard that if you turn the brightness of the display down, you can get more time out of it?

Regardless, 5 hour battery life is not acheivable with real world use.

I have an iBook which they advertise about 6 hours. With OS9 I can get not far from that, but with OSX running it goes down dramatically to about 3 or 4. This is presumably because the OS is doing so much more and using processing power. It also swaps more, using the HDD more intensively and that will drain the power quite significantly. I am going to up my memory soon and see if that makes a difference.

Shouldn't OS X be better on the batteries when it comes to processor use as when you're not using an app, it shouldn't put much of a drain on the processor?? Am I just being overly tired and stupid?

I'm sure you're right re: the HDD use in X though. I wonder if the way one had the HDDs set up and/or partitioned would have an impact here?? Less movement of the read/write head... What do you think?

OS X is likely to work the processor harder than OS9. The reason for this is the extra stability that OS X exhibits. The extra stability is due to multi threading and better managed memory. The OS needs to do more work managing these threads and the memory and so will be more active than OS9. This extra activity uses more processor cycles, and therefore more power. You will find elsewhere on this site discussions as to whether OS X is a UNIX or not. These describe OS X as a micro Kernel operating system, where there are many kernels all working together to run an application. The communication between these micro kernels needs to be controlled by the OS, all taking up more processing power. There is little that we can do about this use of the processor - the slight loss in speed and batter power is more than returned (in my opinion) by the enormous gain in the stabililty of OSX.

Regarding the HDD - I am not sure about partitioning. I presume that a logic partition equates reasonably to the physical positioning of the data on the disk. Otherwise keeping your disk de-fragmented will help.

I've got a iBook 2001 (one of the new ones, aka iceBook) and I've gotten close to the five hours by turning down the brightness and just doing some light reading of html developer documentation. I haven't had this thing long enough to really put it through it's paces, but I was surprised that under light use, it seems to be living up to expectations.

And OSX feels pretty snappy on this thing too.
jdog- X or 9.1? In 9.1, you can change settings in the Energy Saver control panel. Between this and turning the display brightness down can put a TiBook's battery life over four hours. You probably know about the settings already ...

Hey ... has anyone else here gotten one of those "incomplete" iBook batteries ... one without the white polycarb plate or foot? (Yeah, Apple already exchanged mine ... I was just curious to see how common this was. They sent me two of these mutant batteries in a row.) I have noticed far superior battery life on the new iBook (60-80 minutes better, depending on settings).

Speaking of processor cycling ... is there any word out there about whether we'll have any control over this (applet, new system preference setting) in OS X in the future?