iBook Battery Life

[danaeris]

So, I've had my iBook for about a year, and I swear, the battery life has decreased.

Anyone else have this happen to them? I just don't believe that my laptop used to run out of batteries this fast.

Comments

[sol3.livejournal.com]

My understanding is that the battery itself is fine - but the power manager drifts/gets confused over time - resetting it should take care of it, but the details of that are different for each model of power/ibook

--Dg

[princeofwands.livejournal.com]

My iBook (new in March 2002) held pretty steady battery life up until I noticed a sharp and sudden drop (by almost half!) in late June 2003.

[jadasc.livejournal.com]

This has happened to me as well; I'll be looking here for solutions. :)

[nytemuse.livejournal.com]

Actually, a year is quite within acceptable limits. Rechargeable batteries will run out of steam eventually and oftentimes it starts happening in a year, especially of heavy use.
That's really the only factor that convinced me to buy the extra 5 year warranty on my new laptop...Radio Shack warranties cover battery replacements. Not that I currently ever run the laptop off anything but AC, but it's nice to have the option.

[random-vamp.livejournal.com]

Yeah, battery life does tend to go down with time. How long is yours lasting now on a full charge?

Also, one thing that improves battery life is to allow them to full drain occasionally. You may want to try allowing it to run until it shuts off and charging from there to see if it improves battery life.

Also, I believe the AppleCare program may repalce batteries, if you've had it for less than a year or got the extended version.

[auros]

one thing that improves battery life is to allow them to full drain occasionally

I'd always heard that to, but apparently it's wrong.

Normal. Buy a new one.

[nathanjw]

Most lithium-ion batteries have a stable life of about two years. Both my housemate and I replaced the batteries in our iBooks after about that long, when battery lifetime had dropped to about 45 minutes (from ~4 hours).

There's a program called XBattery which can tell you what the battery reports its storage capacity to be. An iBook battery in good condition should be about 4 amp-hours. After two years, mine was down to about 800 mAh. This is more severe than most people experience, probably because for most of the first year I ran NetBSD exclusively on the iBook, not OS X, and ended up running the battery down a lot more. Lithium-ion batteries last longer when they experience many short, shallow charge cycles rather than fewer deep (full or near-full discharge) cycles.

[auros]

Lithium-ion batteries last longer when they experience many short, shallow charge cycles rather than fewer deep (full or near-full discharge) cycles.

Really? I'd always been told that the best for rechargeables was to let them get all the way drained, then recharge, and that the worst was to run them down about half, then recharge...

Oh, hey, nifty, my employer has a detailed article on the care of rechargeable batteries! And apparently everything I knew about this subject was wrong. :-)

The most annoying fact I've gleaned from this: "Rechargeable batteries should not be stored in a fully charged condition." So, what, I'm supposed to wait until after my wireless keyboard and mouse run out of power before I start the four to six hour charge cycle for the other set of batteries?

Also... "The relationship between DOD (depth of discharge) and cycle life is logarithmic. In other words, the number of cycles yielded by a battery goes up exponentially the lower the DOD. Research studies have shown that the typical cellular phone user depletes their battery about 25 to 30 percent before recharging. Testing has shown that at this low level of DOD a lithium-ion battery can expect between 5 and 6 times the cycle numbers of a battery discharged to the one hundred percent DOD level continuously."

I guess my habit of just keeping my phone on a charger at work, in the car, or at home, and only taking it off when I'm actually walking around, is probably a good thing, not a bad one as I'd always been led to believe.

[nathanjw]

It also varies a bit by battery technology, so we have to remember that lithium-ion is relatively new and has slightly different charge cycle properties than NiCad or NiMH (like other technologies, "everything we learned was wrong"). also, a lot of the deep-discharge thing that was often recommended with NiCad was to avoid a "cell memory" effect, though there's still quite a bit of dispute as to how real that effect is, and whether end-users (especially home users) were really seeing cell memory or something else.