[mpancha]

What exactly does the battery health represent? This is the reading I get from iStat:



The odd thing, I figured it was just how much of a charge I hold, or how healthy it is. But, a month ago, that value was 65%. Today its 68%.

Also, the past few days, when my battery says I have 1% remaining, or 1 minute remaining, my laptop keeps going for a good 10-15 minutes. It wasn't like this a month-ish ago. I run my laptop at the "better performance:" setting with my airport turned on, and brightness at 100%.

Any ideas?

Thanks in advance.

[Dork.]

Not at all familiar with that app, I'll have to look into it one of these days.

My guess is that "Battery Health" is a measurement of the what your battery can store vs. its known, fresh-out-of-the-box maximum capacity. Your battery may have a theorteical maximum capacity of (for example) 4400 mAH. But if your battery can currently store only 3000 mAH, that would be about 68%. I'm assuming that after 466 cycles, your battery is at least 3 years old. It looks like you have a good one there!

(mAH = milliAmp-hours = the amount of charge the battery can hold. All batteries deteriorate over time, and laptop batteries have active circuitry that can measure the amount of charge left.)

The circuitry that monitors how much charge is left is prone to drifting from time to time. Sometimes, the meter might run to '0' while there's still some charge left. If that happens, once the battery fully runs out, if you plug it back in and let it recharge, the power circuitry will re-calibrate and your maximum charge rating might go up a few mAH. The battery didn't all of a sudden get better, the calibration was just a bit off.

Incidentally, your current maximum mAH rating is the total rating of all the cells in your battery, But sometimes individual cells can start to fail faster than others. If that is happeneing, you'll consistently see the laptop going to sleep when it thinks it has 20 or 30 minutes of life left. That's because the other cells still have charge, but one cell is failing early and the computer needs all cells to be powered properly. If that starts happenign to you, there's nothing left to do but get a new battery, because it will die soon....

[mpancha]

Thanks Dork, you answered my questions.

Yea, the battery is roughly 3 years old, its an iBook G4, I think it will hit 3 years in spring of 07.

iStat >> one of my favorite dashboard apps, you can get it off Apple's dashboard section (iStat pro - Dashboard - Status)

Thanks again.