iBook Battery - How Long should it last?

The one in my wife's clamshell lasted about 3 1/2 years before its maximum charge dropped below an hour.

It really depends on how much you've used it. The batteries degrade over time and over charging cycles. I think it would be quite possible to burn through one in a year and a half. I also know that I'm still getting a decent charge on my late 01 iBook which spends a good chunk of its time plugged in. If you've got a clamshell with the original battery, I think you've done well.

G

Sounds about right to me. I understand that typical li-ion batteries are rated for 300 "deep-cycles" at which point you might have about half the capacity. All rechargeable batteries will lose a little bit of capacity after each charge - I believe part of it comes from losing water in the cell.

I hardly ever use the battery on my iBook - it's usually plugged in. When I do use the battery, I might use maybe 10% of capacity before recharging it. It understand the battery can last a really long time if the vast majority of the usage is for short cycles before recharging.

FWIW, after my original blueberry iBook battery failed in about 3 1/2 years and maybe only a dozen deep discharge cycles, I read up on lithium ion batteries. It seems li-ion start degrading, used or not, from the time of initial manufacture.

Aging is a concern with most lithium-ion batteries and many manufacturers remain silent about this issue. Some capacity deterioration is noticeable after one year, whether the battery is in use or not. The battery frequently fails after two or three years.

http://www.batteryuniversity.com/partone-5.htm

YMMV

Cheers,

Darrell