Battery lifespan on PowerBook?

1. Ted Lee - 15 October 2008

   How long is it reasonable to expect a battery to last? (15" PowerBook G4.) My first battery started to show signs of aging after about a year and a half (the computer no longer gave a "low battery" warning but just quit most unceremoniously after a couple of hours of use). My second battery is now showing the same signs after about year -- it says it's gone through 128 cycles. The machine is plugged in most of the time but tends to be used a couple of hours a day on just the battery -- I have to admit I don't remember the last time I intentionally fully discharged it, but it certainly doesn't feel to me like it's happened a couple of times a week, which is what that cycle count says. Right now it's fully charged but if I pull the plug it says I only have 2.5 hours of battery usage left (full brightness, wifi on, bluetooth off, doing nothing.) Says full charge capacity 3287mAh, but remaining capacity (right after unplugging) 3263.

   Ted Lee
   Minnetonka, MN