Battery Gauge Question

[PrometheusG5]

Is the battery gauge on my PowerBook G4 accurate? Any battery I use seems to hover between 97-99% charged, and only ever shows 100% when I am charging a drained battery. Once it's charged, the percentage goes to 99 or 98.

My concern is how can I tell if I am getting the most juice from my batteries, and is that percentage accurate? Is there some 3rd party utility or something that can give me a better idea on my battery's life?

[mkrishnan]

Regarding the 97-99% issue, see these threads -- not sure if this is your issue or not, but it sounds like normal operation:

http://forums.macrumors.com/showthread.php?t=58126&highlight=battery+charge+99%25

http://forums.macrumors.com/showthread.php?t=67117&highlight=battery+charge+99%25

Regarding a more accurate way to tell your charge state, open a terminal and type this:

ioreg -l | grep -i IOBatteryInfo

Make sure you make the term screen really wide (>125 characters) before you do it. Compare current and capacity to get a better idea. I got this trick from this thread a while ago, and you can compare notes with other people there:

http://forums.macrumors.com/showthread.php?t=60447&highlight=battery+charge+99%25

[mkrishnan]

Oh, BTW, on my iBook G4/800 12" with the indicator at 99%, this is what I got at the moment (after a full discharge cycle on battery this afternoon, plugging into the wall again around 8PM, and hitting full recharge around 10 or 11PM):

| | | | "IOBatteryInfo" = ({"Capacity"=4400,"Amperage"=1200,
"Current"=4399,"Voltage"=12603,"Flags"=838860805})

So like the old joke, the value of two can be safely approximated as three for large values of two.

Also that's after six months of use, and when I looked back at that thread it seems it hasn't deteriorated much yet. Yay iBook! :)

[PrometheusG5]

Regarding the 97-99% issue, see these threads -- not sure if this is your issue or not, but it sounds like normal operation:

http://forums.macrumors.com/showthread.php?t=58126&highlight=battery+charge+99%25

http://forums.macrumors.com/showthread.php?t=67117&highlight=battery+charge+99%25

Regarding a more accurate way to tell your charge state, open a terminal and type this:

ioreg -l | grep -i IOBatteryInfo

Make sure you make the term screen really wide (>125 characters) before you do it. Compare current and capacity to get a better idea. I got this trick from this thread a while ago, and you can compare notes with other people there:

http://forums.macrumors.com/showthread.php?t=60447&highlight=battery+charge+99%25

Thanks. At least I know it is normal operation. For awhile I thought there was something wrong with the battery. Then it happened with my spare batteries, so I began to suspect the PowerBook. It's a rev B 17".

[JzzTrump22]

I just got a new powerbook and it does the same thing. When i drain th ebattery and re-charge it will hit 100%. But once it's charged and say i restart the machine or shutdown and come back the next day, the battery will only be at 98-99 and will still say its'e fully charged. Even the light where power supply goes is green.

[mkrishnan]

| | | | "IOBatteryInfo" = ({"Capacity"=4400,"Amperage"=1200,
"Current"=4399,"Voltage"=12603,"Flags"=838860805})

This is weird.... I've been using my battery more recently. My capacity when I first got my iBook according to this command was 4400. Six months later, it was still exactly the same 4400 (as above). Today:

"IOBatteryInfo" = ({"Capacity"=4498, "Amperage"=1173, "Current"=4438, "Voltage"=12295, "Flags"=4})

It's quite a bit higher.... Strange. Anyone else experience this? Does this number fluctuate?