[cdc]

Hi,

I heart rumors like: it is better to use the AC whenever you can, instead of the battery of you ibook. Does it mean, that I shouldn't use the battery when I am at home or when I am not travelling to save the life-time of the battery?

Anyone experienced that?

[ghporter]

With lithium-ion batteries, it really doesn't hurt to either use the battery OR have the laptop plugged in. You can have your iBook plugged in for an extended period and not hurt the battery. You can wander around the house with the iBook running until the power management system turns it off and not hurt the battery. You can do anything in between, too. Don't sweat it.

A Li-Ion battery supposedly has some set (but rather high) number of discharge/recharge cycles before it gives up, but partial discharges and recharges don't really count even proportionally. Eventually the battery will die, but leaving the laptop plugged in will not affect that since the computer doesn't "charge" the battery when it's fully charged-it just leaves it alone.

[cdc]

"A Li-Ion battery supposedly has some set (but rather high) number of discharge/recharge cycles"

thus actually the rumor is half true...it is better to plug in your ibook, since that means not using the battery and thus has no effect of the number of discharge/recharge cycles!

[Dork.]

It's not quite that simple, either. LiIon batteries do have a set number of charge/discharge cycles, but they also do deteriorate even when they're fully charged. Battery technology has been improving over the years, and many of the problems are more of a nusiance now than anything else, but they still exist. Batteries are still a "consumable" item, with a practical lifetime of one to three years. Individual cells may last longer, but you have multiple cells in a battery pack, and if only one cell fails the battery is just about useless.

I think that if you want to draw the most life out of your battery, you need to make sure you fully discharge it at least once a month. Just use it until it sleeps, then fully charge it before unplugging it again. All other times, use it however you want to.
This isn't as important as it was, say, four or five years ago, but it's still a good thing to do. I've been doing it, and my 3-year-old iBook battery is still giving > 2 hrs. on a charge.