[Bruck]

I got my powerbook almost a year ago, and when I got it battery life was horrible. I did a test and saw that my capacity was low. I got applecare to replace it, the new one was better. Now I re-checked because my battery had been lasting less and less lately, It shows less capacity?


How does a battery suddenly think its smaller than it once was? Is it the way i use it?

I keep my powerbook plugged in ALL the time except when traveling to and from work. Oh and of course when I use it on a plane or such. I am probably going to head over to the apple store and complain till they give me a new battery, but I've had enough already. The new batteries from NewerTechnology should solve my problem AND THEN SOME!!!

This is probably the route I will go.

[JKT]

It's a Li-ion battery. They all have finite life spans and will gradually reduce in capacity as time goes by no matter how you use them. It's just the nature of battery technology - even storing them without ever being used will cause their capacity to fall to nothing eventually. However, some ways of using them will accelerate their decline relative to others. Constant charge/full discharge cycles will shorten their life span (shallow charging is better - that is, discharge only a little before recharging); heat will shorten their life span (so if you live in a warm climate, use your PowerBook in hot conditions, use your battery in situations where it will get hot such as when the CPU/GPU is saturated requiring full fan blast in the PB, your battery will lose its capacity faster).

Best practice for your battery is to:

1. Practice shallow charge/discharge cycles with only one monthly full discharge/recharge if possible.
2. Remove your battery if you aren't using it and are running off the mains and preferably store it at around 70% charge. This stops it from getting hot when your PB is going full blast. (However, it is also necessary to occasionally use the battery to get the electrons flowing - non-use can also impact the overall life span).
3. Avoid using or storing it in hot places if you can.

Other than that, there isn't a lot you can do - in 3 to 5 years of normal use the battery will likely be knackered anyway.

Read this from Apple for more info.

[powerduck]

JKT could you explain to me why the continuous degradation causes the capacity to apparently decline in increments rather than on a curve. I had the same problem as Bruck: powerbook arrived with bad battery (Apple care tells you based on approximate usage times "within normal limits" but won't tell you the "normal limits" in terms of measurable capacity). From there the measured capacity would remain constant over numerous charge/discharge cycles (for weeks at a time) until some event (a crash, restart etc.) caused a sudden drop in the range of 0.3 to 0.5 Ah. From there, it would again remain stable for a while, until....