[italian soda]

This powerbook(not mine) has its battery going lower and lower of its max capacity everytime I recharge it
(100%->99%->98% etc.). I regularly uses the battery and I never let the battery go completely dead. Don't know why this happens, is there a need of me replacing the battery? I just bought it in less than 3 months

[v.noir]

I wouldn't worry about it. Mine varies between reporting anywhere between 94%-100% after being fully charged. Had it for 18 months or so.

[PB PM]

This is a feature in OSX, it doesn't keep the battery at 100% to help extend the life of the battery. The number of cycle charges is more important, most batteries can handle around 300 (meaning the the total amount of times the battery has been fully discharged and recharged is around or above that number) before they start to have extreamly short charge time. Use Google to look for CoconutBattery, it is an app that will tell you all you need to know about your batteries life.

[v.noir]

Come to think of it, it is usually 98% or 99% for me. System Profiler tells me the cycle count for my (original) battery is 166.

[PB PM]

Remember that is 98 or 99% of what the battery still holds, which is often not the same as the 98-99% it started with. CoconutBattery shows how much your battery held at its peek, and what % of that it still holds.

[v.noir]

Oh yes indeed, i've seen screenshots but never used it. It tells you a great deal. How does it know the original capacity?

[Dorian Gray]

Originally Posted by v.noir Oh yes indeed, i've seen screenshots but never used it. It tells you a great deal. How does it know the original capacity?

It doesn't, it merely presents the nominal capacity (according to battery model). Individual lithium-ion cells vary significantly in capacity when new and deteriorate at different rates, even when made on the same assembly line. Batteries are clumsy, messy, finicky, temperamental things that require much pampering and voodoo to work well. In short, they are the bane of consumer electronics and probably will be for the foreseeable future.

[ast3r3x]

Originally Posted by PB PM This is a feature in OSX, it doesn't keep the battery at 100% to help extend the life of the battery. The number of cycle charges is more important, most batteries can handle around 300 (meaning the the total amount of times the battery has been fully discharged and recharged is around or above that number) before they start to have extreamly short charge time. Use Google to look for CoconutBattery, it is an app that will tell you all you need to know about your batteries life.

A feature OS X? I thought it was the power manager.

[Brad]

Originally Posted by PB PM Use Google to look for CoconutBattery, it is an app that will tell you all you need to know about your batteries life.

Or just plug this command into the Terminal to get all the same information:

/usr/sbin/ioreg -p IODeviceTree -n "battery" -w 0 | grep IOBatteryInfo

[atomicbartbeans]

Originally Posted by italian soda ...I never let the battery go completely dead...

Actually, it is healthy to fully discharge a Li-ion battery once in a while. That is also a requirement for calibrating the battery in OS X... the computer must run out of juice and go to sleep on its own.

Try discharging fully and recharging, see if it changes.

[Brad]

Originally Posted by atomicbartbeans Actually, it is healthy to fully discharge a Li-ion battery once in a while.

The key phrase here is "once in a while." Full discharges will slightly diminish the battery capacity, but as abb said, they're a necessary evil for proper calibration. Once every couple of months should be okay.

[alcimedes]

At 21 months my battery is listed with 92% original capacity.

[SKMDC]

I don't think he's referring to his capacity, I think he's referring to the % his capacity is being charged up. Even though my iBook battery is at 80% it still gets charged up to 100% in the menu bar.

If his menu bar charge % is decreasing incrementally (getting lower daily) he needs to take it in, it's happened to me and there is an internal problem.

[Brad]

If he never calibrates it, the menu bar value may slowly creep away from 100%, though, since the system may think it still has the original capacity.

[SKMDC]

here's what happened with mine, about four months after I had my iBook, the % in the menu bar never got to 100%, then after a bit of time (a week) it kept getting lower, I switched batteries and the same thing happened to my two extra batteries.

Eventually it would go no higher then 50% til it putzed out all together, which is when I took it in, It wasn't the power cord it was whatever the powercord connects to.

I guess he could check it by swapping batteries with someone.

But my point was you guys are all talking about the capacity of the battery according to coconut battery, or capacity meter. If he's new to all this that may confuse him or her, and think that seeing 80% in the menu bar is ok.

[PB PM]

The PMU can cause battery problems, it was an major issue with many G3 Powerbooks once they got to be a year or two old.

[stoo]

The charge indicator lights on my (3 year old, ~90% original capacity) battery stopped working. Very odd...

[PB PM]

Could be that the LCD light was damaged, or burned out.

[Brad]

Originally Posted by PB PM Could be that the LCD light was damaged, or burned out.

You mean LEDs? LEDs don't burn out unless they've taken some serious damage or gone through many years of wear. The D is for diode and it doesn't operate the same way as a normal light bulb filament.

[PB PM]

Yes, typo... yesterday was a long day.